Posted on by Matt Williams

New Study Provides Explanation for Pluto’s Giant Blades of Ice

Pluto’s bladed terrain as seen from New Horizons during its July 2015 flyby. Credits: NASA/JHUAPL/SwRI

When it made its historic flyby of Pluto in July of 2015, the New Horizons spacecraft gave scientists and the general public the first clear picture of what this distant dwarf planet looks like. In addition to providing breathtaking images of Pluto’s “heart”, its frozen plains, and mountain chains, one of the more interesting features it detected was Pluto’s mysterious “bladed terrain”.

According to data obtained by New Horizons, these features are made almost entirely out of methane ice and resemble giant blades. At the time of their discovery, what caused these features remained unknown. But according to new research by members of the New Horizons team, it is possible that these features are the result of a specific kind of erosion that is related to Pluto’s complex climate and geological history.

Ever since the New Horizons probe provided a detailed look at Pluto’s geological features, the existence of these jagged ridges has been a source of mystery. They are located at the highest altitudes on Pluto’s surface near it’s equator, and can reach several hundred feet in altitude. In that respect, they are similar to penitentes, a type of structure found in high-altitude snowfields along Earth’s equator.

Penitentes, on the southern end of the Chajnantor plain in Chile. Credits: Wikimedia Commons/ESO

These structures are formed through sublimation, where atmospheric water vapor freezes to form standing, blade-like ice structures. The process is based on sublimation, where rapid changes in temperature cause water to transition from a vapor to a solid (and back again) without changing into a liquid state in between. With this in mind, the research team considered various mechanisms for the formation of these ridges on Pluto.

What they determined was that Pluto’s bladed terrain was the result of atmospheric methane freezing at extreme altitudes on Pluto, which then led to ice structures similar to the ones found on Earth.The team was led by Jeffrey Moore, a research scientist at NASA’s Ames Research Center who was also a New Horizons’ team member. As he explained in a NASA press statement:

“When we realized that bladed terrain consists of tall deposits of methane ice, we asked ourselves why it forms all of these ridges, as opposed to just being big blobs of ice on the ground. It turns out that Pluto undergoes climate variation and sometimes, when Pluto is a little warmer, the methane ice begins to basically ‘evaporate’ away.”

But unlike on Earth, the erosion of these features are related to changes that take place over the course of eons. This should come as no surprise seeing as how Pluto’s orbital period is 248 years (or 90,560 Earth days), meaning it takes this long to complete a single orbit around the Sun. In addition, the eccentric nature of it orbit means that its distance from the Sun ranges considerably, from 29.658 AU at perihelion to 49.305 AU at aphelion.

Maps based on New Horizons’ data on the topography (top) and composition (bottom) of Pluto’s surface. Both indicate the section of Pluto where the bladed terrain was observed. Credits: NASA/JHUAPL/SwRI/LPI

When the planet is farthest from the Sun, methane freezes out of the atmosphere at high altitudes. And as it gets closer to the Sun, these ice features melt and turn directly into atmospheric vapor again. As a result of this discovery, we now know that the surface and air of Pluto are apparently far more dynamic than previously thought. Much in the same way that Earth has a water cycle, Pluto may have a methane cycle.

This discovery could also allow scientists to map out locations of Pluto which were not photographed in high-detail. When the New Horizons mission conducted its flyby, it took high-resolution pictures of only one side of Pluto – designated as the “encounter hemisphere”. However, it was only able to observe the other side at lower resolution, which prevented it from being mapped in detail.

But based on this new study, NASA researchers and their collaborators have been able to conclude that these sharp ridges may be a widespread feature on Pluto’s “far side”. The study is also significant in that it advances our understanding of Pluto’s global geography and topography, both past and present. This is due to the fact that it demonstrated a link between atmospheric methane and high-altitude features. As such, researchers can now infer elevations on Pluto by looking for concentrations of methane in its atmosphere.

Not long ago, Pluto was considered one of the least-understood bodies in our Solar System, thanks to its immense distance from the Sun. However, thanks to ongoing studies made possible by the data collected by the New Horizons mission, scientists are becoming increasingly familiar with what its surface looks like, not to mention the types of geological and climatological forces that have shaped it over time.

And be sure to enjoy this video that details the discovery of Pluto’s bladed terrain, courtesy of NASA’s Ames Research Center:

Further Reading: NASA

Posted on by Matt Williams

New Study Could Help Locate Subsurface Deposits of Water Ice on Mars

Mars Express' view of Meridiani Planum. Credits: ESA/DLR/FU Berlin (G. Neukum)

It is a well-known fact that today, Mars is a very cold and dry place. Whereas the planet once had a thicker atmosphere that allowed for warmer temperatures and liquid water on its surface, the vast majority of water there today consists of ice that is located in the polar regions. But for some time, scientists have speculated that there may be plenty of water in subsurface ice deposits.

If true, this water could be accessed by future crewed missions and even colonization efforts, serving as a source of rocket fuel and drinking water. Unfortunately, a new study led by scientists from the Smithsonian Institution indicates that the subsurface region beneath Meridiani Planum could be ice-free. Though this may seem like bad news, the study could help point the way towards accessible areas of water ice on Mars.

This study, titled “Radar Sounder Evidence of Thick, Porous Sediments in Meridiani Planum and Implications for Ice-Filled Deposits on Mars“, recently appeared in the Geophysical Research Letters. Led by Dr. Thomas R. Watters, the Senior Scientist with the Center for Earth and Planetary Studies at the Smithsonian Institution, the team examined data collected by the ESA’s Mars Express mission in the Meridiani Planum region.

Artist’s impression of a global view of Mars, centered on the Meridiani Planum region. Credit: Air and Space Museum/Smithsonian Institution

Despite being one of the most intensely explored regions on Mars, particularly by missions like the Opportunity rover, the subsurface structure of Meridiani Planum has remained largely unknown. To remedy this, the science team led by Dr. Watters examined data that had been collected by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument aboard the ESA’s Mars Express orbiter.

Developed by researchers at the University of Rome in partnership with NASA’s Jet Propulsion Laboratory (and with the help of private contractors), this device used low-frequency radio pulses to study Mars’ ionosphere, atmosphere, surface, and interior structure. The way these pulses penetrated into certain materials and were reflected back to the orbiter was then used to determine the bulk density and compositions of those materials.

After examining the Meridiani Planum region, the Mars Express probe obtained readings that indicated that the subsurface area had a relatively low dielectric constant. In the past, these kinds of readings have been interpreted as being due to the presence of pure water ice. And in this case, the readings seemed to indicate that the subsurface was made up of porous rock that was filled with water ice.

However, with the help of newly-derived compaction models for Mars, the team concluded that these signals could be the result of ice-free, porous, windblown sand (aka. eolian sands). They further theorized that the Meridiani Planum region, which is characterized by some rather unique physiographic and hydrologic features, could have provided an ideal sediment trap for these kinds of sands.

Artist’s impression of the Mars Express rover, showing radar returns from its MARSIS instrument. Credit: ESA/NASA/JPL/KU/Smithsonian

“The relatively low gravity and the cold, dry climate that has dominated Mars for billions of years may have allowed thick eolian sand deposits to remain porous and only weakly indurated,” they concluded. “Minimally compacted sedimentary deposits may offer a possible explanation for other nonpolar region units with low apparent bulk dielectric constants.”

As Watters also indicated in a Smithsonian press statement:

“It’s very revealing that the low dielectric constant of the Meridiani Planum deposits can be explained without invoking pore-filling ice. Our results suggest that caution should be exercised in attributing non-polar deposits on Mars with low dielectric constants to the presence of water ice.”

On its face, this would seem like bad news to those who were hoping that the equatorial regions on Mars might contain vast deposits of accessible water ice. It has been argued that when crewed missions to Mars begin, this ice could be accessed in order to supply water for surface habitats. In addition, ice that didn’t need to come from there could also be used to manufacture hydrazine fuel for return missions.

This would reduce travel times and the cost of mounting missions to Mars considerably since the spacecraft would not need to carry enough fuel for the entire journey, and would therefore be smaller and faster. In the event that human beings establish a colony on Mars someday, these same subsurface deposits could also used for drinking, sanitation, and irrigation water.

A subsurface view of Miyamoto crater in Meridiani Planum from the MARSIS radar sounder. . Credit: ESA/NASA/JPL/KU/Smithsonian

As such, this study – which indicates that low dielectric constants could be due to something other than the presence of water ice – places a bit of a damper on these plans. However, understood in context, it provides scientists with a means of locating subsurface ice. Rather than ruling out the presence of subsurface ice away from the polar regions entirely, it could actually help point the way to much-needed deposits.

One can only hope that these regions are not confined to the polar regions of the planet, which would be far more difficult to access. If future missions and (fingers crossed!) permanent outposts are forced to pump in their water, it would be far more economical to do from underground sources, rather than bringing it in all the way from the polar ice caps.

Further Reading: Smithsonian NASM, Geophysical Research Letters

Posted on by Matt Williams

Newly Discovered Star Cluster Analyzed by Gaia Probe

Gaia mapping the stars of the Milky Way. Credit: ESA/ATG medialab; background: ESO/S. Brunier

In 2013, the European Space Agency (ESA) deployed the Gaia mission, a space observatory designed to measure the positions of movements of celestial bodies. For the past four years, Gaia has been studying distant stars, planets, comets, asteroids, quasars and other astronomical objects, and the data it has acquired will be used to construct the largest and most precise 3D space catalog ever made, totaling 1 billion objects.

Using data provided by Gaia, a team of international scientists conducted a study of the recently-discovered star cluster known as Gaia 1. Located about 15,000 light years from Earth and measuring some 29 light years in radius, much about this cluster has remained unknown. As such, this study helped place constraints on a number of mysteries of this star cluster, which include its age, metallicity and origin.

For the sake of their study, which recently appeared in the journal Astronomy and Astrophysics under the title “Detailed Chemical Abundance Analysis of the Thick Disk Star Cluster Gaia 1“, the team conducted a detailed chemical abundance study of Gaia 1 to determine its unknown parameters. From this, accurate estimates on its age and composition are likely to now be possible.

Sky map based on the first release of Gaia data (DR1). Credit: ESA/Gaia/DPAC/A. Moitinho & M. Barros, CENTRA – University of Lisbon.

This star cluster was first identified in May 2017, thanks to first data release – aka. Data Release 1 (DR1) – from the ESA. Based on photometry provided by Gaia, the Two Micron All-Sky Survey (2MASS), the Wide-field Infrared Survey Explorer (WISE), and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1) – the object was characterized as being an intermediate-age (6.3 billion years) and moderately metal-rich system.

This combined photometry also indicated that the cluster had a radius of about 29 light years and contained as much as 20,000 Solar Masses. However, further studies found that the cluster was actually far more metal-rich than previously thought. This indicated that Gaia 1 was likely to be significantly younger, with estimates now claiming that it was at least 3 billion years old.

In addition, these subsequent studies also raised the possibility that the cluster was extra-galactic in origin, based on the fact that it orbits about 5,500 light years (~1.7 kpc) above the Milky Way’s disk. To remedy this, the team – led by Andreas Koch of the University of Lancaster and the Center for Astronomy Heidelberg – used Gaia data in order to conduct a detailed study of just how metal-rich the cluster was to get a better idea of its age.

As they stated in their study: “[T]his work focuses on a detailed chemical abundance analysis of four red giant members of Gaia 1, based on high-resolution spectroscopy, which we complement by an investigation of the orbital properties of this transition object.” This consisted of measuring the abundances of 14 elements within these red giant stars, which were selected from the 2MASS survey.

What they determined was that the Gaia 1 was more metal poor than previously expected, which indicated that it is older than the revised age estimates indicated – between 3 billion and 5.3 billion years old. In addition, they also measured the proper motions and orbits of the four target stars, using data obtained from the fifth U.S. Naval Observatory CCD Astrograph Catalog (UCAC5).

This information revealed that in the course of their orbits, the four target stars would reach a maximum distance of 3,262 light years (1.0 kpc) above the galactic disk, which was an indication that they were not extra-galactic in origin. Last, but not least, they indicated that Gaia 1’s structure does not truly conform to that of a globular cluster, as it was originally designated. As they conclude in their study:

“This confirms that Gaia 1 is rather a massive and luminous open cluster than a low-mass globular cluster. Finally, orbital computations of the target stars bolster our chemical findings of Gaia 1’s present-day membership with the thick disk, even though it remains unclear, which mechanisms put it in that place.”

While this study has helped place constraints on one of a newly-discovered Gaia object, the team acknowledges that there is still much to be discovered about this star cluster. They also acknowledge that there is a margin of error when it comes to their study, and that further research is needed before Gaia 1 can be properly classified.

The band of light (the Milky Way) that is visible in the night sky, showing the stellar disk of our galaxy. Credit: Bob King

“However, the hint of a metallicity spread between different studies in the literature may point towards a more complex origin that could involve a once more massive progenitor,” they state. “Thus the question as to its exact formation and origin remains unclear and needs to await more data such as the precise and accurate parallaxes that Gaia can offer.”

This newly-discovered cluster, and all attempts to better understand it, are merely the tip of the iceberg when it comes to what the Gaia mission has revealed so far. The second official release of Gaia data – aka. Gaia DR2 – is scheduled to take place in April of 2018. This will be followed by a third release in 2020 and, barring any mission extensions, a fourth and final release in 2022.

Further Reading: Astronomy and Astrophysics

Posted on by Susie Murph

Astronomy Cast Ep. 458: The Science of Cassini

And now Cassini’s gone. Smashed up in the atmosphere of Saturn. But planetary scientists are going to be picking through all those pictures and data for decades. Let’s look back at some of the science gathered up by Cassini so far, and we can still learn from this epic journey.

We usually record Astronomy Cast every Friday at 1:30 pm PDT / 4:30 pm EDT/ 20:30 PM UTC (8:30 GMT). You can watch us live on AstronomyCast.com, or the AstronomyCast YouTube page.

Visit the Astronomy Cast Page to subscribe to the audio podcast!

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If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

Posted on by Tammy Plotner

Messier 57 – The Ring Nebula

Hubble image of the Ring Nebula (aka. Messier 57). Credit: NASA/ESA/ Hubble Heritage (STScI/AURA) – ESA /Hubble Collaboration
Hubble image of the Ring Nebula (aka. Messier 57). Credit: NASA/ESA/ Hubble Heritage (STScI/AURA) – ESA /Hubble Collaboration

Welcome back to Messier Monday! We continue our tribute to our dear friend, Tammy Plotner, by looking at the the Big Ring itself, the planetary nebula known as Messier 57. Enjoy!

In the 18th century, while searching the night sky for comets, French astronomer Charles Messier kept noting the presence of fixed, diffuse objects in the night sky. In time, he would come to compile a list of approximately 100 of these objects, with the purpose of making sure that astronomers did not mistake them for comets. However, this list – known as the Messier Catalog – would go on to serve a more important function.

One of these objects is known as Messier 57, a planetary nebula that is also known as the Ring Nebula. This object is located about 2,300 light years from Earth in the direction of the Lyra constellation. Because of its proximity to Vega, the brightest star in Lyra and one of the stars that form the Summer Triangle, the nebula is relatively easy to find using binoculars or a small telescope.

What You Are Looking At:

Here you see the remainders of a sun-like star… At one time in its life, it may have had twice the mass of Sol, but now all that’s left is a white dwarf that burns over 100,000 degrees kelvin. Surrounding it is an envelope about 2 to 3 light years in size of what once was its outer layers – blown away in a cylindrical shape some 6000 to 8000 years ago. Like looking down the barrel of a smoking gun, we’re looking back in time at the end of a Mira-like star’s evolutionary phase.

It’s called a planetary nebula, because once upon a time before telescopes could resolve them, they appeared almost planet-like. But, as for M57, the central star itself is no larger than a terrestrial planet! The tiny white dwarf star, although it could be as much as 2300 light years away, has an intrinsic brightness of about 50 to 100 times that of our Sun.

One of the most beautiful features of M57 is the structure in the ring itself, sometimes called braiding – but scientifically known as “knots” in the gaseous structure. As C.R. O’Dell (et al) indicated in their 2003 study:

“We have studied the closest bright planetary nebulae with the Hubble Space Telescope’s WFPC2 in order to characterize the dense knots already known to exist in NGC 7293. We find knots in all of the objects, arguing that knots are common, simply not always observed because of distance. The knots appear to form early in the life cycle of the nebula, probably being formed by an instability mechanism operating at the nebula’s ionization front. As the front passes through the knots they are exposed to the photoionizing radiation field of the central star, causing them to be modified in their appearance. This would then explain as evolution the difference of appearance like the lacy filaments seen only in extinction in IC 4406 on the one extreme and the highly symmetric “cometary” knots seen in NGC 7293. The intermediate form knots seen in NGC 2392, NGC 6720, and NGC 6853 would then represent intermediate phases of this evolution.”

However, examining things like planetaries nebulae in different wavelengths of light can tell us so much more about them. Behold the beauty when see through the Spitzer Space Telescope! As M.M. Roth explained in a 2007 study:

“Emission nebulae like H II regions, Planetary Nebulae, Novae, Herbig Haro objects etc. are found as extended objects in the Milky Way, but also as point sources in other galaxies, where they are sometimes observable out to very large distances due to the high contrast provided by some prominent emission lines. It is shown how 3D spectroscopy can be used as a powerful tool for observations of both large resolved emission nebulae and distant extragalactic objects, with special emphasis on faint detection limits.”

History of Observation:

This deep space object was first discovered in early January 1779 by Antoine Darquier who wrote in his notes:

“This nebula, to my knowledge, has not yet been noticed by any astronomer. One can only see it with a very good telescope, it is not resembling any of those [nebula] already known; it has the apparent dimension of Jupiter, is perfectly round and sharply limited; its dull glow resembles the dark part of the Moon before the first and after the last quarter. Meanwhile, the center appears a bit less pale than the remaining part of its surface.”

Although Darquier did not post a date, it is believed his observation preceded Messier’s independent recovery made on January 31, 1779 when he states that Darquier picked it up before him:

“A cluster of light between Gamma and Beta Lyrae, discovered when looking for the Comet of 1779, which has passed it very close: it seems that this patch of light, which is round, must be composed of very small stars: with the best telescopes it is impossible to distinguish them; there stays only a suspicion that they are there. M. Messier reported this patch of light on the Chart of the Comet of 1779. M. Darquier, at Toulouse, discovered it when observing the same comet, and he reports: ‘Nebula between gamma and beta Lyrae; it is very dull, but perfectly outlined; it is as large as Jupiter and resembles a planet which is fading’.”

A few years later, Sir William Herschel would also observe Messier Object 57 with his superior telescope and in his private notes he writes:

“Among the curiosities of the heavens should be placed a nebula, that has a regular, concentric, dark spot in the middle, and is probably a Ring of stars. It is of an oval shape, the shorter axis being to the longer as about 83 to 100; so that, if the stars form a circle, its inclination to a line drawn from the sun to the center of this nebula must be about 56 degrees. The light is of the resolvable kind [i.e., mottled], and in the northern side three very faint stars may be seen, as also one or two in the southern part. The vertices of the longer axis seem less bright and not so well defined as the rest. There are several small stars very bear, but none seems to belong to it.”

Admiral Smyth would go on in later years to add his own detailed observations to history’s records:

“This annular nebula, between Beta and Gamma on the cross-piece of the Lyre, forms the apex of a triangle which it makes with two stars of the 9th magnitude; and its form is that of an elliptic ring, the major axis of which trends sp to nf [SW to NE]. This wonderful object seems to have been noted by Darquier, in 1779; but neither he nor his contemporaries, Messier and Méchain, discerned its real form, seeing in this aureola of glory only “a mass of light in the form of a planetary disc, very dingy in colour.”

“Sir W. Herschel called it a perforated resolvable nebula, and justly ranked it among the curiosities of the heavens. He considered the vertices of the longer axis less bright and not so well defined as the rest; and he afterwards added: ‘By the observations of the 20-feet telescope, the profundity of the stars, of which it probably consists, must be of a higher than the 900th order, perhaps 950.'”

“This is a vast view of the ample and inconceivable dimensions of the spaces of the Universe; and if the oft-cited cannon-ball, flying with the uniform velocity of 500 miles an hour, would require millions of years to reach Sirius, what an incomprehensible time it would require to pass so overwhelming an interval as 950 times the distance! And yet, could we arrive there, by all analogy, no boundary would meet the eye, but thousands and ten thousands of other remote and crowded systems would still bewilder the imagination.

“In my refractor this nebula has a most singular appearance, the central vacuity being black, so as to countenance the trite remark of its having a hole through it. Under favourable circumstances, when the instrument obeys the smooth motion of the equatorial clock, it offers the curious phenomenon of a solid ring of light in the profundity of space. The annexed sketch affords a notion of it. Sir John Herschel, however, with the superior light of his instrument, found that the interior is far from absolutely dark. “It is filled,’ he says, ‘with a feeble but very evident nebulous light, which I do not remember to have been noticed by former observers.'”

Since Sir John’s observation, the powerful telescope of Lord Rosse has been directed to this subject, and under powers 600, 800, and 1000, it displayed very evident symptoms of resolvability at its minor axis. The fainter nebulous matter which fills it, was found to be irregularly distributed, having several stripes or wisps in it, and the regularity of the outline was broken by appendages branching into space, of which prolongations the brightest was in the direction of the major axis.

Locating Messier 57:

M57 is a breeze to locate because it is positioned between Beta and Gamma Lyrae (the westernmost pair of the lyre’s stars), at about one-third the distance from Beta to Gamma. While it is easily seen in binoculars, it is a little difficult to identify because of its small size, so binoculars must be very steady to distinguish it from the surrounding star field.

In even a small telescope at minimum power, you’ll quickly notice a very small, but perfect ring structure which takes very well to magnification. Despite low visual brightness, M57 actually takes well to urban lighting conditions and can even be spied during fairly well moonlit nights. Larger aperture telescopes will easily see braiding in the nebula structure and often glimpse the central star. May you also see the many faces of the “Ring”!

The location of Messier 57 in the Lyra Constellation. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)

And here are the quick facts on Messier 57 to help you get started:

Object Name: Messier 57
Alternative Designations: M57, NGC 6720, the “Ring Nebula”
Object Type: Planetary Nebula
Constellation: Lyra
Right Ascension: 18 : 53.6 (h:m)
Declination: +33 : 02 (deg:m)
Distance: 2.3 (kly)
Visual Brightness: 8.8 (mag)
Apparent Dimension: 1.4×1.0 (arc min)

We have written many interesting articles about Messier Objects here at Universe Today. Here’s Tammy Plotner’s Introduction to the Messier Objects,  M1 – The Crab Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons.

Be to sure to check out our complete Messier Catalog. And for more information, check out the SEDS Messier Database.

Sources:

Posted on by Nancy Atkinson

Australia To Create Its Own Space Agency

The Parkes radio telescope, one of the telescopes comprising CSIRO’s Australia Telescope National Facility. Credit: CSIRO

This year’s International Astronautical Congress is being held in Adelaide, Australia and the opening ceremonies of this meeting of ‘all things space’ included a special announcement. The Australian government announced that it will establish a new national space agency, with the hopes of growing Australia’s already vibrant space industry.

Michaelia Cash, Australian’s acting Minister of Industry, Innovation and Science was quoted as saying that Australia will not have a NASA but an agency “right for our nation, right for our industry … that will provide the vehicle for Australia to have a long-term strategic plan for space – a plan that supports the innovative application of space technologies and grows our domestic space industry, including through defense space procurement.”

Australia’s space industry is worth about $4 billion and already employs about 11,500 people. But proponents for creating a space agency for the country say it will help coordinate and expand the efforts.

Of course Australia has been very active in space exploration, being part of every deep-space mission NASA has flown with tracking and communications as part the Deep Space Network and the precursor system of dishes around the world. The tracking and communications dish at Parkes, Honeysuckle Creek, Tidbinbilla and Canberra were notoriously part of the Apollo missions, and several other large radio dishes in Australia have been listening to space to tease out astronomical details. Additionally, the Square Kilometer Array being built in Australia, New Zealand and South Africa will help us answer fundamental questions in astronomy and cosmology.

In depth: how we *really* watched the footage from the Apollo 11 Moon landing, thanks to the Australian radio dishes.

But still, many have said that Australia is one of the few major developed countries that do not have a space agency. New Zealand established their space agency last year. You can see a list of all the world’s space agencies from Heather Archuletta’s Pillownaut website.

Reportedly, the plan is to double the size of Australia’s current space capacity within five years and add thousands of new jobs, while taking advantage of new technology such as cubesats.

“We have longstanding ties with NASA, exploring space together and generating all of these jobs. And that’s the key point, it is a jobs industry-first agency,” astrophysicist Alan Duffy told ABC. “It’s designed to create satellites and new uses for the images that come from those satellites, and I don’t mean giant, bus-sized satellites of the ‘60s and ‘70s. Thanks to smartphones something the size of a toaster has the same capabilities as some of these historic launches. So we get to space cheaper and we can do more when we’re there.”

Reportedly, more details of the new space agency will be announced this week during the IAC, which is a gathering of thousands of global space experts, heads of other space agencies and private companies.

Sources: ABC, Sydney Morning Herald

Posted on by Matt Williams

Rare Element Could Point the Way to Past Life on Mars

Future missions could determine the presence of past life on Mars by looking for signs of extreme metal-metabolizing bacteria. Credit: NASA.

Over the past few decades, our ongoing studies of Mars have revealed some very fascinating things about the planet. In the 1960s and early 70s, the Mariner probes revealed that Mars was a dry, frigid planet that was most likely devoid of life. But as our understanding of the planet has deepened, it has come to be known that Mars once had a warmer, wetter environment that could have supported life.

This in turn has inspired multiple missions whose purpose it has been to find evidence of this past life. The key questions in this search, however, are where to look and what to look for? In a new study led by researchers from the University of Kansas, a team of international scientists recommended that future missions should look for vanadium. This rare element, they claim, could point the way towards fossilized evidence of life.

Their study, titled “Imaging of Vanadium in Microfossils: A New Potential Biosignature“, recently appeared in the scientific journal Astrobiology. Led by Craig P. Marshall, an associate professor of geology at the University of Kansas, the international team included members from the Argonne National Laboratory, the Geological Technical Services Division of Saudi Aramco, the University of Liege, and the University of Sydney.

The microphone for the upcoming Mars mission will be attached to the SuperCam, seen here in this illustration zapping a rock with its laser. Credit: NASA/JPL-Caltech

To be clear, finding signs of life on a planet like Mars is no easy task. As Craig Marshall indicated in a University of Kansas press release:

“You’ve got your work cut out if you’re looking at ancient sedimentary rock for microfossils here on Earth – and even more so on Mars. On Earth, the rocks have been here for 3.5 billion years, and tectonic collisions and realignments have put a lot of stress and pressure on rocks. Also, these rocks can get buried, and temperature increases with depth.”

In their paper, Marshall and his colleagues recommend that missions like NASA’s Mars 2020 rover, the ESA’s ExoMars 2020 rover, and other proposed surface missions could combine Raman spectroscopy with the search for vanadium to find evidence of fossilized life. On Earth, this element has been found in crude oils, asphalts, and black shales that have been formed by the slow decay of biological organic material.

In addition, paleontologists and astrobiologists have used Raman spectroscopy – a technique that reveals the cellular compositions of samples –  on Mars for some time to search for signs of life. In this respect, the addition of vanadium would provide material that would act as a biosignature to confirm the existence of organic life in samples under study. As Marshall explained:

“People say, ‘If it looks like life and has a Raman signal of carbon, then we have life. But, of course, we know there can be carbonaceous materials made in other processes — like in hydrothermal vents — consistent with looking like microfossils that also have some carbon signal. People also make wonderful carbon structures artificially that look like microfossils — exactly the same. So, we’re at a juncture now where it’s really hard to tell if there’s life only based on morphology and Raman spectroscopy.”

Artist’s impression of the Mars 2020 with its sky crane landing system deployed. Credit: NASA/JPL

This is not the first time that Marshall and his co-authors have advocated using vanadium to search for signs of life. Such was the subject of a presentation they made at the Astrobiology Science Conference in 2015. What’s more, Marshall and his team emphasize that it would be possible to perform this technique using instruments that are already part of NASA’s Mars 2020 mission.

Their proposed method also involves new technique known as X-ray fluorescence microscopy, which looks at elemental composition. To test this technique, the team examined thermally altered organic-walled microfossils which were once organic materials )called acritarchs). From their data, they confirmed that traces of vanadium are present within microfossils that were indisputably organic in origin.

“We tested acritarchs to do a proof-of-concept on a microfossil where there’s no shadow of a doubt that we’re looking at preserved ancient biology,” Marshall said. “The age of this microfossil we think is Devonian. These guys are aquatic microorganisms — they’re thought to be microalgae, a eukaryotic cell, more advanced than bacterial. We found the vanadium content you’d expect in cyanobacterial material.”

These microfossilized bit of life, they argue, are probably not very distinct from the kinds of life that could have existed on Mars billions of years ago. Other scientific research has also indicated that vanadium is the result of organic compounds (like chlorophyll) from living organisms undergoing a transformation process caused by heat and pressure (i.e. diagenetic alteration).

Artist’s impression of ESA’s ExoMars rover (foreground) and Russia’s stationary surface science platform (background) on the surface of Mars. Credit: ESA/ATG medialab

In other words, after living creatures die and become buried in sediment, vanadium forms in their remains as a result of being buried under more and more layers of rock – i.e. fossilization. Or, as Marshall explained it:

“Vanadium gets complexed in the chlorophyll molecule. Chlorophylls typically have magnesium at the center — under burial, vanadium replaces the magnesium. The chlorophyll molecule gets entangled within the carbonaceous material, thus preserving the vanadium. It’s like if you have a rope stored in your garage and before you put it away you wrap it so you can unravel it the next time you need it. But over time on the garage floor it becomes tangled, things get caught in it. Even when you shake that rope hard, things don’t come out. It’s a tangled mess. Similarly, if you look at carbonaceous material there’s a tangled mess of sheets of carbon and you’ve got the vanadium mixed in.”

The work was supported by an ARC International Research Grant (IREX) – which sponsors research that seeks to find biosignatures for extracellular life – with additional support from the Australian Synchrotron and the Advanced Photon Source at the Argonne National Laboratory. Looking forward, Marshall and his colleagues hope to conduct further research that will involve using Raman spectroscopy to study carbonaceous materials.

At present, their research appears to have attracted the interesting of the European Space Agency. Howell Edwards, who also conducts research using Raman spectroscopy (and who’s work has been supported by an ARC grant), is part of the ESA’s Mars Explorer team, where he is responsible for instrumentation on the ExoMars 2020 rover. But, as Marshall indicated, the team also hopes that NASA will consider their study:

“Hopefully someone at NASA reads the paper. Interestingly enough, the scientist who is lead primary investigator for the X-ray spectrometer for the space probe, they call it the PIXL, was his first graduate student from Macquarie University, before his KU times. I think I’ll email her the paper and say, ‘This might be of interest.’” 

The next decade is expected to be a very auspicious time for exploration missions to Mars. Multiple rovers will be exploring the surface, hoping to find the elusive evidence of life. These missions will also help pave the way for NASA’s crewed mission to Mars by the 2030s, which will see astronauts landing on the surface of the Red Planet for the first time in history.

If, in fact, these missions find evidence of life, it will have a profound effect on all future mission to Mars. It will also have an immeasurable impact on humanity’s perception of itself, knowing at long last that billions of years ago, life did not emerge on Earth alone!

Further Reading: University of Kansas, Astrobiology

Posted on by Matt Williams

Hubble Spots Unique Object in the Main Asteroid Belt

Artist’s impression shows the binary asteroid 288P, located in the Main Asteroid Belt between the planets Mars and Jupiter. Credit: ESA/Hubble, L. Calçada.

In 1990, the NASA/ESA Hubble Space Telescope was deployed into Low Earth Orbit (LEO). As one of NASA’s Great Observatories – along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope – this instrument remains one of NASA’s larger and more versatile missions. Even after twenty-seven years of service, Hubble continues to make intriguing discoveries, both within our Solar System and beyond.

The latest discovery was made by a team of international astronomers led by the Max Planck Institute for Solar System Research. Using Hubble, they spotted a unique object in the Main Asteroid Belt – a binary asteroid known as 288P – which also behaves like a comet. According to the team’s study, this binary asteroid experiences sublimation as it nears the Sun, which causes comet-like tails to form.

The study, titled “A Binary Main-Belt Comet“, recently appeared in the scientific journal Nature. The team was led by Jessica Agarwal of the Max Planck Institute for Solar System Research, and included members from the Space Telescope Science Institute, the Lunar and Planetary Laboratory at the University of Arizona, the Johns Hopkins University Applied Physics Laboratory (JHUAPL), and the University of California at Los Angeles.

Using the Hubble telescope, the team first observed 288P in September 2016, when it was making its closest approach to Earth. The images they took revealed that this object was not a single asteroid, but two asteroids of similar size and mass that orbit each other at a distance of about 100 km. Beyond that, the team also noted some ongoing activity in the binary system that was unexpected.

As Jessica Agarwal explained in a Hubble press statement, this makes 288P the first known binary asteroid that is also classified as a main-belt comet. “We detected strong indications of the sublimation of water ice due to the increased solar heating – similar to how the tail of a comet is created,” she said. In addition to being a pleasant surprise, these findings are also highly significant when it comes to the study of the Solar System.

Since only a few objects of this type are known, 288P is an extremely important target for future asteroid studies. The various features of 288P also make it unique among the few known wide asteroid binaries in the Solar System. Basically, other binary asteroids that have been observed orbited closer together, were different in size and mass, had less eccentric orbits, and did not form comet-like tails.

The observed activity of 288P also revealed a great deal about the binary asteroids past. From their observations, the team concluded that 288P has existed as a binary system for the past 5000 years and must have accumulated ice since the earliest periods of the Solar System. As Agarwal explained:

“Surface ice cannot survive in the asteroid belt for the age of the Solar System but can be protected for billions of years by a refractory dust mantle, only a few meters thick… The most probable formation scenario of 288P is a breakup due to fast rotation. After that, the two fragments may have been moved further apart by sublimation torques.”

Image depicting the two areas where most of the asteroids in the Solar System are found: the Main Asteroid Belt and the Trojans. Credit: ESA/Hubble, M. Kornmesser

Naturally, there are many unresolved questions about 288P, most of which stem from its unique behavior. Given that it is so different from other binary asteroids, scientists are forced to wonder if it merely coincidental that it presents such unique properties. And given that it was found largely by chance, it is unlikely that any other binaries that have similar properties will be found anytime soon.

“We need more theoretical and observational work, as well as more objects similar to 288P, to find an answer to this question,” said Agarwal. In the meantime, this unique binary asteroid is sure to provide astronomers with many interesting opportunities to study the origin and evolution of asteroids orbiting between Mars and Jupiter.

In particular, the study of those asteroids that show comet-like activity (aka. main-belt comets) is crucial to our understanding of how the Solar System formed and evolved. According to contrasting theories of its formation, the Asteroid Belt is either populated by planetesimals that failed to become a planet, or began empty and gradually filled with planetesimals over time.

In either case, studying its current population can tell us much about how the planets formed billions of years ago, and how water was distributed throughout the Solar System afterwards. This, in turn, is crucial to determining how and where life began to emerge on Earth, and perhaps elsewhere!

Be sure to check out this animation of the 288P binary asteroid too, courtesy of the ESA and Hubble:

 

Further Reading: Hubble, Nature

Posted on by Fraser Cain

Where Do We Go Next? Building the Deep Space Gateway

Where do we go next? The Deep Space Gateway
Where do we go next? The Deep Space Gateway


I don’t have to tell you that the vision of human space exploration in the Solar System has kind of stalled. Half a century ago, humans set foot on the Moon, and we haven’t been back since. Instead, we’ve thoroughly explored every cubic meter of low Earth orbit, going around and around the Earth. In fact, back in 2016, the International Space Station celebrated 100,000 orbits around the Earth.

The space shuttle was the last US vehicle capable of taking humans up into orbit, and it was retired back in 2011. So things look pretty bleak for sending humans out to explore the Solar System.

Earlier this year, however, NASA announced their next great step in their human space exploration efforts: the Deep Space Gateway. And if all goes well, we’ll see humans living and working farther from Earth, and for longer periods than ever before.

After the space shuttle program was wrapped up, NASA had a bunch of challenges facing it. Perhaps the greatest of these, was what to do with the enormous workforce that built and maintained the space shuttle fleet. Thousands were laid off, and moved to other aerospace jobs and other industries, but the space agency worked to develop the next big launch system after the shuttle.

Originally there were the Ares rockets, as part of the Constellation Program, but these were canceled and replaced with the Space Launch System. We’ve done a whole episode on the SLS, but the short version is that this new rocket will be capable of lifting more cargo into orbit than any rocket ever.

The first version, known as the Block 1 will be capable of lofting 70,000 kg into low-Earth orbit, while the upcoming Block 2 will be able to carry 130,000 kg into LEO – more than the mighty Saturn V rocket.

What are you going to do with a rocket this powerful? Launch new space telescopes, robotic missions to the outer Solar System, and put humans into space, of course.

In addition to the SLS, NASA is also working on a new capsule, known as the Orion Crew Module. This Apollo-esque capsule will be capable of carrying a crew of 4 astronauts out beyond low-Earth orbit, and returning them safely back to Earth.

But if you can send astronauts out beyond low-Earth orbit, where will they go?

Artist's impression of the Deep Space Gateway, currently under development by Lockheed Martin. Credit: NASA
Artist’s impression of the Deep Space Gateway, currently under development by Lockheed Martin. Credit: NASA

The Deep Space Gateway.

The plan is to put a brand new space station into a cis-lunar orbit. Specifically, it’s known as a near-rectilinear halo orbit. It won’t actually be orbiting the Moon, but it’ll be on an orbit that allows it to serve as a stepping stone to the Moon. Sort of a bridge between Lagrange points. This station will range in distance from 1,500 to 70,000 km from the Moon in a way that keeps it relatively easy to reach.

From the outside, it’ll look like a smaller version of the International Space Station, with a group of 4 pressurized modules connected together: a power module, habitation module, cargo logistics pod, and an EVA module.

Space inside the Gateway will be cramped, with astronauts needing to share their living quarters, reconfiguring the space as necessary. Seriously, the ISS is going to feel like a luxury hotel after spending time in the Gateway.

Artist illustration of Habitation Module. Credit: Lockheed Martin
Artist illustration of Habitation Module. Credit: Lockheed Martin

The station will be solar powered, with arrays providing 40 kW of energy. It’ll also have 12 kW ion thrusters which will be used for station keeping, as well as traditional hydrazine thrusters. The first habitation module will be capable of supplying the astronauts for 30-60 days, but a later cargo logistics pod will extend the length of missions.

Right now, there are a group of contractors being considered to build the Deep Space Gateway. The designs I’m showing you come from Lockheed Martin, but things could change.

The goal of the Deep Space Gateway will be to keep humans alive in space outside the Earth’s protective magnetosphere for at least a year, studying the effects of deep space on the human body.

But in the long term, the Gateway will serve as a stepping stone to Mars. The astronauts will assemble the future Deep Space Transport, a spacecraft that will carry humans to the Red Planet. But more on that later.

On the International Space Station, astronauts are protected by the Earth’s magnetosphere from solar radiation and cosmic rays. But on board the Deep Space Gateway, there’ll be no such protection. Instead, the station will need to be reinforced with radiation protection. At the same time, the region actually has less space junk, so it won’t need to same kind of micrometeorite protection.

In addition to being a science platform, the DSG will serve as a base of operations for exploring the Moon. In the near term, NASA is planning new lander and rover missions to the Moon. The Gateway could serve as a dock for missions blasting off from the Moon, where astronauts could unload science samples, and refurbish a rover for another mission down on the lunar surface.

Another intriguing idea is that the Deep Space Gateway could be used as a place to study samples from Mars without a risk of contaminating Earth. Under the current planetary contamination guidelines, samples from Mars need to be sterilized before they can be brought to Earth.

It’s hard to search for life in your samples, when you need to kill all life in your samples. But I’m sure the astronauts would be willing to take the risk of catching Martian flu for a chance to discover there’s life on Mars.

When will we actually see the Deep Space Gateway?

Not for a few years, sadly. Building the Gateway is going to require a few launches of the SLS, and there are already a bunch of missions queued up to use this new launcher.

SLS Block 1 Expanded View. Credit: NASA
SLS Block 1 Expanded View. Credit: NASA

The first launch of SLS will be an uncrewed test with an Orion capsule, sometime in 2019, known as EM-1. This will be followed by the launch of the Europa Clipper mission, also in 2019.

Once those missions are out of the way, the first crewed launch with SLS blasts off some time between 2021 and 2023. Designated as EM-2, this is when the construction of the Deep Space Gateway begins. 4 astronauts will spend 3 weeks beyond low Earth orbit, delivering the first module to the Deep Space Gateway: the Solar Power Electric Bus.

In 2024, EM-3 will have another crew of 4 blast off with the Deep Space Gateway’s Habitation Module. EM-4 should lift off by 2025 with the Logistics module. Finally, some time around 2026, mission EM-5 will deliver the station’s Airlock module.

SLS Block 2. Credit: NASA
SLS Block 2. Credit: NASA

What comes next? After the Deep Space Gateway, there’ll be the Deep Space Transport. If you’ve seen The Martian, think of the Hermes spacecraft that ferries the crew to and from Mars. The details are thin right now, but if all goes well, the pieces of the Transport will launch to the Gateway by 2027.

The various components will be assembled by the astronauts over the course of several launches, and once completed, the Deep Space Transport would make a series of 1-3 year missions to and from Mars. It’ll carry a crew of a six astronauts in a large habitation module and keep them alive for the journey.

The first mission could head out in 2033, with a human flyby of Mars. Side note, wouldn’t it be heartbreaking to get that close to Mars, and not actually be able to set foot on the surface? Anyway, future missions to Mars will include landings, and perhaps a visit to the SpaceX luxury Martian hotel where the astronauts can relax and apologize to each other for what they did when they all got space madness.

But this is so far in the future, it’s pretty hard to even wrap my mind around it yet.

Of course, these are all long term plans. And as I’ve mentioned in previous episodes, long term plans have a tendency of getting canceled. Who knows if the Deep Space Gateway actually get constructed, or if NASA will shift its support to private missions to Mars.

We’ll just have to stay tuned.