Tag: science

Two super-Earths found orbiting nearby red dwarf star

2:40 pm

Worlds without end: Astronomers have detected evidence of two super-Earths orbiting Gliese 887, only 11 light years away and the brightest red dwarf star in the night sky.

They used a technique known as “Doppler wobble”, which enables them to measure the tiny back and forth wobbles of the star caused by the gravitational pull of the planets. The regular signals correspond to orbits of just 9.3 and 21.8 days, indicating two super-Earths – Gliese 887b and Gliese 887c – both larger than the Earth yet moving rapidly, much faster even than Mercury. Scientists estimate the temperature of Gliese 887c to be around 70oC.

Because Gliese 887 is a very constant star, not very active, and with relatively few strong flares, they think these planets have a chance of retaining their atmospheres.

Be aware that these are like most exoplanets only candidate exoplanets. Until their existence is confirmed by other researchers, it is possible the detection is a false one.

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Perseverance launch delayed two days

8:37 am

NASA and ULA have agreed to delay the launch of the new Mars rover Perseverance two days, from July 20th to July 22nd, because of “a contamination concern.”

NASA’s Mars rover Perseverance was scheduled to launch toward the Red Planet on July 20 from a pad at the Cape Canaveral Air Force Station in Florida. But a problem cropped up as engineers worked to encapsulate the rover in the nosecone of its Atlas V rocket, which was built by United Launch Alliance.

“NASA and United Launch Alliance are now targeting Wednesday, July 22, for launch of the Mars 2020 mission due to a processing delay encountered during encapsulation activities of the spacecraft,” NASA officials said in an update. “Additional time was needed to resolve a contamination concern in the ground support lines in NASA’s Payload Hazardous Servicing Facility (PHSF).”

This contamination likely relates to their effort to keep the rover free from Earth biology.

The official launch window closes on August 11th, though they can still launch as late as August 15th and get to their targeted landing site in Jezero Crater on Mars.

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A host of new solar systems

11:20 am

A gallery of baby solar systems

Worlds without end: Astronomers this month released a large collection of images taken during the past four years by the Gemini South Telescope in Chile of young stars that also have debris disks and are likely solar systems in the process of forming.

The image to the right, reduced slightly to post here, is only a sampling of the 26 disk systems found out of 104 young stars photographed. Go to the link to see some higher resolution examples.

Of the 26 images of debris disks obtained by the Gemini Planet Imager (GPI), 25 had “holes” around the central star that likely were created by planets sweeping up rocks and dust. Seven of the 26 were previously unknown; earlier images of the other 19 were not as sharp as those from GPI and often didn’t have the resolution to detect an inner hole. The survey doubles the number of debris disks imaged at such high resolution.

“One of the things we found is that these so-called disks are really rings with inner clearings,” said Esposito, who is also a researcher at the SETI Institute in Mountain View, California. “GPI had a clear view of the inner regions close to the star, whereas in the past, observations by the Hubble Space Telescope and older instruments from the ground couldn’t see close enough to the star to see the hole around it.”

The data strongly confirms most theories about planet formation in these debris disks, as one of the youngest stars did not have any gaps in its disk, suggesting no larger bodies had yet formed to clear out a region.

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Astronomers claim discovery of six exomoons

9:03 am

The uncertainty of science: Astronomers are now claiming they have detected evidence of the existence of six exomoons orbiting different stars with transiting exoplanets.

“These exomoon candidates are so small that they can’t be seen from their own transits. Rather, their presence is given away by their gravitational influence on their parent planet,” Wiegert said.

If an exoplanet orbits its star undisturbed, the transits it produces occur precisely at fixed intervals.

But for some exoplanets, the timing of the transits is variable, sometimes occurring several minutes early or late. Such transit timing variations – known as TTVs – indicate the gravity of another body. That could mean an exomoon or another planet in the system is? affecting the transiting planet.

What they have basically done is applied the technique used to identify exoplanet candidates when the planet does NOT transit the star (the wobble caused by gravity and indicated by spectral changes), and looked to see if they can see the same variations in these exoplanets.

This is fun stuff, but it is so uncertain as to be almost laughable. If you read the press release closely, you will discover that their work has been submitted for publication, but has not yet been even peer reviewed.

Their concept is good, but I would not pay much attention to these “results.”

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More strange terrain in the Martian “Death Valley”

2:39 pm

More strange terrain in Hellas Basin
Click for full image.

Today’s cool image, rotated cropped, and reduced to post here, might show what the science team for the high resolution camera of Mars Reconnaissance Orbiter (MRO) have labeled “strange banded terrain”, but anyone who has spent any time perusing images of Hellas Basin, what I have labeled the basement of Mars because it has the lowest elevation on the planet, will recognize the features.

They might be inexplicable, but for Hellas Basin they are entirely familiar. Just take a look at some of my earlier posts:
» Read more

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Perseverance: update on launch rehearsal and helicopter

11:25 am

Two news stories today about the launch of the United States’ next Mars rover, Perservance.

First, ULA yesterday successfully completed a dress rehearsal countdown with the Atlas 5 rocket that will launch Perseverance on July 20 at 9:15 am (Eastern)..

The rover will be mounted onto the rocket at the end of this week.

Second, JPL provided this press release describing how Perseverance’s test helicopter Ingenuity will be deployed on the Martian surface, where it will then test to see if such helicopters will work in the Martian atmosphere.

Sixty Martian days (dubbed sols) after landing in Jezero Crater on February 18, Perseverance will find a nice large flat area and deploy the helicopter six sols later. The helicopter will then begin its 30-sol test program. If it is found to work, future rovers will almost certainly be equipped with such helicopters, acting as scouts able to go places the rover cannot.

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A gravel pile floating in space that might hit the Earth

2:10 pm

flat rock near Osprey
Click for full image.

Come October the probe OSIRIS-REx will attempt a quick touchdown on the asteroid Bennu to grab some tiny particles, all smaller than 0.8 inches across.

Bennu is what scientists have described as a “rubble-pile” asteroid. They use that name because it is simply a conglomeration of a lot of rocks, pebbles, boulders, and stones, all jagged and of all sizes. The overall gravity has never been strong enough to squeeze them together, at least as far as we can see, and so they are piled up loosely across the asteroid’s surface wherever we look.

I think a better name for this asteroid would a floating gravel pile, since the material on it, as clearly shown in the image to the right (reduced and rotated to post here), more resembles the tailings one finds at a mine or quarry. This photo was taken by OSIRIS-REx on May 26, 2020 during its first dress rehearsal over its back-up touch-and-go sample grab site, Osprey. As the release caption notes,

The field of view is 12 ft (3.8 m). For reference, the bright rock [near] the tip of the boulder is 1 ft (0.3 m) across, which is about the size of a loaf of bread.

I have rotated the image 90 degrees so that east is up, because the full mosaic of the entire Osprey landing site, shown below, is oriented that way, and by rotating it to match it is easier to locate this image within it.
» Read more

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Two new multi-wavelength Hubble images of planetary nebulae

11:05 am

Hubble images of the Butterfly and Jewel Bug planetary nebulae
Click for full image.

Cool images from Hubble! Astronomers have used the Hubble Space Telescope’s entire suite of instruments to produce spectacular new multi-wavelength images of two planetary nebulae, stars that for some reasons not yet entirely understood are surrounded by breath-taking jets and cloud-formations of all shapes and sizes.

The two images are to the right, cropped and reduced to post here.

Planetary nebulas, whose stars shed their layers over thousands of years, can turn into crazy whirligigs while puffing off shells and jets of hot gas. New images from the Hubble Space Telescope have helped researchers identify rapid changes in material blasting off stars at the centers of two nebulas — causing them to reconsider what is happening at their cores.

In the case of NGC 6302, dubbed the Butterfly Nebula, two S-shaped streams indicate its most recent ejections and may be the result of two stars interacting at the nebula’s core. In NGC 7027, a new cloverleaf pattern — with bullets of material shooting out in specific directions — may also point to the interactions of two central stars. Both nebulas are splitting themselves apart on extremely short timescales, allowing researchers to measure changes in their structures over only a few decades.

This is the first time both nebulas have been studied from near-ultraviolet to near-infrared light, a complex, multi-wavelength view only possible with Hubble.

The press release suggests that the most likely and popular explanation for the formation of planetary nebula is the interaction of two closely orbiting stars. While this might be true, it remains only one theory among many, all of which explain some of what we see and none of which explain everything. As I noted in my November 2014 cover story about planetary nebulae for Sky & Telescope:
» Read more

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Enigmatic layering and chasms on Mars

2:27 pm

Enigmatic layering and chasms
Click for full image.

Overview map

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on April 28, 2020 by the high resolution camera on Mars Reconnaissance Orbiter. (MRO). The science team entitled it “Enigmatic Uplifts in Echus Montes,” indicating a sense of bafflement on their part about this geology.

The features here are certainly somewhat puzzling. At first glance the terrain is reminiscent of Martian chaos terrain, mesas cut by canyons in an almost random pattern. As I explained at the link,

Chaos terrain is typically a collection of mesas separated by straight-lined canyons. It is found in many places on Mars, most often in the transition zone between the southern highlands and the northern lowlands where an intermittent ocean might once have existed. It is believed to form by erosion, possibly caused by either flowing water or ice, moving along fault lines. As the erosion widened the faults, they turned into canyons separating closely packed mesas. With time, the canyons widened and the mesas turned into a collection of hills.

What makes this particular image puzzling however is that there seem to be multiple layers of mesas and canyons. Look at the top of the rectangular mesa in the upper middle of the image. It appears to have its own miniature chaos terrain on its plateau. Somehow that first layer of chaos was abandoned when the more prominent larger canyons started to form around it.

The location of this feature is indicated by the black cross on the overview map to the right. It is in the middle of the large and wide northward trending part of the giant valley dubbed Kasei Valles. And as usual, knowing the location helps explain what we are seeing.
» Read more

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A fast radio burst that beats every sixteen days

11:59 am

Astronomers have now added to the mystery of fast radio bursts (FRBs), of which about a hundred are known, by discovering one in a nearby galaxy that has a regular outburst every 16.35 days.

Earlier this year CHIME worked with astronomers in Europe to pinpoint the origin of a particular FRB emission — called FRB 180916.J0158+65 — to a galaxy located 500 million light years from Earth.

Now CHIME has determined that FRB 180916 pulses at predictable intervals more than two weeks apart. “It tells us that the origin of at least some FRBs is astrophysically regular in nature, but on long enough time scales that they may be tied to something different than a rotating, compact object — perhaps something like an orbiting system,” said Newburgh, whose lab builds instrumentation for collecting data about the history of the cosmos

Or to put it another way, they really haven’t any idea yet what exactly causes these bursts. The new data however will help formulate better theories, that I guarantee will be contradicted by subsequent new data. At the moment there is so little known about FRBs that any theory must be looked at with great skepticism.

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Yutu-2 to resume travels after day of rest

9:58 am

The new colonial movement: After lunar day of no activity, China has reactivated its Yutu-2 rover on its 19th lunar day on the far side of the Moon.

The Yutu 2 rover had remained stationary during lunar day 18 (May 16-29), while teams back on Earth upgraded ground stations in preparation for the Tianwen-1 Mars mission, due to launch in late July or early August. Upgrades to the tracking and command facilities at Jiamusi, northeast China, and Kashi in the northwest were completed June 13 according to CLEP, meaning normal roving service can now resume.

While the rover has been stationary, the Yutu 2 science team have identified a nearby crater for examination. The 4-foot-wide (1.3 meters), 8-inch-deep (20 centimeters) crater contains reflective material which may be similar in nature to suspected impact melt glass the rover discovered last year. After checking out the crater, Yutu 2 will continue its journey northwest from the Chang’e 4 landing site. Yutu 2 has driven a total of 1,469 feet (447.68 meters) since setting down on the far side of the moon in January 2019.

Generally Yutu-2 has averaged about a hundred feet for each lunar day of actual travel.

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Astronomers discover giant arc spanning a third of the night sky

9:05 am

Astronomers have discovered a giant arc of hydrogen gas near the Big Dipper that span a third of the night sky and is thought to be the leftover shockwave from a supernova.

Ultraviolet and narrowband photography have captured the thin and extremely faint trace of hydrogen gas arcing across 30°. The arc, presented at the recent virtual meeting of the American Astronomical Society, is probably the pristine shockwave expanding from a supernova that occurred some 100,000 years ago, and it’s a record-holder for its sheer size on the sky.

Andrea Bracco (University of Paris) and colleagues came upon the Ursa Major Arc serendipitously when looking through the ultraviolet images archived by NASA’s Galaxy Evolution Explorer (GALEX). They were looking for signs of a straight, 2° filament that had been observed two decades ago — but they found out that that length of gas was less straight than they thought, forming instead a small piece of a much larger whole.

This is a great illustration of the uncertainty of science. Earlier observations spotted only 2 degrees of this arc, and thus thought it was a straight filament. Newer more sophisticated observations show that this first conclusion was in error, that it was much bigger, and curved.

I wonder what even more and better observations would reveal.

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Antares’ vast blobby atmosphere

9:12 am

The atmosphere of Antares
Click for full image.

Using the Atacama Large Millimeter/submillimeter Array (ALMA) and the Jansky Very Large Array (VLA), astronomers have been able to map out the gigantic atmosphere of gas that surrounds the red gas supergiant star Antares, the closest such star to our solar system.

The ALMA and VLA map of Antares is the most detailed radio map yet of any star, other than the Sun. ALMA observed Antares close to its surface (its optical photosphere) in shorter wavelengths, and the longer wavelengths observed by the VLA revealed the star’s atmosphere further out. As seen in visible light, Antares’ diameter is approximately 700 times larger than the Sun. But when ALMA and the VLA revealed its atmosphere in radio light, the supergiant turned out to be even more gigantic.

“The size of a star can vary dramatically depending on what wavelength of light it is observed with,” explained Eamon O’Gorman of the Dublin Institute for Advanced Studies in Ireland and lead author of the study published in the June 16 edition of the journal Astronomy & Astrophysics. “The longer wavelengths of the VLA revealed the supergiant’s atmosphere out to nearly 12 times the star’s radius.”

The image to the right, cropped and reduced to post here, is what these two telescopes detected. As you can see, the outer atmosphere of the star is very uneven, confirming what other observations of both Antares and Betelgeuse has seen.

These stars are giant gasbags. It appears their shape fluctuates depending on the local “weather” in each star’s atmosphere.

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Trace Gas Orbiter detects oxygen layer in Martian atmosphere

8:35 am

Europe’s Trace Gas Orbiter, in orbit around Mars, has detected for the first time the green atmospheric layer in Martian atmosphere caused by the interaction of oxygen and sunlight.

From what I can tell from the press release at the link, they did not “see” this green glow, they detected it spectroscopically. So, any images you see portraying it are simply artist renditions, not the real thing.

The detection is important, nonetheless. First, it confirms that there is oxygen in Mars’ atmosphere. Second, it is the first time this has been detected in the atmosphere other than Earth. Third, the detection matched closely to their computer models, suggesting that the models are a reasonable simulation of this aspect of Mars’ atmosphere.

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Lego Antikythera Mechanism

6:01 pm

An evening pause: From the youtube webpage:

The Antikythera Mechanism is the oldest known scientific computer, built in Greece at around 100 BCE. Lost for 2000 years, it was recovered from a shipwreck in 1901. But not until a century later was its purpose understood: an astronomical clock that determines the positions of celestial bodies with extraordinary precision. In 2010, we built a fully-functional replica out of Lego.

Hat tip Shaun Karry.

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Cassini evidence suggests volcanoes on Titan

4:04 pm

Scientists are now proposing that. based on a close look at data and imagery of Titan from the Cassini mission archive, that this moon of Saturn might have volcanoes, and that they might even be active today.

Volcano-like features seen in polar regions of Saturn’s moon Titan by NASA’s Cassini spacecraft could be evidence of explosive eruptions that may continue today, according to a new paper by Planetary Science Institute Senior Scientist Charles A. Wood and coauthor Jani Radebaugh of Brigham Young University.

Morphological features such as nested collapses, elevated ramparts, halos, and islands indicate that some of the abundant small depressions in the north polar region of Titan are volcanic collapse craters, according to “Morphologic Evidence for Volcanic Craters near Titan’s North Polar Region” that appears in the Journal of Geophysical Research: Planets. A few similar depressions occur near the south pole of Titan. “The close association of the proposed volcanic craters with polar lakes is consistent with a volcanic origin through explosive eruptions followed by collapse, as either maars or calderas,” Wood said. “The apparent freshness of some craters may mean that volcanism has been relatively recently active on Titan or even continues today.”

The data being somewhat think, there is a great deal of uncertainty with this theory. Nonetheless, it makes perfect sense, and in fact it would be a surprise if some sort of volcanic activity was not occurring on Titan.

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Deciphering the strange geology of Mars — or anything!

10:03 am

Eroding Medusae Fossae Formation ash deposits
Click for full image.

Today’s cool image is for once not taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Instead, the image to the right, cropped and reduced to post here, was taken by Mars Odyssey on April 5, 2020, and shows the scouring and erosion caused by winds over many eons in a region dubbed Zephyria Planum. (Note that the image might fool your eye. Sunlight is coming from the east, and the rough terrain at the top is higher than the smooth plain at the bottom.)

Years ago, when I first started to rummage through the archives of images from the various Mars orbiters, I would have seen this image and posted it because I was completely baffled by what I saw, and thought that mystery made it worth showing to the public. Since then my incessant probing of research papers as well as asking a lot of questions of scientists has taught me a lot more about what scientists now surmise of the Martian geology. This greater knowledge in turn makes it possible for me to look at an image like this and immediately make a reasonable guess as to an explanation. This photo, while still containing much that is mysterious, is no longer completely baffling to me.

This willingness to ask questions and dig deeper is fundamental to all things. To have a deeper understanding and not simply guess about any subject, you always have to recognize that your assumptions are likely wrong, and that to learn anything you have to repeatedly ask what I call “the next question.” The first answer will force you to recognize that your first guesses are wrong, raise more questions, which in turn will lead to more questions, and then more questions, and so forth.

Whether I am researching Mars or early space history or politics, this rule always applies. Don’t leap to a conclusion. Think it possible you could be wrong. Ask the next question. And the next. You will repeatedly find that what you thought you knew was not correct, and in the end you will gain a deeper understanding of what is actually known about any subject, as well as what is unknown. And knowing the unknowns is probably the most important thing you can learn.

To gain a better understanding of today’s particular image, our first questions must start with context. Where is this feature on Mars? What is the surrounding history of that location? And what is already known about this place?

The location immediately reveals a great deal, as shown in the overview map below.
» Read more

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Dozens of scientists forced out because of foreign ties, mostly with China

9:19 am

An investigation by the National Institute of Health (NIH) has resulted in 54 scientists either resigning or being fired because they had illegally kept secret their financial ties to foreign governments, almost all of which were with China.

Some 54 scientists have resigned or been fired as a result of an ongoing investigation by the National Institutes of Health into the failure of NIH grantees to disclose financial ties to foreign governments. In 93% of those cases, the hidden funding came from a Chinese institution.

The new numbers come from Michael Lauer, NIH’s head of extramural research. Lauer had previously provided some information on the scope of NIH’s investigation, which had targeted 189 scientists at 87 institutions. But his presentation today to a senior advisory panel offered by far the most detailed breakout of an effort NIH launched in August 2018 that has roiled the U.S. biomedical community, and resulted in criminal charges against some prominent researchers, including Charles Lieber, chair of Harvard University’s department of chemistry and chemical biology.

“It’s not what we had hoped, and it’s not a fun task,” NIH Director Francis Collins said in characterizing the ongoing investigation. He called the data “sobering.”

The article, from the liberal journal Science, tries to imply that there is something bigoted about this investigation because the bulk of those forced out happened to be Asian, but that is junk journalism. China itself is bigoted, and targets those of Asian ancestry for its spying. If we are to defend our nation from them, we have to accept the fact that the ethnic statistics here will not be balanced.

The bottom line remains: If you want to get an American government research grant, you cannot have financial ties with hostile foreign governments. And if you lie about those ties, than we can safely assume you are an agent for those hostile governments, and are really a spy subject to arrest and prosecution.

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Help scientists plan Curiosity’s future travels

1:27 pm

The Curiosity science team is asking the help of ordinary citizens in improving the software it uses to plan Curiosity’s future travels.

Using the online tool AI4Mars to label terrain features in pictures downloaded from the Red Planet, you can train an artificial intelligence algorithm to automatically read the landscape.

Is that a big rock to the left? Could it be sand? Or maybe it’s nice, flat bedrock. AI4Mars, which is hosted on the citizen science website Zooniverse, lets you draw boundaries around terrain and choose one of four labels. Those labels are key to sharpening the Martian terrain-classification algorithm called SPOC (Soil Property and Object Classification).

The goal is not to have citizens plan the rover’s route, but to use their judgments to refine the software that the scientists and engineers use to plan the route. This refinement will also be applicable to Perseverance when it gets to Jezero Crater in February 2021.

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Isidis Basin, on whose margin Perseverance will roam

1:20 pm

Pedestal craters in Isidis Basin
Click for full image.

Overview map

Today’s cool image to the right, cropped and reduced to post here, highlights the floor of one of Mars’ largest basins, dubbed Isidis Planitia, and located at the transition zone between the planet’s northern lowland plains and the southern cratered highlands.

The overview map below of Isidis Basin provides some context. The white box shows where this particular image is located. Jezero Crater, indicated by the red circle (which is also about the size of the crater), is where the rover Perseverance is going to land and roam come February 2021, should all go well. For scale, Isidis is about the size of the eastern half of the United States. If Chicago was located at Jezero Crater, Baltimore would be on the basin’s eastern edge, at around 4 o’clock.

This particular section of the full photo, taken on April 5, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), shows many features very typical of the floor of Isidis Basin, which also immediately reveal a great deal about its possible history.

In this small snippet we can see what at first glance appear to be pedestal craters standing up like mesas, with ordinary craters scattered about on that lower surrounding terrain. Clearly, if these are pedestal craters they had to have been created first, and then over a very long time erosion processes ate away at that plain, leaving these pedestals (which had become resistant to erosion because the impact had packed their material together and made it harder) behind as mesas.

Then, after this period of erosion was complete enough additional time was required for at least one or two rounds of cratering to occur, leaving behind the many more younger craters on the plain floor, many of which are now partly buried by dust and sand.

The problem is that these mesas are almost certainly not pedestal craters, despite their appearance. » Read more

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New Horizons sees stellar parallax

3:04 pm

New Horizons is now far enough away from Earth that its perspective of the universe shifts at least two nearby stars into slightly different positions than seen on Earth.

On April 22-23, the spacecraft turned its long-range telescopic camera to a pair of the closest stars, Proxima Centauri and Wolf 359, showing just how they appear in different places than we see from Earth. Scientists have long used this “parallax effect” – how a star appears to shift against its background when seen from different locations — to measure distances to stars.

An easy way to see parallax is to place one finger at arm’s length and watch it jump back and forth when you view it successively with each eye. Similarly, as Earth makes it way around the Sun, the stars shift their positions. But because even the nearest stars are hundreds of thousands of times farther away than the diameter of Earth’s orbit, the parallax shifts are tiny, and can only be measured with precise instrumentation. “No human eye can detect these shifts,” Stern said.

But when New Horizons images are paired with pictures of the same stars taken on the same dates by telescopes on Earth, the parallax shift is instantly visible. The combination yields a 3D view of the stars “floating” in front of their background star fields.

The resulting 3D image, available at the link, is very cool. Both stars clearly appear closer than the surrounding background stars, which of course is true as they are among the closest stars to the Sun.

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NASA confirms Webb launch delayed again

9:16 am

NASA officials yesterday confirmed that, due to the new work conditions and the lock down imposed by the Wuhan flu panic, the launch of the James Webb Space telescope will not occur in March 2021.

“We will not launch in March,” said Thomas Zurbuchen, the space agency’s associate administrator for science. “Absolutely we will not launch in March. That is not in the cards right now. That’s not because they did anything wrong. It’s not anyone’s fault or mismanagement.”

Zurbuchen made these comments at a virtual meeting of the National Academies’ Space Studies Board. He said the telescope was already cutting it close on its schedule before the COVID-19 pandemic struck the agency and that the virus had led to additional lost work time. “This team has stayed on its toes and pushed this telescope forward at the maximum speed possible,” he said. “But we’ve lost time. Instead of two shifts fully staffed, we could not do that for all the reasons that we talk about. Not everybody was available. There were positive cases here and there (in the surrounding area, not on site). And so, perhaps, we had only one shift.”

No new target date has been set, though the comments even hinted that they might not be able to do it in 2021.

Webb will cost 20 times more than originally budgeted ($500 million vs $10 billion) and is now more than a decade behind schedule. In the process, those overages and delays wiped out almost all of NASA’s other astronomy projects during the 2010s.

But don’t worry! Once Webb launches the task of wiping out more astronomy projects with overages and delays will be courageously taken up by NASA’s Roman Space Telescope (formerly WFIRST), already behind schedule and over budget, and it is still only in the design phase.

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Astrobotic wins contract to land VIPER rover at Moon’s south pole

9:03 am

Capitalism in space: NASA today awarded the private company Astrobotic a $199 million contract to provide the lander that place place the agency’s VIPER rover down near Moon’s south pole.

The target date for the mission is late 2023, and is intended as a scouting mission for the Artemis manned landing to follow.

During its 100-Earth-day mission, the approximately 1,000-pound VIPER rover will roam several miles and use its four science instruments to sample various soil environments. Versions of its three water-hunting instruments are flying to the Moon on earlier CLPS lander deliveries in 2021 and 2022 to help test their performance on the lunar surface prior to VIPER’s mission. The rover also will have a drill to bore approximately 3 feet into the lunar surface.

The key to this mission continues to be NASA’s shift from building things to hiring others to build them. If Astrobotic is successfully, they will then be positioned to offer their lander design to others, since it belongs to them, not NASA.

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Fading Martian slope streaks

2:30 pm

Fading Martian slope streaks
Click for full image.

Cool image time! I’ve covered the topic of the mysterious slope streaks on Mars previously in great detail (see here and here). Essentially they are generally dark streaks (but sometimes light) that appear randomly on slopes and then fade over time. Unlike recurring slope lineae, another changing streak found on Martian slopes, the coming and going of slope streaks is not tied to the seasons. They can appear at any time in the year, and will take several Martian years to fade away.

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 March 26, 2020. It shows numerous slope streaks down the eastern interior rim of a crater in the transition zone between the northern lowlands and the southern cratered highlands in a region dubbed Arabia Terra.

Though I can find no previous high resolution image of this crater to measure any temporal changes, you can clearly see that this slope has experienced many streaks over time, with some darker than others. The different shades suggest that the lighter streaks are older and have faded, with the darker streaks more recent events.

At the moment there is no strong consensus on the causes of these streaks. As one science paper noted, “The processes that form slope streaks remain obscure. No proposed mechanism readily accounts for all of their observed characteristics and peculiarities.” We know they occur in equatorial regions and dusty locations, and that they are triggered by some disturbance at the topmost point of the streak, which then causes a chain reaction down the slope. Other than that, the facts are puzzling, and suggest that these streaks are a phenomenon wholly unique to Mars.

The crater itself, located at 24 degrees north latitude, has some other mysteries. The features on its floor, for instance, are very puzzling. Though suggestive of the buried glaciers found in many craters in the mid-latitudes, this crater is a bit too far south. Maybe its higher altitude allows for some ice to remain here? Then again, the features on that floor might have nothing to do with ice. Maybe we are looking at sand carved by wind? Or hardened mud that was once wet?

I am merely guessing, a dangerous thing to do when one’s knowledge is limited. Then again, it’s fun, so please join in with your own guesses.

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Parker successfully completes fifth solar fly-by

9:42 am

The Parker Solar Probe has signaled scientists that it has successfully completed its fifth solar fly-by without damage.

On June 9, 2020, NASA’s Parker Solar Probe signaled the success of its fifth close pass by the Sun, called perihelion, with a radio beacon tone. The spacecraft completed the fifth perihelion of its mission two days prior, flying within 11.6 million miles from the Sun’s surface, reaching a top speed of about 244,225 miles per hour, which matches the spacecraft’s own records for closest human-made object to the Sun and fastest human-made object, set during its fourth orbit on January 29.

Mission controllers at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, received a “status A” beacon from the spacecraft at 4:40 p.m. EDT. Status A is the best of four possible status signals, and indicates that the spacecraft is operating nominally and the instrument suites are collecting science data. This beacon tone comes after a five-day period where communications with the spacecraft were not possible.

The data from this fly-by will arrive during the summer. Meanwhile, the spacecraft will next do a fly-by of Venus to slow it down further so that it can get even closer to the Sun on its next orbit.

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OSIRIS-REx spots sun-caused erosion on Bennu

10:08 am

Rock on Bennu showing exfoliation
Click for full figure.

An analysis of images taken by OSIRIS-REx of the asteroid Bennu has allowed scientists to identify places where the changing temperatures from day to night has caused the surfaces of rocks to flake away, a process geologists label exfoliation.

The image on the right, cropped and reduced to post here, is from figure 1 in the paper. The yellow arrow points to a typical example of exfoliation, which is a process you can see on many rocks here on Earth.

Rocks expand when sunlight heats them during the day and contract as they cool down at night, causing stress that forms cracks that grow slowly over time. Scientists have thought for a while that thermal fracturing could be an important weathering process on airless objects like asteroids because many experience extreme temperature differences between day and night, compounding the stress. For example, daytime highs on Bennu can reach almost 127 degrees Celsius or about 260 degrees Fahrenheit, and nighttime lows plummet to about minus 73 degrees Celsius or nearly minus 100 degrees Fahrenheit. However, many of the telltale features of thermal fracturing are small, and before OSIRIS-REx got close to Bennu, the high-resolution imagery required to confirm thermal fracturing on asteroids didn’t exist.

The mission team found features consistent with thermal fracturing using the spacecraft’s OSIRIS-REx Camera Suite (OCAMS), which can see features on Bennu smaller than one centimeter (almost 0.4 inches). It found evidence of exfoliation, where thermal fracturing likely caused small, thin layers (1 – 10 centimeters) to flake off of boulder surfaces. The spacecraft also produced images of cracks running through boulders in a north-south direction, along the line of stress that would be produced by thermal fracturing on Bennu.

The typical erosion processes that can cause exfoliation (weather, gravity) are not possible on tiny Bennu, so the solution appears to rest with sunlight and sunlight alone.

This is not really a surprising result, but it is the first time it has been documented by data.

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Sunspot update: The deep minimum deepens

12:07 pm

NOAA last week did its monthly update of 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.

May 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.

Since last month NOAA has done some further revisions to this graph, and improved it significantly since their first redesign, released in April. You can see the difference just by comparing it to my previous update last month. For scales covering longer periods, they have eliminated the diamonds, making the curve much more readable. They have also increased the size of the graph, which also serves to make it more readable as well. Kudos to the people at NOAA for these changes.

As you can see, sunspot activity in May plunged from the slight uptick in April. This is even more clearly shown by the SILSO graph below.
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