Tag: science

Bennu’s equatorial craters

10:05 am

Bennu's craters
Click for full image.

The OSIRIS-REx science team today released a neat image of Bennu, highlighting the string of impact craters along the rubble-pile asteroid’s equatorial ridge. The image to the right, cropped and reduced to post here, shows that image. From the release:

Bennu’s darkest boulder, Gargoyle Saxum , is visible on the equator, near the left limb. On the asteroid’s southern hemisphere, Bennu’s largest boulder, Benben Saxum , casts a long shadow over the surface. The field of view is 0.4 miles (0.7 km). For reference, the largest crater in the center of the image is 257 ft (78 m) wide, which is almost the size of a football field.

The photo was taken from a distance of six miles on April 28. The craters illustrate well the rubble pile/sandbox nature of this asteroid. They all look like what you’d expect if the impact was able to easily drive itself deep into the a pile of sand and loose rocks. The resulting crater thus has a very indistinct rim and a sloping floor down to a central point.

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The salty liquid water on Mars

9:49 am

Map of seasonal salty liquid water on Mars
Click for full unannotated image.

The map above, reduced and annotated by me, comes from a new science paper that has attempted to model where on Mars we might find liquid very salty water, based on the planet’s known temperature and make-up. From the press release:

The team of researchers used laboratory measurements of Mars-relevant salts along with Martian climate information from both planetary models and spacecraft measurements. They developed a model to predict where, when, and for how long brines are stable on the surface and shallow subsurface of Mars. They found that brine formation from some salts can lead to liquid water over 40% of the Martian surface but only seasonally, during 2% of the Martian year.

“In our work, we show that the highest temperature a stable brine will experience on Mars is -48°C (-55° F). This is well below the lowest temperature we know life can tolerate,” says Dr. Rivera-Valentín. “For many years we have worried about contaminating Mars with terrestrial life as we have sent spacecraft to explore its surface. These new results reduce some of the risk of exploring Mars,” noted Dr. Alejandro Soto at the Southwest Research Institute and co-author of the study. [emphasis mine]

I have added a red rectangle to the map, showing the candidate landing zone for SpaceX’s Starship. This paper illustrates again that this choice is a good one. We know from other research that there is a lot of ice very close to the surface here. This research indicates that for a little less than one percent of each year, some of that ice will turn to liquid brine.

Whether it will be easier to process the ice or the brine into drinkable water remains unknown. This location however will give future colonists that option.

That this model also suggests that there is little risk of contaminating Mars accidently with terrestrial life is really not a surprise. All the research of Mars for decades has found that it is inhospitable to terrestrial life. This data however is further confirmation, and tells us once again that worrying about contaminating the planet is a irrelevancy. For scientific reasons some precautions should be taken, but to spend a lot of time and money sterilizing the spacecraft we send there will be a fool’s errand. For humans to settle Mars will require a very very high level of engineering and adaptation, something we humans are very naturally good at, but something that shouldn’t be burdened with unnecessary tasks or restrictions.

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Sunspot update: The deep minimum continues

1:00 pm

Last week NOAA updated its graph for tracking the monthly activity of sunspots on the Sun’s visible hemisphere. Below is that updated graph, annotated by me to show the past and new solar cycle predictions.

April 2020 sunspot activity

The graph above has been modified to show the predictions of the solar science community for both the previous and upcoming solar maximums. The green curves show the community’s two original predictions from April 2007 for the previous maximum, with half the scientists predicting a very strong maximum and half predicting a weak one. The blue curve is their revised May 2009 prediction. The red curve is the new prediction, first posted by NOAA in April 2020.

Because of the design of this graph, revamped by NOAA in April, it is difficult at this scale — which for context shows both the past cycle and the predicted future cycle — to see the addition of the April sunspot total, when compared to last month’s graph. Trust me, it is there. In April sunspot activity went up, but trivially so, with only four sunspots during the month, three of which had a magnetic polarity assigning them to the next solar maximum.

The solar minimum remains very deep, deeper than the very deep previous minimum, and possibly the least active in two hundred years. The presence however of more sunspots for the new cycle strengthens the expectation that we will not be entering a grand minimum, with no sunspots for decades. It just appears that, as predicted, the next solar maximum will be a very weak one.

How this weak activity will effect the climate remains an unknown. In the past, such as the weak maximum that just ended as well as during past weak maximums at the beginning of the 1800s and the 1900s, the Earth’s climate cooled. It also cooled during the Little Ice Age in the 1600s, during the last grand minimum.

Whether the same will happen in the next decade remains unknown. Global warming activists will claim impossible, we are all going to die from overheating. The data for the past decade proves them wrong, though in the coming years they might be vindicated.

All we can do is wait, pay attention to the data, and make our conclusions from that.

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The epidemic model that panicked the world was junk

12:17 pm

A software engineer has done a careful fact-based analysis of the code that runs the computer model of now disgraced and fired Neil Ferguson of Imperial College in London — the computer model that had predicted millions would die in mere weeks from COVID-19 and thus triggered the worldwide panic over it — and found that it is buggy, unreliable, produces different results with the same data, and often does so for completely irrelevant factors (such as simply running it on different computers).

Hat tip Rand Simberg at Transterrestrial Musings.

The conclusion from this software engineer:

All papers based on this code should be retracted immediately. Imperial’s modelling efforts should be reset with a new team that isn’t under Professor Ferguson, and which has a commitment to replicable results with published code from day one.

On a personal level, I’d go further and suggest that all academic epidemiology be defunded. This sort of work is best done by the insurance sector. Insurers employ modellers and data scientists, but also employ managers whose job is to decide whether a model is accurate enough for real world usage and professional software engineers to ensure model software is properly tested, understandable and so on. Academic efforts don’t have these people, and the results speak for themselves.

The second paragraph applies equally to all computer modeling in the climate field, which has been repeatedly found to have similar problems.

Science should be based on data, from the field, not models predicting that data. Models have a minor use as a guide, but it is beyond dangerous to depend on them in any manner at all. Had our politicians relied on the available data when COVID-19 first started to spread, instead of these fake models, they would not have panicked, and would have instead done what they should have, focused on protecting the elderly and the sick, the only part of the population under serious threat.

Similarly, had the public and the press ignored these bad models and focused on that same data, they too would not have been frozen in fear, and would have demanded a more rational approach to the epidemic.

I know I have been repeating myself on this subject, but it must be driven home. The modelers are unreliable. The modelers are often driven by political agendas, not the facts. The modelers must not be relied upon for any long term policy.

Repeat this mantra to yourself, over and over again. It should sound a warning in your brain every time you read another article predicting doomsday from something, from global warming, from sea level rise, from the ozone hole, from some disease, from any crises these frauds want to latch onto.

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Evidence suggests Ryugu was once closer to Sun

11:38 am

The uncertainty of science: Spectral data collected of the surface of Ryugu by Japan’s Hayabusa-2 probe suggests that the asteroid once spent a period of time much closer to the Sun.

The combined data show an oddly striated world. Ryugu’s equator and poles are tinged blue and are brighter compared with its darker, reddish mid-latitudes. These color differences wouldn’t be obvious to the human eye, although the brightness changes might be.

…As Tomokatsu Morota (University of Tokyo) and colleagues write in the May 8th Science, Ryugu’s boulders likely start bluish. Then a combination of solar wind exposure, meteoroid impacts, and solar heating reddens them. This redder stuff migrates to the asteroid’s mid-latitudes over time, because topographically those are the lowest on Ryugu’s surface. That movement leaves the higher equator and polar regions relatively bluer and brighter.

Based on this data, the scientists posit that Ryugu was closer to the Sun from 800,000 to 8 million years ago, and that the evidence also suggests that the asteroid is only at most 17 million years old.

To put it mildly, there are great uncertainties to these conclusions.

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Chinese manned test capsule returns to Earth

9:03 am

The new colonial movement: China’s first unmanned test flight of its new manned capsule, still unnamed, ended today with that capsule’s safe return to Earth.

Before re-entry into the atmosphere, the capsule executed a skip maneuver employing aerodynamic lift in the high upper atmosphere. The technique is used to extend the re-entry time for vehicles returning to Earth from the Moon to avoid having to shed a large amount of velocity in a short time causing very high rates of peak heating. The skip reentry was used by Apollo Command Module returning from the Moon, as well as the Soviet Zond Probes and the Chinese Chang’e 5-T1.

Following atmospheric reentry, and at a determined altitude, two deceleration parachutes were opened, stabilizing the vehicle. Then, the three main parachutes were deployed, slowing the flight speed of descent. According to the China Aerospace Science and Technology Corporation (CASC), moments before touching down the heat shield was discarded and six airbags were deployed and inflated to help it land softly.

More here from China’s propaganda press, which included this detail:

Different from the three-capsule structure of Shenzhou spaceships currently in use, the new spacecraft comprises a return capsule, which is the command center and the living place for astronauts, and a service capsule, which provides power and energy, according to the CAST.

In other words, the Shenzhou copied the Soyuz design, while this new spacecraft copied the American design used in all our manned capsules.

I have embedded below the fold a short video released by China’s state-run press, showing the reentry. That capsule sure looks a lot like an Apollo capsule. It also looks surprisingly scorched.
» Read more

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Arctic ozone hole closes

10:13 am

The uncertainty of science: The largest ozone hole ever detected over the north pole has now closed.

After looming above the Arctic for nearly a month, the single largest ozone hole ever detected over the North Pole has finally closed, researchers from the European Union’s Copernicus Atmosphere Monitoring Service (CAMS) reported. “The unprecedented 2020 Northern Hemisphere ozone hole has come to an end,” CAMS researchers tweeted on April 23.

The hole in the ozone layer — a portion of Earth’s atmosphere that shields the planet from ultraviolet radiation — first opened over the Arctic in late March when unusual wind conditions trapped frigid air over the North Pole for several weeks in a row. Those winds, known as a polar vortex, created a circular cage of cold air that led to the formation of high-altitude clouds in the region. The clouds mixed with man-made pollutants like chlorine and bromine, eating away at the surrounding ozone gas until a massive hole roughly three times the size of Greenland opened in the atmosphere, according to a statement from the European Space Agency (ESA). [emphasis mine]

Note that the north pole hole occurred because of unusually frigid and cold conditions, something I thought we were never going to see again because of global warming.

The last paragraph of the article at the link reveals a lot of ignorance by its writer, Brandon Specktor, where he discusses the south pole ozone hole. First, he says it “has existed for roughly four decades.” Wrong. The south pole ozone hole was first detected in the 1950s, and has likely existed every winter for eons.

Next, he wonders if it is “starting to close.” Wrong. That ozone hole opens every winter and closes every summer, like clockwork. When winter arrives and the south pole is in darkness, oxygen molecules are no longer being ionized by sunlight and thus there is a drop in the production of ozone, producing the hole. When sunlight begins hitting the upper atmosphere in the spring it starts ionizing oxygen molecules again to produce ozone, and the hole goes away.

Then he notes that scientists hope the hole will “heal” and forever disappear by 2050. Wrong. The data says instead that the south pole ozone hole is a natural phenomenon that occurs every winter. It is not a wound against the earth.

Finally, he claims that the south pole ozone hole exists almost entirely because of us evil humans, first because of global warming and second because until 1987 we put ozone-depleting pollutants into the atmosphere. Wrong. As I said, the ozone hole is almost entirely a natural phenomenon, caused each winter because sunlight is no longer hitting the upper atmosphere above Antarctica and thus oxygen molecules are no longer being ionized into ozone. Those pollutants might have made it slightly larger in the late 20th century, but then, that theory has a problem, as most of those pollutants were released in the northern hemisphere, where they would have little or no interaction with the atmosphere of the southern hemisphere. (The atmospheres of the two hemispheres are largely independent.) Yet it was only in the south that we have generally seen an ozone hole

I predict, very confidently, that come 2050 climate scientists will discover, “unexpectedly”, that the south pole ozone hole has not “closed” or “healed”, but continues to reappear, each winter. And they will have by then discovered that depending on circumstances, a north pole ozone hole also appears during some colder winters, which despite their repeatedly failed predictions of global warming will likely continue to happen.

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The closest black hole: 1,000 light years away?

8:48 am

The uncertainty of science: Astronomers now think they have detected evidence of a stellar-mass black hole only a thousand light years away and orbiting a star system that is visible to the naked eye.

Thomas Rivinius, an astronomer with the European Southern Observatory (ESO), and his colleagues studied the unusual star system HR 6819 in this way using a 2.2-meter telescope in Chile, operated by ESO and the Max Planck Society. They thought it was a binary system, but there was an extra wobble in the periodic light shifts of one of the stars that indicated something else was asserting its presence. It turned out to be a triple system, with one star in a fast 40-day orbit with an unseen companion and another star on a more distant, slow-moving trajectory, they write today in Astronomy & Astrophysics. The invisible companion’s mass was large enough—four times the mass of the Sun—that, if it was a star, “we would have seen it,” Rivinius says.

Though there are a lot of uncertainties, this discovery is reasonable, and expected. In the coming years astronomers will surely find more such stellar-mass black holes, with some even closer to Earth.

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The eroding edge of Mars’ largest volcanic ash field

1:45 pm

Eroding yardangs at the edge of Mars' largest volcanic ash field
Click for full image.

Cool image time! In the regions between the biggest volcanoes on Mars is the Medusae Fossae Formation, a immense deposit of volcanic ash that extends across as much surface area as the nation of India. As planetary scientist Kevin Lewis of Johns Hopkins University explained to me previously,

In general, much of the [formation] seems to be in net erosion now, retaining very few craters on the surface. …One hypothesis is that this long term erosion, since it’s so enormous, is the primary source of the dust we see covering the much of the planet’s surface.

The image above, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on January 25, 2020. It shows one very small area at the very edge of the Medusae ash deposit, in a region where that deposit is clearly being eroding away by the prevailing southeast-to-northwest winds. The mesas of this ash that remain are called yardangs, their ash more tightly pressed together so that it resists erosion a bit longer than the surrounding material.

In the context map below the location of these yardangs is indicated by the white cross, right on the edge of the Medusae ash field.
» Read more

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A failed star with cloud bands like Jupiter’s

9:32 am

The uncertainty of science: Astronomers think they have detected cloud bands similar to Jupiter’s on a brown dwarf about 6.5 light years away.

A team of astronomers has discovered that the closest known brown dwarf, Luhman 16A, shows signs of cloud bands similar to those seen on Jupiter and Saturn. This is the first time scientists have used the technique of polarimetry to determine the properties of atmospheric clouds outside of the solar system, or exoclouds.

Brown dwarfs are objects heavier than planets but lighter than stars, and typically have 13 to 80 times the mass of Jupiter. Luhman 16A is part of a binary system containing a second brown dwarf, Luhman 16B. At a distance of 6.5 light-years, it’s the third closest system to our Sun after Alpha Centauri and Barnard’s Star. Both brown dwarfs weigh about 30 times as much as Jupiter.

Despite the fact that Luhman 16A and 16B have similar masses and temperatures (about 1,900° F or 1,000° C), and presumably formed at the same time, they show markedly different weather. Luhman 16B shows no sign of stationary cloud bands, instead exhibiting evidence of more irregular, patchy clouds. Luhman 16B therefore has noticeable brightness variations as a result of its cloudy features, unlike Luhman 16A.

This conclusion is based on studying the polarized light coming from both brown dwarfs. For Luhman 16A, the result suggested bands. For Luhman 16B, the result suggested patchy, irregular clouds like on Earth.

The emphasis should be on the words “suggested” and “uncertainty.” This is good science, but the data is very sparse. We will need to actually see at these objects to really determine their weather.

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First Fast Radio Burst discovered inside the Milky Way

2:22 pm

The uncertainty of science: Astronomers now think they have discovered the first Fast Radio Burst (FRB) to have occurred inside the Milky Way, only 30,000 light years away, and from this now hypothesize that the bursts come from a particular kind of neutron star called a magnetar because of its super-powerful magnetic field.

The key is that, using multiple different telescopes, they also detected X-ray emissions from the same object.

The X-ray counterpart to the SGR 1935+2154 burst was not particularly strong or unusual, said astrophysicist Sandro Mereghetti of the National Institute for Astrophysics in Italy, and research scientist with the ESA’s INTEGRAL satellite. But it could imply that there’s a lot more to FRBs than we can currently detect.

“This is a very intriguing result and supports the association between FRBs and magnetars,” Mereghetti told ScienceAlert. “The FRB identified up to now are extragalactic. They have never been detected at X/gamma rays. An X-ray burst with luminosity like that of SGR1935 would be undetectable for an extragalactic source.”

Of course, more data is needed, as well as more detections, but it appears that astronomers are beginning to hone in on the solution to the source of FBRs.

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The edge of Mars’ north polar ice cap

1:55 pm

The scarp face of the Martian north polar ice cap
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on December 29, 2019 by the high resolution camera of Mars Reconnaissance Orbiter (MRO) and shows the many-layered scarp face of the Martian north polar ice cap. I have also rotated the image so that north is at the top. The overall height of this scarp is quite high, more than 3,500 feet.

There are a number of very cool features in this image. For example, note what at first look like puffs of clouds just below the contact between the bright and dark layers. I count almost two dozen, with the largest near the center. They are not cloud puffs, however, but areas scoured by past avalanches. According to Patricio Becerra at the University of Bern in Switzerland,

An image from a few years ago shows evidence for the same patches, so they likely happened a while back. When the avalanches or “block falls” occur, they scour the Basal Unit [the dark layer] and break up the exposed surface, causing a brighter/cloudier appearance of the ground than the undisturbed parts.

Avalanches on the scarps of the North Pole icecap occur in great numbers at the beginning of every Martian summer. As sunlight hits the scarp, it causes the carbon dioxide frost layer that settled on the cap during the winter to sublimate away as vapor, and like the freeze-melt cycle on Earth, this sublimation disturbs any unstable ice boulders on the scarp face.

During the early Martian summer, images from MRO routinely capture many such avalanches. Scientists think there could be hundreds to thousands every summer. In many ways, this is similar to the large pieces of ice that routinely calf off the foot of glaciers here on Earth, and that tourists take cruise ships to see in the inside passage of Alaska.

For context, the overview map below indicates with a gold cross where on the icecap’s edge this image is located. The red and pink areas indicate the vast dune fields that surround the icecap.
» Read more

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Scientists better constrain time frame of Mars’ active dynamo

12:33 pm

Using data from the MAVEN orbiter, scientists have now constrained the time frame when Mars’ dynamo was active and producing a global magnetic field, between 3.7 and 4.5 billion years ago.

Magnetism in certain rocks on Mars’ surface indicate that the Martian dynamo was active between 4.3 and 4.2 billion years ago, but the absence of magnetism over three large basins – Hellas, Argyre, and Isidis – that formed 3.9 billion years ago has led most scientists to believe the dynamo was inactive by that time.

Mittelholz’s team analyzed new data from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) orbiter and found clear evidence of a magnetic field coming from the Lucus Planum lava flow that formed about 3.7 billion years ago – much later than at other areas studied.

There is of course a lot of uncertainty here.

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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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