Tag: science

More evidence Mars’s glaciers formed across many ice ages

11:26 am

The uncertainty of science: New research using the boulders found on the top of Martian glaciers has now strengthened the evidence that Mars must have undergone many previous ice age cycles going back as much as 800 million years, with those glaciers waxing and waning during each cycle.

This new data helps map the cycles earlier than 20 million years ago, which have been difficult to map out based solely on the orbital data available from Earth and from Mars orbit. The results suggest that before then there were from six to twenty additional cycles during the last 300 to 800 million years.

These numbers are decidedly uncertain. It is likely that there were many more cycles, as suggested by the many layers seen at the edges of the north and south polar ice caps.

Be aware as well that if you read the press release you should know that it falsely implies that this research is the first to map out these ice age cycles. This is not true. All this research has done is provide more evidence for cycles prior to 20 million years ago, cycles that scientists have long believed must have happened based on other data.

In the end, for us to map out the full climate history of Mars will require numerous ice core samples at the planet’s poles, something that will not be possible until people are living and working on Mars routinely.

3 comments

Mysterious colors on Mars, near the landing site of Europe’s rover

10:17 am

Mysterious colors on Mars
Click for full image.

Cool image time! Today the science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) released a new captioned image, which I have cropped and reduced to post here to the right.

The photo was taken October 12, 2020, and shows a small very colorful area on top of an isolated hill. To quote the caption, written by Sharon Wilson:

An isolated, elongated mound (about 1 mile wide and 3.75 miles long) rises above the smooth, surrounding plains. Horizontal layers are exposed at the northern end of the mound, and its surface is characterized by a very unusual quasi-circular pattern with varying colors that likely reflect diverse mineral compositions.

…The origin of this mound is unknown, but its formation may be related to the clay-bearing rocks in the nearby Oxia Planum region.

» Read more

Leave a comment

Chang’e-5’s lunar samples less dense than expected

8:59 am

Because the lunar samples retrieved by China’s Chang’e-5 probe were less dense than expected, it ended up recovering only 3.8 pounds of material rather than the targeted 4.4 pounds.

The probe had estimated the lunar rocks to have a density of 1.6 grams per cubic millimetre, based on data from past missions by other countries, said Pei Zhaoyu, the mission spokesman. Going by that figure, the probe stopped taking samples after just 12 hours, apparently assessing that the target had been reached. “However, from tests, the actual density might not be that high,” Pei told reporters.

This is not a failure, but a discovery. In order to make sure the lander did not recover too much material, weighing too much, they needed to set limits based on the expected weight of the material recovered. That these samples taken from the Mons Rümker volcano complex are lighter than expected reveals something about them. It suggests the lava here was different than lava samples taken elsewhere.

3 comments

InSight scientists give up on heat sensor mole

9:25 pm

After another failed attempt earlier this month to dig with the German-made mole on the InSight Mars lander, the science team has decided to abandon all further efforts.

After getting the top of the mole about 2 or 3 centimetres under the surface, the team tried one last time to use a scoop on InSight’s robotic arm to scrape soil onto the probe and tamp it down to provide added friction. After the probe conducted 500 additional hammer strokes on 9 January, with no progress, the team called an end to their efforts.

This means the heat sensor, one of the two instruments carried by InSight, is also a failure, and will not be able to provide any data about the planet’s interior temperature.

From the beginning InSight appears to have been a poorly run and badly chosen project. Other than a weather station, it carried only two instruments, a seismometer and a heat sensor. Its launch was delayed two years when the French attempt to build the seismometer failed and JPL had to take over, fortunately with success. Now the failure of the German-made mole has made the heat sensor a failure.

To send a lander to Mars at a cost of a billion dollars with so little payoff seems in hindsight to have been bad use of money. Plenty of other NASA planetary missions have done far better for far less.

24 comments

Another professor arrested for hiding ties to China

9:11 pm

An MIT professor has been arrested for hiding his extensive ties to the Chinese communist government, even as he took almost $20 million in grants from the Department of Energy.

According to prosecutors, Gang Chen, a mechanical engineering professor at MIT, has held various positions on behalf of the PRC aimed at promoting China’s technological and scientific capabilities. He allegedly shared his expertise directly with Chinese government officials, “often in exchange for financial compensation,” said prosecutors in the U.S. attorney’s office in Boston.

The Chinese consulate in New York allegedly requested that Chen, a naturalized U.S. citizen, act as an “overseas expert” for the PRC. He was also a member of two talent programs that the PRC has used to place Chinese students at American universities.

This is not the NASA scientist who pled guilty to similar charges yesterday.

It appears to me that the Trump Justice Department is trying to wrap up as many of its cases of academics spying for China as it can before Joe Biden takes over.

4 comments

Craters in slush on Mars

1:11 pm

Dust devil steak across a slushy plain on Mars
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on October 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was taken not for any particular research project, but as one of the periodic images the camera team needs to take maintain the camera’s proper temperature. When they need to do this, they often will take a picture in an area not previously viewed at high resolution. Sometimes the image is boring. Sometimes they photograph some geology that is really fascinating, and begs for some young scientist to devote some effort to studying it.

In this case the photo was of the generally featureless northern lowland plains. What the image shows us is a scattering of impact craters that appear to have cut into a flat plain likely saturated with ice very close to the surface.

How can I conclude so confidently that these craters impacted into ice close to the surface? The location gives it away.
» Read more

Leave a comment

The target landing ellipse on Mars for Perseverance

2:59 pm

Perseverance's landing ellipse on Mars
Click for full image.

In just over a month, on February 18, 2021, the American rover Perseverance will come screaming through the thin atmosphere of Mars at a speed of over 12,000 miles per hour to hopefully land successfully in Jezero Crater.

The map to the right, cropped and reduced to post here, was released last week by the Perseverance science team and shows the landing ellipse in that crater. It also shows the much larger landing ellipses of previous landers/rovers. As they noted,
» Read more

3 comments

Giant iceberg from Antarctica breaking up

1:10 pm

As should have been expected, the giant iceberg the size of Delaware that had broken from the Antarctic ice pack in 2017 and was drifting directly towards South Georgia Island (a wildlife preserve), is now breaking up without doing any harm to the island itself.

Seawater has been cutting like a knife through A-68A, the enormous Antarctic iceberg drifting in the southern Atlantic Ocean. On January 11, 2021, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the NOAA-20 satellite acquired this image showing the remainder of A-68A, along with two large pieces that broke off in December 2020.

The U.S. National Ice Center (USNIC) reported on January 8 that A-68A measured 74 kilometers long and 44 kilometers wide. That equates to an area about twice the size of Houston—still sizable, but quite a bit smaller than its Delaware-sized status in July 2017 when it calved from the Larsen C Ice Shelf. The pieces that broke from A-68A in December (forming A-68D and A-68E) are smaller, but remain large enough to be tracked by the USNIC.

Every report about this, including today’s, waxes eloquently about the terrible threat the iceberg poses to the wildlife on South Georgia Island should it become grounded there, even though all past data, let me repeat, all past data indicated that it would not hit the island but drift around as it broke up.

And, surprise surprise, that is exactly what it has been doing.

4 comments

The colorful and bright knobs of Ariadnes Colles on Mars

1:50 pm

Colorful and bright knob in Ariadnes Colles
Click for full image.

Today’s cool image gives us a sample of the strange colorful hills in an even stranger knobby depression on Mars called Ariadnes Colles. The photo to the right, cropped and color enhanced to post here, was taken on September 10, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It focuses on just one of those colorful hills. The color strip only covers the western half, which is why that is the only part of the hill in color.

Ariadnes Colles is a patch of chaotic terrain 110 by 100 miles in size, located in the southern cratered highlands due south of Mars’s volcano country, at latitude 34 degrees south. What makes this particular patch of chaos distinct from the many others on Mars is that the hills, knobs, and mesas within it are routinely bright and colorful, compared to the darker surrounding terrain. Moreover, as noted in this Mars Express press release for images of Ariadnes Colles from that orbiter,

In contrast to other chaotic terrains … Adrianes Colles is not a water-source region. It is still debated, therefore, whether Ariadnes Colles was formed by the action of water or wind.

The darker material in the southern areas is most likely sand or volcanic ash; some slopes of the flat-topped features have been covered by this dark material that was blown up on the slopes.

The sand or volcanic ash most likely come from the Medusae Fossae Formation several hundred miles to the north, the largest volcanic ash deposit on Mars. The colors on the hill likely come from a variety of minerals.

The overview map below shows the entire patch, with the location of the hill above indicated by the white dot in the red rectangle that shows the full image location.
» Read more

One comment

Astronomers discover first periodic erupting supermassive black hole

11:40 am

Astronomers observing a galaxy 570 million light years away have discovered that the periodic energetic flares that occur there every 114 days are not supernovae but eruptions from the supermassive black hole at the center of the galaxy, caused each time an orbiting star gets too close during its perihelion and has material stripped away from it.

ASASSN-14ko was first detected by the All-Sky Automated Survey for Supernovae (ASAS-SN), a global network of 20 robotic telescopes headquartered at The Ohio State University (OSU) in Columbus. When Payne examined all the ASAS-SN data on the phenomenon, she noticed a series of 17 regularly spaced flares.

Based on this discovery, the astronomers predicted that the galaxy would experience another burst on May 17 of last year and coordinated ground- and space-based facilities to make observations. They have since successfully predicted and witnessed flares on September 7 and December 26.

Though the press release tries to sell itself by saying these flares were initially mistaken for supernovae, a close reading suggests the astronomers thought this for only a very short time. As soon as they took their first close look and noticed the regularly space events, they abandoned the supernovae idea immediately.

Most supermassive black holes at the center of galaxies are active, emitting large amounts of energy in bursts or in a steady stream. That is why astronomers label them Active Galactic Nuclei, or AGNs. This is the first to do so in a periodic manner.

That most are active illustrates the mystery of the supermassive black hole in the center of the Milky Way. Sagittarius A* (pronounced A-star) is not active, even though it really should be.

5 comments

NASA extends mission of Juno and InSight probes

8:08 am

NASA has decided to extend the missions of Juno and InSight probes, giving both several more years to gather data.

InSight main goal for the two-year extension will be to gather more seismic data of Mars. They will also continue their efforts to get the heat sensor into the ground, but that will have a lower priority.

Juno will be able to slowly adjust its orbit to better study Jupiter’s north polar regions, thus developing a more complete first rough map of the gas giant’s internal structure and atmosphere. The changing orbit will also allow the first close fly-bys of some of Jupiter’s moons, the first in more than twenty years.

The moon flybys could begin in mid-2021 with an encounter with Ganymede, Jupiter’s largest moon, at a distance of roughly 600 miles (1,000 kilometers), Bolton said last year.

After a series of distant passes, Juno will swoop just 200 miles (320 kilometers) above Europa in late 2022 for a high-speed flyby. Only NASA’s Galileo spacecraft, which ended its mission in 2003, has come closer to Europa.

There are two encounters with Jupiter’s volcanic moon Io planned in 2024 at distances of about 900 miles (1,500 kilometers), according to the flight plan presented by Bolton last year. Juno will be able to look for changes on the surfaces of Jupiter’s moons since they were last seen up close by NASA’s Voyager and Galileo probes.

While it will take images, Juno’s camera is not particularly high resolution. The main effort will be to use its instruments to study the surface make-up of the moons.

9 comments

Hayabusa-2 begins journey to two asteroids

7:59 am

On January 5, 2021, after successfully delivering its samples of Ryugu to Earth, Hayabusa-2 fired up its ion engines and began its ten-year journey to two different asteroids.

Hayabusa2’s first extended-mission destination is the roughly 2,300-foot-wide (700 meters) asteroid (98943) 2001 CC21, which the probe will fly by at high speed in 2026, if all goes according to plan. A more in-depth rendezvous with yet another space rock, 1998 KY26, is scheduled to follow in 2031.

In a previous post I had mistakenly left out the first target asteroid. However, their primary target remains the tiny 100-foot-wide 1998 KY26, since it is so small. This will be the first close-up view of such a small asteroid, in space. Since such asteroids are many, it will tell us much about the make-up and history of the solar system.

2 comments

Partly engulfed Martian craters

5:01 pm

An engulfed crater on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on October 31, 2020. It shows a crater that appears buried in a sea of material so that pretty much the only thing visible is top of its rim.

The full image shows a second larger crater to the northwest that looks the same. In both cases the material fills the craters also fills the surrounding terrain.

Yet, both craters appear to be surrounded by a faint skirt of uplifted material.

What caused this situation?
» Read more

One comment

Congress frees Europa Clipper from SLS

9:10 am

It appears that Congress has at last removed its requirement that the unmanned probe Europa Clipper must be launched on the continually delayed and very expensive SLS rocket.

Almost unnoticed, tucked into the 2021 fiscal NASA funding section of the recently passed omnibus spending bill, is a provision that would seem to liberate the upcoming Europa Clipper mission from the Space Launch System (SLS).

According to Space News, the mandate that the Europa Clipper mission be launched on an SLS remains in place only if the behind-schedule and overpriced heavy lift rocket is available and if concerns about hardware compatibility between the probe and the launcher are resolved. Otherwise, NASA is free to search for commercial alternatives to get the Europa Clipper to Jupiter’s ice-shrouded moon.

Not only will this secure Europa Clipper’s launch schedule, which had deadlines imposed by orbital mechanics that SLS was not going to meet, the more than $1 billion in savings by using a SpaceX Falcon Heavy will allow the probe to do more while giving NASA more money for other planetary missions.

This is excellent news. It signals that Congress’s long love affair with SLS because of the ample pork it sends to many districts might finally be waning. If so, there is a good chance it will finally be killed, freeing up its bloated budget.

Sadly, in a sane world some of those savings would be used to reduce the overall federal deficit even as some was also used to expand NASA’s space effort. We are not in a sane world, however, so expect no reduction in the federal budget, at all.

Still, this is a move by Congress towards some fiscal responsibility that will make NASA’s efforts more efficient. For that small improvement we should be grateful.

3 comments

Colliding galaxies!

2:19 pm

Colliding galaxies!
Click here and here to see full images.

Cool images from Hubble! The two photos to the right, cropped and reduced to post here, shows two different galaxies undergoing a collision with another galaxy. Both images are from of a montage of six galaxy merger images from the Hubble Space Telescope, released yesterday.

To celebrate a new year, the NASA/ESA Hubble Space Telescope has published a montage of six beautiful galaxy mergers. Each of these merging systems was studied as part of the recent HiPEEC survey to investigate the rate of new star formation within such systems. These interactions are a key aspect of galaxy evolution and are among the most spectacular events in the lifetime of a galaxy.

It is during rare merging events that galaxies undergo dramatic changes in their appearance and in their stellar content. These systems are excellent laboratories to trace the formation of star clusters under extreme physical conditions.

The first galaxy merger to the right is dubbed NGC 6052, and is located in the constellation of Hercules about 230 million light-years away. This pair of colliding galaxies, according to the caption, “were first discovered in 1784 by William Herschel and were originally classified as a single irregular galaxy because of their odd shape. However, we now know that NGC 6052 actually consists of two galaxies that are in the process of colliding.”

The second image shows two galaxies, IC 694 and NGC 3690, about 700 millions after they had completed a close pass of each other. From the caption: “As a result of this interaction, the system underwent a fierce burst of star formation. In the last fifteen years or so six supernovae have popped off in the outer reaches of the galaxy, making this system a distinguished supernova factory.”

You can see all six merger images here, though to my eye these two are the most impressive.

2 comments

Draping moraines on Mars

1:07 pm

Draping moraines on Mars
Click for full image.

Cool image time! The photo on the right, rotated, cropped, reduced, and annotated to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter on October 6, 2020. It shows the northern interior rim of 42-mile-wide Greg Crater in the southern cratered highlands of Mars.

What makes it interesting is the curving ridge that appears to drape itself around several larger hilltops. That ridge is a moraine, the debris or glacial till that accumulates at the foot of glaciers as push their way down hill. As the glacier had flowed those hills became obstacles, so that the glacier (and its moraine) were forced to go around.

The overview map and wider view from the context camera on MRO below give the setting.
» Read more

Leave a comment

Rover update: Curiosity on the shore of a sand sea

1:24 pm

Curiosity stops on the shore of a sand sea, while Yutu-2 continues its journey west away from Chang’e-2. On the way: Perseverance and China’s first Mars rover on Tianwen-1.

A sand sea on Mars
Click for full image.

Curiosity

The photo on the right, taken in late December, shows the large sand lake the science team has labeled “the Sands of Forvie” that the rover has been working its way uphill to reach since it left the Mary Anning drill site back in November.

Since they arrived there, they have used the rover to roll across the sand, cutting into a ripple to expose its interior, followed by high resolution close-up images. They have also used the rover to analyze the chemical composition of the sand’s grains, from that interior section, from the top of several ripples, and from the troughs in between.

Once finished here, the rover will be turned east again to continue its journey around this sand sea to the very base of Mount Sharp. The overview map below shows the planned route.
» Read more

Leave a comment

A glacier filled canyon on Mars?

11:26 am

Large glacial flow exiting Mamers Valles
Click for full image.

The photo to the right, rotated, cropped, and reduced to post here, was taken on September 9, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the northern half of a 15-mile wide canyon on Mars whose floor appears to be completely filled by a glacier. The full picture shows both the north and south rims, and captures the canyon’s outlet from the southern cratered highlands into the chaotic terrain of Deuteronilus Mensae, the region of Mars I like to call glacier country. This region of canyons and mesas forms the transition zone down to the northern lowland plains, and is a region where almost every MRO image shows glacial-type features.

The size and age of this glacial feature is what makes it stand out. First, note the craters on its surface. The glacier has to be quite old and inactive for a long time for those craters to still exist as they appear. Any movement would have distorted them, and they show little distortion.

The overview map below gives a sense of this glacier’s size.
» Read more

Leave a comment

Tianwen-1 to arrive in Mars orbit February 10

4:03 pm

The new colonial movement: China’s space agency, CNSA, today announced that its first Mars orbiter/lander/rover, Tianwen-1, will arrive in Mars orbit on February 10th, with the lander/rover dropping to the surface in May.

After entering orbit, Tianwen-1 will begin to prepare for a landing attempt of the mission’s rover. The orbiter will begin imaging the main candidate landing site within the huge impact basin Utopia Planitia, to the south of NASA’s Viking 2 landing site.

Getting ready for the attempt will take time however, with CNSA stating that the landing won’t take place until May.

At the moment they say that all systems are working as planned, and that they have one more course correction, the fourth, to do before entering orbit.

11 comments

A Martian “glacier” made of volcanic ash

2:19 pm

A Martian
Click for full image.

Of the numerous cool images I’ve posted on Mars, many have documented the growing evidence that in the mid-latitudes of the Red Planet are many buried glaciers of ice.

Today’s cool image to the right, rotated, cropped and reduced to post here, shows something that at first might resemble the features one would expect from an ice glacier, but in reality is actually a flow of volcanic ash being blown almost like a river, with the prevailing winds blowing from the south to the north.

The photo was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on November 1, 2020. The location, very close to the equator and in the transition zone dubbed the Cerberus Plains, is also smack dab between Mars’s biggest volcanoes, a region I like to dub Mars’s volcano country. The overview map below gives the context.
» Read more

One comment

Sunspot update: December sunspot activity once again higher than predicted

1:11 pm

The uncertainty of science: It is time to once again take a look at the state of the Sun’s on-going sunspot cycle. Below is NOAA’s January 1, 2021 monthly graph, documenting the Sun’s monthly sunspot activity and annotated by me to show previous solar cycle predictions.

The ramp up to solar maximum continued in December. Though there was a drop from the very high activity seen in November, the number of sunspots in December still far exceeded the prediction as indicated by the red curve.

» Read more

4 comments

The seasonal cloud over Arsia Mons on Mars

9:21 pm

Water-ice cloud over Arsia Mons
The cloud as seen in 2018.

Scientists have now documented the seasonal nature of the strangely elongated cloud that was first spotted in 2018 above the giant volcano Arsia Mons (the southernmost volcano of the three volcanoes east of Olympus Mons).

From their abstract:

We find that the AMEC [Arsia Mons Elongated Cloud] repeated regularly each morning for a number of months, and that it is an annually‐repeating phenomenon that takes place every Martian Year around the southern hemisphere spring and summer. The AMEC follows a rapid daily cycle: it starts to expand from Arsia Mons at dawn at an altitude of about ∼45 km, and for ∼2.5 hours it expands westward as fast as 170 m/s (around 600 km/h). The cloud then detaches from Arsia Mons and evaporates before noon. In previous Martian Years, few observations of this phenomenon are available because most cameras orbiting Mars are placed in orbits where they can only observe during the afternoon, whereas this cloud takes place in the early morning, when observational coverage is much lower.

They also state that they will outline their theories as to the cause of the cloud in a follow-up paper.

I can’t help wondering if it is related to other evidence that suggested past glacial activity on the western flanks of Arsia Mons. There are many pits surrounding this volcano, and many might contain residue ice. One wonders if, during the warm spring and summer months at dawn the arrival of the sun might cause this cloud to form, and then vanish as the day passes, just like the dew does on Earth.

That is my uneducated guess, and likely wrong. We shall have to wait for their theoretical paper for a more educated guess.

4 comments

Surprisingly low number of observation proposals from astronomers for Webb telescope

4:03 pm

In preparation for the launch of the James Webb Space Telescope in ’21, the Space Telescope Science Institute (STScI) that will operate it has begun accepting observation proposals from astronomers, and has apparently discovered that the number of proposals, dubbed the subscription rate, is surprisingly low.

The stats of the James Webb space telescope cycle 1 proposal round came in the other day. In summary: an over subscription rate of 1:4. A little less even.

There was immediate spin how the stats were a good thing. Enthusiasm from around the globe! So many investigators! But that does not change that the 1:4 oversubscription is a disappointment. If I were part of the project, this would and should worry me.

If they got exactly the right number of proposals to precisely use all of the telescope’s observation time, the subscription rate would be 1. An oversubscription rate of 1.4 seems good, but in truth it is tiny compared to Hubble and other space telescopes, and horrible considering the cost of Webb (almost $10 billion, 20x what it was originally budgeted).

The author at the link provides some technical reasons for the low interest, some of which are the fault of the Webb management team (such as a very complicated proposal process) and some that are beyond their control (the Wuhan panic). He also provides suggestions that might help.

Either way, the relatively low interest I think is rooted in Webb’s initial genesis. It was pushed by the cosmological community and its design thus optimized for studying the early universe. Other astronomical fields were pushed aside or given a lower priority so that the telescope does not serve them as well.

The result is that a lot of astronomers have been finding other more appropriate and already functioning telescopes to do their work, bypassing Webb entirely. They are probably also bypassing Webb because it seems foolish to spend the inordinate amount of time putting together a proposal for a telescope a decade behind schedule that carries an enormous risk of failure once it is launched.

10 comments

Puerto Rican government commits $8 million to rebuild Arecibo

8:16 am

The government of Puerto Rico earlier this week announced that it has allocated $8 million to rebuild the Arecibo Observatory.

Via an executive order, Gov. Wanda Vazquez made reconstruction of the observatory public policy. In a ceremony at La Fortaleza, the seat of the island’s government, Vazquez said that the Puerto Rican government believes that the telescope’s collapse provides a great opportunity to redesign it, taking into account the lessons learned and recommendations from the scientific community so that it remains relevant for decades to come.

…Vazquez said that she and her administration want the scope to once again become a world class center and the $8 million being allocated for reconstruction includes funds to repair the environmental damage caused by the collapse, something that has already begun under the supervision of the National Science Foundation (NSF).

We shall see what happens. $8 million is not really enough to rebuild Arecibo. And the NSF has been trying to unload it from its budgetary responsibility for almost a decade. I would be shocked if that agency now suddenly decided to fund its reconstruction.

Only if Congress gets involved will this likely change, and that wouldn’t surprise me, considering how nonchalant our present Congress is about spending money that doesn’t exist.

7 comments

Summer at the Martian south pole

1:34 pm

Overview of the Martian south pole

Today we have two cool images, both giving us a tiny glimpse at what it is like in the middle of summer on the fringes of Mars’ south pole ice cap. Their location is indicated by the blue crosses on the overview map on the right.

To review, the south pole on Mars is, like its north pole, mostly made up of a permanent icecap of water. In the south, this icecap is mostly mixed with dust and debris in the area outlined in black and dubbed the layered deposits. On top of this is a smaller thick water ice cap, indicated by light blue, which is in turn topped by a thin cap of frozen carbon dioxide, or dry ice, indicated by white. During the winter the entire pole, down to 60 degrees latitude also gets covered by a temporary mantle of dry ice, that sublimates away each spring.

Now for our cool images!
» Read more

Leave a comment

The seas of Titan, deep and alien

11:29 am

Radar track through the estuaries of Titan's large sea, Kraken Mare

The uncertainty of science: In a new paper scientists have taken the radar data from the more than 120 fly-bys by Cassini of Titan to map out the estimated depths for several of Titan’s seas, using that data to also better constrain the make-up of those seas. From their abstract:

Our analysis reveals that the seafloor at the center of Moray Sinus—an estuary located at the northern end of Kraken Mare, is up to 85 m deep. The radar waves are absorbed to an extent such that the liquid composition is compatible with 70% methane, 16% nitrogen, and 14% ethane (assuming ideal mixing). The analysis of the altimetry data in the main body of Kraken Mare showed no evidence for signal returns from the sea floor, suggesting the liquid is either too deep or too absorptive for Cassini’s radio waves to penetrate. However, if the liquid in the main body of Kraken Mare is similar in composition to Moray Sinus, as one would expect, then its depth exceeds 100 m.

The image above, cropped and reduced to post here, is figure two from the paper. » Read more

5 comments

Published results from Curiosity as it traversed Vera Rubin Ridge

9:34 am

The science results from American Mars rover Curiosity during its traverse of Vera Rubin Ridge at the base of Mount Sharp in Gale Crater have now been released to the public.

This link takes you to the overview paper, available online for free. The abstract notes the key finding, which confirms previously released research:

We conclude Vera Rubin ridge formed because groundwater recrystallized and hardened the rocks that now make up the ridge. Wind subsequently sculpted and eroded Mount Sharp, leaving the harder ridge rocks standing because they resisted erosion compared with surrounding rocks. The implication of these results is that liquid water was present at Mount Sharp for a very long time, not only when the crater held a lake but also much later, likely as groundwater.

The fundamental geological mystery of Mars remains. The evidence strongly says that liquid water must have existed for long periods on the surface of Mars. At the same time, other evidence strongly says that the climate and atmosphere of Mars has never been warm enough or thick enough to allow for liquid water on the planet’s surface.

So far, no global model proposed by any theorist that allows liquid water in the past on Mars has been accepted with any enthusiasm by the planetary community. While possible, the models carry too many assumptions and are based on what is presently far too limited data. We simply do not yet know enough about Mars and its past history to explain this conundrum.

The paper also outlines a number of models for allowing liquid water in the localized area of Gale Crater alone. As with the global models, none fits all the facts, or is entirely satisfactory for explaining the data.

Regardless, the results from Vera Rubin Ridge confirm once again that enough liquid water once did exist on Mars to have allowed it to be habitable for life, even if we have so far found no evidence of any past life.

One comment

First look at Ryugu samples

8:55 am

Japanese scientists have taken their first look at the Ryugu sample material brought back by Hayabusa-2 and found they resemble charcoal.

The samples Japanese space officials described Thursday are as big as 1 centimeter (0.4 inch) and rock hard, not breaking when picked up or poured into another container. Smaller black, sandy granules the spacecraft collected and returned separately were described last week.

…The sandy granules the Japan Aerospace Exploration Agency described last week were from the spacecraft’s first touchdown in April 2019.

The larger fragments were from the compartment allocated for the second touchdown on Ryugu, said Tomohiro Usui, space materials scientist. To get the second set of samples in July last year, Hayabusa2 dropped an impactor to blast below the asteroid’s surface, collecting material from the crafter so it would be unaffected by space radiation and other environmental factors.

Usui said the size differences suggest different hardness of the bedrock on the asteroid. “One possibility is that the place of the second touchdown was a hard bedrock and larger particles broke and entered the compartment.”

The analysis of these samples has only just begun. Dating them is likely next, and that will probably reveal some startling results.

7 comments

A Martian polliwog

3:32 pm

Three-mile-wide crater with exit breach
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on September 30, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It shows one half of what scientists have dubbed a pollywog crater, in which there is a single breach in the crater wall, aligned with the low point in the crater’s floor. Such craters suggest that they were once water- or ice-filled, and that they drained out through the breach either quickly in a single event or slowly over multiple events.

The second image below was taken by the wide angle context camera on MRO, and not only shows this entire crater, but several other adjacent craters, all of which show evidence of glacial fill in their interiors. The latitude here is 34 degrees south, placing these craters within the mid-latitude bands where such glacial features have been found by scientists in great numbers.
» Read more

4 comments

A Mars mosaic from Curiosity using its close-up camera

9:36 am

During the three-plus months in the summer when Curiosity stayed at one location for its most recent drilling campaign, the science team used its ChemCam Remote Micro-Imager camera (RMI), originally designed to take very close-up photos, to create a 216 photo mosaic of the long distance horizon. They have now released that mosaic, which you can see as a video at the link. The mosaic itself is a very long strip, which is best viewed up close and scrolling across it, as the video does. As the scientists note,

During Curiosity’s first year on Mars, it was recognized that, thanks to its powerful optics, RMI could also go from a microscope to a telescope and play a significant role as a long-distance reconnaissance tool. It gives a typical circular “spyglass” black and white picture of a small region. So RMI complements other cameras quite nicely, thanks to its very long focal length. When stitched together, RMI mosaics reveal details of the landscape several kilometers from the rover, and provides pictures that are very complementary to orbital observations, giving a more human-like, ground-based perspective.

From July to October of 2020, Curiosity stayed parked at the same place to perform various rock sampling analyses. This rare opportunity of staying at the same location for a long time was used by the team to target very distant areas of interest, building an ever-growing RMI mosaic between September 9 and October 23 (sols 2878 and 2921) that eventually became 216 overlapping images. When stitched into a 46947×7260 pixel panorama, it covers over 50 degrees of azimuth along the horizon, from the bottom layers of “Mount Sharp” on the right to the edge of “Vera Rubin Ridge” on the left.

The camera’s resolution is so good that it was able in the mosaic to resolve large boulders on the crater wall of Gale Crater almost 37 miles away.

One comment
1 … 81 82 83 84 85 … 275