Tag: science

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

April 20, 2020 8:48 am Robert Zimmerman

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.

Strange terrain in the Martian lowlands

April 17, 2020 12:42 pm Robert Zimmerman

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

Space radiation may increase risk of cancer

April 17, 2020 8:59 am Robert Zimmerman

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

April 17, 2020 8:40 am Robert Zimmerman

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?

Rover update: Curiosity heads downhill

April 16, 2020 2:49 pm Robert Zimmerman

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

Movie of OSIRIS-REx touch-and-go rehearsal

April 16, 2020 10:47 am Robert Zimmerman

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.

Astronomers claim to have discovered most powerful supernova ever

April 15, 2020 9:38 pm Robert Zimmerman

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

April 15, 2020 1:28 pm Robert Zimmerman

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

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

April 15, 2020 10:25 am Robert Zimmerman

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.

Confirmed: Comet ATLAS has broken apart

April 15, 2020 8:47 am Robert Zimmerman

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.

OSIRIS-REx successfully completes touch-and-go rehearsal

April 15, 2020 8:44 am Robert Zimmerman

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.

New changes to the brain found from long space missions

April 15, 2020 8:38 am Robert Zimmerman

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

April 14, 2020 11:01 am Robert Zimmerman

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

April 13, 2020 1:14 pm Robert Zimmerman

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

April 13, 2020 12:55 pm Robert Zimmerman

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:
» Read more

The icy Phlegra Mountains: Mars’ future second city

April 10, 2020 1:35 pm Robert Zimmerman

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.
» Read more

BepiColumbo successfully completes Earth flyby

April 10, 2020 9:28 am Robert Zimmerman

The Earth seen from BepiColumbo

BepiColumbo, the joint European-Japanese mission to Mercury, has successfully completed its fly-by of Earth.

The image to the right is one of the images of Earth it took during the fly-by. The white streak in the upper right is part of the spacecraft.

Mission scientists switched on a number of the duo’s instruments for the Earth pass, to test and calibrate them. Unfortunately, the main camera on Europe’s MPO couldn’t operate because of its position in the stack. But small inspection cameras to the side of Bepi did manage to grab some black & white pictures of the Earth and Moon.

The quote call’s the spacecraft a “duo” because it really is two orbiters presently latched together, the European Mercury Planetary Orbiter (MPO) and the Japanese Mercury Magnetospheric Orbiter (MMO). When it gets to Mercury these will separate.

OSIRIS-REx to do sample-grab rehearsal at Bennu

April 10, 2020 9:11 am Robert Zimmerman

The OSIRIS-REx science team today released a step-by-step description of the first touch-and-go sample grab rehearsal, planned for April 14, 2020.

During the rehearsal, dubbed “Checkpoint,” they expect the spacecraft to get less than 250 feet from the surface of the asteroid Bennu before pulling away.

Checkpoint rehearsal, a four-hour event, begins with the spacecraft leaving its safe-home orbit, 0.6 miles (1 km) above the asteroid. The spacecraft then extends its robotic sampling arm – the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – from its folded, parked position out to the sample collection configuration. Immediately following, the spacecraft slews, or rotates, into position to begin collecting navigation images for NFT guidance. NFT allows the spacecraft to autonomously guide itself to Bennu’s surface by comparing an onboard image catalog with the real-time navigation images taken during descent. 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.

Before reaching the 410-ft (125-m) Checkpoint altitude, the spacecraft’s solar arrays move into a “Y-wing” configuration that safely positions them away from the asteroid’s surface. This configuration also places the spacecraft’s center of gravity directly over the TAGSAM collector head, which is the only part of the spacecraft that will contact Bennu’s surface during the sample collection event.

In the midst of these activities, the spacecraft continues capturing images of Bennu’s surface for the NFT navigation system. The spacecraft will then perform the Checkpoint burn and descend toward Bennu’s surface for another nine minutes, placing the spacecraft around 243 ft (75 m) from the asteroid – the closest it has ever been.

They will do a second rehearsal on June 23, getting within 100 feet of the surface. The actual touch-and-go sample grab is now scheduled for August 25.

Masten’s lunar lander wins NASA contract

April 9, 2020 9:46 am Robert Zimmerman

Capitalism in space: Masten’s XL-1 lunar lander has won a NASA contract to bring a suite of science instruments to the Moon’s south polar regions, the launch targeted for December 2022.

The company also hopes to sell payload space on the lander to other customers.

Masten won a task order for NASA’s Commercial Lunar Payload Services (CLPS) program valued at $75.9 million. Masten will deliver nine science and technology demonstration payloads to the lunar surface near the south pole by December 2022 on the company’s XL-1 lander.

The CLPS payloads, with a mass of about 80 kilograms, will serve as the initial, anchor customer for that mission, Sean Mahoney, chief executive of Masten, said in an interview. He said there are “hundreds” of kilograms of additional payload space available on the lander, and that the company is working to line up additional customers.

Masten is now the third private company with an active contract with NASA to land science payloads on the Moon. Astrobotic and Intuitive Machines are the others, with their missions targeting 2021 for launch.

A river canyon on Mars?

April 8, 2020 1:35 pm Robert Zimmerman

Cool image time! In the most recent download of new images from the high resolution camera of Mars Reconnaissance Orbiter (MRO) were two photos, found here and here, that struck me as very intriguing. Both were titled simply as a “Terrain Sample” image, which generally means the picture was taken not because of any specific request by another scientist doing specific research but because the camera team needs to take an image to maintain the camera’s proper temperature, and in doing so they try to time it so that they can do some random exploring as well.

As it turned out, the two images were more than simply random, as they both covered different parts of the same Martian feature, what looks like a branching dry dendritic river drainage. Below is a mosaic of those two images, fit together as one image, with a wider context image to the right, taken by Mars Odyssey, showing the entire drainage plus the surrounding landscape with the white arrow added to help indicate the drainage’s location.
» Read more

Universe’s expansion rate found to differ in different directions

April 8, 2020 9:54 am Robert Zimmerman

The uncertainty of science: Using data from two space telescopes, astronomers have found that the universe’s expansion rate appears to differ depending on the direction you look.

This latest test uses a powerful, novel and independent technique. It capitalizes on the relationship between the temperature of the hot gas pervading a galaxy cluster and the amount of X-rays it produces, known as the cluster’s X-ray luminosity. The higher the temperature of the gas in a cluster, the higher the X-ray luminosity is. Once the temperature of the cluster gas is measured, the X-ray luminosity can be estimated. This method is independent of cosmological quantities, including the expansion speed of the universe.

Once they estimated the X-ray luminosities of their clusters using this technique, scientists then calculated luminosities using a different method that does depend on cosmological quantities, including the universe’s expansion speed. The results gave the researchers apparent expansion speeds across the whole sky — revealing that the universe appears to be moving away from us faster in some directions than others.

The team also compared this work with studies from other groups that have found indications of a lack of isotropy using different techniques. They found good agreement on the direction of the lowest expansion rate.

More information here.

The other research mentioned in the last paragraph in the quote above describes results posted here in December. For some reason that research did not get the publicity of today’s research, possibly because it had not yet been confirmed by others. It now has.

What this research tells us, most of all, is that dark energy, the mysterious force that is theorized to cause the universe’s expansion rate to accelerate — not slow down as you would expect– might not exist.

Update: I’ve decided to embed, below the fold, the very clear explanatory video made by one of the scientists doing that other research. Very helpful in explaining this very knotty science.

Comet ATLAS appears to be breaking apart

April 8, 2020 9:40 am Robert Zimmerman

Comet ATLAS, which astronomer hope could be the brightest comet in decades, is unfortunately showing evidence of breaking up, which if so could short circuit any spectacular comet show.

In a recent Astronomical Telegram, astronomers Quanzhi Ye (University of Maryland) and Qicheng Zhang (Caltech) report that photographs taken on April 2nd and April 5th of the comet revealed a marked change in the appearance of its core or pseudo-nucleus from starlike and compact to elongated and fuzzy. A second team of astronomers led by I. A. Steele (Liverpool John Moores University) confirmed the discovery. This change in appearance is “consistent with a sudden decline or cessation of dust production, as would be expected from a major disruption of the nucleus,” wrote Zhang and Ye.

An elongated nucleus is often a bad sign and could mean the comet’s headed for disintegration much like what happened to Comet Elenin (C/2010 X1) prior to its September 2011 perihelion passage when its core crumbled and the object rapidly dissipated. Addition evidence of ATLAS’s breakup comes from an unexpected shift in the direction of its orbital motion caused by “non-gravitational” forces. Fragmentation exposes fresh ice to sunlight which quickly vaporizes. The expanding gases act like a natural rocket engine and gently push the comet from its appointed path.

The article outlines in detail how bright ATLAS could become, because of its size and orbit and proximity to Earth as it passes closest to the Sun in late May. Assuming it does not disintegrate, it could end up brighter than Venus. Or not. Predicting the eventual brightness of a newly discovered comet is more guesswork than science. That the comet might be falling apart suggests its eventually brightness will be less that hoped.

Weird flat plateau on Mars

April 7, 2020 10:43 am Robert Zimmerman

Click for full image.

Cool image time! The image to the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on December 15, 2020, and was actually a follow-up observation from an earlier image taken by the camera on Europe’s Trace Gas Orbiter (TGO), according to Dr. Livio Tornabene of the University of Western Ontario. As he explained in an email:

The team is rather polarized with their verdict on what exactly the feature is… while at first glance it appears to be a lava flow, it very well could be that these deposits eroded to yield this flow/lobate like appearance and isn’t lava at all. So as someone that is both involved with [TGO] and [MRO], I noticed that the lobate feature causing quite the debate had no coverage from [MRO].

It appears that some scientists think that instead of lava, this is a mud flow. Research presented [pdf] during the 2019 Lunar & Planetary Conference in Texas found evidence that mud could flow like lava under the right conditions.

At this point neither Tornabene nor anyone working on the TGO team have yet analyzed this new MRO image to see if they can answer this question. That this feature is located in a region just to the southeast of Marineris Valles where there is evidence both of volcanic activity and sedimentary deposition, makes answering the question even more challenging.

The data from TGO indicated [pdf] that the plateau was about 30 to 65 feet thick. Based on crater counts the age is thought to be between 1.6 to 1.9 billion years old.

What struck me about the plateau is that though it really does look like a flow, it also appears remarkably flat and smooth. Even more puzzling is that, according to the TGO paper, the plateau slopes downhill very gently (a 1% grade) to the south, not to the north as suggested by the shape of the flow. Maybe later geological events tilted the entire feature after it solidified, thus changing the grade?

Meanwhile that channel near the bottom of the image crosses through the grade and the flow, as if it was cut after the flow was placed. In other words, the flow and channel were formed separately, at different times.

Ah, the mysteries of planetary geology. If only we could just go there with a geologist’s hammer. These questions would then be so much more simple to answer.

Big sections break off of interstellar Comet 2I/Borisov

April 7, 2020 9:23 am Robert Zimmerman

The uncertainty of science: New observations of the interstellar Comet 2I/Borisov as it exits our solar system indicate that large fragments have recently broken from it, and that the comet might possibly be on the verge of breaking up.

Astronomers have seen evidence of two fragments, but the data suggests these are relatively small compared to the entire comet. On the other hand,

Before perihelion, Jewitt’s analysis of Hubble images showed that Comet Borisov is much smaller than had been thought. The comet’s nucleus is not directly visible, but in the January 10th Astrophysical Journal Letters, Jewitt put its diameter between 0.4 and 1 kilometer. That’s small enough that solar vaporization of surface ices on the side facing the Sun could spin up its rotation beyond gravity’s ability to hold it together.

However, the comet’s size is tricky to estimate, as its surface appears to be emitting so much gas and dust that it obscures the nucleus. The fragment that Jewitt observed is about as bright as the comet itself, but because its surface is so icy and active, he thinks the fragment’s mass is less than 1% of the whole comet. That would make the split more like a side mirror dropping off a car than a car falling apart. Why the fragment split from the comet is unclear, but possibilities include thermal vaporization after new material was exposed, as well as the force from the comet’s spin if it’s spinning as fast as Jewitt suggests.

Whether the comet is about to break up remains unknown. Wouldn’t it be nice if someone was racing to put a mission together to visit it?

Changing Mars

April 6, 2020 1:12 pm Robert Zimmerman

The maculae splotch dubbed Maui
For the full images click here (2019) and here (2020).

While Mars appears to be a dead planet, with no clear evidence of life so far discovered, the planet is hardly inactive. Things are changing there continuously, even if it happens at a slower pace than here on Earth.

To the right are two images, rotated, cropped, and reduced to post here, taken by the high resolution camera of Mars Reconnaissance Orbiter. The first was on January 19, 2019, shortly after the end of the global dust storm that engulfed Mars during that Martian year. The second was taken on February 14, 2020, half a Martian year later. Both show one of a string of dark splotches located on the western flanks of the giant volcano Olympus Mons. Scientists call these splotches maculae, and because of their superficial resemblance to the islands of Hawaii, have given them names matching those islands. This particular patch is dubbed Maui. Below is a map showing all the splotches and their position relative to Olympus Mons, taken from a 2019 presentation [pdf].
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