Welcome back to our planetary weather series! Today, we look at Earth’s overheated “sister planet”, Venus!
Venus is often called Earth’s “Sister Planet” because of all the things they have in common. They are comparable in size, have similar compositions, and both orbit within the Sun’s habitable zone. But beyond that, there are some notable differences that makes Venus a molten hellhole, and about the last place anyone would want to visit!
Much of this has to do with Venus’ atmosphere, which is incredibly dense and entirely hostile to life as we know it. And because of its natural density and composition, the average surface temperature of Venus is hot enough to melt lead. All of this adds up to some pretty interesting weather patterns, which are also incredibly hostile!
Venus Atmosphere:
Although carbon dioxide is invisible, the clouds on Venus are made up of opaque clouds of sulfuric acid, so we can’t see down to the surface using conventional methods. Everything we know about the surface of Venus has been gathered by spacecraft equipped with radar imaging instruments, which can peer through the dense clouds and reveal the surface below.
From the many flybys and atmospheric probes sent into its thick clouds, scientists have learned that Venus’ atmosphere is incredibly dense. In fact, the mass of Venus atmosphere is 93 times that of Earth’s, and the air pressure at the surface is estimated to be as high as 92 bar – i.e. 92 times that of Earth’s at sea level. If it were possible for a human being to stand on the surface of Venus, they would be crushed by the atmosphere.
The composition of the atmosphere is extremely toxic, consisting primarily of carbon dioxide (96.5%) with small amounts of nitrogen (3.5%) and traces of other gases – most notably sulfur dioxide. Combined with its density, the composition generates the strongest greenhouse effect of any planet in the Solar System.
It is also the hottest planet in the Solar System, experiencing mean surface temperatures of 735 K (462 °C; 863.6 °F). Above the dense CO² layer, thick clouds consisting mainly of sulfur dioxide and sulfuric acid droplets scatter about 90% of the sunlight back into space.
The planet is also isothermal, which means that there is little variation in Venus’ surface temperature between day and night, or the equator and the poles. The planet’s minute axial tilt – less than 3° compared to Earth’s 23.5° – and its very slow rotational period (the planet takes around 243 days to complete a single rotation) also minimizes seasonal temperature variation.
Artist’s impression of the surface of Venus. Credit: ESA/AOES
The only appreciable variation in temperature occurs with altitude. The highest point on Venus, Maxwell Montes, is therefore the coolest point on the planet, with a temperature of about 655 K (380 °C; 716 °F) and an atmospheric pressure of about 4.5 MPa (45 bar).
Meteorological Phenomena:
The weather on Venus is one of the aspects of the planet under constant study from Earth-based telescopes and space missions to Venus. And from what we’ve seen, the weather on Venus is very extreme. The entire atmosphere of the planet circulates around quickly, with winds reaching speeds of up to 85 m/s (300 km/h; 186.4 mph) at the cloud tops, which circle the planet every four to five Earth days.
At this speed, these winds move up to 60 times the speed of the planet’s rotation, whereas Earth’s fastest winds are only 10-20% of the planet’s rotational speed. Spacecraft equipped with ultraviolet imaging instruments are able to observe the cloud motion around Venus, and see how it moves at different layers of the atmosphere. The winds blow in a retrograde direction, and are the fastest near the poles.
Closer to the equator, the wind speeds die down to almost nothing. Because of the thick atmosphere, the winds move much slower as you get close to the surface of Venus, reaching speeds of about 5 km/h. Because it’s so thick, though, the atmosphere is more like water currents than blowing wind at the surface, so it is still capable of blowing dust around and moving small rocks across the surface of Venus.
Over the past six years wind speeds in Venus’ atmosphere have been steadily rising (ESA
Several flybys past the planet have also indicated that its dense clouds are capable of producing lightning, much like the clouds on Earth. Their intermittent appearance indicates a pattern associated with weather activity, and the lightning rate is at least half of that on Earth. Since Venus does not experience rainfall (except in the form of sulfuric acid), it has been theorized that the lightning is being caused by a volcanic eruption.
What is the weather like on Venus? Terrible, would be the short answer. The long answer is that it is extremely hot, the air pressure is extremely high, there are very strong winds, sulfuric acid rain (at higher altitudes) and lightning storms driven by volcanic eruptions. It is little wonder then why the only practical option for colonizing Venus involves creating floating cities above the cloud layer.
The canes venatici constellation, located in the northern skies in proximity to Bootes, Ursa Major and Coma Berenices. Credit: maps.seds.org
Welcome back to Constellation Friday! Today, in honor of the late and great Tammy Plotner, we will be dealing with Canes Venatici constellation.
In the 2nd century CE, Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy) compiled a list of the then-known 48 constellations. His treatise, known as the Almagest, would be used by medieval European and Islamic scholars for over a thousand years to come. Today, this list has been expanded to include the 88 constellations recognized by the IAU.
The small northern constellation of Canes Venatici represents the hunting dogs – Chara and Asterion – of Boötes. It is also one of three constellations that represent dogs, along with Canis Major and Canis Minor. Given its comparatively recent origin, there is no real mythology associated with this asterism. However, it does have an interesting history.
Canes Venatici depicted in Hevelius’s star atlas. Note that, per the conventions of the time, the image is mirrored. Credit: Wikipedia Commons/Atlas Coelestis
History of Observation:
During Classic Antiquity, the stars of Canes Venatici did not appear very brightly in the night sky. As such, they were listed by Ptolemy as unfigured stars below the constellation Ursa Major in the Almagest, rather than as a distinct constellation. During the Middle Ages, the identification of these stars as being the dogs of Boötes arose due to a mistranslation.
Some of the component stars in the nearby constellation of Boötes (which was known as the “herdsman”) were traditionally described as representing his cudgel. When the Almagest was translated from Greek to Arabic, the translator – the Arab astronomer Hunayn ibn Ishaq – did not know the Arabic word for cudgel.
As such, he chose the closest translation in Arabic – “al-`asa dhat al-kullab” -which literally means “the spearshaft having a hook” (possibly in reference to a shepherd’s crook). When the Arabic text was later translated into Latin, the translator mistook the Arabic word “kullab” for “kilab” – which means “dogs” – and wrote the name as hastile habens canes (“spearshaft having dogs”).
This representation of Boötes having two dogs remained popular and became official when, in 1687, Johannes Hevelius decided to designate them as a separate constellation. The northern of the two hunting dogs was named Asterion (‘little star’) while the southern dog was named Chara – from the Greek word for ‘joy’,.
Canes Venatici can be seen in the orientation they appear to the eyes in this 1825 star chart from Urania’s Mirror. Credit: Wikipedia Commons/Library of Congress
Notable Features:
The constellation’s brightest star is Cor Caroli, which is perhaps one of the most splendid of all colorful double stars. The name literally means “Charles’ heart”, and was named by Sir Charles Scarborough in honor of Charles I – who was executed in the aftermath of the English Civil War. The star is also associated with Charles II of England, who was restored to the throne after the interregnum following his father’s death.
Cor Caroli is a binary star with a combined apparent magnitude of 2.81 which marks the northern vertex of the Diamond of Virgo asterism. The two stars are 19.6 arc seconds apart and are easily resolved in small telescopes and steady binoculars. The system lies approximately 110 light years from Earth. It’s main star, a² Canum Venaticorum, is the prototype of a class of Spectral Type A0 variable stars (the so-called a² Canum Venaticorum stars).
These stars have a strong stellar magnetic field, which is believed to produce starspots of enormous extent. Due to these starspots, the brightness of a² Canum Venaticorum stars varies considerably during their rotation. Their brightness also varies between magnitude +2.84 and +2.98 with a period of 5.47 days. The companion, a¹ Canum Venaticorum (a spectral type F0 star), is considerably fainter at +5.5 magnitude.
Y CVn, “La Superba”, and a simulation of what it would look like close-up, created using Celestia. Credit: Wikipedia Commons/Kirk39
Next up is Y Canum Venaticorum (Y CVn), which was named “La Superba” by 19th century astronomer Angelo Secchi for its uncommonly beautiful red color. This name was certainly appropriate, since it is one of the reddest stars in the sky, and one the brightest of the giant red “carbon stars”.
La Superba is the brightest J-star in the sky, a very rare category of carbon stars that contain large amounts of carbon-13. Its surface temperature is believed to be about 2800 K (~2526 °C; 4580 °F), making it one of the coldest true stars known. Its appearance, temperature and composition are all indications that it is currently in the Red Giant phase of its life-cycle.
Y CVn is almost never visible to the naked eye since most of its output is outside the visible spectrum. Yet, when infrared radiation is considered, Y CVn has a luminosity 4400 times that of the Sun, and its radius is approximately 2 AU. If it were placed at the position of our sun, the star’s surface would extend beyond the orbit of Mars.
Canes Venatici is also home to several Deep Sky Objects. For starters, there’s the tremendous globular cluster known as Messier 3 (M3). Messier 3 has an apparent magnitude of 6.2, making it visible to the naked eye. It was first resolved into stars by William Herschel around 1784. This cluster is one of the largest and brightest, made up of around 500,000 stars, and is located about 33,900 light-years away from our solar system.
Messier 51, aka. the Whirlpool Galaxy, is a spiral nebula – a large galaxy with a well defined spiral structure located over 60,000 light-years across. Credit: NASA
Then there’s the Whirlpool Galaxy, also known as Messier 51 or NGC 5194. This interacting, grand-design spiral galaxy is located at a distance of approximately 23 million light-years from Earth. It is one of the most famous spiral galaxies in the night sky, for both its grace and beauty. The galaxy and its companion (NGC 5195) are easily observed by amateur telescopes, and the two galaxies may even be seen with larger binoculars.
Canes Venatici is also home of the Sunflower Galaxy (aka. Messier 63 and NGC 5055), an unbarred spiral galaxy consisting of a central galactic disc surrounded by many short spiral arm segments. It is part of the M51 galaxy group, which also includes the Whirlpool Galaxy (M51). In the mid-1800s, Lord Rosse identified the spiral structure within the galaxy, making this one of the first galaxies in which “spiral nebulae” were identified.
Now hop over to the barred spiral galaxy known as Messier 94 for some comparison. It was discovered by Pierre Méchain in 1781 and catalogued by Charles Messier two days later. Although some references describe M94 as a barred spiral galaxy, the “bar” structure appears to be more oval-shaped. The galaxy is also notable in that it has two ring structures, an inner ring with a diameter of 70″ and an outer ring with a diameter of 600″.
These rings appear to form at resonance locations within the disk of the galaxy. The inner ring is the site of strong star formation activity and is sometimes referred to as a starburst ring. This star formation is fueled by gas that is dynamically driven into the ring by the inner oval-shaped bar-like structure.
Messier 63, also known as the Sunflower Galaxy, seen here in an image from the Hubble Space Telescope. Credit: NASA/ESA/HST
For a completely different galaxy, try Messier 106 (NGC 4258). This spiral galaxy is about 22 to 25 million light-years away from Earth. It is also a Seyfert II galaxy, which means that due to x-rays and unusual emission lines detected, it is suspected that part of the galaxy is falling into a supermassive black hole in the center. Nearby NGC 4217 is a possible companion galaxy.
The constellation does not have any stars with known planets, and there is one meteor shower associated with the constellation – the Canes Venaticids.
Finding Canes Venatici:
While it basically consists of only two bright stars, the Canes Venatici constellation is still fairly easy to locate and is bordered by Ursa Major, Boötes and Coma Berenices. It can be spotted with the naked eye on a clear night where light conditions are favorable. However, for those using binoculars, finderscopes and small telescopes, the constellation has much to offer the amateur astronomer and stargazer.
The location of the Canes Venatici constellation. Credit: IAU/Sky&Telescope magazine
It’s brightest star, Cor Calroli can be found at RA 12h 56m 01.6674s Dec +38° 19′ 06.167″, while beautiful Y Canum Venaticorum (aka. “La Superba”) can be seen at RA 12f 45m 07s Dec +45° 26′ 24″. And M51 is easy to find by following the easternmost star of the Big Dipper, Eta Ursae Majoris, and going 3.5° southeast. Its declination is +47°, so it is circumpolar for observers located above 43°N latitude.
CERN visualization showing two electrons (green), one to two muons (red lines) resulting from a collision between two Z bosons. Credit: CERN
During the 19th and 20th centuries, physicists began to probe deep into the nature of matter and energy. In so doing, they quickly realized that the rules which govern them become increasingly blurry the deeper one goes. Whereas the predominant theory used to be that all matter was made up of indivisible atoms, scientists began to realize that atoms are themselves composed of even smaller particles.
From these investigations, the Standard Model of Particle Physics was born. According to this model, all matter in the Universe is composed of two kinds of particles: hadrons – from which Large Hadron Collider (LHC) gets its name – and leptons. Where hadrons are composed of other elementary particles (quarks, anti-quarks, etc), leptons are elementary particles that exist on their own.
Definition:
The word lepton comes from the Greek leptos, which means “small”, “fine”, or “thin”. The first recorded use of the word was by physicist Leon Rosenfeld in his book Nuclear Forces (1948). In the book, he attributed the use of the word to a suggestion made by Danish chemist and physicist Prof. Christian Moller.
The Standard Model of Particle Physics, showing all known elementary particles. Credit: Wikipedia Commons/MissMJ/PBS NOVA/Fermilab/Particle Data GroupThe term was chosen to refer to particles of small mass, since the only known leptons in Rosenfeld’s time were muons. These elementary particles are over 200 times more massive than electrons, but have only about one-ninth the the mass of a proton. Along with quarks, leptons are the basic building blocks of matter, and are therefore seen as “elementary particles”.
Types of Leptons:
According to the Standard Model, there are six different types of leptons. These include the Electron, the Muon, and Tau particles, as well as their associated neutrinos (i.e. electron neutrino, muon neutrino, and tau neutrino). Leptons have negative charge and a distinct mass, whereas their neutrinos have a neutral charge.
Electrons are the lightest, with a mass of 0.000511 gigaelectronvolts (GeV), while Muons have a mass of 0.1066 Gev and Tau particles (the heaviest) have a mass of 1.777 Gev. The different varieties of the elementary particles are commonly called “flavors”. While each of the three lepton flavors are different and distinct (in terms of their interactions with other particles), they are not immutable.
A neutrino can change its flavor, a process which is known as “neutrino flavor oscillation”. This can take a number of forms, which include solar neutrino, atmospheric neutrino, nuclear reactor, or beam oscillations. In all observed cases, the oscillations were confirmed by what appeared to be a deficit in the number of neutrinos being created.
Muons, a type of lepton, shown being produced by the Large Hadron Collider. Credit: CERN
One observed cause has to do with “muon decay” (see below), a process where muons change their flavor to become electron neutrinos or tau neutrinos – depending on the circumstances. In addition, all three leptons and their neutrinos have an associated antiparticle (antilepton).
For each, the antileptons have an identical mass, but all of the other properties are reversed. These pairings consist of the electron/positron, muon/antimuon, tau/antitau, electron neutrino/electron antineutrino, muon neutrino/muan antinuetrino, and tau neutrino/tau antineutrino.
The present Standard Model assumes that there are no more than three types (aka. “generations”) of leptons with their associated neutrinos in existence. This accords with experimental evidence that attempts to model the process of nucleosynthesis after the Big Bang, where the existence of more than three leptons would have affected the abundance of helium in the early Universe.
Properties:
All leptons possess a negative charge. They also possess an intrinsic rotation in the form of their spin, which means that electrons with an electric charge – i.e. “charged leptons” – will generate magnetic fields. They are able to interact with other matter only though weak electromagnetic forces. Ultimately, their charge determines the strength of these interactions, as well as the strength of their electric field and how they react to external electrical or magnetic fields.
None are capable of interacting with matter via strong forces, however. In the Standard Model, each lepton starts out with no intrinsic mass. Charged leptons obtain an effective mass through interactions with the Higgs field, while neutrinos either remain massless or have only very small masses.
History of Study:
The first lepton to be identified was the electron, which was discovered by British physicist J.J. Thomson and his colleagues in 1897 using a series of cathode ray tube experiments. The next discoveries came during the 1930s, which would lead to the creation of a new classification for weakly-interacting particles that were similar to electrons.
The first discovery was made by Austrian-Swiss physicist Wolfgang Pauli in 1930, who proposed the existence of the electron neutrino in order to resolve the ways in which beta decay contradicted the Conservation of Energy law, and Newton’s Laws of Motion (specifically the Conservation of Momentum and Conservation of Angular Momentum).
The positron and muon were discovered by Carl D. Anders in 1932 and 1936, respectively. Due to the mass of the muon, it was initially mistook for a meson. But due to its behavior (which resembled that of an electron) and the fact that it did not undergo strong interaction, the muon was reclassified. Along with the electron and the electron neutrino, it became part of a new group of particles known as “leptons”.
In 1962, a team of American physicists – consisting of Leon M. Lederman, Melvin Schwartz, and Jack Steinberger – were able to detect of interactions by the muon neutrino, thus showing that more than one type of neutrino existed. At the same time, theoretical physicists postulated the existence of many other flavors of neutrinos, which would eventually be confirmed experimentally.
The tau particle followed in the 1970s, thanks to experiments conducted by Nobel-Prize winning physicist Martin Lewis Perl and his colleagues at the SLAC National Accelerator Laboratory. Evidence of its associated neutrino followed thanks to the study of tau decay, which showed missing energy and momentum analogous to the missing energy and momentum caused by the beta decay of electrons.
In 2000, the tau neutrino was directly observed thanks to the Direct Observation of the NU Tau (DONUT) experiment at Fermilab. This would be the last particle of the Standard Model to be observed until 2012, when CERN announced that it had detected a particle that was likely the long-sought-after Higgs Boson.
Today, there are some particle physicists who believe that there are leptons still waiting to be found. These “fourth generation” particles, if they are indeed real, would exist beyond the Standard Model of particle physics, and would likely interact with matter in even more exotic ways.
For more information, SLAC’s Virtual Visitor Center has a good introduction to Leptons and be sure to check out the Particle Data Group (PDG) Review of Particle Physics.
Portrait of Giovanni Domenico Cassini, with the Paris Observatory in the background. Credit: Wikipedia Commons
During the Scientific Revolution, which took place between the 15th and 18th centuries, numerous inventions and discoveries were made that forever changed the way humanity viewed the Universe. And while this explosion in learning owed its existence to countless individuals, a few stand out as being especially worthy of praise and remembrance.
One such individual is Gionvanni Domenico Cassini, also known by his French name Jean-Dominique Cassini. An Italian astronomer, engineer, and astrologer, Cassini made many valuable contributions to modern science. However, it was his discovery of the gaps in Saturn’s rings and four of its largest moons for which he is most remembered, and the reason why the Cassini spacecraft bears his name.
Early Life and Education:
Giovanni Domenico Cassini was born on June 8th, 1625, in the small town of Perinaldo (near Nice, France) to Jacopo Cassini and Julia Crovesi. Educating by Jesuit scientists, he showed an aptitude for mathematics and astronomy from an early age. In 1648, he accepted a position at the observatory at Panzano, near Bologna, where he was employed by a rich amateur astronomer named Marquis Cornelio Malvasia.
During his time at the Panzano Observatory, Cassini was able to complete his education and went on to become the principal chair of astronomy at the University of Bologna by 1650. While there, he made several scientific contributions that would have a lasting mark.
La Meridiana, the meridian line calculated by Cassini while living in Bologna. Credit: Wikipedia Commons/Ilario/Cassinam
This included the calculation of an important meridian line, which runs along the left aisle of the San Petronio Basilica in Bologna. At 66.8 meters (219 ft) in length, it is one of the largest astronomical instruments in the worl and allowed for measurements that were (at the time) uniquely precise. This meridian also helped to settle the debate about whether or not the Universe was geocentric or heliocentric.
During his time in Italy, Cassini determined the obliquity of the Earth’s ecliptic – aka. it’s axial tilt, which he calculated to be 23° and 29′ at the time. He also studied the effects of refraction and the Solar parallax, worked on planetary theory, and observed the comets of 1664 and 1668.
In recognition of his engineering skills, Pope Clement IX employed Cassini with regard to fortifications, river management and flooding along the Po River in northern Italy. In 1663, Cassini was named superintendent of fortifications and oversaw the fortifying of Urbino. And in 1665, he was named the inspector for the town of Perugia in central Italy.
Paris Observatory:
In 1669, Cassini received an invitation by Louis XIV of France to move to Paris and help establish the Paris Observatory. Upon his arrival, he joined the newly-founded Academie Royale des Sciences (Royal Academy of Sciences), and became the first director of the Paris Observatory, which opened in 1671. He would remain the director of the observatory until his death in 1712.
An engraving of the Paris Observatory during Cassini’s time. Credit: Public Domain
In 1673, Cassini obtained his French citizenship and in the following year, he married Geneviève de Laistre, the daughter of the lieutenant general of the Comte de Clermont. During his time in France, Cassini spent the majority of his time dedicated to astronomical studies. Using a series of very long air telescopes, he made several discoveries and collaborated with Christiaan Huygens in many projects.
In the 1670s, Cassini began using the triangulation method to create a topographic map of France. It would not be completed until after his death (1789 or 1793), when it was published under the name Carte de Cassini. In addition to being the first topographical map of France, it was the first map to accurately measure longitude and latitude, and showed that the nation was smaller than previously thought.
In 1672, Cassini and his colleague Jean Richer made simultaneous observations of Mars (Cassini from Paris and Richer from French Guiana) and determined its distance to Earth through parallax. This enabled him to refine the dimensions of the Solar System and determine the value of the Astronomical Unit (AU) to within 7% accuracy. He and English astronomer Robert Hooke share credit for the discovery of the Great Red Spot on Jupiter (ca. 1665).
In 1683, Cassini presented an explanation for “zodiacal light” – the faint glow that extends away from the Sun in the ecliptic plane of the sky – which he correctly assumed to be caused by a cloud of small particles surrounding the Sun. He also viewed eight more comets before his death, which appeared in the night sky in 1672, 1677, 1698, 1699, 1702 (two), 1706 and 1707.
Illustration of Jupiter and the Galilean satellites. Credit: NASA
In ca. 1690, Cassini was the first to observe differential rotation within Jupiter’s atmosphere. He created improved tables for the positions of Jupiter’s Galilean moons, and discovered the periodic delays between the occultations of Jupiter’s moons and the times calculated. This would be used by Ole Roemer, his colleague at the Paris Observatory, to calculate the velocity of light in 1675.
In 1683, Cassini began the measurement of the arc of the meridian (longitude line) through Paris. From the results, he concluded that Earth is somewhat elongated. While in fact, the Earth is flattened at the poles, the revelation that Earth is not a perfect sphere was groundbreaking.
Cassini also observed and published his observations about the surface markings on Mars, which had been previously observed by Huygens but not published. He also determined the rotation periods of Mars and Jupiter, and his observations of the Moon led to the Cassini Laws, which provide a compact description of the motion of the Moon. These laws state that:
The Moon takes the same amount of time to rotate uniformly about its own axis asit takes to revolve around the Earth. As a consequence, the same face is always pointed towards Earth.
The Moon’s equator is tilted at a constant angle (about 1°32′ of arc) to the plane of the Earth’s orbit around the Sun (i.e. the ecliptic)
The point where the lunar orbit passes from south to north on the ecliptic (aka. the ascending node of the lunar orbit) always coincides with the point where the lunar equator passes from north to south on the ecliptic (the descending node of the lunar equator).
A collage of Saturn (bottom left) and some of its moons: Titan, Enceladus, Dione, Rhea and Helene. Credit: NASA/JPL/Space Science Institute
Thanks to his leadership, Giovanni Cassini was the first of four successive Paris Observatory directors that bore his name. This would include his son, Jaques Cassini (Cassini II, 1677-1756); his grandson César François Cassini (Cassini III, 1714-84); and his great grandson, Jean Dominique Cassini (Cassini IV, 1748-1845).
Observations of Saturn:
During his time in France, Cassini also made his famous discoveries of many of Saturn’s moons – Iapetus in 1671, Rhea in 167, and Tethys and Dione in 1684. Cassini named these moons Sidera Lodoicea (the stars of Louis), and correctly explained the anomalous variations in brightness to the presence of dark material on one hemisphere (now called Cassini Regio in his honor).
In 1675, Cassini discovered that Saturn’s rings are separated into two parts by a gap, which is now called the “Cassini Division” in his honor. He also theorized that the rings were composed of countless small particles, which was proven to be correct.
Death and Legacy:
After dedicating his life to astronomy and the Paris Observatory, Cassini went blind in 1711 and then died on September 14th, 1712, in Paris. And although he resisted many new theories and ideas that were proposed during his lifetime, his discoveries and contributions place him among the most important astronomers of the 17th and 18th centuries.
A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu
As a traditionalist, Cassini initially held the Earth to be the center of the Solar System. In time, he would come to accept the Solar Theory of Nicolaus Copernicus within limits, to the point that he accepted the model proposed by Tycho Brahe. However, he rejected the theory of Johannes Kepler that planets travel in ellipses and proposed hat their paths were certain curved ovals (i.e. Cassinians, or Ovals of Cassini)
Cassini also rejected Newton’s Theory of Gravity, after measurements he conducted which (wrongly) suggested that the Earth was elongated at its poles. After forty years of controversy, Newton’s theory was adopted after the measurements of the French Geodesic Mission (1736-1744) and the Lapponian Expedition in 1737, which showed that the Earth is actually flattened at the poles.
For his lifetime of work, Cassini has been honored in many ways by the astronomical community. Because of his observations of the Moon and Mars, features on their respective surfaces were named after him. Both the Moon and Mars have their own Cassini Crater, and Cassini Regio on Saturn’s moon Iapetus also bears his name.
Then there is Asteroid (24101) Cassini, which was discovered by C.W. Juels at in 1999 using the Fountain Hills Observatory telescope. Most recently, there was the joint NASA-ESA Cassini-Huygens missions which recently finished its mission to study Saturn and its moons. This robotic orbiter and lander mission was named in honor of the two astronomers who were chiefly responsible for discovering Saturn system of moons.
Artist’s impression of the Cassini space probe, part of the Cassini-Huygens mission to explore Saturn and its moons. Credit: NASA/JPL
In the end, Cassini’s passion for astronomy and his contributions to the sciences have ensured him a lasting place in the annals of history. In any discussion of the Scientific Revolution and of the influential thinkers who made it happen, his name appears alongside such luminaries as Copernicus, Galileo, and Newton.
Soviet Cosmonaut Valentina Tereshkova photographed inside the Vostok-6 spacecraft on June 16, 1963. Credit: Roscosmos
When it comes to the “Space Race” of the 1960s, several names come to mind. Names like Chuck Yeager, Yuri Gagarin, Alan Shepard, and Neil Armstrong, but to name a few. These men were all pioneers, braving incredible odds and hazards in order to put a man into orbit, on the Moon, and bring humanity into the Space Age. But about the first women in space?
Were the challenges they faced any less real? Or were they even more difficult considering the fact that space travel – like many professions at the time – was still thought to be a “man’s game”? Well, the first woman to break this glass ceiling was Valentina Tereshkova, a Soviet Cosmonaut who has the distinction of being the first woman ever to go into space as part of the Vostok 6 mission.
Early Life:
Tereshkova was born in the village of Maslennikovo in central Russia (about 280 km north-east of Moscow) after her parents migrated from Belarus. Her father was a tractor driver and her mother worked in a textile plant. Her father became a tank officer and died during the Winter War (1939-1940) when the Soviet Union invaded Finland over a territorial dispute.
Russian BT-5 tank destroyed during the Winter War (1939-1940). Credit: Wikipedia Commons/SA-kuva/Finnish Army Pictures
Between 1945 to 1953, Tereshkova went to school but dropped out when she was sixteen, and completed her education through correspondence. Following in her mother’s footsteps, she began working at a textile factory, where she remained until becoming part of the Soviet cosmonaut program.
She became interested in parachuting from a young age and trained in skydiving at the local Aeroclub. In 1959, at the age of 22, she made her first jump. It was her expertise in skydiving that led to her being selected as a cosmonaut candidate a few years later. In 1961, she became the secretary of the local Komsomol (Young Communist League) and later joined the Communist Party of the Soviet Union.
Vostok Program:
Much like Yuri Gagarin, Tereshkova took part in the Vostok program, which was the Soviet Unions’ first attempt at putting crewed missions into space. After the historic flight of Gagarin in 1961, Sergey Korolyov – the chief Soviet rocket engineer – proposed sending a female cosmonaut into space as well.
At the time, the Soviets believed that sending women into space would achieve a propaganda victory against the U.S., which maintained a policy of only using military and test pilots as astronauts. Though this policy did not specifically discriminate on the basis of gender, the lack of women combat and test pilots effectively excluded them from participating.
Valentina Tereshkova, pilot-cosmonaut, first female cosmonaut, Hero of the USSR. Pictured as a Major of the Soviet Air Forces. Credit: RIA Novosti/Alexander Mokletsov
In April 1962, five women were chosen for the program out of hundreds of potential candidates. These included Tatyana Kuznetsova, Irina Solovyova, Zhanna Yorkina, Valentina Ponomaryova, and Valentina Tereshkova. In order to qualify, the women needed to be parachutists under 30 years of age, under 170 cm (5’7″) in height, and under 70 kg (154 lbs.) in weight.
Along with four colleagues, Tereshkova spent several months in training. This included weightless flights, isolation tests, centrifuge tests, rocket theory, spacecraft engineering, parachute jumps, and pilot training in jet aircraft. Their examinations concluded in November 1962, after which Tereshkova and Ponomaryova were considered the leading candidates.
A joint mission profile was developed that would see two women launched into space on separate Vostok missions in March or April of 1963. Tereshkova, then 25, was chosen to be the first woman to go into space, for multiple reasons. First, there was the fact that she conformed to the height and weight specifications to fit inside the relatively cramped Vostok module.
Second, she was a qualified parachutist, which given the nature of the Vostok space craft (the re-entry craft was incapable of landing) was absolutely essential. The third, and perhaps most important reason, was her strong “proletariat” and patriotic background, which was evident from her family’s work and the death of her father (Vladimir Tereshkova) during the Second World War.
The Vostok 6 capsule at the Science Museum, London. Credit: Wikipedia Commons/Andrew Grey
Originally, the plan was for Tereshkova to launch first in the Vostok 5 ship while Ponomaryova would follow her into orbit in Vostok 6. However, this flight plan was altered in March 1963, with a male cosmonaut flying Vostok 5 while Tereshkova would fly aboard Vostok 6 in June 1963. After watching the successful launch of Vostok 5 on 14 June, Tereshkova (now 26) began final preparations for her own flight.
Launch:
Tereshkova’s Vostok 6 flight took place on the morning of June 16th, 1963. After performing communications and life support checks, she was sealed inside the capsule and the mission’s two-hour countdown began. The launch took place at 09:29:52 UTC with the rocket lifting off faultlessly from the Baikonur launchpad.
During the flight – which lasted for two days and 22 hours – Tereshkova orbited the Earth forty-eight times. Her flight took place only two days after Vostok 5 was launched, piloted by Valery Bykovsky, and orbited the Earth simultaneously with his craft. In the course of her flight, ground crews collected data on her body’s reaction to spaceflight.
Aside from some nausea (which she later claimed was due to poor food!) she maintained herself for the full three days. Like other cosmonauts on Vostok missions, she kept a flight log and took photographs of the horizon – which were later used to identify aerosol layers within the atmosphere – and manually oriented the spacecraft.
First woman in space Soviet cosmonaut Valentina Tereshkova is seen during a training session aboard a Vostok spacecraft simulator on January 17, 1964. Credit: AFP Photo / RIA Novosti
On the first day of her mission, she reported an error in the control program, which made the spaceship ascend from orbit instead of descending. The team on Earth provided Tereshkova with new data to enter into the descent program which corrected the problem. After completing 48 orbits, her craft began descending towards Earth.
Once the craft re-entered the atmosphere, Tereshkova ejected from the capsule and parachuted back to earth. She landed hard after a high wind blew her off course, which was fortunate since she was descending towards a lake at the time. However, the landing caused her to seriously bruise her face, and heavy makeup was needed for the public appearances that followed.
Vostok 6 would be the last of the Vostok missions, despite there being plans for further flights involving women cosmonauts. None of the other four in Tereshkova’s early group got a chance to fly, and, in October of 1969, the pioneering female cosmonaut group was dissolved. It would be 19 years before another woman would fly as part of the Soviet space program – Svetlana Savitskaya, who flew as part of the Soyuz T-7 mission.
After Vostok 6:
After returning home, certain elements within the Soviet Air Force attempted to discredit Tereshkova. There were those who said that she was drunk when she reported to the launch pad and was insubordinate while in orbit. These charges appeared to be related to the sickness she experienced while in space, and the fact that she issued corrections to the ground control team – which was apparently seen as a slight.
Nikita Khrushchev, Valentina Tereshkova, Pavel Popovich and Yury Gagarin at Lenin Mausoleum on June 22nd, 1963. Credit: Wikipedia Commons/RIA Novosti Archive
She was also accused of drunken and disorderly conduct when confronting a militia Captain in Gorkiy. However, General Nikolai Kamanin – the head of cosmonaut training in the Soviet space program at the time – defended Tereshkova’s character and dismissed her detractors instead. Tereshkova’s reputation remained unblemished and she went on to become a cosmonaut engineer and spent the rest of her life in key political positions.
In November of 1963, Tereshkova married Andrian Nikolayev, another Soviet cosmonaut, at a wedding that took place at the Moscow Wedding Palace. Khrushchev himself presided, with top government and space program leaders in attendance. In June of 1964, she gave birth to their daughter Elena Andrianovna Nikolaeva-Tereshkova, who became the first person in history to have both a mother and father who had traveled into space.
She and Nikolayev divorced in 1982, and Nikolayev died in 2004. She went on to remarry an orthopaedist named Yuliy G. Sharposhnikov, who died in 1999. After her historic flight, Tereshkova enrolled at the Zhukovsky Air Force Academy and graduated with distinction as a cosmonaut engineer. In 1977, she earned her doctorate in engineering.
Her fame as a cosmonaut also led to several key political positions. Between 1966 and 1974, she was a member of the Supreme Soviet of the Soviet Union. She was also a member of the Presidium of the Supreme Soviet from 1974 to 1989, and a Central Committee Member from 1969 to 1991. Her accomplishments also led to her becoming a representative of the Soviet Union abroad.
The wedding ceremony of pilot-cosmonauts Valentina Tereshkova and Andriyan Nikolayev, Nov. 3rd, 1963. Credit: RIA Novosti Archive/Alexander Mokletsov
After the collapse of the Soviet Union, Tereshkova lost her political office but remained an important public figure. To this day, she is revered as a hero and a major contributor to the Russian space program. In 2011, she was elected to the State Duma (the lower house of the Russian legislature) where she continues to serve.
In 2008, Tereshkova was invited to Prime Minister Vladimir Putin’s residence in Novo-Ogaryovo for the celebration of her 70th birthday. In that same year, she became a torchbearer of the 2008 Summer Olympics torch relay in Saint Petersburg, Russia. She has also expressed interest in traveling to Mars, even if it were a one-way trip.
Legacy and Honors:
For her accomplishments, Tereshkova has received many honors and awards. She has been decorated with the Hero of the Soviet Union medal (the USSR’s highest award) as well as the Order of Lenin, the Order of the October Revolution, and many other medals.
Foreign governments have also awarded her with the Karl Marx Order, the Hero of Socialist Labor of Czechoslovakia, the Hero of Labor of Vietnam, the Hero of Mongolia, the UN Gold Medal of Peace, and the Simba International Women’s Movement Award. She has honorary citizenship in multiple cities from Bulgaria, Slovakia, Belarus and Mongolia in the east, to Switzerland, France, and the UK in the west.
Commemorative Hungarian stamp featuring Soviet cosmonauts Valentina Tereshkova and Andrian G. Nikolayev (her husband). Credit: Wikipedia Commons/Darjac
Due to her pioneering role in space exploration, a number of astronomical objects and features are named in her honor. For example, the Tereshkova crater on the far side of the Moon was named after her. The minor planet 1671 Chaika (which translates to “Seagull” in Russian) is named in honor of her Vostok 6 mission call sign.
Numerous monuments and statues have been erected in her honor and the Monument to the Conquerors of Space in Moscow features her image. Streets all across the former Soviet Union and Eastern Bloc nations were renamed in her honor, as was the school in Yaroslavl where she studied as a child. The Yaroslavl Planetarium, built in 2011, was created in her honor, and the Museum of V.V. Tereshkova – Cosmos exists near her native village of Maslennikovo.
The Space Age was a time of truly amazing accomplishments. Not only did astronauts like Tereshkova break the surly bonds of Earth, but they also demonstrated that space exploration knows no gender restrictions. And though it would be decades before people like Svetlana Savitskaya and Sally Ride would into space, Tereshkova will forever be remembered as the woman who blazed the trail for all female astronauts.
When we do finally learn the full truth about our place in the galaxy, and we’re invited to join the Galactic Federation of Planets, I’m sure we’ll always be seen as a quaint backwater world orbiting a boring single star.
The terrifying tentacle monsters from the nightmare tentacle world will gurgle horrifying, but clearly condescending comments about how we’ve only got a single star in the Solar System.
The beings of pure energy will remark how only truly enlightened civilizations can come from systems with at least 6 stars, insulting not only humanity, but also the horrifying tentacle monsters, leading to another galaxy spanning conflict.
Yes, we’ll always be making up for our stellar deficit in the eyes of aliens, or whatever those creepy blobs use for eyes.
What we lack in sophistication, however, we make up in volume. In our Milky Way, fully 2/3rds of star systems only have a single star. The last 1/3rd is made up of multiple star systems.
The Milky Way as seen from Devil’s Tower, Wyoming. Image Credit: Wally Pacholka
We’re taking binary stars, triple star systems, even exotic 7 star systems. When you mix and match different types of stars in various Odd Couple stellar apartments, the results get interesting.
Consider our own Solar System, where the Sun and planets formed together out a cloud of gas and dust. Gravity collected material into the center of the Solar System, becoming the Sun, while the rest of the disk spun up faster and faster. Eventually our star ignited its fusion furnace, blasting out the rest of the stellar nebula.
But different stellar nebulae can lead to the formation of multiple stars instead. What you get depends on the mass of the cloud, and how fast it’s rotating.
Check out this amazing photograph of a multiple star system forming right now.
ALMA image of the L1448 IRS3B system, with two young stars at the center and a third distant from them. Spiral structure in the dusty disk surrounding them indicates instability in the disk, astronomers said. Credit: Bill Saxton, ALMA (ESO/NAOJ/NRAO), NRAO/AUI/NSF
In this image, you can see three stars forming together, two at the center, about 60 astronomical units away from each other (60 times the distance from the Earth to the Sun), and then a third orbiting 183 AU away.
It’s estimated these stars are only 10,000 to 20,000 years old. This is one of the most amazing astronomy pictures I ever seen.
When you have two stars, that’s a binary system. If the stars are similar in mass to each other, then they orbit a common point of mass, known as the barycenter. If the stars are different masses, then it can appear that one star is orbiting the other, like a planet going around a star.
When you look up in the sky, many of the single stars you see are actually binary stars, and can be resolved with a pair of binoculars or a small telescope. For example, in a good telescope, Alpha Centauri can be resolved into two equally bright stars, with the much dimmer Proxima Centauri hanging out nearby.
The two bright stars are (left) Alpha Centauri and (right) Beta Centauri. The faint red star in the center of the red circle is Proxima Centauri. Credit: Skatebiker at English Wikipedia (CC BY-SA 3.0)
You have to be careful, though, sometimes stars just happen to be beside each other in the sky, but they’re not actually orbiting one another – this is known as an optical binary. It’s a trap.
Astronomers find that you can then get binary stars with a third companion orbiting around them. As long as the third star is far enough away, the whole system can be stable. This is a triple star system.
You can get two sets of binary stars orbiting each other, for a quadruple star system.
In fact, you can build up these combinations of stars up. For example, the star system Nu Scorpii has 7 stars in a single system. All happily orbiting one another for eons.
If stars remained unchanging forever, then this would be the end of our story. However, as we’ve discussed in other articles, stars change over time, bloating up as red giants, detonating as supernovae and turning into bizarre objects, like white dwarfs, neutron stars and even black holes. And when these occur in multiple star systems, well, watch the sparks fly.
There are a nearly infinite combinations you can have here: main sequence, red giant, white dwarf, neutron star, and even black holes. I don’t have time to go through all the combinations, but here are some highlights.
VFTS 352 is the hottest and most massive double star system to date where the two components are in contact and sharing material. ESO/L. Calçada
For starters, binary stars can get so close they actually touch each other. This is known as a contact binary, where the two stars actually share material back and forth. But it gets even stranger.
When a main sequence star like our Sun runs out of hydrogen fuel in its core, it expands as a red giant, before cooling and becoming a white dwarf.
When a red giant is in a binary system, the distance and evolution of its stellar companion makes all the difference.
If the two stars are close enough, the red giant can pass material over to the other star. And if the red giant is large enough, it can actually engulf its companion. Imagine our Sun, orbiting within the atmosphere of a red giant star. Needless to say, that’s not healthy for any planets.
An even stranger contact binary happens when a red giant consumes a binary neutron star. This is known as a Thorne-Zytkow object. The neutron star spirals inward through the atmosphere of the red giant. When it reaches the core, it either becomes a black hole, gobbling up the red giant from within, or an even more massive neutron star. This is exceedingly rare, and only one candidate object has ever been observed.
A white dwarf accreting material from a companion star. Credit: NASA/CXC/M. Weiss
When a binary pair is a white dwarf, the dead remnant of a star like our Sun, then material can transfer to the surface of the white dwarf, causing novae explosions. And if enough material is transferred, the white dwarf explodes as a Type 1A supernova.
If you’re a star that was unlucky enough to be born beside a very massive star, you can actually kicked off into space when it explodes as a supernova. In fact, there are rogue stars which such a kick, they’re on an escape trajectory from the entire galaxy, never to return.
If you have two neutron stars in a binary pair, they release energy in the form of gravitational waves, which causes them to lose momentum and spiral inward. Eventually they collide, becoming a black hole, and detonating with so much energy we can see the explosions billions of light-years away – a short-period gamma ray burst.
The combinations are endless.
How Earth could look with two suns. Credit: NASA/JPL-Caltech/Univ. of Ariz.
It’s amazing to think what the night sky would look like if we were born into a multiple star system. Sometimes there would be several stars in the sky, other times just one. And rarely, there would be an actual night.
How would life be different in a multiple star system? Let me know your thoughts in the comments.
In our next episode, we try to untangle this bizarre paradox. If the Universe is infinite, how did it start out as a singularity? That doesn’t make any sense.
We glossed over it in this episode, but one of the most interesting effects of multiple star systems are novae, explosions of stolen material on the surface of a white dwarf star. Learn more about it in this video.
Messier 28, Messier 22 and Kaus Borealis. Credit: Wikisky
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Globular Cluster known as Messier 28. Enjoy!
Back in the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list would come to include 100 of the most fabulous objects in the night sky.
One of these objects was the globular cluster now known as Messier 28. Located in the direction of the Sagittarius constellation, some 17,900 light-years from Earth, this “nebulous” cluster is easily detectable in the night sky. It is also the third largest known clustering of millisecond pulsars in the known Universe.
Description:
Compressed into a sphere measuring about 60 light years in diameter, globular star cluster Messier 28 happily orbits our galactic center about 19,000 light years away from Earth. In all of its thousands upon thousands of stars, M28 contains 18 known RR Lyrae variables and a W Virginis variable star. This very different variable is a Type II, or population II Cepheid that has a precise change rate which occurs every 17 days.
Image of Messier 28, based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive. Credit: STScI/NASA/ST-EFC/ESA/CADC/NRC/CSA
There has also been a second long period variable discovered, which could very well be an RV Tauri type, too. However, one of M28’s biggest claims to fame happened in 1986, when it became the first globular cluster known to contain a millisecond pulsar. This was discovered by the Lovell Telescope at Jodrell Bank Observatory. The work on the pulsar was later picked up by Chandra researchers.
As Martin C. Weisskopf (et al) of the Space Sciences Department put it in a 2002 study of the object:
“We report here the results of the first Chandra X-Ray Observatory observations of the globular cluster M28 (NGC 6626). We detect 46 X-ray sources of which 12 lie within one core radius of the center. We measure the radial distribution of the X-ray sources and fit it to a King profile finding a core radius. We measure for the first time the unconfused phase-averaged X-ray spectrum of the 3.05-ms pulsar B1821–24 and find it is best described by a power law with photon index. We find marginal evidence of an emission line centered at 3.3 keV in the pulsar spectrum, which could be interpreted as cyclotron emission from a corona above the pulsar’s polar cap if the magnetic field is strongly different from a centered dipole. We present a spectral analyses of the brightest unidentified source and suggest that it is a transiently accreting neutron star in a low-mass X-ray binary, in quiescence. In addition to the resolved sources, we detect fainter, unresolved X-ray emission from the central core.”
And the search has far from ended as even more X-ray counterparts have been discovered inside this seemingly quiet globular cluster! As W. Becker and C.Y. Hui of the Max Planck Institute wrote in their 2007 study:
“A recent radio survey of globular clusters has increased the number of millisecond pulsars drastically. M28 is now the globular cluster with the third largest population of known pulsars, after Terzan 5 and 47 Tuc. This prompted us to revisit the archival Chandra data on M28 to evaluate whether the newly discovered millisecond pulsars find a counterpart among the various X-ray sources detected in M28 previously. The radio position of PSR J1824-2452H is found to be in agreement with the position of CXC 182431-245217 while some faint unresolved X-ray emission near to the center of M28 is found to be coincident with the millisecond pulsars PSR J1824-2452G, J1824-2452J, J1824-2452I and J1824-2452E.”
The globular cluster Messier 28, image by the Hubble Space Telescope. Credit: NASA/ESA/HST
“We have analyzed archival HST/WFPC2 images in both the F555W & F814W bands of the core field of the globular cluster M 28 in an attempt to identify the optical counterpart of the magnetospherically active millisecond pulsar PSR B1821-24. Examination of the radio derived error circle yielded several potential candidates, down to a magnitude of V 24.5 (V0 23.0). Each were further investigated, both in the context of the CMD of M 28, and also with regard to phenomenological models of pulsar magnetospheric emission. The latter was based on both luminosity-spindown correlations and known spectral flux density behaviour in this regime from the small population of optical pulsars observed to date. None of the potential candidates exhibited emission expected from a magnetospherically active pulsar. The fact that the magnetic field & spin coupling for PSR B1821-24 is of a similar magnitude to that of the Crab pulsar in the vicinity of the light cylinder has suggested that the millisecond pulsar may well be an efficient nonthermal emitter. ASCA’s detection of a strong synchrotron-dominated X-ray pulse fraction encourages such a viewpoint. We argue that only future dedicated 2-d high speed photometry observations of the radio error-circle can finally resolve this matter.”
History of Observation:
This globular cluster was an original discovery in July 1764 of Charles Messier who wrote in his notes:
“In the night of the 26th to the 27th of the same month, I have discovered a nebula in the upper part of the bow of Sagittarius, at about 1 degree from the star Lambda of that constellation, and little distant from the beautiful nebula which is between the head and the bow: that new one may be the third of the older one, and doesn’t contain any star, as far as I have been able to judge when examining it with a good Gregorian telescope which magnifies 104 times: it is round, its diameter is about 2 minutes of arc; one sees it with difficulty with an ordinary refractor of 3 feet and a half of length. I have compared the middle with the star Lambda Sagittarii, and I have concluded its right ascension of 272d 29′ 30″, and its declination of 37d 11′ 57″ south.”
As always, Sir William Herschel would often revisit with Messier’s objects for his own private observations and in his notes he states:
“It may be called insulated though situated in a part of the heavens that is very rich in stars. It may have a nucleus, for it is much compressed towards the centre, and the situation is too low for seeing it well. The stars of the cluster are pretty numerous.” It would be his son, John Herschel who would give M28 its New General Catalog Number and describe it as “Not very bright; but very rich, excessively compressed globular cluster; stars of 14th to 15th magnitude; much brighter toward the middle; a fine object.”
The location of Messier 28, in the direction of the Sagittarius Constellation. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
Regardless of whether or not you use binoculars or a telescope on M28, part of the joy of this object is understand how very rich the stellar field is in which it appears. As John Herschel once said of M28 in his many observations, “Occurs in the milky way, of which the stars here are barely visible and immensely numerous.”
Locating Messier 28:
Finding M28 is another easy object once you’ve familiarized yourself with the “teapot” asterism of the constellation of Sagittarius. In binoculars, simply center Lambda in the field of view and you will see Messier 28 as a small, faded grey circular area in the 1:00 position away from the marker star.
In the finderscope of telescope, you can start by centering on Lambda and go to the eyepiece and simply shift the telescope to the northwest slowly and Messier 28 will pop into view. While this globular cluster is easily bright enough to be seen in the smallest of optics, it will require at least a 4″ telescope before it begins any resolution of individual stars and telescopes in the 10″ and larger range will fully appreciate all it has to offer.
And here are the quick facts to help you get started:
Object Name: Messier 28 Alternative Designations: M28, NGC 6626 Object Type: Class IV Globular Cluster Constellation: Sagittarius Right Ascension: 18 : 24.5 (h:m) Declination: -24 : 52 (deg:m) Distance: 18.3 (kly) Visual Brightness: 6.8 (mag) Apparent Dimension: 11.2 (arc min)
Image of the "Face of Mars" by the Mars Reconnaissance Orbiter, with the Viking 1 image inset (bottom right). Credit: NASA/JPL
The surface of Mars has been the subject of fascination for centuries. Even sinceGiovanni Schiaparelli first announced that he had observed the “Martian Canals” in 1877, the Red Planet has been a source of endless speculation. Even today, crystal-clear images sent directly from the surface by rovers are still the subject of pareidolia – where people see familiar patterns in random features.
Nowhere has this tendency of seeing what we want to see on the surface of Mars been made more clean than with the Cydonia region. Located in the northern hemisphere, this region of Mars is known for its many interesting land forms. The most famous of these is the “Face of Mars”, which has attracted immense scientific and popular curiosity over the past few decades.
Location:
The area called Cydonia is in the northern hemisphere of Mars, in between the heavily cratered regions of the south (the Arabia Terra highlands) and the smooth plains to the north (Acidalia Planitia). The area includes the regions of flat-topped mesa-like featured (“Cydonia Mensae”), a region of small hills or knobs, (“Cydonia Colles”) and a complex of intersecting valleys (“Cydonia Labyrinthus”).
Image of the Cydonia region under infrared light taken by the Viking 1 orbiter. Credit: NASA/JPL
Because of its geographical location, it is possible that Cydonia was once a coastal plain region, billions of years ago when the northern hemisphere of Mars is believed to have been covered with water. The name – like many featured on Mars – is drawn from classical antiquity; in this case, from the historic city-state of Kydonia, which was located on the island of Crete.
Exploration:
Cydonia was first photographed by the Viking 1 and 2 orbiters. Between the two, eighteen images were taken of the region, all of which were of limited resolution. Of these, only five were considered suitable for studying surface features. Because of their limited quality, a particular mesa resembled a humanoid face (see below).
It would be another 20 years before other spacecraft photographed the region as they conducted observations of Mars. These included NASA’s Mars Global Surveyor, which orbited Mars from 1997 to 2006; the Mars Reconnaissance Orbiter (MRO), which reached the planet in 2006 and is still in operation; and the ESA’s Mars Express probe – which has been in orbit since 2003.
Each of these missions provided images of Cydonia which were much better in terms of resolution and debunked the existence of an artificial “Face of Mars” feature. After analyzing images taken by the Mars Global Surveyor, NASA declared that “a detailed analysis of multiple images of this feature reveals a natural looking Martian hill whose illusory face-like appearance depends on the viewing angle and angle of illumination”.
A section of the Cydonia region, taken by the Viking 1 orbiter and released on July 25, 1976. Credit: NASA/JPL
Notable Features:
As already noted, Cydonia’s best known feature is the famous “Face of Mars“. This 2 km long mesa, which was first photographed by the Viking 1 orbiter on July 25th, 1976, initially was thought to resemble a human face. At the time, the NASA science team dismissed this as a “trick of light and shadow”. But a second image, acquired 35 orbits later at a different angle, confirmed the existence of the “Face of Mars”.
Vincent DiPietro and Gregory Molenaar, two computer engineers at NASA’s Goddard Space Flight Center, independently discovered this image while searching through the NASA archives. From 1982 onward, these images would lead widespread speculation about what could have caused it, and fueled interest in the possible existence of a civilization on Mars.
In addition, DiPeitro and Molenaar noticed several mountains near the “Face” that had angular peaks, which they referred to as “pyramids“. One in particular, a 500 meter-tall mountain located to the south-west, was especially geometric in shape. Richard Hoagland, a famous conspiracy theorist, dubbed it the “D&M Pyramid” (in honor of DiPietro and Molenaar), a name which stuck.
Last, but not least, there is also the area to the north of the “Face” that was dubbed “the city”, because of its supposed resemblance to a series of monuments. These consisted predominately of more ‘pyramids’ that are arranged in a circular pattern around a series of smaller rocky features, known as the “City Square” (see below).
Mosaic created from images taken by the Viking orbiter, showing landforms in Cydonia with popular, informal names. Credit: NASA/JPL
Later images provided by the Mars Global Surveyor, the MRO and the Mars Express all resolved these features with far greater accuracy, showing them to be natural features with no evidence of construction of manipulation. In all cases, psychologists indicated that the desire to see familiar shapes and patterns was an example of pareidolia.
As for the Cydonia region, future missions to the planet may take an interest in exploring it further. However, this will most likely to get a better understanding of the regions past and see it was indeed a coastal region at one time. There will be NO attempts to search for signs of ziggurats, pyramids, ancient sarcophagi, or any other indications of a lost civilization.
We’ve covered the Fermi Paradox many times over several articles on Universe Today. This is the idea that the Universe is huge, and old, and the ingredients of life are everywhere. Life could and should have have appeared many times across the galaxy, but it’s really strange that we haven’t found any evidence for them yet.
Today, CERN announced that the LHCb experiment had revealed the existence of two new baryon subatomic particles. Credit: CERN/LHC/GridPP
What if it were possible to observe the fundamental building blocks upon which the Universe is based? Not a problem! All you would need is a massive particle accelerator, an underground facility large enough to cross a border between two countries, and the ability to accelerate particles to the point where they annihilate each other – releasing energy and mass which you could then observe with a series of special monitors.
Well, as luck would have it, such a facility already exists, and is known as the CERN Large Hardron Collider (LHC), also known as the CERN Particle Accelerator. Measuring roughly 27 kilometers in circumference and located deep beneath the surface near Geneva, Switzerland, it is the largest particle accelerator in the world. And since CERN flipped the switch, the LHC has shed some serious light on some deeper mysteries of the Universe.
Purpose:
Colliders, by definition, are a type of a particle accelerator that rely on two directed beams of particles. Particles are accelerated in these instruments to very high kinetic energies and then made to collide with each other. The byproducts of these collisions are then analyzed by scientists in order ascertain the structure of the subatomic world and the laws which govern it.
The Large Hadron Collider is the most powerful particle accelerator in the world. Credit: CERN
The purpose of colliders is to simulate the kind of high-energy collisions to produce particle byproducts that would otherwise not exist in nature. What’s more, these sorts of particle byproducts decay after very short period of time, and are are therefor difficult or near-impossible to study under normal conditions.
The term hadron refers to composite particles composed of quarks that are held together by the strong nuclear force, one of the four forces governing particle interaction (the others being weak nuclear force, electromagnetism and gravity). The best-known hadrons are baryons – protons and neutrons – but also include mesons and unstable particles composed of one quark and one antiquark.
Design:
The LHC operates by accelerating two beams of “hadrons” – either protons or lead ions – in opposite directions around its circular apparatus. The hadrons then collide after they’ve achieved very high levels of energy, and the resulting particles are analyzed and studied. It is the largest high-energy accelerator in the world, measuring 27 km (17 mi) in circumference and at a depth of 50 to 175 m (164 to 574 ft).
The tunnel which houses the collider is 3.8-meters (12 ft) wide, and was previously used to house the Large Electron-Positron Collider (which operated between 1989 and 2000). This tunnel contains two adjacent parallel beamlines that intersect at four points, each containing a beam that travels in opposite directions around the ring. The beam is controlled by 1,232 dipole magnets while 392 quadrupole magnets are used to keep the beams focused.
Superconducting quadrupole electromagnets are used to direct the beams to four intersection points, where interactions between accelerated protons will take place.Credit: Wikipedia Commons/gamsiz
About 10,000 superconducting magnets are used in total, which are kept at an operational temperature of -271.25 °C (-456.25 °F) – which is just shy of absolute zero – by approximately 96 tonnes of liquid helium-4. This also makes the LHC the largest cryogenic facility in the world.
When conducting proton collisions, the process begins with the linear particle accelerator (LINAC 2). After the LINAC 2 increases the energy of the protons, these particles are then injected into the Proton Synchrotron Booster (PSB), which accelerates them to high speeds.
They are then injected into the Proton Synchrotron (PS), and then onto the Super Proton Synchrtron (SPS), where they are sped up even further before being injected into the main accelerator. Once there, the proton bunches are accumulated and accelerated to their peak energy over a period of 20 minutes. Last, they are circulated for a period of 5 to 24 hours, during which time collisions occur at the four intersection points.
During shorter running periods, heavy-ion collisions (typically lead ions) are included the program. The lead ions are first accelerated by the linear accelerator LINAC 3, and the Low Energy Ion Ring (LEIR) is used as an ion storage and cooler unit. The ions are then further accelerated by the PS and SPS before being injected into LHC ring.
While protons and lead ions are being collided, seven detectors are used to scan for their byproducts. These include the A Toroidal LHC ApparatuS (ATLAS) experiment and the Compact Muon Solenoid (CMS), which are both general purpose detectors designed to see many different types of subatomic particles.
Then there are the more specific A Large Ion Collider Experiment (ALICE) and Large Hadron Collider beauty (LHCb) detectors. Whereas ALICE is a heavy-ion detector that studies strongly-interacting matter at extreme energy densities, the LHCb records the decay of particles and attempts to filter b and anti-b quarks from the products of their decay.
CERN, which stands for Conseil Européen pour la Recherche Nucléaire (or European Council for Nuclear Research in English) was established on Sept 29th, 1954, by twelve western European signatory nations. The council’s main purpose was to oversee the creation of a particle physics laboratory in Geneva where nuclear studies would be conducted.
Illustration showing the byproducts of lead ion collisions, as monitored by the ATLAS detector. Credit: CERN
Soon after its creation, the laboratory went beyond this and began conducting high-energy physics research as well. It has also grown to include twenty European member states: France, Switzerland, Germany, Belgium, the Netherlands, Denmark, Norway, Sweden, Finland, Spain, Portugal, Greece, Italy, the UK, Poland, Hungary, the Czech Republic, Slovakia, Bulgaria and Israel.
Construction of the LHC was approved in 1995 and was initially intended to be completed by 2005. However, cost overruns, budget cuts, and various engineering difficulties pushed the completion date to April of 2007. The LHC first went online on September 10th, 2008, but initial testing was delayed for 14 months following an accident that caused extensive damage to many of the collider’s key components (such as the superconducting magnets).
On November 20th, 2009, the LHC was brought back online and its First Run ran from 2010 to 2013. During this run, it collided two opposing particle beams of protons and lead nuclei at energies of 4 teraelectronvolts (4 TeV) and 2.76 TeV per nucleon, respectively. The main purpose of the LHC is to recreate conditions just after the Big Bang when collisions between high-energy particles was taking place.
Major Discoveries:
During its First Run, the LHCs discoveries included a particle thought to be the long sought-after Higgs Boson, which was announced on July 4th, 2012. This particle, which gives other particles mass, is a key part of the Standard Model of physics. Due to its high mass and elusive nature, the existence of this particle was based solely in theory and had never been previously observed.
The discovery of the Higgs Boson and the ongoing operation of the LHC has also allowed researchers to investigate physics beyond the Standard Model. This has included tests concerning supersymmetry theory. The results show that certain types of particle decay are less common than some forms of supersymmetry predict, but could still match the predictions of other versions of supersymmetry theory.
In May of 2011, it was reported that quark–gluon plasma (theoretically, the densest matter besides black holes) had been created in the LHC. On November 19th, 2014, the LHCb experiment announced the discovery of two new heavy subatomic particles, both of which were baryons composed of one bottom, one down, and one strange quark. The LHCb collaboration also observed multiple exotic hadrons during the first run, possibly pentaquarks or tetraquarks.
Since 2015, the LHC has been conducting its Second Run. In that time, it has been dedicated to confirming the detection of the Higgs Boson, and making further investigations into supersymmetry theory and the existence of exotic particles at higher-energy levels.
The ATLAS detector, one of two general-purpose detectors at the Large Hadron Collider (LHC). Credit: CERN
In the coming years, the LHC is scheduled for a series of upgrades to ensure that it does not suffer from diminished returns. In 2017-18, the LHC is scheduled to undergo an upgrade that will increase its collision energy to 14 TeV. In addition, after 2022, the ATLAS detector is to receive an upgrade designed to increase the likelihood of it detecting rare processes, known as the High Luminosity LHC.
The collaborative research effort known as the LHC Accelerator Research Program (LARP) is currently conducting research into how to upgrade the LHC further. Foremost among these are increases in the beam current and the modification of the two high-luminosity interaction regions, and the ATLAS and CMS detectors.
Who knows what the LHC will discover between now and the day when they finally turn the power off? With luck, it will shed more light on the deeper mysteries of the Universe, which could include the deep structure of space and time, the intersection of quantum mechanics and general relativity, the relationship between matter and antimatter, and the existence of “Dark Matter”.
![The Standard Model of Elementary Particles. Image: By MissMJ - Own work by uploader, PBS NOVA [1], Fermilab, Office of Science, United States Department of Energy, Particle Data Group, CC BY 3.0](https://www.universetoday.com/wp-content/uploads/2016/05/Standard_Model_of_Elementary_Particles.svg_.png)
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