Comet Finlay in Bright Outburst, Visible in Small Telescopes

Comet Finlay on December 16th showing a bright coma and short tail. Credit: FRAM team

Short-period comet 15P/Finlay, which had been plunking along at a dim magnitude +11, has suddenly brightened in the past couple days to +8.7, bright enough to see in 10×50 or larger binoculars. Czech comet observer Jakub Cerny and his team photographed the comet on December 16th and discovered the sudden surge. Wonderful news!

While comets generally brighten as they approach the Sun and fade as they depart, any one of them can undergo a sudden outburst in brightness. You can find Finlay right now low in the southwestern sky at nightfall near the planet Mars. While outbursts are common, astronomers still aren’t certain what causes them. It’s thought that sub-surface ices, warmed by the comet’s approach to the Sun, expand until the pressure becomes so great they shatter the ice above, sending large fragments flying and exposing fresh new ice. Sunlight gets to work vaporizing both the newly exposed vents and aerial shrapnel. Large quantities of dust trapped in the ice are released and glow brightly in the Sun’s light, causing the comet to quickly brighten.

Some comets flare up dramatically. Take 29P/Schwassmann-Wachmann. Normally a dim bulb at 17th magnitude, once or twice a year it flares to magnitude 12 and occasionally 10!

Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt
Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November 2007. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt

Whatever the reason, outbursts can last from days to weeks. It’s anybody’s guess how long 15P/Finlay will remain a relatively easy target for comet hungry skywatchers.  While not high in the sky, especially from the northern U.S., it can be seen during early evening hours if you plan well.

By pure good chance, Comet Finlay will track with Mars through December into early January. They'll make a remarkably close pair on the evening of December 23rd. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print. Source: Chris Marriott's SkyMap software
By good luck, Comet Finlay will track with Mars through December into early January. On December 23rd, they’ll come together in a remarkably close conjunction. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars’ location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print for outside use. Source: Chris Marriott’s SkyMap software

Comet Finlay was discovered by William Henry Finlay from South Africa on September 26, 1886. It reaches perihelion or closest approach to the Sun on December 27th and was expected to brighten to magnitude +10 when nearest Earth in mid-January at 130 million miles (209 million km). Various encounters with Jupiter since discovery have increased its original period of 4.3 years to the current 6.5 years and shrunk its perihelion distance from 101 million to 90 million miles.

Comet Finlay appears considerably fainter in this pre-outburst photo taken on December 14th. Credit: Alfons Diepvens
Comet Finlay appears considerably fainter in this pre-outburst photo taken on December 14th. Credit: Alfons Diepvens

Looking at the map above it’s amazing how closely the comet’s path parallels that of Mars this month. Unlike Comet Siding Spring’s encounter with that planet last October, Finlay’s proximity is line of sight only. Still, it’s nice to have a fairly bright planet nearby to point the way to our target. Mars and Finlay’s paths intersect on December 23rd, when the duo will be in close conjunction only about 10? apart (1/3 the diameter of the Full Moon) for observers in the Americas. They’ll continue to remain almost as close on Christmas Eve. Along with Comet Q2 Lovejoy, this holiday season is turning out to be a joyous occasion for celestial fuzzballs!

To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15 degrees high in the southwestern sky. Source: Stellarium
To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15° high in the southwestern sky. Source: Stellarium

What is the Average Surface Temperature of the Planets in our Solar System?

Artist's impression of the planets in our solar system, along with the Sun (at bottom). Credit: NASA

It’s is no secret that Earth is the only inhabited planet in our Solar System. All the planets besides Earth lack a breathable atmosphere for terrestrial beings, but also, many of them are too hot or too cold to sustain life. A “habitable zone” which exists within every system of planets orbiting a star. Those planets that are too close to their sun are molten and toxic, while those that are too far outside it are icy and frozen.

But at the same time, forces other than position relative to our Sun can affect surface temperatures. For example, some planets are tidally locked, which means that they have one of their sides constantly facing towards the Sun. Others are warmed by internal geological forces and achieve some warmth that does not depend on exposure to the Sun’s rays. So just how hot and cold are the worlds in our Solar System? What exactly are the surface temperatures on these rocky worlds and gas giants that make them inhospitable to life as we know it?

Mercury:

Of our eight planets, Mercury is closest to the Sun. As such, one would expect it to experience the hottest temperatures in our Solar System. However, since Mercury also has no atmosphere and it also spins very slowly compared to the other planets, the surface temperature varies quite widely.

What this means is that the side exposed to the Sun remains exposed for some time, allowing surface temperatures to reach up to a molten 465 °C. Meanwhile, on the dark side, temperatures can drop off to a frigid -184°C. Hence, Mercury varies between extreme heat and extreme cold and is not the hottest planet in our Solar System.

Venus imaged by Magellan Image Credit: NASA/JPL
Venus is an incredibly hot and hostile world, due to a combination of its thick atmosphere and proximity to the Sun. Image Credit: NASA/JPL

Venus:

That honor goes to Venus, the second closest planet to the Sun which also has the highest average surface temperatures – reaching up to 460 °C on a regular basis. This is due in part to Venus’ proximity to the Sun, being just on the inner edge of the habitability zone, but also to Venus’ thick atmosphere, which is composed of heavy clouds of carbon dioxide and sulfur dioxide.

These gases create a strong greenhouse effect which traps a significant portion of the Sun’s heat in the atmosphere and turns the planet surface into a barren, molten landscape. The surface is also marked by extensive volcanoes and lava flows, and rained on by clouds of sulfuric acid. Not a hospitable place by any measure!

Earth:

Earth is the third planet from the Sun, and so far is the only planet that we know of that is capable of supporting life. The average surface temperature here is about 14 °C, but it varies due to a number of factors. For one, our world’s axis is tilted, which means that one hemisphere is slanted towards the Sun during certain times of the year while the other is slanted away.

This not only causes seasonal changes, but ensures that places located closer to the equator are hotter, while those located at the poles are colder. It’s little wonder then why the hottest temperature ever recorded on Earth was in the deserts of Iran (70.7 °C) while the lowest was recorded in Antarctica (-89.2 °C).

Mars' thin atmosphere, visible on the horizon, is too weak to retain heat. Credit: NASA
Mars’ thin atmosphere, visible on the horizon, is too weak to retain heat. Credit: NASA

Mars:

Mars’ average surface temperature is -55 °C, but the Red Planet also experiences some variability, with temperatures ranging as high as 20 °C at the equator during midday, to as low as -153 °C at the poles. On average though, it is much colder than Earth, being just on the outer edge of the habitable zone, and because of its thin atmosphere – which is not sufficient to retain heat.

In addition, its surface temperature can vary by as much as 20 °C due to Mars’ eccentric orbit around the Sun (meaning that it is closer to the Sun at certain points in its orbit than at others).

Jupiter:

Since Jupiter is a gas giant, it has no solid surface, so it has no surface temperature. But measurements taken from the top of Jupiter’s clouds indicate a temperature of approximately -145°C. Closer to the center, the planet’s temperature increases due to atmospheric pressure.

At the point where atmospheric pressure is ten times what it is on Earth, the temperature reaches 21°C, what we Earthlings consider a comfortable “room temperature”. At the core of the planet, the temperature is much higher, reaching as much as 35,700°C – hotter than even the surface of the Sun.

Saturn and its rings, as seen from above the planet by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute. Assembled by Gordan Ugarkovic.
Saturn and its rings, as seen from above the planet by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute/Gordan Ugarkovic

Saturn:

Due to its distance from the Sun, Saturn is a rather cold gas giant planet, with an average temperature of -178 °Celsius. But because of Saturn’s tilt, the southern and northern hemispheres are heated differently, causing seasonal temperature variation.

And much like Jupiter, the temperature in the upper atmosphere of Saturn is cold, but increases closer to the center of the planet. At the core of the planet, temperatures are believed to reach as high as 11,700 °C.

Uranus:

Uranus is the coldest planet in our Solar System, with a lowest recorded temperature of -224°C. Despite its distance from the Sun, the largest contributing factor to its frigid nature has to do with its core.

Much like the other gas giants in our Solar System, the core of Uranus gives off far more heat than is absorbed from the Sun. However, with a core temperature of approximately 4,737 °C, Uranus’ interior gives of only one-fifth the heat that Jupiter’s does and less than half that of Saturn.

Neptune photographed by Voyage. Image credit: NASA/JPL
Neptune photographed by Voyager 2. Image credit: NASA/JPL

Neptune:

With temperatures dropping to -218°C in Neptune’s upper atmosphere, the planet is one of the coldest in our Solar System. And like all of the gas giants, Neptune has a much hotter core, which is around 7,000°C.

In short, the Solar System runs the gambit from extreme cold to extreme hot, with plenty of variance and only a few places that are temperate enough to sustain life. And of all of those, it is only planet Earth that seems to strike the careful balance required to sustain it perpetually.

Universe Today has many articles on the temperature of each planet, including the temperature of Mars and the temperature of Earth.

You may also want to check out these articles on facts about the planets and an overview of the planets.

NASA has a great graphic here that compares the temperatures of all the planets in our Solar System.

Astronomy Cast has episodes on all planets including Mercury.

Orion Off-Loaded for Cross Country Trek to Florida Home Base

The Orion crew module was recovered Dec. 5, 2014 after splashdown in the Pacific Ocean about 600 miles off the coast of San Diego, California. Credit: U.S. Navy

After a brilliant first test flight, and historic Pacific Ocean splashdown and recovery on Dec. 5, 2014, NASA’s Orion spacecraft was brought onshore inside the USS Anchorage to the US Naval Base San Diego and has now been offloaded for the cross country trek back her home base in Florida.

Orion was off-loaded from the well deck of the USS Anchorage Monday night after the amphibious ship docked in San Diego.

NASA officials pronounced the two orbit, 4.5 hour flight maiden test flight of Orion on the Exploration Flight Test-1 (EFT-1) mission to be a complete success.

The EFT-1 spacecraft was recovered at sea, brought to land, and off-loaded by a combined team from NASA, the U.S. Navy, and Orion prime contractor Lockheed Martin.

NASA's Orion spacecraft is being offloaded from the well deck of the USS Anchorage at Naval Base San Diego in California  and has been secured in its crew module recovery cradle to prepare for return to Kennedy Space Center in Florida.  Credit:  NASA/Amber Philman
NASA’s Orion spacecraft is being offloaded from the well deck of the USS Anchorage at Naval Base San Diego in California and has been secured in its crew module recovery cradle to prepare for return to Kennedy Space Center in Florida. Credit: NASA/Amber Philman

Years of planning, rehearsals, and hard work on land, in the air, and at sea paid off handsomely for the Orion Recovery Team, led by the Ground Systems Development and Operations Program (GSDO) based at NASA’s Kennedy Space Center in Florida.

“The recovery of Orion was flawless,” said Jeremy Graeber, NASA recovery director. “We wanted to be patient, take our time. We didn’t rush.”

Navy teams in Zodiac boats had attached a collar and winch line to Orion at sea and then safely towed it into the flooded well deck of the USS Anchorage and positioned it over rubber “speed bumps.”

Next they secured Orion inside its recovery cradle and transported it back to US Naval Base San Diego where it was off-loaded from the USS Anchorage.

Orion has now been moved about a mile to the “Mole Pier” where Lockheed Martin has conducted the first test inspection of the crew module and collected test data.

The Orion crew module is being moved into a covered structure at the Mole Pier at Naval Base San Diego in California where it will be prepared for return to NASA's Kennedy Space Center in Florida. Orion was secured on its crew module recovery cradle in the well deck of the USS Anchorage after it was recovered from the Pacific Ocean.   Credit: NASA/Cory Huston
The Orion crew module is being moved into a covered structure at the Mole Pier at Naval Base San Diego in California where it will be prepared for return to NASA’s Kennedy Space Center in Florida. Orion was secured on its crew module recovery cradle in the well deck of the USS Anchorage after it was recovered from the Pacific Ocean. Credit: NASA/Cory Huston

Next, it was placed into the crew module transportation fixture with a rigorous environmental control system and generator to ensure the crew module’s safety during transport.

Orion will be hauled on a flatbed truck across the US for a nearly two-week trip back to Kennedy where it will arrive just in time for the Christmas holidays.

Technicians at KSC will examine every nook and cranny of Orion, and will disassemble it for up close inspection and lessons learned.

NASA’s first Orion spacecraft blasts off at 7:05 a.m. atop United Launch Alliance Delta 4 Heavy Booster at Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida on Dec. 5, 2014.   Launch pad remote camera view.   Credit: Ken Kremer - kenkremer.com
NASA’s first Orion spacecraft blasts off at 7:05 a.m. atop United Launch Alliance Delta 4 Heavy Booster at Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida on Dec. 5, 2014. Launch pad remote camera view. Credit: Ken Kremer – kenkremer.com

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

Ken Kremer

Curiosity Rover Data Indicates Gale Crater Mountain Used to be a Lake

Artist rendition of how the "lake" at Gale Crater on Mars may have looked millions of years ago. Credit and copyright: Kevin Gill.

What is now a mountain, was once a lake. That’s the conclusion of the Curiosity Mars rover science team after studying data and imagery from the rover, which indicates that the mountain the rover is now climbing in Gale Crater – Aeolis Mons, or Mount Sharp — was built by sediments deposited in a large lake bed over tens of millions of years.

“Gale Crater had a large lake at the bottom — perhaps even a series of lakes,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program during a press briefing on Monday, “that may have been big enough to last millions of years.”

This evenly layered rock photographed by the Mast Camera (Mastcam) on NASA's Curiosity Mars Rover on Aug. 7, 2014, shows a pattern typical of a lake-floor sedimentary deposit not far from where flowing water entered a lake. Credit:  NASA/JPL-Caltech/MSSS.
This evenly layered rock photographed by the Mast Camera (Mastcam) on NASA’s Curiosity Mars Rover on Aug. 7, 2014, shows a pattern typical of a lake-floor sedimentary deposit not far from where flowing water entered a lake. Credit: NASA/JPL-Caltech/MSSS.

This isn’t the first time that the Mars Science Laboratory team has made the conclusion that a lake once existed in Gale Crater, or even that the water was long-lived. A year ago, the team said that an ancient fresh water lake at the Yellowknife Bay area near Curiosity’s landing site once existed for periods spanning perhaps millions to tens of millions of years in length – before eventually evaporating completely after Mars lost its thicker atmosphere.

But now, the team has garnered a bigger picture of Gale Crater, and they suggest that water could have covered nearly the entirety of the 154-kilometer-wide crater around 3.5 billion years ago, and that the 5-kilometer-high mountain that now towers over the crater could have been formed by repeated cycles of sediment buildup and erosion.

“If our hypothesis for Mount Sharp holds up, it challenges the notion that warm and wet conditions were transient, local, or only underground on Mars,” said Ashwin Vasavada, Curiosity deputy project scientist. “A more radical explanation is that Mars’ ancient, thicker atmosphere raised temperatures above freezing globally, but so far we don’t know how the atmosphere did that.”

By continuing the study of this crater, Vasavada said, the team is “more sure than ever that we’re going to learn about the early history of Mars, it’s changing climate, and the potential for Mars to support life.”

A few months ago, when Curiosity was still a few kilometers away from the base of Aeolis Mons, the science team started noticing distinct patterns on the rocks from images taken by the rover. There were tilted beds of sandstone all facing south in the direction of the mountain. The planetary geologists concluded that these tilted beds of sandstone formed where streams emptied into standing bodies of water, probably lakes.

This diagram depicts rivers feeding into a lake. Where the river enters the water body, the water's flow decelerates, sediments drop out, and a delta forms, depositing a prism of sediment that tapers out toward the lake's interior. Progressive build-out of the delta through time leads to formation of sediments that are inclined in the direction toward the lake body. Credit:  NASA/JPL-Caltech/MSSS/Imperial College.
This diagram depicts rivers feeding into a lake. Where the river enters the water body, the water’s flow decelerates, sediments drop out, and a delta forms, depositing a prism of sediment that tapers out toward the lake’s interior. Progressive build-out of the delta through time leads to formation of sediments that are inclined in the direction toward the lake body. Credit:
NASA/JPL-Caltech/MSSS/Imperial College.

Sediments carried by flowing water sink when they enter a body of water, forming a sloped wall that slowly advances forward as sediment continues to fall.

In September of this year, when Curiosity arrived at the rocks that form the base of Aeolis Mons at a region the team calls “Kimberley,” they saw a new type of rock, one that forms when tiny particles of sediment slowly settle out within a lake, forming mud at the lake bottom. These ‘mudstones’ are very finely layered, suggesting that the river and lake system was going through cycles of change.

“Layered sandstone or pebble beds at the Kimberley record a build-out or accretion of sediment from north to south,” said Curiosity science team member Sanjeev Gupta, “ and that build-out of inclined beds strongly suggests rivers depositing sediment into a standing body of water.”

This image from Curiosity's Mastcam shows inclined beds of sandstone interpreted as the deposits of small deltas fed by rivers flowing down from the Gale Crater rim and building out into a lake where Mount Sharp is now. It was taken March 13, 2014, just north of the "Kimberley" waypoint. Credit:  NASA/JPL-Caltech/MSSS
This image from Curiosity’s Mastcam shows inclined beds of sandstone interpreted as the deposits of small deltas fed by rivers flowing down from the Gale Crater rim and building out into a lake where Mount Sharp is now. It was taken March 13, 2014, just north of the “Kimberley” waypoint. Credit:
NASA/JPL-Caltech/MSSS

Over a span of perhaps millions of years, water flowed from the northern rim of Gale Crater toward the center, bringing sediment that slowly formed the lower layers of Mount Sharp.

After the crater filled to a height of at least a few hundred yards and the sediments hardened into rock, the accumulated layers of sediment were sculpted over time into a mountainous shape by wind erosion that carved away the material between the crater perimeter and what is now the edge of the mountain.

While this is definitely not the first time that evidence of water has been discovered on Mars — evidence from several Mars missions point to wet environments on ancient Mars – scientist have yet to put together a model of Mars’ ancient climate that could have produced long periods warm enough for stable water on the surface.

This illustration depicts a lake of water partially filling Mars' Gale Crater, receiving runoff from snow melting on the crater's northern rim. Image Credit:  NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS
This illustration depicts a lake of water partially filling Mars’ Gale Crater, receiving runoff from snow melting on the crater’s northern rim.
Image Credit:
NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS

But this latest finding suggests Mars may have maintained a climate that could have produced long-lasting lakes at many locations on the Red Planet, which leads to potentially long-lasting habitable environments.

To learn more about this intriguing region on Mars, over the next few months the Curiosity rover will continue to climb up the lower layers of Aeolis Mons to see if the hypothesis for how it formed holds up. The team will also look at the chemistry of the rocks to see if the water that was once present would’ve been of the kind that could support microbial life.

“With only 30 vertical feet of the mountain behind us, we’re sure there’s a lot more to discover,” said Vasavada.

Further reading: NASA
Additional graphics from the press briefing.

Meteorite May Contain Proof of Life on Mars, Researchers Say

The idea that Mars could have supported life at one time is the subject of ongoing debate. Image credit: NASA

Mars is currently home to a small army robotic rovers, satellites and orbiters, all of which are busy at work trying to unravel the deeper mysteries of Earth’s neighbor. These include whether or not the planet ever had liquid water on its surface, what the atmosphere once looked like, and – most importantly of all – if it ever supported life.

And while much has been learned about Martian water and its atmosphere, the all-important question of life remains unanswered. Until such time as organic molecules – considered to be the holy grail for missions like Curiosity – are found, scientists must look elsewhere to find evidence of Martian life.

According to a recent paper submitted by an international team of scientists, that evidence may have arrived on Earth three and a half years ago aboard a meteorite that fell in the Moroccan desert. Believed to have broken away from Mars 700,000 years ago, so-called Tissint meteorite has internal features that researchers say appear to be organic materials.

The paper appeared in the scientific journal Meteoritics and Planetary Sciences. In it, the research team – which includes scientists from the Swiss Federal Institute of Technology in Lausanne (EPFL) – indicate organic carbon is located inside fissures in the rock. All indications are the meteorite is Martian in origin.

“So far, there is no other theory that we find more compelling,” says Philippe Gillet, director of EPFL’s Earth and Planetary Sciences Laboratory. He and his colleagues from China, Japan and Germany performed a detailed analysis of organic carbon traces from a Martian meteorite, and have concluded that they have a very probable biological origin.

Artist's conception of an fragment as it blasts off from Mars. Boulder-sized planetary fragments could be a mechanism that carried life between Mars and Earth, UA planetary scientist Jay Melosh says. (Credit: The Planetary Society)
Artist’s conception of an fragment as it blasts off from Mars as a result of a meteor impact. Credit: The Planetary Society

The scientists argue that carbon could have been deposited into the fissures of the rock when it was still on Mars by the infiltration of fluid that was rich in organic matter.

If this sounds familiar, you may recall a previous Martian meteorite named ALH84001, found in the Allen Hills region in Antarctica. In 1996 NASA researchers announced they had found evidence within ALH84001 that strongly suggested primitive life may have existed on Mars more than 3.6 billion years ago. While subsequent studies of the now famous Allen Hills Meteorite shot down theories that the Mars rock held fossilized alien life, both sides continue to debate the issue.

This new research on the Tissint meteorite will likely be reviewed and rebutted, as well.

The researchers say the meteorite was likely ejected from Mars after an asteroid crashed on its surface, and fell to Earth on July 18, 2011, and fell in Morocco in view of several eyewitnesses.

Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Several research teams have already shown that this component is organic in nature, but they are still debating where the carbon came from.

Chemical, microscopic and isotope analysis of the carbon material led the researchers to several possible explanations of its origin. They established characteristics that unequivocally excluded a terrestrial origin, and showed that the carbon content were deposited in the Tissint’s fissures before it left Mars.

This research challenges research proposed in 2012 that asserted that the carbon traces originated through the high-temperature crystallization of magma. According to the new study, a more likely explanation is that liquids containing organic compounds of biological origin infiltrated Tissint’s “mother” rock at low temperatures, near the Martian surface.

A piece of the Tissint meteorite that came to Earth via Mars. Credit: EPFL/Alain Herzog
A piece of the Tissint meteorite that landed on Earth on July 18th, 2011. Credit: EPFL/Alain Herzog

These conclusions are supported by several intrinsic properties of the meteorite’s carbon, e.g. its ratio of carbon-13 to carbon-12. This was found to be significantly lower than the ratio of carbon-13 in the CO2 of Mars’s atmosphere, previously measured by the Phoenix and Curiosity rovers.

Moreover, the difference between these ratios corresponds perfectly with what is observed on Earth between a piece of coal – which is biological in origin – and the carbon in the atmosphere.

The researchers note that this organic matter could also have been brought to Mars when very primitive meteorites – carbonated chondrites – fell on it. However, they consider this scenario unlikely because such meteorites contain very low concentrations of organic matter.

“Insisting on certainty is unwise, particularly on such a sensitive topic,” warns Gillet. “I’m completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars – at least in the past.”

Be sure to check out these videos from EPFL News, which include an interview with Philippe Gillet, EPFL and co-author of the study:

And this video explaining the history of the Tissint meteor:

Further Reading: EPFL

The Inner Planets of Our Solar System

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

Our Solar System is an immense and amazing place. Between its eight planets, 176 moons, 5 dwarf planets (possibly hundreds more), 659,212 known asteroids, and 3,296 known comets, it has wonders to sate the most demanding of curiosities. Our Solar System is made up of different regions, which are delineated based on their distance from the Sun, but also the types of planets and bodies that can be found within them.

In the inner Solar System, we find the “Inner Planets” – Mercury, Venus, Earth, and Mars – which are so named because they orbit closest to the Sun. In addition to their proximity, these planets have a number of key differences that set them apart from planets elsewhere in the Solar System.

For starters, the inner planets are rocky and terrestrial, composed mostly of silicates and metals, whereas the outer planets are gas giants. The inner planets are also much more closely spaced than their outer Solar System counterparts. In fact, the radius of the entire region is less than the distance between the orbits of Jupiter and Saturn.

The positions and names of planets and dwarf planets in the solar system. Credit: Planets2008/Wikimedia Commons
The positions and names of planets and dwarf planets in the solar system.
Credit: Planets2008/Wikimedia Commons

This region is also within the “frost line,” which is a little less than 5 AU (about 700 million km) from the Sun. This line represents the boundary in a system where conditions are warm enough that hydrogen compounds such as water, ammonia, and methane are able to take liquid form. Beyond the frost line, these compounds condense into ice grains.Some scientists refer to the frost line as the “Goldilocks Zone” — where conditions for life may be “just right.”

Generally, inner planets are smaller and denser than their counterparts, and have few to no moons or rings circling them. The outer planets, meanwhile, often have dozens of satellites and rings composed of particles of ice and rock.

The terrestrial inner planets are composed largely of refractory minerals, such as the silicates, which form their crusts and mantles, and metals such as iron and nickel which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather. All of them have impact craters and tectonic surface features as well, such as rift valleys and volcanoes.

Mercury:

Of the inner planets, Mercury is the closest to our Sun and the smallest of the terrestrial planets. This small planet looks very much like the Earth’s Moon and is even a similar grayish color, and it even has many deep craters and is covered by a thin layer of tiny particle silicates.

Its magnetic field is only about 1 percent that of Earth’s, and it’s very thin atmosphere means that it is hot during the day (up to 430°C) and freezing at night (as low as -187 °C) because the atmosphere can neither keep heat in or out. It has no moons of its own and is comprised mostly of iron and nickel. Mercury is one of the densest planets in the Solar System.

The inner planets to scale. From left to right: Earth, Mars, Venus, and Mercury. Credit: Wikimedia Commons/Lsmpascal
The inner planets to scale. From left to right: Earth, Mars, Venus, and Mercury. Credit: Wikimedia Commons/Lsmpascal

Venus:

Venus, which is about the same size as Earth, has a thick toxic atmosphere that traps heat, making it the hottest planet in the Solar System. This atmosphere is composed of 96% carbon dioxide, along with nitrogen and a few other gases. Dense clouds within Venus’ atmosphere are composed of sulphuric acid and other corrosive compounds, with very litter water.

Only two spacecraft have ever penetrated Venus’s thick atmosphere, but it’s not just man-made objects that have trouble getting through. There are fewer crater impacts on Venus than other planets because all but the largest meteors don’t make it through the thick air without disintegrating. Much of Venus’ surface is marked with volcanoes and deep canyons — the biggest of which is over 6400 km (4,000 mi) long.

Venus is often called the “morning star” because, with the exception of Earth’s moon, it’s the brightest object we see in the sky. Like Mercury, Venus has no moon of its own.

Earth:

Earth is the third inner planet and the one we know best. Of the four terrestrial planets, Earth is the largest, and the only one that currently has liquid water, which is necessary for life as we know it. Earth’s atmosphere protects the planet from dangerous radiation and helps keep valuable sunlight and warmth in, which is also essential for life to survive.

Inner Solar System. Image credit: NASA
Illustration of the Inner Planets and their orbits around the Sun Image credit: NASA

Like the other terrestrial planets, Earth has a rocky surface with mountains and canyons, and a heavy metal core. Earth’s atmosphere contains water vapor, which helps to moderate daily temperatures. Like Mercury, the Earth has an internal magnetic field. And our Moon, the only one we have, is comprised of a mixture of various rocks and minerals.

Mars:

Mars is the fourth and final inner planet, and also known as the “Red Planet” due to the rust of iron-rich materials that form the planet’s surface. Mars also has some of the most interesting terrain features of any of the terrestrial planets. These include the largest mountain in the Solar System – Olympus Mons – which rises some 21,229 m (69,649 ft) above the surface, and a giant canyon called Valles Marineris. Valles Marineris is 4000 km (2500 mi) long and reaches depths of up to 7 km (4 mi)!

For comparison, the Grand Canyon in Arizona is about 800 km (500 mi) long and 1.6 km (1 mi) deep. In fact, the extent of Valles Marineris is as long as the United States and it spans about 20 percent (1/5) of the entire distance around Mars. Much of the surface is very old and filled with craters, but there are geologically newer areas of the planet as well.

A top-down image of the orbits of Earth and Mars. Image: NASA
A top-down image of the orbits of Earth and Mars. Credit: NASA

At the Martian poles are polar ice caps that shrink in size during the Martian spring and summer. Mars is less dense than Earth and has a smaller magnetic field, which is indicative of a solid core, rather than a liquid one.

Mars’ thin atmosphere has led some astronomers to believe that the surface water that once existed there might have actually taken liquid form, but has since evaporated into space. The planet has two small moons called Phobos and Deimos.

Beyond Mars are the four outer planets: Jupiter, Saturn, Uranus, and Neptune.

We have written many interesting articles about the inner planets here at Universe Today. Here’s The Solar System Guide as well as The Inner and Outer Planets in Our Solar System.

For more information, check out this article from NASA on the planets of the Solar System and this article from Solstation about the inner planets.

Astronomy Cast also has episodes on all of the inner planets including this one about Mercury.

This Short Film is a Stunning Preview of Human Space Exploration

One day – and it really is only matter of time – humans will set foot on the surfaces of other far-flung worlds in our Solar System, leaving the Earth and Moon far behind to wander the valleys of Mars, trek across the ice of Europa, and perhaps even soar through the skies of Titan like winged creatures from ancient legends. But until then we must rely on the exploration of our robotic emissaries and our own boundless imagination and curiosity to picture what such voyages would be like. Here in “Wanderers,” video artist Erik Wernquist has used both resources in abundance to visualize fascinating off-world adventures yet to be undertaken by generations to come.
Continue reading “This Short Film is a Stunning Preview of Human Space Exploration”

Cool NASA Animation Beautifully Details Every Step of Orion’s First Launch!

Orion atop Delta 4 Heavy Booster. Credit: NASA/Kim Shiflett

Video Caption: Animation details NASA’s Orion Exploration Flight Test-1 (EFT-1) mission launching on Dec. 4. 2014. Credit: NASA

It’s not Science Fiction! It’s Not Star Trek!

No. It’s a really, really big NASA Mission! It’s Orion!

In fact, it’s the biggest and most important development in US Human Spaceflight since the end of the Space Shuttle Program in 2011.

Orion is launching soon on its first flight, the pathfinding Exploration Flight Test-1 (EFT-1) mission and sets NASA on the path to send humans to Mars in the 2030s.

Watch this cool NASA animation beautifully detailing every key step of Orion’s First Launch!

Orion is designed to take humans farther than they’ve ever gone before. Even farther into deep space than NASA’s Apollo moon landing which ended more than four decades ago!

We are T-MINUS 4 Days and Counting to the inaugural blastoff of Orion as of today, Sunday, November 30, 2014.

To learn even more about the 8 major events and goals happening during Orion’s EFT-1 mission be sure to check out my recent story with NASA’s fabulous new set of infographics – here.

Every aspect of the final processing steps now in progress by engineers and technicians from NASA, rocket provider United Launch Alliance, and Orion prime contractor Lockheed Martin is proceeding smoothly and marching towards launch.

Orion’s move to Launch Complex-37. Credit: Mike Killian
Orion’s move to Launch Complex-37. Credit: Mike Killian

Orion will lift off on a United Launch Alliance Delta IV Heavy rocket on its inaugural test flight to space on the uncrewed Exploration Flight Test-1 (EFT-1) mission at 7:05 a.m. EST on December 4, 2014, from Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.

The two-orbit, four and a half hour Orion EFT-1 flight around Earth will lift the Orion spacecraft and its attached second stage to an orbital altitude of 3,600 miles, about 15 times higher than the International Space Station (ISS) – and farther than any human spacecraft has journeyed in 40 years.

EFT-1 will test the rocket, second stage, jettison mechanisms as well as avionics, attitude control, computers and electronic systems inside the Orion spacecraft.

Then the spacecraft will carry out a high speed re-entry through the atmosphere at speeds approaching 20,000 mph and scorching temperatures near 4,000 degrees Fahrenheit to test the heat shield, before splashing down for a parachute assisted landing in the Pacific Ocean.

Orion is NASA’s next generation human rated vehicle that will carry America’s astronauts beyond Earth on voyages venturing farther into deep space than ever before – beyond the Moon to Asteroids, Mars, and other destinations in our Solar System.

NASA TV will provide several hours of live coverage

Delta 4 Heavy rocket and super secret US spy satellite roar off Pad 37 on June 29, 2012 from Cape Canaveral, Florida. NASA’s Orion EFT-1 capsule will blastoff atop a similar Delta 4 Heavy Booster in December 2014. Credit: Ken Kremer- kenkremer.com
Here’s how Orion EFT-1 Launch will look!
Delta 4 Heavy rocket and super secret US spy satellite roars off Pad 37 on June 29, 2012, from Cape Canaveral, Florida. NASA’s Orion EFT-1 capsule will blastoff atop a similar Delta 4 Heavy Booster in December 2014. Credit: Ken Kremer- kenkremer.com

Watch for Ken’s ongoing Orion coverage and he’ll be onsite at KSC in the days leading up to the historic launch on Dec. 4.

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

Ken Kremer

Launch - It’s going to be loud. It’s going to be bright. It’s going to be smoky. Engines are fired, the countdown ends and Orion lifts off into space atop the United Launch Alliance Delta IV Heavy rocket from the launch pad at Cape Canaveral in Florida.  Credit: NASA
Launch – It’s going to be loud. It’s going to be bright. It’s going to be smoky. Engines are fired, the countdown ends and Orion lifts off into space atop the United Launch Alliance Delta IV Heavy rocket from the launch pad at Cape Canaveral in Florida. Credit: NASA

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Learn more about Orion, SpaceX, Antares, NASA missions and more at Ken’s upcoming outreach events:

Dec 1-5: “Orion EFT-1, SpaceX CRS-5, Antares Orb-3 launch, Curiosity Explores Mars,” Kennedy Space Center Quality Inn, Titusville, FL, evenings

IMG_7780a_Delta 4 Heavy_Ken Kremer

Dive teams attach tow lines to Orion test capsule during Aug. 15 recovery test at Norfolk Naval Base, VA.  Credit: Ken Kremer/kenkremer.com
Dive teams attach tow lines to Orion test capsule during Aug. 15, 2013 recovery test at Norfolk Naval Base, VA. Credit: Ken Kremer/kenkremer.com

Orion on Track at T MINUS 1 Week to First Blastoff – Photos

Orion atop Delta 4 Heavy Booster. Credit: NASA/Kim Shiflett

At T MINUS 1 Week on this Thanksgiving Holiday, all launch processing events remain on track for the first blast off of NASA’s new Orion crew vehicle on Dec. 4, 2014 which marks the first step on the long road towards sending Humans to Mars in the 2030s.

Orion will lift off on a United Launch Alliance Delta IV Heavy rocket on its inaugural test flight to space on the uncrewed Exploration Flight Test-1 (EFT-1) mission at 7:05 a.m. EST on December 4, 2014 from Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.

Technicians and engineers installed Orion’s batteries and have been conducting a thorough checkout of all the electrical and battery connections between the crew module, service module and Delta IV Heavy second stage while working inside the mobile service tower at pad 37.

With access doors at Space Launch Complex 37 opened, the Orion and Delta IV Heavy stack is visible in its entirety inside the Mobile Service Tower where the vehicle is undergoing launch preparations.  Credit: NASA/Kim Shiflett
With access doors at Space Launch Complex 37 opened, the Orion and Delta IV Heavy stack is visible in its entirety inside the Mobile Service Tower where the vehicle is undergoing launch preparations. Credit: NASA/Kim Shiflett

There is some margin time available in the schedule in case additional testing and checkouts are required.

Orion’s launch window opens at 7:05 a.m. EST on Dec. 4 at the beginning of a launch window that extends 2 hours, 39 minutes.

One week ago, top NASA and Lockheed Martin managers gave the “GO” to continue with launch preparations after the vehicle passed the Flight Readiness Review (FRR) on Thursday, Nov. 20.

This past week the doors of the Mobile Servicing Tower (MST) at pad 37 were opened to reveal the Orion spacecraft stack atop the Delta IV Heavy that will carry the spacecraft into orbit.

NASA's Orion EFT-1 spacecraft atop Delta 4 Heavy Booster at Cape Canaveral, Florida ahead of launch set for Dec. 4, 2014.   Credit: NASA/Kim Shiflett
NASA’s Orion EFT-1 spacecraft atop Delta 4 Heavy Booster at Cape Canaveral, Florida ahead of launch set for Dec. 4, 2014. Credit: NASA/Kim Shiflett

The Delta IV Heavy is the world’s most powerful rocket.

The MST will be rolled back from the rocket stack on Wednesday evening, Dec. 3 starting 8 hours, 15 minutes before launch to allow the rocket to be fueled and continue into the final stage of launch operations and the countdown to liftoff on Thursday morning Dec. 4.

I’ll be at the pad during MST rollback reporting live for Universe Today.

Orion’s move to Launch Complex-37. Credit: Mike Killian
Orion’s move to Launch Complex-37. Credit: Mike Killian

The two-orbit, four and a half hour Orion EFT-1 flight around Earth will lift the Orion spacecraft and its attached second stage to an orbital altitude of 3,600 miles, about 15 times higher than the International Space Station (ISS) – and farther than any human spacecraft has journeyed in 40 years.

Orion is NASA’s next generation human rated vehicle that will carry America’s astronauts beyond Earth on voyages venturing farther into deep space than ever before – beyond the Moon to Asteroids, Mars and other destinations in our Solar System.

NASA’s Orion EFT 1 crew module enters the Payload Hazardous Servicing Facility on Sept. 11, 2014 at the Kennedy Space Center, FL, beginning the long journey to the launch pad and planned liftoff on Dec. 4, 2014.  Credit: Ken Kremer - kenkremer.com
NASA’s Orion EFT 1 crew module enters the Payload Hazardous Servicing Facility on Sept. 11, 2014 at the Kennedy Space Center, FL, beginning the long journey to the launch pad and planned liftoff on Dec. 4, 2014. Credit: Ken Kremer – kenkremer.com

Watch for Ken’s ongoing Orion coverage and he’ll be onsite at KSC in the days leading up to the historic launch on Dec. 4.

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

Ken Kremer

………….

Learn more about Orion, SpaceX, Antares, NASA missions and more at Ken’s upcoming outreach events:

Dec 1-5: “Orion EFT-1, SpaceX CRS-5, Antares Orb-3 launch, Curiosity Explores Mars,” Kennedy Space Center Quality Inn, Titusville, FL, evenings

These three RS-68 engines will power each of the attached Delta IV Heavy Common Booster Cores (CBCs) that will launch NASA’s maiden Orion on the EFT-1 mission in December 2014.   Credit: Ken Kremer/kenkremer.com
These three RS-68 engines will power each of the attached Delta IV Heavy Common Booster Cores (CBCs) that will launch NASA’s maiden Orion on the EFT-1 mission in December 2014. Credit: Ken Kremer/kenkremer.com
Orion flight test profile for the Exploration Flight Test-1 (EFT-1) launching on Dec. 4, 2014. Credit: NASA
Orion flight test profile for the Exploration Flight Test-1 (EFT-1) launching on Dec. 4, 2014. Credit: NASA