Tag: science

Europa’s mysterious stained grooves

11:18 am

Europa's jumbled icepack
Click for full image.

From 1995 to 2003 the Galileo orbiter circled Jupiter 34 times. During those orbits the spacecraft made numerous close fly-bys of Jupiter’s moons, including eleven past the tantalizingly mysterious moon Europa.

The image to the right was taken during the eighth fly-by of Europa. It is one of three Galileo images of Europa that scientists have pulled from the Galileo archive and subjected to modern computer processing in order to improve what can be seen. The other two can be found here and here. From the release for the image to the right:

All three images were captured along the same longitude of Europa as Galileo flew by on Sept. 26, 1998, in the spacecraft’s 17th orbit of Jupiter (orbit E17). It was the eighth of Galileo’s 11 targeted flybys of Europa. High-resolution images were taken through a clear filter in grayscale (black and white). Using lower-resolution, color images of the same region from a different flyby (orbit E14), technicians recently mapped color onto the higher-resolution images.

In other words, they laid the colors from a lower resolution color image on top of the high resolution black & white image so that we could see these three images in color. The blue and white areas are made of up water ice, while the reddish areas are made up of “more non-ice materials.”

The vagueness for describing the non-ice materials is intentional, as scientists still do not know what they made of. They do believe that this material came from the planet’s interior, as the red material is always found aligned with the cracks, fissures, and grooves, as illustrated clear by this image.

What has always struck me about this surface of Europa since I first saw similar Galileo images back in 1998 and wrote about them for the magazine The Sciences is how much it resembles the Arctic ice pack as seen by early explorers during their attempts to reach the North Pole, jumbled jigsaw pieces of ice packed together but moving slowly so that the cracks between them shift and change over time.

The resemblance adds weight to the theory that there is a liquid ocean below Europa’s icepack, and the red material hints at some intriguing chemistry coming from that ocean.

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Starlink satellites, not aliens, are those strings of lights in the night sky

1:12 pm

Apparently many people have been seeing the reflected strings of SpaceX’s new Starlink satellites in the night sky, and are calling news organizations asking about them.

Some viewers have noticed the “lights” in the sky will go dark, one by one. This is due to the reflection of light from the moon and Earth and how the position of the satellites change.

Elon Musk, the founder and CEO of SpaceX, detailed a plan this week to “mitigate the impact of their Starlink satellite constellation on night sky observation,” according to an article on Tech Crunch.

In that Tech Crunch article, Musk describes how they are installing sun visors on the satellites to prevent the reflections and make them hopefully invisible to the Earthbound observers.

This will make the astronomy crowd happy, which wants its new big ground-based telescopes to be useful. I think they should instead be focusing their effort in building more space-based telescopes.

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The Sun fluctuates far less than other similar stars

12:24 pm

A new survey of 369 sun-like stars has confirmed what earlier studies have shown, that the Sun is remarkable inactive compared with similar stars.

A comprehensive catalogue containing the rotation periods of thousands of stars has been available only for the last few years. It is based on measurement data from NASA’s Kepler Space Telescope, which recorded the brightness fluctuations of approximately 150000 main sequence stars (i.e. those that are in the middle of their lifetimes) from 2009 to 2013. The researchers scoured this huge sample and selected those stars that rotate once around their own axis within 20 to 30 days. The Sun needs about 24.5 days for this. The researchers were able to further narrow down this sample by using data from the European Gaia Space Telescope. In the end, 369 stars remained, which also resemble the Sun in other fundamental properties.

The exact analysis of the brightness variations of these stars from 2009 to 2013 reveals a clear picture. While between active and inactive phases solar irradiance fluctuated on average by just 0.07 percent, the other stars showed much larger variation. Their fluctuations were typically about five times as strong. “We were very surprised that most of the Sun-like stars are so much more active than the Sun,” says Dr. Alexander Shapiro of MPS.

It is possible that this inactivity might be because the Sun just happens to be going through a quiet phase, but that is becoming increasingly less likely as the surveys find more and more sun-like stars, and none as inactive as the Sun.

If the Sun is this unusual, we must ask if this inactivity is a fundamental requirement for life to form. Active stars provide a more inhospitable environment. If inactive stars like the Sun are very rare, however, that suggests that life itself in the universe could be very rare as well.

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Hubble photographs break-up of Comet ATLAS

10:53 am

The break-up of Comet ATLAS
For the full images go to April 20 and April 23.

Cool image time! Scientists using the Hubble Space Telescope have captured the break-up of Comet ATLAS over a period of several days. The two images to the right, cropped and annotated to post here, were taken on April 20th and April 23rd respectively.

Hubble identified about 30 fragments on April 20, and 25 pieces on April 23. They are all enveloped in a sunlight-swept tail of cometary dust. “Their appearance changes substantially between the two days, so much so that it’s quite difficult to connect the dots,” said David Jewitt, professor of planetary science and astronomy at UCLA, Los Angeles, California, leader of one of two teams who photographed the doomed comet with Hubble. “I don’t know whether this is because the individual pieces are flashing on and off as they reflect sunlight, acting like twinkling lights on a Christmas tree, or because different fragments appear on different days.”

That there are fewer pieces in the later image could also be because the smaller fragments had crumbled even more during the three days between photos, and thus were simply too small to see any longer.

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A Martian lava flood plain

1:21 pm

A Martian lava flood plain?
Click for full image.

Cool image time! The photo to the right, cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on March 2, 2020, and shows some inexplicable shallow pits and depressions in the middle of a relatively flat and featureless plain.

Make sure you click on the image to see the full photo. Though the plain looks remarkably smooth, a handful of dark splotches are scattered about, almost all of which occur on top of small craters.

What causes these depressions? The MRO team calls this “Landforms near Cerberus Tholi.” Cereberus Tholi is a a collection of several indistinct and relatively small humps that scientists think might be shield volcanoes.

More clues come from the overall context.
» Read more

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More data from interstellar Comet 2I/Borisov as it zipped past Sun in December

10:00 am

Astronomers studying interstellar Comet 2I/Borisov as it zipped past Sun in December have found that while in many ways it resembled solar system comets, the differences were revealing.

During its trip through the solar system, the comet lost nearly 61 million gallons (230 million liters) of water — enough to fill over 92 Olympic-size swimming pools. As it moved away from the Sun, Borisov’s water loss dropped off — and did so more rapidly than any previously observed comet. Xing said this could have been caused by a variety of factors, including surface erosion, rotational change and even fragmentation. In fact, data from Hubble and other observatories show that chunks of the comet broke off in late March.

…Swift’s water production measurements also helped the team calculate that Borisov’s minimum size is just under half a mile (0.74 kilometer) across. The team estimates at least 55% of Borisov’s surface — an area roughly equivalent to half of Central Park — was actively shedding material when it was closest to the Sun. That’s at least 10 times the active area on most observed solar system comets. Borisov also differs from solar system comets in other aspects. For example, astronomers working with Hubble and the Atacama Large Millimeter/submillimeter Array, a radio telescope in Chile, discovered Borisov produced the highest levels of carbon monoxide ever seen from a comet at that distance from the Sun.

Because more of the comet’s entire surface had water ice than seen in solar system comets, it suggests that the comet has never been close to another star before. That the water release dropped off precipitously however also suggests that that surface layer of ice was not very deep.

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Of almost 3,300 prisoners infected with COVID-19, 96% have no symptoms

10:05 am

Almost 3,300 prisoners in four state U.S. prison have tested positive for the Wuhan flu, with 96% exhibiting no symptoms at all.

When the first cases of the new coronavirus surfaced in Ohio’s prisons, the director in charge felt like she was fighting a ghost. “We weren’t always able to pinpoint where all the cases were coming from,” said Annette Chambers-Smith, director of the Ohio Department of Rehabilitation and Correction. As the virus spread, they began mass testing.

They started with the Marion Correctional Institution, which houses 2,500 prisoners in north central Ohio, many of them older with pre-existing health conditions. After testing 2,300 inmates for the coronavirus, they were shocked. Of the 2,028 who tested positive, close to 95% had no symptoms. “It was very surprising,” said Chambers-Smith, who oversees the state’s 28 correctional facilities.

As mass coronavirus testing expands in prisons, large numbers of inmates are showing no symptoms. In four state prison systems — Arkansas, North Carolina, Ohio and Virginia — 96% of 3,277 inmates who tested positive for the coronavirus were asymptomatic, according to interviews with officials and records reviewed by Reuters. That’s out of 4,693 tests that included results on symptoms.

Being a Reuters story, the goal is to spin this result as a terrifying disaster: “We can’t contain it! The disease is everywhere!”

In truth, this result is once again remarkably encouraging. It once again shows that the Wuhan flu is simply no threat to a very large percentage of the population, and that if enough of that population would stop social distancing and allow the infection to spread, they would end up killing it because it would soon have no place to go.

It also lends weight to the hypothesis that death rate from coronavirus is really not much different than the flu. There are almost certainly a vast number of people out there infected with the Wuhan virus who have showed no symptoms, meaning that our present estimates of the death rate are much too high.

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Movie of OSIRIS-REx’s 1st landing rehearsal

12:55 pm

Closest NavCam-2 image during rehearsal
Click for full movie.

The OSIRIS-REx science team has released a short movie taken by one of the spacecraft’s navigation camera (NavCam-2) during its first landing rehearsal on April 14. The image to the right, cropped to post here, is the closest image in the sequence, and shows the relatively smooth Nightingale target landing site near the bottom of the image, approximately 50 feet in diameter.

According to the release,

NavCam 2 captures images for the spacecraft’s Natural Feature Tracking (NFT) navigation system. The NFT system allows the spacecraft to autonomously guide itself to Bennu’s surface by comparing real-time images with an onboard image catalog. As the spacecraft descends to the surface, the NFT system updates the spacecraft’s predicted point of contact depending on OSIRIS-REx’s position in relation to Bennu’s landmarks. During the sample collection event, scheduled for August, the NavCam 2 camera will continuously image Bennu’s surface so that the NFT system can update the spacecraft’s position and velocity relative to Bennu as it descends towards the targeted touchdown point.

When the image above was taken the spacecraft was at its closest point, about 213 feet above the surface. Based on this movie, it looks like the system was working, and the spacecraft was refining its aim to head towards Nightingale.

Still, the landing site is not in the center of the image, which I would think is a concern, especially because Nightingale is only one-third the size of the kind of smooth target areas they had designed the system for. (When launched they expected to see smooth areas at least 160 feet across, and designed the system for this.)

The second rehearsal is presently scheduled for June 23, and will drop OSIRIS-REx to within 82 feet of the surface.

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Scientists fine tune the cause of the super-rotation of Venus’ atmosphere

10:39 am

Scientists using data collected from the Japanese Venus orbiter Akatsuki have now refined their theories on the atmospheric processes that cause that atmosphere to rotate sixty times faster than the planet.

This super-rotation increases with altitude, taking only four Earth days to circulate around the entire planet towards the top of the cloud cover. The fast-moving atmosphere transports heat from the planet’s dayside to nightside, reducing the temperature differences between the two hemispheres.

What they found was that at equatorial latitudes the heat transfer is generated by what they call “atmospheric tidal waves”, generated by the dayside solar heat. At high latitudes the transfer is instead caused by atmospheric turbulence.

From what I can gather, they are calling these tidal waves because the Sun’s heat causes the atmosphere to expand upward on the day side, much as the Moon’s gravity pulls the ocean upward on Earth. It then is quickly drawn to the colder night side, driven I think in one direction because of the planet’s slow rotation.

As always, we must recognize the uncertainties. The data here is somewhat limited because there have been so few atmospheric orbiters so far sent to study Venus. While several future missions are under study in the U.S. and Russia, only India appears to have one targeted for launch, though the date has been pushed back from 2020 to 2023.

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China names its 2020 Mars mission

10:19 am

China’s official state-run press today announced that their 2020 Mars mission will be called Tianwen-1, noting that this name will be applied to all further planetary missions.

The link goes to that government state-run press, which provides no further information on Tianwen-1, such as where on Mars its lander/rover will land, its exact launch date, the instruments on board, etc. So far very very few details have been released.

What this propaganda press announcement does do is spout a lot of blather about how wonderful China is, and how we should all be thankful the communists have been in charge there. Here are some snippets to lighten your day:

  • …signifying the Chinese nation’s perseverance in pursuing truth and science
  • …a window for the Chinese public and the world to get a better understanding of China’s aerospace progress.
  • Chinese space engineers and scientists have overcome various difficulties and achieved aerospace development through self-reliance and independent innovation.
  • …promoting human welfare on the basis of equality, mutual benefit, peaceful utilization and inclusive development.

While China’s achievements in space are real (though much of the engineering was stolen or borrowed from others), these propaganda claims are junk and lies. Chinese space engineers are “self-reliant” and have “independence”? Don’t make me laugh. Everything done in their space program is dictated and controlled from the top, by the Chinese government and the Communist Party. No one is free to do anything, without their permission.

As for China’s pursuit of “truth and science”, their behavior during the Wuhan flu epidemic, originating from their country and very possibly caused deliberately or incompetently by them, makes this claim ludicrous on its face. They have lied, arrested scientists, blocked research, and distorted the scope and magnitude of the epidemic from day one.

Even a tiny bit of truth from them, from the beginning, might have prevented the panic that has overtaken the world which in turn appears to have triggered the next great economic depression, what I like to now call the Great Wuhan Depression.

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The first complete geologic map of Moon

9:15 am

Geologic map of Moon

Using data from several recent lunar orbiters, scientists have compiled and now released the first comprehensive geologic map of the Moon.

To create the new digital map, scientists used information from six Apollo-era regional maps along with updated information from recent satellite missions to the moon. The existing historical maps were redrawn to align them with the modern data sets, thus preserving previous observations and interpretations. Along with merging new and old data, USGS researchers also developed a unified description of the stratigraphy, or rock layers, of the moon. This resolved issues from previous maps where rock names, descriptions and ages were sometimes inconsistent.

“This map is a culmination of a decades-long project,” said Corey Fortezzo, USGS geologist and lead author. “It provides vital information for new scientific studies by connecting the exploration of specific sites on the moon with the rest of the lunar surface.”

The image to the right shows the Moon’s near side.

The complete map file is free to download, and I guarantee that scientists and engineers in China are downloading it even as I type, planning to use it to establish their ownership to the Moon’s most valuable real estate that we scouted for them.

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Stucco on Mars

1:13 pm

Stucco on Mars
Click for full image.

As a break from Wuhan flu madness I give you another cool image, cropped and reduced to post here, taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I call this stucco on Mars because that is exactly what it looks like. It is as someone laid down a layer of damp concrete and then ran over it roughly with a trowel to raise the knobs scattered across the surface.

The uncaptioned MRO image calls this “Aligned Mounds with Broad Summit Pits”. Those aligned mounds run across the top of the image. I suspect they are pedestal craters, left over because the impact had packed and hardened the crater so that it resisted erosion as the surrounding terrain was worn away.

The two insets, posted below at full resolutoin, focus on one of those pedestal craters as well as the distinct mesa at the bottom of the photo.
» Read more

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First exoplanet imaged was nothing more than a debris cloud

2:41 pm

The uncertainty of science: What had originally been thought to be the first image ever taken of an exoplanet has now turned out to be only the fading and expanding cloud of debris, left over from a collusion.

The object, called Fomalhaut b, was first announced in 2008, based on data taken in 2004 and 2006. It was clearly visible in several years of Hubble observations that revealed it was a moving dot. Until then, evidence for exoplanets had mostly been inferred through indirect detection methods, such as subtle back-and-forth stellar wobbles, and shadows from planets passing in front of their stars.

Unlike other directly imaged exoplanets, however, nagging puzzles arose with Fomalhaut b early on. The object was unusually bright in visible light, but did not have any detectable infrared heat signature. Astronomers conjectured that the added brightness came from a huge shell or ring of dust encircling the planet that may possibly have been collision-related. The orbit of Fomalhaut b also appeared unusual, possibly very eccentric. “Our study, which analyzed all available archival Hubble data on Fomalhaut revealed several characteristics that together paint a picture that the planet-sized object may never have existed in the first place,” said Gáspár.

The team emphasizes that the final nail in the coffin came when their data analysis of Hubble images taken in 2014 showed the object had vanished, to their disbelief. Adding to the mystery, earlier images showed the object to continuously fade over time, they say. “Clearly, Fomalhaut b was doing things a bona fide planet should not be doing,” said Gáspár.

The interpretation is that Fomalhaut b is slowly expanding from the smashup that blasted a dissipating dust cloud into space. Taking into account all available data, Gáspár and Rieke think the collision occurred not too long prior to the first observations taken in 2004. By now the debris cloud, consisting of dust particles around 1 micron (1/50th the diameter of a human hair), is below Hubble’s detection limit. The dust cloud is estimated to have expanded by now to a size larger than the orbit of Earth around our Sun.

This is not the first exoplanet that astronauts thought they had imaged, only to find out later that it was no such thing.

Remember this when next you hear or read some scientist telling you they are certain about their results, or that the science is “settled.” Unless you can get close enough to get a real picture in high resolution, or have tons of data from many different sources over a considerable period of time, and conclusions must always be subject to skepticism

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Rock droplets hitting a Martian plain

12:42 pm

Depressions in Amazonis Planitia
Click for full image.

Cool image time! The photo the right, rotated, cropped, and reduced to post here, is not only cool, it contains a punchline. It was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on February 11, 2020 and shows one small area between two regions in the northern lowlands of Mars, dubbed Amazonia Planitia (to the south) and Arcadia Planitia (to the north) respectively.

This region is thought to have a lot of water ice just below the surface., so much in fact that Donna Viola of the University of Arizona has said, “I think you could dig anywhere to get your water ice.”

I think this image illustrates this fact nicely. Assuming the numerous depressions seen here were caused by impacts, either primary or secondary, it appears that when they hit the ground the heat of that impact was able to immediately melt a wide circular area. My guess is that an underwater ice table immediately turned to gas so that the dusty material mantling the surface then sagged, creating these wider circular depressions.

Of course, this is merely an off-the-cuff theory, and not to be taken too seriously. Other processes having nothing to do with impacts could explain what we see. For example, vents at the center of these craters might have allowed the underground ice to sublimate away, thus allowing the surface to sag.

So what’s the punchline?
» Read more

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Interstellar Comet 2I/Borisov has an excess of carbon monoxide

8:48 am

Astronomers using two difference space telescopes have found that Comet 2I/Borisov, the first known interstellar comet, has an abundance of carbon monoxide when compared to solar system comets.

The team used Hubble’s unique ultraviolet sensitivity to spectroscopically detect carbon monoxide gas escaping from comet Borisov’s solid comet nucleus. Hubble’s Cosmic Origins Spectrograph observed the comet on four separate occasions, from Dec. 11, 2019 to Jan. 13, 2020, which allowed the researchers to see the object’s chemical composition change quickly, as different ice mixtures, including carbon monoxide, oxygen, and water, sublimated under the warmth of the Sun.

The Hubble astronomers were surprised to find that the interstellar comet’s coma, the gas cloud surrounding the nucleus, contains a high amount of carbon monoxide gas, at least 50% more abundant than water vapor. This amount is more than three times higher than the previously measured quantity for any comet entering the inner solar system. The water measurement was made by NASA’s Neil Gehrels-Swift satellite, whose observations were conducted in tandem with the Hubble study.

Carbon monoxide ice is very volatile. It doesn’t take much sunlight to heat the ice and convert it to gas that escapes from a comet’s nucleus. For carbon monoxide, this activity occurs very far from the Sun, about 11 billion miles away, more than twice the distance of Pluto at its farthest point from the Sun. In contrast, water remains in its icy form until about 200 million miles from the Sun, the approximate distance of the inner edge of the asteroid belt.

However, for comet Borisov, the Hubble measurements suggest that some carbon monoxide ice was locked inside the comet’s nucleus, revealed only when the Sun’s heat stripped away layers of water ice. “The amount of carbon monoxide did not drop as expected as the comet receded from the Sun. This means that we are seeing the primitive layers of the comet, which really reflect what this object is made of,” Bodewits explained. “Because of the abundance of carbon monoxide ice that survived so close to the Sun, we think that comet Borisov comes from a much colder place and from a very different debris disk around a star than our own.”

With solar system comets, the ratios between water and carbon monoxide are the reverse, with much more water detected. They theorize, based on these results, that the comet might have come from a cool red dwarf star, but with the available data that is nothing more than a guess at this point.

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Strange terrain in the Martian lowlands

12:42 pm

Strange terrain in northern lowlands
Click for full image.

Cool image time! The science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) yesterday released a new captioned image, entitled “Disrupted Sediments in Acidalia Planitia”, noting that the photo

…shows a pitted, blocky surface, but also more unusually, it has contorted, irregular features.

Although there are impact craters in this area, some of the features … are too irregular to be relic impact craters or river channels. One possibility is that sedimentary layers have been warped from below to create these patterns. The freezing and thawing of subsurface ice is a mechanism that could have caused this.

The image to the right, rotated, cropped, and reduced to post here, shows the lower quarter of the full image. While in some areas it does appear as if changes below the surface caused the surface to warp and collapse, as suggested by the caption, in other places it looks more like the top layers themselves sublimated away without disturbing what was below them.

Note for example the pits near the bottom of the photograph. They clearly show sedimentary layers on their cliff walls, including the tiny circular mesa in the middle of the rightmost pit.

If these pits were collapsing from below, their cliffs would be more disturbed, because it would have been those lower layers that sublimated first. Instead, it appears that the top layer disappeared first, followed by each lower layer, one by one.

This region of strange terrain is located in the middle of the northern lowland plains. The overview map below gives some context, with the small white box showing this photo’s location.
» Read more

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Space radiation may increase risk of cancer

8:59 am

Using mice and models, scientists have concluded that humans who spend long periods in space, exposed to its radiation, will have a 3% higher risk for cancer.

A team led by researchers at Colorado State University and Frederick National Laboratory for Cancer Research, which is part of the National Institutes for Health, used a novel approach to test assumptions in a model used by NASA to predict these health risks. Based on the NASA model, the team found that astronauts will have more than a three percent risk of dying of cancer from the radiation exposures they will receive on a Mars mission. That level of risk exceeds what is considered acceptable. [emphasis mine]

And how did they come to this conclusion?

…For the study, Weil and first author Dr. Elijah Edmondson, a veterinary pathologist and researcher based at the Frederick National Laboratory for Cancer Research in Maryland, used a unique stock of genetically diverse mice, mimicking a human population. Mice were divided into three groups with the first group receiving no radiation exposure and the other two receiving varying levels of exposure.

Edmondson, who conducted the research while completing a veterinary residency in pathology at CSU, said that for this type of research project, genetic variability is crucial. “Humans are very genetically diverse,” he explained. “You want to model that when it’s appropriate and feasible to do so.”

Weil said although the research team saw different tumor types, similar to humans, but the heavy ions did not cause any unique types of cancer. They also saw differences by sex. In humans, women are more susceptible to radiation-induced cancers than men; one of the main reasons is that women live longer, allowing sufficient time for cancer to develop. In assessing the cancer risk between male and female mice in the study, scientists said the findings parallel human data.

Edmondson said the study validates the NASA model to measure cancer risks for humans from space radiation.

In a sense, this study is junk. First, it discovers the obvious (radiation increases your chances of getting cancer). Second, it is too model-dependent, so assigning any precise percentage to that increase in humans is absurd, especially when based on a sample comprised of mice.

Third, and most important, it completely forgets the reality that life is risk, exploration is dangerous, and to do great things you need to take greater chances. That NASA concludes these questionable numbers are unacceptable means that NASA will never send humans anywhere beyond Earth orbit. Ever.

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Chang’e-4 and Yutu-2 reactivated for 17th lunar day on Moon’s surface

8:40 am

Engineers have reactivated both the lander Chang’e-4 and the rover Yutu-2 for their seventeenth lunar day on the far side of the Moon.

The report comes from the state-run Chinese press, so of course, it provides no useful new information other than what I wrote above. It did have this bit of Chinese propaganda, however:

The Chang’e-4 mission embodies China’s hope to combine wisdom in space exploration with four payloads developed by the Netherlands, Germany, Sweden and Saudi Arabia. [emphasis mine]

China’s wisdom sure did everyone a lot of good in Wuhan, didn’t it?

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Rover update: Curiosity heads downhill

2:49 pm

Curiosity's last look across the Greenheugh Pedimont
Click for higher resolution.

[For the overall context of Curiosity’s travels, see my March 2016 post, Pinpointing Curiosity’s location in Gale Crater. For the updates in 2018 go here. For a full list of updates before February 8, 2018, go here.]

After finally reaching the top of the Greenheugh Pedimont (see both the March 4 and March 8, 2020 rover updates) and spending more than a month there, drilling one hole, getting samples, and taking a lot of photos, the Curiosity science team in the past week has finally sent the rover retreating back downhill, following the same route it used to climb uphill.

The panorama above was taken on April 10, 2020, and shows the last view looking south across that pedimont towards Mount Sharp, before that descent. As you can see, trying to traverse that terrain would have been very difficult, and probably very damaging to Curiosity’s wheels.
» Read more

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Movie of OSIRIS-REx touch-and-go rehearsal

10:47 am

Checkpoint rehearsal: last image
Click for movie.

The OSIRIS-REx science team yesterday released a short movie, compiled from thirty images taken during the April 14, 2020 rehearsal of the spacecraft’s planned August touch-and-go sample grab from the asteroid Bennu.

The rehearsal brought the spacecraft through the first two maneuvers of the sampling event to a point approximately 213 feet (65 meters) above the surface, before backing the spacecraft away. These images were recorded over a ten-minute span between the execution of the rehearsal’s “Checkpoint” burn, approximately 394 feet (120 meters) above the surface, and the completion of the back-away burn, which occurred approximately 213 feet (65 meters) above the surface. The spacecraft’s sampling arm – called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – is visible in the central part of the frame, and the relatively clear, dark patch of Bennu’s sample site Nightingale is visible in the later images, at the top. The large, dark boulder that the spacecraft approaches during the sequence is 43 feet (13 meters) on its longest axis.

The image to the right is the last frame of the movie, as the spacecraft has begun its retreat. The smoother area of Nightingale is at the top.

Based on the video, it appears as if the spacecraft would have missed the Nightingale target site had the rehearsal continued to touchdown. This might not be so, however. And even if it is, the reason for the rehearsal is to allow engineers to refine the process to make it more accurate. We shall see what changes in the second rehearsal in about a month or so.

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Astronomers claim to have discovered most powerful supernova ever

9:38 pm

The uncertainty of science: Astronomers have now calculated that a supernova that was spotted in 2016 was possibly the brightest ever detected, and might have been caused by the merger of two massive stars, each about sixty times as massive as the Sun.

SN 2016aps was discovered by the Panoramic Survey Telescope and Rapid Response System (Pan- STARRS) Survey for Transients on February 22, 2016 with an apparent magnitude of 18. Also known as PS16aqy, the explosion occurred in a low-mass galaxy some 3.1 billion light-years from Earth.

University of Birmingham’s Dr. Matt Nicholl and colleagues believe SN 2016aps could be an example of an extremely rare ‘pulsational pair-instability’ supernova, possibly formed from two massive stars that merged before the explosion. Such an event so far only exists in theory and has never been confirmed through astronomical observations.

…The researchers observed SN 2016aps for two years, until it faded to 1% of its peak brightness. Using these measurements, they calculated the mass of the supernova was between 50 to 100 solar masses. Typically supernovae have masses of between 8 and 15 solar masses.

They theorize that the supernova became especially bright when the explosion collided with a gas shell that already surrounded both stars.

Lots of assumptions and guesswork here, based on a tiny amount of data. The biggest lack is that they don’t have any observations of the star (or stars) prior to the supernova, so any theory about what those stars were like is exactly that, a theory.

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Baby Martian volcanoes

1:28 pm

Cratered cone near Noctis Fossae
Click for full image.

Cool image time! I came across this strange feature shown on the right in my normal rummaging through the archive of the high resolution camera on Mars Reconnaissance Orbiter (MRO). The photo, rotated, cropped, and reduced to post here, focuses on what they label a “cratered cone.”

The immediate thought is that this is a volcano cone, and the craters at its peak are not impact craters but calderas. In science however such a knee-jerk conclusion is always dangerous. For example, this might instead be a pedestal crater, where the surrounding terrain was worn away over eons, leaving the crater sitting high and dry.

It is therefore important to look deeper to determine what origin of this feature might be.

First, its location, as shown in the overview map below, provides us our first clue.
» Read more

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Earth-sized exoplanet in habitable zone found in old Kepler data

10:25 am

A review of the data produced by the space telescope Kepler, now retired, has discovered an exoplanet about the same size as Earth and also located in the habitable zone that had been missed previously by software.

Scientists discovered this planet, called Kepler-1649c, when looking through old observations from Kepler, which the agency retired in 2018. While previous searches with a computer algorithm misidentified it, researchers reviewing Kepler data took a second look at the signature and recognized it as a planet. Out of all the exoplanets found by Kepler, this distant world – located 300 light-years from Earth – is most similar to Earth in size and estimated temperature.

This newly revealed world is only 1.06 times larger than our own planet. Also, the amount of starlight it receives from its host star is 75% of the amount of light Earth receives from our Sun – meaning the exoplanet’s temperature may be similar to our planet’s as well. But unlike Earth, it orbits a red dwarf. Though none have been observed in this system, this type of star is known for stellar flare-ups that may make a planet’s environment challenging for any potential life.

A number of Earth-like planets have been found around red dwarf stars. Whether life could evolve in such places is entirely unknown. Red dwarfs are small, and would have likely formed in a nebula cloud with a dearth of many elements and materials needed for life. Moreover, because they are also so dim, the habitable zone is very near the star, meaning that, as the article mentions, strong flares are more dangerous.

At the same time, red dwarfs are the most common star, and the most long-lived, capable of burning for tens of billions of years. With enough time and numbers anything is still possible.

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Confirmed: Comet ATLAS has broken apart

8:47 am

Astronomers have now confirmed the fact that Comet ATLAS has broken into several pieces, and will not put on a spectacular sky show this coming May.

Just a month ago, it looked like the icy wanderer, officially known as C/2019 Y4 Atlas, might put on a dazzling sky show around the time of its closest approach to the sun, or perihelion, which occurs on May 31.

But relatively lackluster behavior soon dimmed such hopes. And optimism surrounding the comet is now pretty much extinguished, for it’s no longer in one piece. Comet Atlas “has shattered both its and our hearts,” astrophysicist Gianluca Masi, the founder and director of the Virtual Telescope Project in Italy, said in an emailed statement on Sunday (April 12). “Its nucleus disintegrated, and last night I could see three, possibly four main fragments.”

A nice picture of the break-up can be seen here.

We are due for another great comet, like Comet Hale-Bopp in the late 1990s. Unfortunately, Comet ATLAS won’t be that comet.

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OSIRIS-REx successfully completes touch-and-go rehearsal

8:44 am

OSIRIS-REx yesterday successfully completed its first dress rehearsal of the maneuver that will allow it in August to touch the surface of the asteroid Bennu and grab a sample.

Four hours after departing its 0.6-mile (1-km) safe-home orbit, the spacecraft performed the Checkpoint maneuver at an approximate altitude of 410 feet (125 meters) above Bennu’s surface. From there, the spacecraft continued to descend for another nine minutes on a trajectory toward – but not reaching – the location of the sampling event’s third maneuver, the “Matchpoint” burn. Upon reaching an altitude of approximately 246 ft (75 m) – the closest the spacecraft has ever been to Bennu – OSIRIS-REx performed a back-away burn to complete the rehearsal.

During the rehearsal, the spacecraft successfully deployed its sampling arm, the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), from its folded, parked position out to the sample collection configuration. Additionally, some of the spacecraft’s instruments collected science and navigation images and made spectrometry observations of the sample site, as will occur during the sample collection event.

They plan one more rehearsal, getting even closer to the asteroid, before the August 25 sample grab.

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New changes to the brain found from long space missions

8:38 am

Scientists have discovered a “significant increase” in the brain’s white matter that occurs after astronauts have completed long missions in weightlessness.

The team conducted brain MRIs of 11 astronauts before they traveled to the ISS, and then again one day after they returned. Scans were then performed at several interval across the following year. “What we identified that no one has really identified before is that there is a significant increase of volume in the brain’s white matter from preflight to postflight,” Kramer says. “White matter expansion in fact is responsible for the largest increase in combined brain and cerebrospinal fluid volumes postflight.”

These changes remained visible one year after spaceflight, which the researchers say indicates they could be permanent alterations. Past research has suggested that changes in the volume of cerebrospinal fluid (CSF) specifically could be a key driver of Visual Impairment Intracranial Pressure in astronauts. The authors of the new study also observed an increase in the velocity of CSF through the cerebral aqueduct, along with deformation of the pituitary gland, which they believe is related to higher intracranial pressure in microgravity.

The uncertainties for this work remain very large. For one thing, the sample (11 astronauts) is very small. For another, the permanence of this change is only suggested and remains unproven.

Nonetheless, this research adds to the growing body of research that suggests that long term weightlessness is generally not good for the human body. It also reinforces the desperate need for research into the effects of even a small amount of artificial gravity. To most efficiently design spacecraft that provide some form of centrifugal force as artificial gravity, we need to find out the minimum required. It could be providing only 10% or 30% Earth gravity could be sufficient. Or not. We just don’t know.

The engineering challenges however go up significantly the more gravity you need to create. For future interplanetary travel this information is critical.

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Seasonal avalanches in Martian dune gully

11:01 am

Seasonal changes in Martian dune gully
Click for full image.

The science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) today released a very cool pair of images, taken a Martian year apart, showing some significant changes that had occurred during that time in a large sand dune slope inside a crater. On the right is that pair, reduced and with the top image slightly lightened to bring out the features. As they wrote in the caption,

One large gully in particular has had major changes in every Martian winter since [MRO’s high resolution camera] began monitoring, triggered by the seasonal dry ice frost that accumulates each year.

This time there was an especially large change, depositing a huge mass of sand. The sand divided into many small toes near its end, or perhaps many individual flows descended near the same spot. Additionally, a long sinuous ridge of sand was deposited. This could be a “levee” that formed along one side of a flow, but there is not much sand past the end of the ridge, so it might also be the main body of a flow.

Nor is this dune gully the only active one in this crater, dubbed Matara Crater, located in the southern cratered highlands at about 50 degrees south latitude. If you look at the full image and compare it with an image from 2009 there are many changes across the entire slope field that extends a considerable distance to the north and south of the cropped section shown above.

At this latitude atmospheric carbon dioxide settles as frost during the winter, then sublimates away with the coming of spring. The freeze-sublimation process disturbs the sand each year, causing these avalanches.

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A scientist picks apart the COVID-19 models, and finds them wanting

1:14 pm

Link here. What he does is what everyone not involved in writing these models (most of which predicted wholesale disaster if we didn’t impose martial law worldwide) should have done. This quote alone tells us the dishonesty of these models:

More surprisingly perhaps, the Imperial College paper published on March 30 states that ‘Our methods assume that changes in the reproductive number — a measure of transmission — are an immediate response to these interventions being implemented rather than broader gradual changes in behavior’ [emphasis in original]. That is to say: in this study, if the virus transmission slows it is ‘assumed’ that this is due to the lockdown and not (for example) that it would have slowed down any way. [emphasis mine] But surely this is a key point, one that is absolutely vital to understanding our whole situation? I may be missing something, but if you are presenting a paper trying to ascertain if the lockdown works, isn’t it a bit of a push to start with an assumption that lockdown works?

In other words, they shaped their prediction so that a lockdown was required to prevent millions of deaths, ignoring the extensive knowledge scientists have about how viral epidemics routinely die out because of the normal spread of infection throughout the population, depriving the virus new and safe hosts to populate.

Or to put it more bluntly, these models were political documents, not scientific research. They, like all the global warming models (that by the way have never succeeded in predicting anything), were aimed not at illuminating our knowledge but in influencing political action, and in this case the destruction of free societies worldwide.

Some people not only deserve to be fired, some might justifiably be hung for the harm they have caused millions. And I am pointing at both the modelers and the politicians who didn’t do the proper due diligence required, and instead panicked, or decided this was a great opportunity to grab some extra power.

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OSIRIS-REx’s sample grab location on Bennu

12:55 pm

Nightingale site on Bennu
Click for full image.

On April 14th engineers for the probe OSIRIS-REx will do the first of two dress rehearsals of their planned touch-and-go sample grab from the asteroid Bennu, presently planned for August 25.

The image to the right was taken on March 3, 2020 from about 1,000 feet away during the spacecraft’s third reconnaissance phase, and is centered on that touch-and-go site, dubbed Nightingale by the science team. It illustrates why that sample grab carries risks that were unexpected. As they point out on the image’s release page, “the rock in the [upper right] of the image is 2 ft (70 cm) long, which is about the length of a small ice chest.” Moreover, across the entire touchdown site are numerous other rocks ranging in size from fists to laptops.

When they designed the mission, they had assumed there would be places on Bennu’s surface made up mostly of dust. areas where such dust would have gathered into ponds, as seen in other asteroids. The expectation also assumed these areas would be larger than any of the smooth areas found on Bennu. As they have noted:
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The icy Phlegra Mountains: Mars’ future second city

1:35 pm

Icy glaciers in the Phlegra Mountains of Mars
Click for full image.

About a thousand miles to the west of the candidate landing site for SpaceX’s Starship spacecraft rises a massive mountain wall dubbed the Phlegra Mountains, rising as much as 11,000 feet above the adjacent lowland northern plains.

Phlegra Montes (its official name) is of special interest because of its apparent icy nature. Here practically every photograph taken by any orbiter appears to show immense glacial flows of some kind, with some glaciers coming down canyons and hollows [#1], some filling craters [#2], some forming wide aprons [#3] at the base of mountains and even at the mountains’ highest peaks [#4], and some filling the flats [#5] beyond the mountain foothills.

And then there are the images that show almost all these types of glaciers, plus others [#6]. Today’s cool image above is an example of this. In this one photo we can see filled craters, aprons below peaks, and flows moving down canyons. It is as if a thick layer of ice has partly buried everything up the highest elevations.

None of this has gone unnoticed by scientists. For the past decade they have repeatedly published papers noting these features and their icy appearance, concluding that the Phlegra Mountains are home to ample buried ice. SpaceX even had one image taken here [#3] as a candidate landing site for Starship, though this is clearly not their primary choice at this time.

The map below gives an overview of the mountains, their relationship to the Starship landing site, and the location by number of the images listed above.
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