Who Was Nicolaus Copernicus?

Astronomer Copernicus, or Conversations with God, by Matejko. Credit: frombork.art.pl/pl/

When it comes to understanding our place in the universe, few scientists have had more of an impact than Nicolaus Copernicus. The creator of the Copernican Model of the universe (aka. heliocentrism), his discovery that the Earth and other planets revolved the Sun triggered an intellectual revolution that would have far-reaching consequences.

In addition to playing a major part in the Scientific Revolution of the 17th and 18th centuries, his ideas changed the way people looked at the heavens, the planets, and would have a profound influence over men like Johannes Kepler, Galileo Galilei, Sir Isaac Newton and many others. In short, the “Copernican Revolution” helped to usher in the era of modern science.

Copernicus’ Early Life:

Copernicus was born on February 19th, 1473 in the city of Torun (Thorn) in the Crown of the Kingdom of Poland. The youngest of four children to a well-to-do merchant family, Copernicus and his siblings were raised in the Catholic faith and had many strong ties to the Church.

His older brother Andreas would go on to become an Augustinian canon, while his sister, Barbara, became a Benedictine nun and (in her final years) the prioress of a convent. Only his sister Katharina ever married and had children, which Copernicus looked after until the day he died. Copernicus himself never married or had any children of his own.

Nicolaus Copernicus portrait from Town Hall in Torun (Thorn), 1580. Credit: frombork.art.pl
Nicolaus Copernicus portrait from Town Hall in Torun (Thorn), 1580. Credit: frombork.art.pl

Born in a predominately Germanic city and province, Copernicus acquired fluency in both German and Polish at a young age, and would go on to learn Greek and Italian during the course of his education. Given that it was the language of academia in his time, as well as the Catholic Church and the Polish royal court, Copernicus also became fluent in Latin, which the majority of his surviving works are written in.

Copernicus’ Education:

In 1483, Copernicus’ father (whom he was named after) died, whereupon his maternal uncle, Lucas Watzenrode the Younger, began to oversee his education and career. Given the connections he maintained with Poland’s leading intellectual figures, Watzenrode would ensure that Copernicus had  great deal of exposure to some of the intellectual figures of his time.

Although little information on his early childhood is available, Copernicus’ biographers believe that his uncle sent him to St. John’ School in Torun, where he himself had been a master. Later, it is believed that he attended the Cathedral School at Wloclawek (located 60 km south-east Torun on the Vistula River), which prepared pupils for entrance to the University of Krakow – Watzenrode’s own Alma mater.

In 1491, Copernicus began his studies in the Department of Arts at the University of Krakow. However, he quickly became fascinated by astronomy, thanks to his exposure to many contemporary philosophers who taught or were associated with the Krakow School of Mathematics and Astrology, which was in its heyday at the time.

A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu
A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu

Copernicus’ studies provided him with a thorough grounding in mathematical-astronomical knowledge, as well as the philosophy and natural-science writings of Aristotle, Euclid, and various humanist writers. It was while at Krakow that Copernicus began collecting a large library on astronomy, and where he began his analysis of the logical contradictions in the two most popular systems of astronomy.

These models – Aristotle’s theory of homocentric spheres, and Ptolemy’s mechanism of eccentrics and epicycles – were both geocentric in nature. Consistent with classical astronomy and physics, they espoused that the Earth was at the center of the universe, and that the Sun, the Moon, the other planets, and the stars all revolved around it.

Before earning a degree, Copernicus left Krakow (ca. 1495) to travel to the court of his uncle Watzenrode in Warmia, a province in northern Poland. Having been elevated to the position of Prince-Bishop of Warmia in 1489, his uncle sought to place Copernicus in the Warmia canonry. However, Copernicus’ installation was delayed, which prompted his uncle to send him and his brother to study in Italy to further their ecclesiastic careers.

In 1497, Copernicus arrived in Bologna and began studying at the Bologna University of Jurists’. While there, he studied canon law, but devoted himself primarily to the study of the humanities and astronomy. It was also while at Bologna that he met the famous astronomer Domenico Maria Novara da Ferrara and became his disciple and assistant.

The Geocentric View of the Solar System
An illustration of the Ptolemaic geocentric system by Portuguese cosmographer and cartographer Bartolomeu Velho, 1568. Credit: bnf.fr

Over time, Copernicus’ began to feel a growing sense of doubt towards the Aristotelian and Ptolemaic models of the universe. These included the problematic explanations arising from the inconsistent motion of the planets (i.e. retrograde motion, equants, deferents and epicycles), and the fact that Mars and Jupiter appeared to be larger in the night sky at certain times than at others.

Hoping to resolve this, Copernicus used his time at the university to study Greek and Latin authors (i.e. Pythagoras, Cicero, Pliny the Elder, Plutarch, Heraclides and Plato) as well as the fragments of historic information the university had on ancient astronomical, cosmological and calendar systems – which included other (predominantly Greek and Arab) heliocentric theories.

In 1501, Copernicus moved to Padua, ostensibly to study medicine as part of his ecclesiastical career. Just as he had done at Bologna, Copernicus carried out his appointed studies, but remained committed to his own astronomical research. Between 1501 and 1503, he continued to study ancient Greek texts; and it is believed that it was at this time that his ideas for a new system of astronomy – whereby the Earth itself moved – finally crystallized.

The Copernican Model (aka. Heliocentrism):

In 1503, having finally earned his doctorate in canon law, Copernicus returned to Warmia where he would spend the remaining 40 years of his life. By 1514, he began making his Commentariolus (“Little Commentary”) available for his friends to read. This forty-page manuscript described his ideas about the heliocentric hypothesis, which was based on seven general principles.

These seven principles stated that: Celestial bodies do not all revolve around a single point; the center of Earth is the center of the lunar sphere—the orbit of the moon around Earth; all the spheres rotate around the Sun, which is near the center of the Universe; the distance between Earth and the Sun is an insignificant fraction of the distance from Earth and Sun to the stars, so parallax is not observed in the stars; the stars are immovable – their apparent daily motion is caused by the daily rotation of Earth; Earth is moved in a sphere around the Sun, causing the apparent annual migration of the Sun; Earth has more than one motion; and Earth’s orbital motion around the Sun causes the seeming reverse in direction of the motions of the planets.

Heliocentric Model
Andreas Cellarius’s illustration of the Copernican system, from the Harmonia Macrocosmica (1708). Credit: Public Domain

Thereafter he continued gathering data for a more detailed work, and by 1532, he had come close to completing the manuscript of his magnum opus – De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres). In it, he advanced his seven major arguments, but in more detailed form and with detailed computations to back them up.

However, due to fears that the publication of his theories would lead to condemnation from the church (as well as, perhaps, worries that his theory presented some scientific flaws) he withheld his research until a year before he died. It was only in 1542, when he was near death, that he sent his treatise to Nuremberg to be published.

Copernicus’ Death:

Towards the end of 1542, Copernicus suffered from a brain hemorrhage or stroke which left him paralyzed. On May 24th, 1543, he died at the age of 70 and was reportedly buried in the Frombork Cathedral in Frombork, Poland. It is said that on the day of his death, May 24th 1543 at the age of 70, he was presented with an advance copy of his book, which he smiled upon before passing away.

In 2005, an archaeological team conducted a scan of the floor of Frombork Cathedral, declaring that they had found Copernicus’ remains. Afterwards, a forensic expert from the Polish Police Central Forensic Laboratory used the unearthed skull to reconstruct a face that closely resembled Copernicus’ features. The expert also determined that the skull belonged to a man who had died around age 70 – Copernicus’ age at the time of his death.

These findings were backed up in 2008 when a comparative DNA analysis was made from both the remains and two hairs found in a book Copernicus was known to have owned (Calendarium Romanum Magnum, by Johannes Stoeffler). The DNA results were a match, proving that Copernicus’ body had indeed been found.

Copernicus' 2010 grave in Frombork Cathedral, acknowledging him as the father of heiocentirsm.Credit:
Copernicus’ 2010 grave in Frombork Cathedral, acknowledging him as a church canon and the father of heliocentricism. Credit: Wikipedia/Holger Weinandt

On May 22nd, 2010, Copernicus was given a second funeral in a Mass led by Józef Kowalczyk, the former papal nuncio to Poland and newly named Primate of Poland. Copernicus’ remains were reburied in the same spot in Frombork Cathedral, and a black granite tombstone (shown above) now identifies him as the founder of the heliocentric theory and also a church canon. The tombstone bears a representation of Copernicus’ model of the solar system – a golden sun encircled by six of the planets.

Copernicus’ Legacy:

Despite his fears about his arguments producing scorn and controversy, the publication of his theories resulted in only mild condemnation from religious authorities. Over time, many religious scholars tried to argue against his model, using a combination of Biblical canon, Aristotelian philosophy, Ptolemaic astronomy, and then-accepted notions of physics to discredit the idea that the Earth itself would be capable of motion.

However, within a few generation’s time, Copernicus’ theory became more widespread and accepted, and gained many influential defenders in the meantime. These included Galileo Galilei (1564-1642), who’s investigations of the heavens using the telescope allowed him to resolve what were seen at the time as flaws in the heliocentric model.

These included the relative changes in the appearances of Mars and Jupiter when they are in opposition vs. conjunction to the Earth. Whereas they appear larger to the naked eye than Copernicus’ model suggested they should, Galileo proved that this is an illusion caused by the behavior of light at a distance, and can be resolved with a telescope.

1973 Federal Republic of Germany 5-mark silver coin commemorating 500th anniversary of Copernicus' birth. Credit: Wikipedia/Berlin-George
1973 Federal Republic of Germany 5-mark silver coin commemorating 500th anniversary of Copernicus’ birth. Credit: Wikipedia/Berlin-George

Through the use of the telescope, Galileo also discovered moons orbiting Jupiter, Sunspots, and the imperfections on the Moon’s surface, all of which helped to undermine the notion that the planets were perfect orbs, rather than planets similar to Earth. While Galileo’s advocacy of Copernicus’ theories resulted in his house arrest, others soon followed.

German mathematician and astronomer Johannes Kepler (1571-1630) also helped to refine the heliocentric model with his introduction of elliptical orbits. Prior to this, the heliocentric model still made use of circular orbits, which did not explain why planets orbited the Sun at different speeds at different times. By showing how the planet’s sped up while at certain points in their orbits, and slowed down in others, Kepler resolved this.

In addition, Copernicus’ theory about the Earth being capable of motion would go on to inspire a rethinking of the entire field of physics. Whereas previous ideas of motion depended on an outside force to instigate and maintain it (i.e. wind pushing a sail) Copernicus’ theories helped to inspire the concepts of gravity and inertia. These ideas would be articulated by Sir Isaac Newton, who’s Principia formed the basis of modern physics and astronomy.

Today, Copernicus is honored (along with Johannes Kepler) by the liturgical calendar of the Episcopal Church (USA) with a feast day on May 23rd. In 2009, the discoverers of chemical element 112 (which had previously been named ununbium) proposed that the International Union of Pure and Applied Chemistry rename it copernicum (Cn) – which they did in 2011.

Crater Copernicus on the Moon. Mosaic of photos by Lunar Reconnaissance Orbiter, . Credit: NASA/LRO
Mosaic image of the Copernicus Crater on the Moon, taken by the Lunar Reconnaissance Orbiter, . Credit: NASA/LRO

In 1973, on the 500th anniversary of his birthday, the Federal Republic of Germany (aka. West Germany) issued a 5 Mark silver coin (shown above) that bore Copernicus’ name and a representation of the heliocentric universe on one side.

In August of 1972, the Copernicus – an Orbiting Astronomical Observatory created by NASA and the UK’s Science Research Council – was launched to conduct space-based observations. Originally designated OAO-3, the satellite was renamed in 1973 in time for the 500th anniversary of Copernicus’ birth. Operating until February of 1981, Copernicus proved to be the most successful of the OAO missions, providing extensive X-ray and ultraviolet information on stars and discovering several long-period pulsars.

Two craters, one located on the Moon, the other on Mars, are named in Copernicus’ honor. The European Commission and the European Space Agency (ESA) is currently conducting the Copernicus Program. Formerly known as Global Monitoring for Environment and Security (GMES), this program aims at achieving an autonomous, multi-level operational Earth observatory.

On February 19th, 2013, the world celebrated the 540th anniversary of Copernicus’ birthday. Even now, almost five and a half centuries later, he is considered one of the greatest astronomers and scientific minds that ever lived. In addition to revolutionizing the fields of physics, astronomy, and our very concept of the laws of motion, the tradition of modern science itself owes a great debt to this noble scholar who placed the truth above all else.

Universe Today has many interesting articles on ancient astronomy, such as What is the Difference Between the Geocentric and Heliocentric Models of the Solar System.

For more information, you should check out Nicolaus Copernicus, the biography of Nicolaus Copernicus, and Planetary Motion: The History of an Idea That Launched the Scientific Revolution.

Astronomy Cast has an episode on Episode 338: Copernicus.

Sources:

What is a Terrestrial Planet?

The terrestrial planets of our Solar System at approximately relative sizes. From left, Mercury, Venus, Earth and Mars. Credit: Lunar and Planetary Institute

In studying our Solar System over the course of many centuries, astronomers learned a great deal about the types of planets that exist in our universe. This knowledge has since expanded thanks to the discovery of extrasolar planets, many of which are similar to what we have observed here at home.

For example, while hundreds of gas giants of varying size have been detected (which are easier to detect because of their size), numerous planets have also been spotted that are similar to Earth – aka. “Earth-like”. These are what is known as terrestrial planets, a designation which says a lot about a planet how it came to be.

Definition:

Also known as a telluric or rocky planet, a terrestrial planet is a celestial body that is composed primarily of silicate rocks or metals and has a solid surface. This distinguishes them from gas giants, which are primarily composed of gases like hydrogen and helium, water, and some heavier elements in various states.

The term terrestrial planet is derived from the Latin “Terra” (i.e. Earth). Terrestrial planets are therefore those that are “Earth-like”, meaning they are similar in structure and composition to planet Earth.

Earth-like planets. Image Credit: JPL
Artist’s concept for the range of Earth-like extrasolar planets that have been discovered in recent years. Credit: NASA/JPL

Composition and Characteristics:

All terrestrial planets have approximately the same type of structure: a central metallic core composed of mostly iron, with a surrounding silicate mantle. Such planets have common surface features, which include canyons, craters, mountains, volcanoes, and other similar structures, depending on the presence of water and tectonic activity.

Terrestrial planets also have secondary atmospheres, which are generated through volcanism or comet impacts. This also differentiates them from gas giants, where the planetary atmospheres are primary and were captured directly from the original solar nebula.

Terrestrial planets are also known for having few or no moons. Venus and Mercury have no moons, while Earth has only the one (the Moon). Mars has two satellites, Phobos and Deimos, but these are more akin to large asteroids than actual moons. Unlike the gas giants, terrestrial planets also have no planetary ring systems.

The Earth's layers. Credit: discovermagazine.com
The Earth’s interior structure, shown here as consisting of multiple “layers”. Credit: discovermagazine.com

Solar Terrestrial Planets:

All those planets found within the Inner Solar System – Mercury, Venus, Earth and Mars – are examples of terrestrial planets. Each are composed primarily of silicate rock and metal, which is differentiated between a dense, metallic core and a silicate mantle. The Moon is similar, but has a much smaller iron core.

Io and Europa are also satellites that have internal structures similar to that of terrestrial planets. In the case of the former, models of the moon’s composition suggest that the mantle is composed primarily of silicate rock and iron, which surrounds a core of iron and iron sulphide. Europa, on the other hand, is believed to have an iron core that is surrounded by an outer layer of water.

Dwarf planets, like Ceres and Pluto, and other large asteroids are similar to terrestrial planets in the fact that they do have a solid surface. However, they differ in that they are, on average, composed of more icy materials than rock.

Extrasolar Terrestrial Planets:

Most of the planets detected outside of the Solar System have been gas giants, owing to the fact that they are easier to spot. However, since 2005, hundreds of potentially terrestrial extrasolar planets have been found – mainly by the Kepler space mission. Most of these have been what is known as “super-Earths” (i.e. planets with masses between Earth’s and Neptune’s).

Examples of extrasolar terrestrial planets include Gliese 876 d, a planet that has a mass 7 to 9 times that of Earth. This planet orbits the red dwarf Gliese 876, which is located approximately 15 light years from Earth. The existence of three (or possibly four) terrestrial exoplanets was also confirmed between 2007 and 2010 in the Gliese 581 system, another red dwarf roughly 20 light years from Earth.

The smallest of these, Gliese 581 e, is only about 1.9 Earth masses, but orbits very close to the star. Two others, Gliese 581 c and Gliese 581 d, as well as a proposed fourth planet (Gliese 581 g) are more-massive super-Earths orbiting in or close to the habitable zone of the star. If true, this could mean that these worlds are potentially habitable Earth-like planets.

The first confirmed terrestrial exoplanet, Kepler-10b – a planet with between 3 and 4 Earth masses and located some 460 light years from Earth – was found in 2011 by the Kepler space mission. In that same year, the Kepler Space Observatory team released a list of 1235 extrasolar planet candidates, including six that were “Earth-size” or “super-Earth-size” (i.e. less than 2 Earth radii) and which were located within their stars’ habitable zones.

Since then, Kepler has discovered hundreds of planets ranging from Moon-sized to super-Earths, with many more candidates in this size range. As of January, 2013, 2740 planet candidates have been discovered.

Categories:

Scientists have proposed several categories for classifying terrestrial planets. Silicate planets are the standard type of terrestrial planet seen in the Solar System, which are composed primarily of a silicon-based rocky mantle and a metallic (iron) core.

Iron planets are a theoretical type of terrestrial planet that consists almost entirely of iron and therefore has a greater density and a smaller radius than other terrestrial planets of comparable mass. Planets of this type are believed to form in the high-temperature regions close to a star, and where the protoplanetary disk is rich in iron. Mercury is possible example, which formed close to our Sun and has a metallic core equal to 60–70% of its planetary mass.

Coreless planets are another theoretical type of terrestrial planet, one that consists of silicate rock but has no metallic core. In other words, coreless planets are the opposite of an iron planet. Coreless planets are believed to form farther from the star where volatile oxidizing material is more common. Though the Solar System has no coreless planets, chondrite asteroids and meteorites are common.

And then there are Carbon planets (aka. “diamond planets”), a theoretical class of planets that are composed of a metal core surrounded by primarily carbon-based minerals. Again, the Solar System has no planets that fit this description, but has an abundance of carbonaceous asteroids.

Until recently, everything scientists knew about planets – which included how they form and the different types that exist – came from studying our own Solar System. But with the explosion that has taken place in exoplanet discovery in the past decade, what we know about planets has grown significantly.

For one, we have come to understand that the size and scale of planets is greater than previously thought. What’s more, we’ve seen for the first time that many planets similar to Earth (which could also include being habitable) do in fact exist in other Solar Systems.

Who knows what we will find once we have the option of sending probes and manned missions to other terrestrial planets?

Universe Today has articles on smallest terrestrial exoplanet and gas planets. For the latest information on confirmed extrasolar planets, be sure to check out the Kepler’s Planet Candidates.

For a full list of all confirmed and potential planets, consult the Extrasolar Planet Encyclopaedia.

Astronomy Cast has episodes on the terrestrial planets including Mars, and an interview with Darin Ragozzine, one of the Kepler Space Mission scientists.

What are the Signs of the Planets?

The symbols of the eight planets, and Pluto, Credit: insightastrology.net

In our long history of staring up at the stars, human beings have assigned various qualities, names, and symbols for all the objects they have found there. Determined to find patterns in the heavens that might shed light on life here on Earth, many of these designations also ascribed (and were based on) the observable behavior of the celestial bodies.

When it came to assigning signs to the planets, astrologists and astronomers – which were entwined disciplines in the past -made sure that these particular symbols were linked to the planets’ names or their history in some way.

Mercury:
This planet is named after the Roman god who was himself the messenger of the gods, noted for his speed and swiftness. The name was assigned to this body largely because it is the planet closest to the Sun, and which therefore has the fastest rotational period. Hence, the symbol is meant to represent Mercury’s helmet and caduceus – a herald’s staff with snakes and wings intertwined.

Mercury, as imaged by the MESSENGER spacecraft, revealing parts of the never seen by human eyes. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Mercury, as imaged by the MESSENGER spacecraft, which was named after the messenger of the gods because it has the fastest orbit around the Sun. Image Credit: NASA/JHU/Carnegie Institution.

Venus:
Venus’ symbol has more than one meaning. Not only is it the sign for “female”, but it also represents the goddess Venus’ hand mirror. This representation of femininity makes sense considering Venus was the goddess of love and beauty in the Roman Pantheon. The symbol is also the chemical sign for copper; since copper was used to make mirrors in ancient times.

Earth:
Earth’s sign also has a variety of meanings, although it does not refer to a mythological god. The most popular view is that the circle with a cross in the middle represents the four main compass points.  It has also been interpreted as the Globus Cruciger, an old Christian symbol for Christ’s reign on Earth.

This symbol is not just limited to Christianity though, and has been used in various culture around the world. These include, but are not limited to,  Norse mythology (where it appears as the Solar or Odin’s Cross), Native American cultures (where it typically represented the four spirits of direction and the four sacred elements), the Celtic Cross, the Greek Cross, and the Egyptian Ankh.

In fact, perhaps owing to the simplicity of the design, cross-shaped incisions have made appearances as petroglyphs in European cult caves dating all the way back to the beginning of the Upper Paleolithic, and throughout prehistory to the Iron Age.

Mars, as photographed with the Mars Global Surveyor, is identified with the Roman god of war. Credit: NASA
Mars, as photographed with the Mars Global Surveyor, is identified with the Roman god of war. Credit: NASA

Mars:
Mars is named after the Roman god of war, owing perhaps to the planet’s reddish hue, which gives it the color of blood. For this reason, the symbol associated with Mars represents the god of wars’ shield and spear. Additionally, it is the same sign as the one used to represent “male”, and hence is associated with self-assertion, aggression, sexuality, energy, strength, ambition and impulsiveness.

Jupiter:
Jupiter’s sign, which looks like an ornate, oddly shaped “four,” also stands for a number of symbols. It has been said to represent an eagle, which was the Jovian god’s bird. Additionally, the symbol can stand for a “Z,” which is the first letter of Zeus  – who was Jupiter’s Greek counterpart.

The line through the symbol is consistent with this, since it would indicate that it was an abbreviation for Zeus’ name. And last, but not least, there is the addition of the swirled line which is believed to represent a lighting bolt – which just happens to  Jupiter’s (and Zeus’) weapon of choice.

Saturn:
Like Jupiter, Saturn resembles another recognizable character – this time, it’s an “h.” However, this symbol is actually supposed to represent Saturn’s scythe or sickle, because Saturn is named after the Roman god of agriculture (after the Greek god Cronus, leader of the Titans, who was also depicted as holding a scythe).

Jupiter's Great Red Spot and Ganymede's Shadow. Image Credit: NASA/ESA/A. Simon (Goddard Space Flight Center)
Jupiter, the largest planet in the Solar System, is appropriately named after the Roman father of the gods. Credit: NASA/ESA/A. Simon (Goddard Space Flight Center)

Uranus:
The sign for Uranus is a combination of two other signs – Mars’ sign and the symbol of the Sun – because the planet is connected to these two in mythology. Uranus represented heaven in Roman mythology, and this ancient civilization believed that the Sun’s light and Mars’ power ruled the heavens.

Neptune:
Neptune’s sign is linked to the sea god Neptune, who the planet was named after. Appropriately, the symbol represents this planet is in the shape of the sea god’s trident.

Pluto:
Although Pluto was demoted to a dwarf planet in 2006, it still retains its old symbol. Pluto’s sign is a combination of a “P” and a “L,” which are the first two letters in Pluto as well as the initials of Percival Lowell, the astronomer who discovered the planet.

A full Moon flyby, as seen from Paris, France. Credit and copyright: Sebastien Lebrigand.
A full Moon flyby, as seen from Paris, France. Credit and copyright: Sebastien Lebrigand.

Moon:
The Moon is represented by a crescent shape, which is a clear allusion to how the Moon appears in the night sky more often than not. Since the Moon is also tied to people’s perceptions, moods, and emotional make-up, the symbol has also come to represents the mind’s receptivity.

Sun:
And then there’s the Sun, which is represented by a circle with a dot in the middle. In the case of the Sun, this symbol represents the divine spirit (circle) surrounding the seed of potential, which is a direct association with ancient Sun worship and the central role the Sun gods played in their respective ancient pantheons.

We have many interesting articles on the planets here at Universe Today. For example, here is other articles including symbols of the planets and symbols of the Sun and Moon.

If you are looking for more information try signs of the planets and symbols of the minor planets.

Astronomy Cast has an episode on each planet including Saturn.

Last-Minute Father’s Day Gift: Give Him a Crater on Mars

Examples of craters various craters on Mars. Credit: NASA/JPL/Univ. of Arizona.

We all know that Mars Needs Moms, but Dad rocks the Red Planet too! If you’re looking for a last-minute gift for Dad, the commercial space company Uwingu has a special Father’s Day promotion where you can name a crater on Mars after your dad (or any other special person in your life.) You’ll get a unique decorative Father’s Day certificate that you can download and print,or for an extra fee you can have the certificate professionally printed and framed.

Uwingu’s Mars Map Crater Naming Project at allows anyone to help name approximately 590,000 unnamed, scientifically cataloged craters on Mars. The company uses out-of-the-box idea to help address funding shortages for researchers, scientists, educators and students. Uwingu’s Mars map grandfathers in all the already named craters on Mars, but opens the remainder up for naming by people around the globe.

“This is an out-of-this-world way to honor dads across this planet,” said Dr. Alan Stern, Uwingu’s CEO. “Help your dad join our Dads on Mars club!”

uwingu

Uwingu also announced that anyone purchasing the 50 largest craters named by Father’s Day will receive a 2-for-1 bonus: a gift certificate of equal value; allowing them to put additional crater names on the Mars map for free anytime in 2015.

Prices for naming craters depend on the size of the crater, and begin at $5. Half of Uwingu’s revenues go to fund the Uwingu Fund for space research and education grants.

As we’ve reported previously, Uwingu knows that the names likely won’t officially be approved by the IAU, but said they will be similar to the names given to features on Mars by the mission science teams (such as Mt. Sharp on Mars –the IAU-approved name is Aeolis Mons) or even like Pike’s Peak, a mountain in Colorado which was named by the public, in a way, as early settlers started calling it that, and it soon became the only name people recognized.

“Mars scientists and Apollo astronauts have named features on the Red Planet and the Moon without asking for the IAU’s permission,” Stern said. In the past, Stern has said that he realizes having people pay to suggest names for with no official standing may be controversial, and he’s willing to take the chance – and the heat – to try a innovative ways to provide funding in today’s climate of funding cuts.

Said Uwingu’s Ellen Butler, “I’m excited to name a crater on the Uwingu Mars map in honor of my own dad. It’ll be fun to share this with him on Father’s Day. I know he’ll love telling his friends that I named a crater for him!”

First Interplanetary CubeSats to Launch on NASA’s 2016 InSight Mars Lander

NASA's two small MarCO CubeSats will be flying past Mars in 2016 just as NASA's next Mars lander, InSight, is descending to land on the surface. MarCO, for Mars Cube One, will provide an experimental communications relay to inform Earth quickly about the landing. Credits: NASA/JPL-Caltech

NASA’s two small MarCO CubeSats will be flying past Mars in 2016 just as NASA’s next Mars lander, InSight, is descending to land on the surface. MarCO, for Mars Cube One, will provide an experimental communications relay to inform Earth quickly about the landing. Credits: NASA/JPL-Caltech
See fly by and cubesat spacecraft graphics and photos below[/caption]

CubeSats are taking the next great leap for science – departing Earth and heading soon for the fourth rock from the Sun.

For the first time, two tiny CubeSat probes will launch into deep space in early 2016 on their first interplanetary expedition – aiming for the Red Planet as part of an experimental technology relay demonstration project aiding NASA’s next Mission to Mars; the InSight lander.

NASA announced the pair of briefcase-sized CubeSats, called Mars Cube One or MarCO, as a late and new addition to the InSight mission, that could substantially enhance communications options on future Mars missions. They were designed and built by NASA’s Jet Propulsion Laboratory (JPL), Pasadena, California.

InSight, which stands for Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport, is a stationary lander. It will join NASA’s surface science exploration fleet currently comprising of the Curiosity and Opportunity missions which by contrast are mobile rovers.

InSight is the first mission to understand the interior structure of the Red Planet. Its purpose is to elucidate the nature of the Martian core, measure heat flow and sense for “Marsquakes.”

The full-scale mock-up of NASA's MarCO CubeSat held by Farah Alibay, a systems engineer for the technology demonstration, is dwarfed by the one-half-scale model of NASA's Mars Reconnaissance Orbiter behind her.  Credits: NASA/JPL-Caltech
The full-scale mock-up of NASA’s MarCO CubeSat held by Farah Alibay, a systems engineer for the technology demonstration, is dwarfed by the one-half-scale model of NASA’s Mars Reconnaissance Orbiter behind her. Credits: NASA/JPL-Caltech

Because of their small size – roughly 4 inches (10 centimeters) square) – and simplicity using off-the-shelf components, they are a favored platform for university students and others seeking low cost access to space – such as the Planetary Society’s recently successful Light Sail solar sailing cubesat demonstration launched in May. Six units are combined together to create MarCO.

Over the past few years many hundreds of cubesats have already been deployed in Earth orbit – including many dozens from the International Space Station (ISS) – but these will be the first going far beyond our Home Planet.

Data relayed by MarCO at 8 kbps in real time could reveal InSight’s fate on the Martian surface within minutes to mission controllers back on Earth, rather than waiting for a potentially prolonged period of agonizing nail-biting lasting an hour or more.

The two probes, known as MarCO-A and MarCO-B, will operate during InSight’s highly complex entry, descent and landing (EDL) operations as it descends through the thin Martian atmosphere. Their function is merely to quickly relay landing data. But the cubesats will have no impact on the ultimate success of the mission. They will intentionally sail by but not land on Mars.

“MarCO is an experimental capability that has been added to the InSight mission, but is not needed for mission success,” said Jim Green, director of NASA’s planetary science division at the agency’s headquarters in Washington, in a statement.

The MarCO Cubesats will serve as a test bed for a revolutionary communications mode that seeks to quickly relay data back to Earth about the status of InSight – in real time – as it plummets down to the Red Planet for the “Seven Minutes of Terror” that hopefully climaxes with a soft landing.

The MarCO duo will fly by past Mars at a planned distance and altitude of about 3,500 kilometers as InSight descends towards the surface during EDL operations. They will rapidly retransmit signals coming from the lander in real time, directly back to NASA’s huge Deep Space Network (DSN) receiving dish antennas back on Earth.

 MarCO cubesats fly by trajectory for rapid communications relay as NASA’s InSight spacecraft lands on Mars in September 2016. Credit: NASA/JPL-Caltech

MarCO cubesats fly by trajectory for rapid communications relay as NASA’s InSight spacecraft lands on Mars in September 2016. Credit: NASA/JPL-Caltech

For this flight, six cubesats will be joined together to provide the additional capability required for the journey to Mars and to accomplish their communications task.

The six-unit MarCO CubeSat has a stowed size of about 14.4 inches (36.6 centimeters) by 9.5 inches (24.3 centimeters) by 4.6 inches (11.8 centimeters) and weighs 14 kilograms.

The solar powered probes will be outfitted with UHF and X-band communications gear as well as propulsion, guidance and more.

The overall cost to design, build, launch and operate MarCO-A and MarCO-B is approximately $13 million, a NASA spokesperson told Universe Today.

InSight and MarCO are slated to blastoff together on March 4, 2016 atop a United Launch Alliance Atlas V rocket from Vandenberg Air Force Base, California.

After launch, both MarCO CubeSats will separate from the Atlas V booster and travel along their own trajectories to the Red Planet.

“MarCO will fly independently to Mars,” says Green.

They will be navigated independently from InSight. They will all reach Mars at approximately the same time for InSight’s landing slated for Sept. 28, 2016.

MarCO’s two solar panels and two radio antennas will unfurl after being released from the Atlas booster. The high-gain, X-band antenna is a flat panel engineered to direct radio waves the way a parabolic dish antenna does,” according to a NASA description.

The softball-size radio “provides both UHF (receive only) and X-band (receive and transmit) functions capable of immediately relaying information received over UHF.”

MarCO cubesat graphic annotated to show dimensions, instruments, physical characteristics and capabilities.  Credit: NASA/JPL-Caltech
MarCO cubesat graphic annotated to show dimensions, instruments, physical characteristics and capabilities. Credit: NASA/JPL-Caltech

During EDL, InSight will transmit landing data via UHF radio to the MarCO cubesats sailing past Mars as well as to NASA’s Mars Reconnaissance Orbiter (MRO) soaring overhead.

MarCO will assist InSight by receiving the lander information transmitted in the UHF radio band and then immediately forward EDL information to Earth using the X-band radio. By contrast, MRO cannot simultaneously receive information over one band while transmitting on another, thus delaying confirmation of a successful landing possibly by an hour or more.

Engineers for NASA's MarCO technology demonstration display a full-scale mechanical mock-up of the small craft in development as part of NASA's next mission to Mars. Mechanical engineer Joel Steinkraus and systems engineer Farah Alibay are on the team at NASA's Jet Propulsion Laboratory, Pasadena, California, preparing twin MarCO (Mars Cube One) CubeSats for a March 2016 launch.  Credit: NASA/JPL-Caltech
Engineers for NASA’s MarCO technology demonstration display a full-scale mechanical mock-up of the small craft in development as part of NASA’s next mission to Mars. Mechanical engineer Joel Steinkraus and systems engineer Farah Alibay are on the team at NASA’s Jet Propulsion Laboratory, Pasadena, California, preparing twin MarCO (Mars Cube One) CubeSats for a March 2016 launch. Credit: NASA/JPL-Caltech

“Ultimately, if the MarCO demonstration mission succeeds, it could allow for a “bring-your-own” communications relay option for use by future Mars missions in the critical few minutes between Martian atmospheric entry and touchdown,” say NASA officials.

It’s also very beneficial and critical to the success of future missions to have a stream of data following the progress of past missions so that lessons can be learned and applied, whatever the outcome.

“By verifying CubeSats are a viable technology for interplanetary missions, and feasible on a short development timeline, this technology demonstration could lead to many other applications to explore and study our solar system,” says NASA.

InSight will smash into the Martian atmosphere at high speeds of approximately 13,000 mph in September 2016 and then decelerate within a few minutes for landing via a heat shield, retro rocket and parachute assisted touchdown on the plains at flat-lying terrain at “Elysium Planitia,” some four degrees north of Mars’ equator, and a bit north of the Curiosity rover.

As I reported in recently here, InSight has now been assembled into its flight configuration and begun a comprehensive series of rigorous environmental stress tests that will pave the path to launch in 2016 on a mission to unlock the riddles of the Martian core.

The countdown clock is ticking relentlessly towards liftoff in less than nine months time in March 2016.

NASA's InSight Mars lander spacecraft in a Lockheed Martin clean room near Denver. As part of a series of deployment tests, the spacecraft was commanded to deploy its solar arrays in the clean room to test and verify the exact process that it will use on the surface of Mars.  Credits: NASA/JPL-Caltech/Lockheed Martin
NASA’s InSight Mars lander spacecraft in a Lockheed Martin clean room near Denver. As part of a series of deployment tests, the spacecraft was commanded to deploy its solar arrays in the clean room to test and verify the exact process that it will use on the surface of Mars. Credits: NASA/JPL-Caltech/Lockheed Martin

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Weekly Space Hangout – June 12, 2015: Astronomy in Chile Educator Ambassadors Program

Host: Fraser Cain (@fcain)

Special Guest: This week we welcome Astronomy in Chile Educator Ambassadors Program Participants:
Michael Prokosch (Seeing Stars Blog, MikeProkosch@shsuobservatory)
Tim Spuck ([email protected])
Brian Koberlein (@briankoberlein / briankoberlein.com)
Vivian White ([email protected]).

Guests:
Jolene Creighton (@jolene723 / fromquarkstoquasars.com)
Brian Koberlein (@briankoberlein / briankoberlein.com)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Alessondra Springmann (@sondy)
Continue reading “Weekly Space Hangout – June 12, 2015: Astronomy in Chile Educator Ambassadors Program”

Dazzling Gallery From India’s MOM Mars Orbiter Camera

Spectacular 3D view of Arsia Mons, a huge volcano on Mars, taken by camera on India's Mars Orbiter Mission (MOM). Credit: ISRO

Spectacular 3D view of Arsia Mons, a huge volcano on Mars, taken by camera on India’s Mars Orbiter Mission (MOM). Credit: ISRO
Story updated with more details and imagery[/caption]

India’s first ever robotic explorer to the Red Planet, the Mars Orbiter Mission, more affectionately known as MOM, has captured an absolutely dazzling array of images of the fourth rock from the Sun.

The Indian Space Research Organization (ISRO), India’s space agency, has recently published a beautiful gallery of images featuring a variety of picturesque Martian canyons, volcanoes, craters, moons and more.

We’ve gathered a collection here of MOM’s newest imagery snapped by the probes Mars Color Camera (MCC) for the enjoyment of Martian fans worldwide.

The spectacular 3D view of the Arsia Mons volcano, shown above, was “created by draping the MCC image on topography of the region derived from the Mars Orbiter Laser Altimeter (MOLA), one of five instruments on board NASA’s Mars Global Surveyor (MGS) spacecraft.

The Arsia Mons image was taken from Mars orbit on 1 April 2015 at a spatial resolution of 556 meters from an altitude of 10707 km. Volcanic deposits can be seen located at the flanks of the Mons, according to ISRO.

The view of Pital crater below was released in late May and taken on 23 April 2015. Pital is a 40 km wide impact crater located in the Ophir Planum region of Mars and the image shows a chain of small impact craters. It is located in the eastern part of Valles Marineris region, says an ISRO description. MCC took the image from an altitude of 808 km.

Pital crater is an impact crater located in Ophir Planum region of Mars, which is located in the eastern part of Valles Marineris region. This  image is taken by Mars Color Camera (MCC) on 23-04-2015 at a spatial resolution of  ~42 m from an altitude of 808 km. Credit: ISRO
Pital crater is an impact crater located in Ophir Planum region of Mars, which is located in the eastern part of Valles Marineris region. This image is taken by Mars Color Camera (MCC) on 23-04-2015 at a spatial resolution of ~42 m from an altitude of 808 km. Credit: ISRO

It is an odd shaped crater, neither circular nor elliptical in shape, possibly due to “regional fracture in the W-E trending fracture zone.”

A trio of images, including one in stunning 3D, shows various portions of Valles Marineris, the largest known canyon in the Solar System.

Three dimensional view of Valles Marineris center portion from India’s MOM Mars Mission.   Credit: ISRO
Three dimensional view of Valles Marineris center portion from India’s MOM Mars Mission. Credit: ISRO

Valles Marineris stretches over 4,000 km (2,500 mi) across the Red Planet , is as much as 600 km wide and measures as much as 7 kilometers (4 mi) deep.

Valles Marineris from India’s Mars Mission.   Credit: ISRO
Valles Marineris from India’s Mars Mission. Credit: ISRO

For context here’s a previously taken global image of the red planet from MOM showing Valles Marinaris and Arsia Mons, which belongs to the Tharsis Bulge trio of shield volcanoes. They are both near the Martian equator.

Olympus Mons, Tharsis Bulge trio of volcanoes and Valles Marineris from ISRO's Mars Orbiter Mission. Note the clouds and south polar ice cap.   Credit: ISRO
Olympus Mons, Tharsis Bulge trio of volcanoes and Valles Marineris from ISRO’s Mars Orbiter Mission. Note the clouds and south polar ice cap. Credit: ISRO

Valles Marineris is often called the “Grand Canyon of Mars.” It spans about as wide as the entire United States.

A gorgeous view of Phobos, the largest of Mars’ two tiny moons, silhouetted against the surface is shown below.

Phobos, one of the two natural satellites of Mars silhouetted against the Martian surface.  Credit: ISRO
Phobos, one of the two natural satellites of Mars silhouetted against the Martian surface. Credit: ISRO

MOM’s goal is to study Mars atmosphere, surface environments, morphology, and mineralogy with a 15 kg (33 lb) suite of five indigenously built science instruments. It is also sniffing for methane, a potential marker for biological activity.

MOM is India’s first deep space voyager to explore beyond the confines of her home planets influence and successfully arrived at the Red Planet after the “history creating” orbital insertion maneuver on Sept. 23/24, 2014 following a ten month journey from Earth.
MOM swoops around Mars in a highly elliptical orbit whose nearest point to the planet (periapsis) is at about 421 km and farthest point (apoapsis) at about 76,000 km, according to ISRO.

It takes MOM about 3.2 Earth days or 72 hours to orbit the Red Planet.

Higher resolution view of a portion of Valles Marineris canyon from India’s MOM Mars Mission.   Credit: ISRO
Higher resolution view of a portion of Valles Marineris canyon from India’s MOM Mars Mission. Credit: ISRO

MOM was launched on Nov. 5, 2013 from India’s spaceport at the Satish Dhawan Space Centre, Sriharikota, atop the nations indigenous four stage Polar Satellite Launch Vehicle (PSLV) which placed the probe into its initial Earth parking orbit.

The $73 million MOM mission was expected to last at least six months. In March, ISRO extended the mission duration for another six months since its healthy, the five science instruments are operating fine and it has sufficient fuel reserves.

And with a communications blackout between Mars and Earth imminent as a result of natures solar conjunction, it’s the perfect time to catch up on all things Martian.

Solar conjunctions occur periodically between Mars and Earth about every 26 months, when the two planets line up basically in a straight line geometry with the sun in between as the two planets travel in their sun-centered orbits.

Since Mars will be located behind the Sun for most of June, communications with all the Terran spacecraft at the planet is diminished to nonexistent.

“MOM faces a communication outage during June 8-25,” according to The Hindu.

Normal science operations resume thereafter.

“Fuel on the spacecraft is not an issue,” ISRO Satellite Centre Director M. Annadurai told The Hindu.

Image of Tyrrhenus Mons in Hesperia Planum region taken by Mars Color Camera (MCC) on 25-02-2015 at a spatial resolution of 166m from an altitude of 3192km.  Tyrrhenus Mons is an ancient martian volcano and image shows its timeworn gullies and wind streaks.  Credit: ISRO
Image of Tyrrhenus Mons in Hesperia Planum region taken by Mars Color Camera (MCC) on 25-02-2015 at a spatial resolution of 166m from an altitude of 3192km. Tyrrhenus Mons is an ancient martian volcano and image shows its timeworn gullies and wind streaks. Credit: ISRO

Including MOM, Earth’s invasion fleet at the Red Planet numbers a total of seven spacecraft comprising five orbiters from NASA, ESA and ISRO as well as the sister pair of mobile surface rovers from NASA – Curiosity and Opportunity.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

How Can We Live on Mars?

The Dragn Crew capsule is more than a modernized Apollo capsule. It will land softly and at least on Earth will be reusable while Musk and SpaceX dream of landing Falcon Crew on Mars. (Photo Credits: SpaceX)

Why live on Earth when you can live on Mars? Well, strictly speaking, you can’t. Mars is a completely hostile environment to human life, combining extreme cold with an unbreathable atmosphere and intense radiation. And while it is understood that the planet once had an atmosphere and lots of water, that was billions of years ago!

And yet, if we want to expand into the Solar System, we’ll need to learn how to live on other planets. And Mars is prime real-estate, compared to a lot of other bodies. So despite it being a challenge, given the right methods and technology, it is possible we could one day live on Mars. Here’s how we’ll do it.

Reasons To Go:

Let’s face it, humanity wants (and needs) to go Mars, and for several reasons.  For one, there’s the spirit of exploration, setting foot on a new world and exploring the next great frontier – like the Apollo astronauts did in the late 60s and early 70s.

Artist illustration of a Mars Colony. Image credit: NASA
Artist illustration of a Mars Colony. Image credit: NASA

We also need to go there if we want to create a backup location for humanity, in the event that life on Earth becomes untenable due to things like Climate Change. We could also go there to search for additional resources like water, precious metals, or additional croplands in case we can no longer feed ourselves.

In that respect, Mars is the next, natural destination. There’s also a little local support, as Mars does provide us some raw materials. The regolith, the material which covers the surface, could be used to make concrete, and there are cave systems which could be converted into underground habitats to protect citizens from the radiation.

Elon Musk has stated that the goal of SpaceX is to help humans get to Mars, and they’re designing rockets, landers and equipment to support that. Musk would like to build a Mars colony with about 1 million people. Which is a good choice, as its probably the second most habitable place in our Solar System. Real estate should be pretty cheap, but the commute is a bit much.

And then there’s the great vistas to think about. Mars is beautiful, after a fashion. It looks like a nice desert planet with winds, clouds, and ancient river beds. But maybe, just maybe, the best reason to go there is because it’s hard! There’s something to be said about setting a goal and achieving it, especially when it requires so much hard work and sacrifice.

Reasons NOT To Go:

Yeah, Mars is pretty great… if you’re not made of meat and don’t need to breathe oxygen. Otherwise, it’s incredibly hostile. It’s not much more habitable than the cold vacuum of space. First, there’s no air on Mars. So if you were dropped on the surface, the view would be spectacular. Then you’d quickly pass out, and expire a couple minutes later from a lack of oxygen.

There’s also virtually no air pressure, and temperatures are incredibly cold. And of course, there’s the constant radiation streaming from space. You also might want to note that the soil is toxic, so using it for planting would first require that it be put through a decontamination process.

A post-processed mosaic of MSL Mastcam images from Sol 582 (NASA/JPL-Caltech/MSSS. Edit by Jason Major)
Afternoon on Mars (MSL Mastcam mosaic)(NASA/JPL-Caltech/MSSS. Edit by Jason Major)

Assuming we can deal with those issues, there’s also the major problem of having limited access to spare parts and medical supplies. You can’t just go down to the store when you’re on Mars if your kidney gives out or if your sonic screwdriver breaks.

There will need to be a constant stream of supplies coming from Earth until the Martian economy is built up enough to support itself. And shipping from Earth will be very expensive, which will mean long period between supply drops.

One more big unknown is what the low gravity will do to the human body over months and years. At 40% of Earth normal, the long-term effects are not something we currently have any information on. Will it shorten our lifespan or lengthen it? We just don’t know.

There’s a long list of these types of problems. If we intend to live on Mars, and stay there permanently, we’ll be leaning pretty hard on our technology to keep us alive, never mind making us comfortable!

Possible Solutions:

In order to survive the lack of air pressure and the cold, humans will need pressurized and heated habitats. Martians, the terrestrial kind, will also need a spacesuit whenever they go outside. Every hour they spend outside will add to their radiation exposure, not to mention all the complications that exposure to radiation brings.

Artist's concept of a habitat for a Mars colony. Credit: NASA
Artist’s concept of a habitat for a Mars colony. Credit: NASA

For the long term, we’ll need to figure out how to extract water from underground supplies, and use that to generate breathable air and rocket fuel. And once we’ve reduced the risk of suffocation or dying of dehydration, we’ll need to consider food sources, as we’ll be outside the delivery area of everyone except Planet Express. Care packages could be shipped up from Earth, but that’s going to come with a hefty price tag.

We’ll need to produce our own food too, since we can’t possible hope to ship it all in on a regular basis. Interestingly, although toxic, Martian soil can be used to grow plants once you supplement it and remove some of the harsher chemicals. NASA’s extensive experience in hydroponics will help.

To thrive on Mars, the brave adventurers may want to change themselves, or possibly their offspring. This could lead to genetic engineering to help future generations adapt to the low gravity, higher radiation and lower air pressure. And why stop at humans? Human colonists could also adapt their plants and animals to live there as well.

Finally, to take things to the next level, humanity could make a few planetary renovations. Basically, we could change Mars itself through the process of terraforming. To do this, we’ll need to release megatons of greenhouse gasses to warm the planet, unleashing the frozen water reserves. Perhaps we’ll crash a few hundred comets into the planet to deliver water and other chemicals too.

An artist's conception of future Mars astronauts. Credit: NASA/JPL-Caltech
An artist’s conception of future Mars astronauts. Credit: NASA/JPL-Caltech

This might take thousands, or even millions of years. And the price tag will be, for lack of a better word, astronomical! Still, the technology required to do all this is within our current means, and the process could restore Mars to a place where we could live on it even without a spacesuit.

And even though we may not have all the particulars worked out just yet, there is something to be said about a challenge. As history has shown, there is little better than a seemingly insurmountable challenge to bring out the best in all of us, and to make what seems like an impossible dream a reality.

To quote the late, great John F. Kennedy, who addressed the people of the United States back when they was embarking on a similarly difficult mission:

We choose to go to the Moon! … We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard; because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one we intend to win

What do you think? Would you be part of the Mars terraforming expedition? Tell us in the comments below.

We have written many interesting articles about Mars here at Universe Today. Here’s How Do We Colonize Mars?, Mars Colony Will Have to Wait, Solar Power is Best for Mars Colonies, and Elon Musk is Sending Humans to Mars in 2024.

For more information, check out NASA’s Journey to Mars, and NASA Quest’s Mars Colony Project.

Astronomy Cast also has episodes on the subject, like Episode 52: Mars, and Episode 95: Humans to Mars, Part 2: Colonists.

What Is The Difference Between Asteroids and Meteorites?

Various meteorites from 2008 TC3. Credit: P. Jenniskens, et. al. Click image for full description

Asteroids, meteors, and meteorites … It might be fair to say these rocks from space inspire both wonder and fear among us Earthlings. But knowing a bit more about each of them and how they differ may eliminate some potential misgivings. While all these rocks originate from space, they have different names depending their location — i.e. whether they are hurtling through space or hurtling through the atmosphere and impacting Earth’s surface.

In simplest terms here are the definitions:

Asteroid: a large rocky body in space, in orbit around the Sun.

Meteoroid: much smaller rocks or particles in orbit around the Sun.

Meteor: If a meteoroid enters the Earth’s atmosphere and vaporizes, it becomes a meteor, which is often called a shooting star.

Meteorite: If a small asteroid or large meteoroid survives its fiery passage through the Earth’s atmosphere and lands on Earth’s surface, it is then called a meteorite.

Another related term is bolide, which is a very bright meteor that often explodes in the atmosphere. This can also be called a fireball.

Let’s look at each in more detail:

Asteroids

An artists impression of an asteroid belt. Credit: NASA
An artists impression of an asteroid belt. Credit: NASA

Asteroids are found mainly in the asteroid belt, between Mars and Jupiter. Sometimes their orbits get perturbed or altered and some asteroids end up coming closer to the Sun, and therefore closer to Earth. In addition to the asteroid belt, however, there have been recent discussions among astronomers about the potential existence of large number asteroids in the Kuiper Belt and Oort Cloud. You can read a paper about this concept here, and a good article discussing the topic here.

The asteroid Vesta as seen by the Dawn spacecraft. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA
The asteroid Vesta as seen by the Dawn spacecraft. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

Asteroids are sometimes referred to as minor planets or planetoids, but in general, they are rocky bodies that do not have an atmosphere. However, a few have their own moons. Our Solar System contains millions of asteroids, many of which are thought to be the shattered remnants of planetesimals – bodies within the young Sun’s solar nebula that never grew large enough to become planets.

The size of what classifies as an asteroid is not extremely well defined, as an asteroid can range from a few meters wide – like a boulder — to objects that are hundreds of kilometers in diameter. The largest asteroid is asteroid Ceres at about 952 km (592 miles) in diameter, and Ceres is so large that it is also categorized as a dwarf planet.

Most asteroids are made of rock, but as we explore and learn more about them we know that some are composed of metal, mostly nickel and iron. According to NASA, a small portion of the asteroid population may be burned-out comets whose ices have evaporated away and been blown off into space. Recently, astronomers have discovered some asteroids that mimic comets in that gas and dust are emanating from them, and as we mentioned earlier, there appears to be a large number of bodies with asteroid-like compositions but comet-like orbits.

How Often Do Asteroids Hit Earth?

Meteor Crater near Winslow, Arizona. Image credit: NASA.
Meteor Crater near Winslow, Arizona. Image credit: NASA.

While we know that some asteroids pass very close to Earth’s orbit around the Sun, we’ve been lucky in the history of humanity that we haven’t had a large asteroid hit Earth in the past several thousand years. It wasn’t until satellite imagery of Earth became widely available that scientists were able to see evidence of past asteroid impacts.

One of the more famous impact craters on Earth is Meteor Crater in Arizona in the US, which was made by an impact about 50,000 years ago. But there are about 175 known impact around the world – a few are quite large, like Vredefort Crater in South Africa which has an estimated radius of 190 kilometers (118 miles), making it the world’s largest known impact structure on Earth. Another notable impact site is off the coast of the Yucatan Peninsula in Mexico, and is believed to be a record of the event that led to the extinction of the dinosaurs 65 million years ago. You can see images of some of the most impressive Earth impact craters here.

These days, asteroid impacts are less of a threat. NASA estimates that about once a year an automobile-sized asteroid enters Earth’s atmosphere, creates an impressive fireball and disintegrates before ever reaching the surface. Studies of Earth’s history indicate that about once every 5,000 years or so on average an object the size of a football field hits Earth and causes significant damage. Once every few million years on average an object large enough to cause regional or global disaster impacts Earth. You can find more information about the frequency of impacts in this article from NASA.


Meteors, Meteoroids and Bolides

A bright meteor from September 21, 1994. Credit: John Chumack.
A bright meteor from September 21, 1994. Credit: John Chumack.

Space debris smaller than an asteroid are called meteoroids. A meteoroid is a piece of interplanetary matter that is smaller than an asteroid and frequently are only millimeters in size. Most meteoroids that enter the Earth’s atmosphere are so small that they vaporize completely and never reach the planet’s surface. When they burn up during their descent, they create a beautiful trail of light known as a meteor, sometimes called a shooting star.

Mostly these are harmless, but larger meteors that explode in the atmosphere – sometimes called bolides — can create shockwaves, which can cause problems. In February 2013 a meteor that exploded over Chelyabinsk, Russia shattered windows with its air blast. This meteoroid or bolide was estimated to be 18 meters (59 feet) in diameter. In 1908, a rocky meteoroid less than 100 meters in diameter is believed to have entered the atmosphere over the Tunguska region of Siberia in 1908 and the resulting shockwave knocked down trees for hundreds of square kilometers

How often is Earth hit by meteroids?

Chelyabinsk fireball recorded by a dashcam from Kamensk-Uralsky north of Chelyabinsk where it was still dawn.
Chelyabinsk fireball recorded by a dashcam from Kamensk-Uralsky north of Chelyabinsk where it was still dawn.

Because of the Chelyabinsk meteor in 2013, astronomers have acquired more information about the frequency of larger meteors that hit Earth, and there is now a growing consensus that the Earth gets hit by bigger space rocks more often than we previously thought. You can read more about that concept here.

This video from the B612 Foundation shows a visualization of the location of 26 space rocks that hit Earth between 2000 and 2013, each releasing energy equivalent to some of our most powerful nuclear weapons. The B612 foundation says that a Hiroshima-scale asteroid explosion happens in our atmosphere on average once a year, but many are not detected because they explode high in the atmosphere, or because most of the Earth’s surface is water and even a large percentage of land is fairly uninhabited by humans.

Estimates vary of how much cosmic dust and meteors enter Earth’s atmosphere each day, but range anywhere from 5 to 300 metric tons. Satellite observations suggest that 100-300 metric tons of cosmic dust enter the atmosphere each day. This figure comes from the rate of accumulation in polar ice cores and deep-sea sediments of rare elements linked to cosmic dust, such as iridium and osmium.

But other measurements – which includes meteor radar observations, laser observations and measurements by high altitude aircraft — indicate that the input could be as low as 5 metric ton per day. Read more about this here.

For a documented list of bolide events, you can check out this page from JPL.

Meteorite

A stunning slice of the Glorieta pallasite meteorite cut thin enough to allow light to shine through its many olivine crystals.  Credit: Mike Miller
A stunning slice of the Glorieta pallasite meteorite cut thin enough to allow light to shine through its many olivine crystals. Credit: Mike Miller

If any part of a meteoroid survives the fall through the atmosphere and lands on Earth, it is called a meteorite. Although the vast majority of meteorites are very small, their size can range from about a fraction of a gram (the size of a pebble) to 100 kilograms (220 lbs) or more (the size of a huge, life-destroying boulder). Meteorites smaller than 2mm are classified as micrometeorites.

Meteorites have traditionally been divided into three broad categories, depending on their structure, chemical and isotopic composition and mineralogy. Stony meteorites are rocks, mainly composed of silicate minerals; iron meteorites that are largely composed of metallic iron-nickel; and, stony-iron meteorites that contain large amounts of both metallic and rocky material.

Meteorites have also been found on the Moon and Mars and conversely, scientists have traced the origination of the meteorites found here on Earth to four other bodies: the Moon, Mars, the asteroid 4 Vesta, and the comet Wild 2. Meteorites are the source of a great deal of the knowledge that we have have about the composition of other celestial bodies.

How Often Do Meteorites Hit Earth?

On Feb. 28, 2009, Peter Jenniskens (SETI/NASA), finds his first 2008TC3 meteorite after an 18-mile long journey. "It was an incredible feeling," Jenniskens said. The African Nubian Desert meteorite of Oct 7, 2008 was the first asteroid whose impact with Earth was predicted while still in space approaching Earth. 2008TC3 and Chelyabinsk are part of the released data set. (Credit: NASA/SETI/P.Jenniskens)
On Feb. 28, 2009, Peter Jenniskens (SETI/NASA), finds his first 2008TC3 meteorite after an 18-mile long journey. “It was an incredible feeling,” Jenniskens said. The African Nubian Desert meteorite of Oct 7, 2008 was the first asteroid whose impact with Earth was predicted while still in space approaching Earth. 2008TC3 and Chelyabinsk are part of the released data set. (Credit: NASA/SETI/P.Jenniskens)

According to the Planetary Science Institute, it is estimated that probably 500 meteorites reach the surface of the Earth each year, but less than 10 are recovered. This is because most fall into water (oceans, seas or lakes) or land in remote areas of the Earth that are not accessible, or are just not seen to fall.

You can read more about meteorites that were found from the Chelyabinsk meteor here.

Summary

In short, the difference between asteroids and meteors all comes down to a question of location. Asteroids are always found in space. Once it enters an atmosphere, it becomes a meteor, and then a meteorite after it hits the ground. Each are made of the same basic materials – minerals and rock – and each originated in space. The main difference is where they are when they are being observed.

We have many great articles on the subject of asteroids and meteorites here at Universe Today, such as this general information article on asteroids, this article and infographic about the difference between comets, asteroids and meteors, and these articles that deal with Ceres and Vesta. And here are some recent articles about the Chelyabinsk meteor that landed in Russia, as well as a 2 billion-year old Martian meteorite that contains evidence of water on Mars.

There is some good information on a NASA page as well as some great information here on Universe Today and Astronomy Cast.

Sources:
JPL’s Near Earth Asteroid Office
Planetary Science Institute
NASA: Asteroids
NASA: Meteors

The Martian Curiosity Looks Back on 1000 Sols of Exploration on the Red Planet

NASA’s Martian Curiosity rover looks backs to 1000 Sols of science and exploration on the surface of the Red Planet. Robot wheel tracks lead back through valley dunes. Gale Crater rim seen in the distant hazy background. Sol 997 (May 28, 2015) navcam camera raw images stitched and colorized. Credit: NASA/JPL-Caltech/ Marco Di Lorenzo/Ken Kremer/kenkremer.com Featured on APOD on June 13, 2015

Looking back 1000 Sols on the Red Planet
NASA’s Martian Curiosity rover looks backs to 1000 Sols of science and exploration on the surface of the Red Planet. Robot wheel tracks lead back through valley dunes. Gale Crater rim seen in the distant hazy background. Sol 997 (May 28, 2015) navcam camera raw images stitched and colorized. Credit: NASA/JPL-Caltech/ Marco Di Lorenzo/Ken Kremer/kenkremer.com
Featured on APOD on June 13, 2015
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The Martian Curiosity celebrates 1000 Sols on Mars!

Marking the occasion with utter glee, the car sized robot snapped a cool mosaic view (above) looking back to 1000 Sols of high impact exploration and discovery on the Red Planet, showing her wheel tracks leading back through valley dunes from the foothills of humongous Mount Sharp and across the alien surface floor and out to the distant rim of the Gale Crater landing site she descended to nearly three years ago in August 2012.

“A thousand thanks to the best team a rover could have. Celebrating 1,000 sols. Here’s to the Martian days ahead!” the robot tweeted.

But at 1K sols she’s not content to just bask in the Martian sunshine during the history making event. Rather, she is as always hard at work, reaching out with the high tech robotic arm and inspecting intriguing rock outcrops spread out all around her.

Check out Curiosity’s current workspace, looking back and hard at work in our new photo mosaics herein created by the imaging team of Marco Di Lorenzo and Ken Kremer. They are also featured at NBC News – here – and Alive Space Images (in Italian) – here and here.

Curiosity rover at work for 1000 Sols on Mars.  This composite multi sol photo mosaic shows outstretched robotic arm inspecting intriguing rock outcrops.   The APXS spectrometer is investigating a target called ‘Ronan’ on the Stimson overlying outcrop.   Navcam camera raw images taken from sols 997 to 1000 are stitched and colorized.  Credit: NASA/JPL/Ken Kremer/kenkremer.com/Marco Di Lorenzo
Curiosity rover at work for 1000 Sols on Mars
This composite multi sol photo mosaic shows outstretched robotic arm inspecting intriguing rock outcrops. The APXS spectrometer is investigating a target called ‘Ronan’ on the Stimson overlying outcrop. Navcam camera raw images taken from sols 997 to 1000 are stitched and colorized. Credit: NASA/JPL/Ken Kremer/kenkremer.com/Marco Di Lorenzo

The raw images for the look back mosaic were taken after she arrived at her current location on Martian Sol 997, or Earth’s Day May 28, 2015.

The Curiosity Mars Science Laboratory (MSL) rover officially celebrated 1000 Martian Sols on May 31, 2015 since she safely touched down on the crater floor on August 5, 2012 following the nail-biting and unprecedented sky crane maneuver that delivered her with pinpoint precision to a landing site nearby Mount Sharp.

“An MSL landmark day. We have reached 1000 sols on Mars. Looking back the remarkable thing is how few serious problems there have been,” says team member Professor John Bridges of the University of Leicester, England, in an update.

Exploring the sedimentary layers of Mount Sharp, which towers 3.4 miles (5.5 kilometers) into the Martian sky, form the primary destination and goal of her scientific expedition.

The six wheeled robot and her team of handlers back on Earth, are eeking out every last drop of science before she and all of Earth’s entire Martian invasion fleet enter solar conjunction, when Mars is behind the sun and little or no communications will be possible for most of the month of June. Activities will be limited per safety protocols.

“However, there is one issue even Curiosity can’t avoid – Conjunction. For much of June, Mars will be obscured from Earth by the Sun. Few science operations,” explains Bridges.

Curiosity rover rolls across Mars at the foothills of Mount Sharp, seen in the background, in this mosaic of images taken on April 11, 2015 (Sol 952).  Navcam camera raw images stitched and colorized. Credit:  NASA/JPL-Caltech/ Marco Di Lorenzo/Ken Kremer/kenkremer.com
Curiosity rover rolls across Mars at the foothills of Mount Sharp, seen in the background, in this mosaic of images taken on April 11, 2015 (Sol 952). Navcam camera raw images stitched and colorized. Credit: NASA/JPL-Caltech/ Marco Di Lorenzo/Ken Kremer/kenkremer.com

NASA’s long-lived Opportunity rover labors on the opposite side of Mars.

After a short drive Curiosity arrived at her current location at “Marias Pass” on Sol 997, where she will stay stationary during the conjunction period out of an abundance of caution.

“A short bump on Sol 997 put Curiosity in a great position to investigate a few different rock units in Marias Pass, using the instruments on the rover’s arm,” wrote MSL and USGS mission scientist Ken Herkenhoff in an update.

She also reached within an eyelash of 10.6 kilometers (6.6 mi) of total driving.

“The 2.5 m drive brings our total odometry to 10,599 m,” noted Herkenoff.

Along the way she discovered the chemical ingredient minerals necessary to support life, as well as low levels of some organic molecules and some traces of methane, and and ample evidence for lakes and streams of liquid water.

“Curiosity is now parked for the next few weeks. But we are parked in front of a beautiful outcrop that shows the contact between the underlying Pahrump unit and the overlying Stimson unit.”

Our arm photo mosaic herein shows the seven foot (2 m) long robotic arm and its APXS spectrometer deployed at the target called “Ronan”, which is part of the overlying Stimson outcrop unit.

The rover is also using the ChemCam, MastCam and MAHLI cameras and spectrometers and other instruments to characterize the outcrop and its texture and composition in detail.

The robotic arm will be stowed during the June conjunction period.

Curiosity arrived at the Pahrump Hills at the base of Mount Sharp back in September 2014. Since then she has conducted an intensive investigation of the rocks and a trio of drilling operations to elucidate how this area fits in context with Mount Sharp and the habitable region discovered on the crater floor at Yellowknife Bay back in the spring of 2013.

In recent weeks, Curiosity has been driving up hills with slopes of as much as 21 degrees, higher than ever before, on an exciting journey endeavoring to slowly ascend up to the lower layers of Mount Sharp.

The current Martian outcrop area under investigation is a place where two distinctive geologic types of bedrock meet and where pale rock meets darker overlying rock.

“Such contacts can reveal clues about how the environmental conditions that produced one type of rock were related to the conditions that produced the other,” says NASA.

“The rover science team wants to examine an outcrop that contains the contact between the pale rock unit the mission analyzed lower on Mount Sharp and a darker, bedded rock unit that the mission has not yet examined up close.”

The team is also scouting around for the presence of mineral veins, like those recently discovered at the “Garden City” outcrop, that formed in the past during periods of flowing liquid water that could be favorable for microbial life forms if they ever existed.

Curiosity investigates a beautiful outcrop of scientifically enticing dark and light mineral veins at ”Garden City” outcrop at the base of Mount Sharp at current location on Mars.   This  photo mosaic was stitched  from Mastcam color camera raw images. Credit:  NASA/JPL-Caltech/MSSS/Ken Kremer/kenkremer.com/Marco Di Lorenzo
Curiosity investigates a beautiful outcrop of scientifically enticing dark and light mineral veins at ”Garden City” outcrop at the base of Mount Sharp at current location on Mars. This photo mosaic was stitched from Mastcam color camera raw images. Credit: NASA/JPL-Caltech/MSSS/Ken Kremer/kenkremer.com/Marco Di Lorenzo

Because there’s a plethora of treacherous dunes, the team has had to monitor operations carefully and alter the route on occasion to maintain safe operations.

Curiosity has already accomplished her primary objective of discovering a habitable zone on the Red Planet that contains the minerals necessary to support microbial life in the ancient past when Mars was far wetter and warmer billions of years ago.

This March 6, 2015 (Sol 917), mosaic of images from the Navcam camera on NASA's Curiosity Mars rover shows the position in which the rover held its arm for several days after a transient short circuit triggered onboard fault-protection programming to halt arm activities on Feb. 27, 2015, Sol 911.  The rover team chose to hold the arm in the same position for several days of tests to diagnose the underlying cause of the Sol 911 event.  Navcam camera raw images stitched and colorized. Credit:  NASA/JPL-Caltech/Ken Kremer/kenkremer.com/Marco Di Lorenzo
This March 6, 2015 (Sol 917), mosaic of images from the Navcam camera on NASA’s Curiosity Mars rover shows the position in which the rover held its arm for several days after a transient short circuit triggered onboard fault-protection programming to halt arm activities on Feb. 27, 2015, Sol 911. The rover team chose to hold the arm in the same position for several days of tests to diagnose the underlying cause of the Sol 911 event. Navcam camera raw images stitched and colorized. Credit: NASA/JPL-Caltech/Ken Kremer/kenkremer.com/Marco Di Lorenzo

To date, Curiosity’s odometer totals over 5.1 miles (8.4 kilometers) since landing inside Gale Crater on Mars in August 2012.

As of today, Sol 1001, June 1, 2015, she has taken over 246,000 amazing images.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer