Tag: science

The slowly changing dunes of Mars

1:15 pm

Map of Mars

In order to better understand the climate and geology of Mars, scientists need to study how the thin Martian atmosphere causes changes to the planet’s numerous sand dunes. To do this, they have been using the high resolution camera on Mars Reconnaissance Orbiter (MRO) to periodically snap photos of the same places repeatedly over time, to track any changes that might occur.

Recently the monthly download dump of images from MRO included one such location in the northwest quadrant of Hellas Basin, what I call the basement of Mars because it the planet’s lowest point. The uncaptioned image was taken on May 20, 2019 and was titled “Hellas Region Sand Dune Changes.” A review of past images shows that MRO has taken pictures of this location several times in the past, in 2011 and in 2017. All these images were taken during the Martian autumn season, and were taken to see if over time there were any significant changes to the dunes due to winds.

My superficial comparison of the 2011 and 2017 images does not show much obvious change. There could be small changes that my quick review did not spot, and there is also the strong possibility that the entire dune field could have shifted as a unit over those three Martian years, a change that would require a more detailed analysis beyond my technical capabilities. Click on both links, put the photographs in separate tabs, and switch quickly between them to see if you can spot any differences.

Comparing the 2011 and 2019 images however shows some significant changes, most of which I think are due to the 2018 global dust storm. Below is that comparison.
» Read more

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More organics detected in Enceladus’ plumes

10:23 am

Using Cassini archived data scientists have detected evidence of new organic molecules in the water-ice plumes coming from the tiger stripe fissures on Saturn’s moon Enceladus.

Powerful hydrothermal vents eject material from Enceladus’ core, which mixes with water from the moon’s massive subsurface ocean before it is released into space as water vapor and ice grains. The newly discovered molecules, condensed onto the ice grains, were determined to be nitrogen- and oxygen-bearing compounds.

On Earth, similar compounds are part of chemical reactions that produce amino acids, the building blocks of life. Hydrothermal vents on the ocean floor provide the energy that fuels the reactions. Scientists believe Enceladus’ hydrothermal vents may operate in the same way, supplying energy that leads to the production of amino acids.

For clarity I should point out that I am using the term “organics” as chemists do. It refers not to life, but to any molecule that is formed using carbon.

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Juno completes long engine burn to avoid Jupiter’s shadow

10:14 am

In order to avoid a twelve-hour plunge through Jupiter’s shadow that would have likely sucked all power from Juno’s solar powered systems and killed the spacecraft, mission engineers have successfully used its attitude thrusters to complete a 10.5 long engine burn.

Juno began the maneuver yesterday, on Sept. 30, at 7:46 p.m. EDT (4:46 p.m. PDT) and completed it early on Oct. 1. Using the spacecraft’s reaction-control thrusters, the propulsive maneuver lasted five times longer than any previous use of that system. It changed Juno’s orbital velocity by 126 mph (203 kph) and consumed about 160 pounds (73 kilograms) of fuel. Without this maneuver, Juno would have spent 12 hours in transit across Jupiter’s shadow – more than enough time to drain the spacecraft’s batteries. Without power, and with spacecraft temperatures plummeting, Juno would likely succumb to the cold and be unable to awaken upon exit.

“With the success of this burn, we are on track to jump the shadow on Nov. 3,” said Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio.

This burn did not use the spacecraft’s main engine, which they fear has a problem that would produce a catastrophic failure if fired. Instead, they used Juno’s small attitude thrusters, which explains the length of the maneuver. In fact, this 10.5 hour burn might actually be the longest chemical engine burn in space ever. While ion engines routinely fire for this long or longer, as far as I can remember no chemical engine in space has ever fired even close to this length of time.

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The sounds of Mars

10:56 am

The InSight seismometer team today issued an update of their results since the instrument began recording quakes on Mars in February.

But after the seismometer was set down by InSight’s robotic arm, Mars seemed shy. It didn’t produce its first rumbling until this past April, and this first quake turned out to be an odd duck. It had a surprisingly high-frequency seismic signal compared to what the science team has heard since then. Out of more than 100 events detected to date, about 21 are strongly considered to be quakes. The remainder could be quakes as well, but the science team hasn’t ruled out other causes.

The press release provides audio for many of these detections, including two 3.3+ earthquakes as well as a strange sequence of what they call “dinks and donks” that appear to occur each evening as the seismometer adjusts to night-time temperatures.

So far the data suggests that Mars’ interior is a relatively quiet place, compared to Earth.

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China to open FAST radio telescope to world

8:48 am

China has decided to allow astronomers worldwide to apply for time on its new FAST radio telescope, the largest such telescope in the world.

Since testing began in 2016, only Chinese scientists have been able to lead projects studying the telescope’s preliminary data. But now, observation time will be accessible to researchers from around the world, says Zhiqiang Shen, director of the Shanghai Astronomical Observatory and co-chair of the Chinese Academy of Sciences’ FAST supervisory committee.

Obviously U.S. astronomers are going to want to use this telescope. I wonder if there will be security issues. I suspect that if they only request time and then make observations, there will be no problems. However, if they need to do anything that will require the use of U.S. technology, in China, then they may find themselves violating the U.S. law that forbids any technology transfer to China.

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Martian impact into lava crust?

1:13 pm

Impact crater north of Pavonis Mons
Click for full image.

Cool image time! The photo on the right, cropped to post here, was taken by the high resolution camera on April 23, 2019. It shows a quite intriguing impact crater on the northern lava slopes of Pavonis Mons, the middle volcano in the chain of three gigantic volcanoes to the west of Valles Marineris.

What makes this image cool is what the impact did when it hit. Note the circular depression just outside the crater’s rim. In the southeast quadrant that ring also includes a number of additional parallel and concentric depressions. Beyond the depression ground appears mottled, almost like splashed mud.

What could have caused this circular depression? Our first clue comes from the crater’s location, as shown in the overview map below and to the right.
» Read more

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First data suggests Comet Borisov resembles solar comets

8:46 am

The first spectrum obtained from Comet Borisov suggests that it is quite similar to comets in our solar system.

The gas detected was cyanogen, made of a carbon atom and a nitrogen atom bonded together. It is a toxic gas if inhaled, but it is relatively common in comets.

The team concluded that the most remarkable thing about the comet is that it appears ordinary in terms of the gas and dust it is emitting. It looks like it was born 4.6 billion years ago with the other comets in our Solar system, yet has come from an – as yet – unidentified star system.

It is still very early, so drawing any firm conclusions at this point is risky.

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Movie of Juno’s 22 close fly-by of Jupiter

8:39 am

As he has done previously, citizen scientist Gerald Eichstädt has created a movie using Juno images of the spacecraft’s twenty-second fly-by of Jupiter.

I have embedded the movie below the fold. This fly-by included the images of Io’s shadow posted by other citizen scientists earlier. Because the movie shows this shadow in the context of the fly-by (near its lowest altitude), it illustrates why the shadow appears far larger than it is, relative to the entire planet.

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Planet X a small black hole?

8:13 am

In one of the wilder theories attempting to explain the orbits of the outer objects found beyond Neptune, two physicists have proposed that the reason Planet X has not been located is because it might be a small black hole.

Previous studies have suggested Planet Nine, which some astronomers refer to as “Planet X,” has a mass between five and 15 times that of Earth and lies between 45 billion and 150 billion kilometers from the sun. At such a distance, an object would receive very little light from the sun, making it hard to see with telescopes.

To detect objects of that mass, whether planets or black holes, astronomers can look for weird blobs of light formed when light “bends” around the object’s gravitational field on its journey through the galaxy (simulated image above). Those anomalies would come and go as objects move in front of a distant star and continue in their orbit.

But if the object is a planet-mass black hole, the physicists say, it would likely be surrounded by a halo of dark matter that could stretch up to 1 billion kilometers on every side. And interactions between dark matter particles in that halo—especially collisions between dark matter and dark antimatter—could release a flash of gamma rays that would betray the object’s presence, the researchers propose in a forthcoming paper posted on the preprint server arXiv.

Anything is possible, but some things are certainly less likely than others. If these scientists turn out to be right, however, they will have achieved one of the biggest coups in the history of science.

And yes, the undiscovered planet out there should be referred to as “Planet X”, not “Planet Nine.” Not only is Pluto a planet, so are a lot of other objects in the solar system that up to recently were not considered so.

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A big planet circling a small star

10:03 am

The uncertainty of science: In contradiction of every existing stellar and planetary formation model, astronomers have found a half-sized Jupiter exoplanet orbiting a tiny red dwarf star.

The red dwarf GJ 3512 is located 30 light-years from us. Although the star is only about a tenth of the mass of the Sun, it possesses a giant planet – an unexpected observation. “Around such stars there should only be planets the size of the Earth or somewhat more massive Super-Earths,” says Christoph Mordasini, professor at the University of Bern and member of the National Centre of Competence in Research (NCCR) PlanetS: “GJ 3512b, however, is a giant planet with a mass about half as big as the one of Jupiter, and thus at least one order of magnitude more massive than the planets predicted by theoretical models for such small stars.”

It appears the universe does not care what this and other scientists think “should” happen. The universe will do what the universe wants to do.

This discovery only underlines how little we understand of the formation of stars and their solar system. Be prepared for many more like surprises in the coming decades and centuries.

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Astronomer: Look for monolith on co-orbiting asteriods

5:37 pm

According to one astronomer in a paper published this week, the most likely place to find alien artifacts would be on the co-orbital asteroids, objects whose orbit is very similar to the Earth and thus always nearby but mostly unseen.

In this context, a co-orbital is an asteroid that goes around the Sun on the same, or similar, orbital path to Earth. Co-orbital objects approach Earth very closely every year at distance is much shorter than anything except the moon.

Consequently, co-orbitals could be a great place to watch Earth from. Not only would any alien probes on co-orbital objects be concealed, but they would also be anchored and able to access solar energy. They could possibly sustain themselves for many thousands of years.

According to this paper, if aliens have visited the solar system in the past they would place their long-term alien probes on such an asteroid, or even give it a comparable co-orbit. And if we look and don’t find anything, that would strongly imply that we are alone in the universe.

Fun stuff, but need I say that not finding alien artifacts at these locations proves nothing.

Hat tip Jeff Bliss.

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Tongue-shaped glaciers on Mars

2:53 pm

Tongue-shaped glacier on Mars
Click for full image.

Cool image time! I could also call this another example of mass wasting, which it appears to be according to my understanding of Martian geological processes. However, the Mars Reconnaissance Orbiter science team dubbed this image “Tongue-Shaped Glaciers in Centauri Montes,” and I have no right to disagree with them.

The image to the right, rotated, cropped, reduced, and brightened to post here, shows the most prominent tongue-shaped glacier in the full image. The two curved ridges to the south of the glacier’s tip are almost certainly old moraines of debris pushed there during earlier events, when the glacier material extended farther out. In fact, if you look close you can see that this tongue lies on top of a larger older tongue that lines up with the closer of these two ridges.

This feature is located at 37 degrees south latitude, which puts it inside Mars’s southern glacial band that extends from 30 to 60 degrees latitude. According to the present defined types of Martian glaciers, this tongue is what scientists have dubbed a lobate debris apron, a glacier that in many ways resembles glaciers we see on Earth.

The location of this feature is especially interesting, especially because other images have found that it is not unique to this region.
» Read more

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Storms on Jupiter

8:55 am

Storms on Jupiter
Click for full resolution image.

The image on the right, reduced to post here, was created by Citizen scientist Kevin Gill from recent Juno images taken of Jupiter, and shows in detail some of the many storms that fill Jupiter’s many bands of color.

We do not have a scale, but my guess is that these storms are probably about the size of the Earth, which means these storms are bigger than any hurricane you can imagine. If you click on the image to look at the full resolution photograph, you can see there are tiny white clouds clumped in the middle of the picture’s three biggest storms. Those clumps are probably also bigger than any single clouds you could find anywhere on Earth.

As I wrote in a post in April 2017 about a similar Juno image:

What should fill us with even more awe is that this only covers a very thin slice of the top of Jupiter’s deep atmosphere. The planet itself is about 89,000 miles in diameter, more than ten times larger than Earth. The depth of its atmosphere is not really known, but it must be deeper than several Earths, piled on top of each other. In that depth there must be many atmospheric layers, each thicker and denser than the one above, and each with its own weather systems and complexities.

It will take centuries of research, including the development of new engineering capable of accessing this place, to even begin to map out its meteorology. And this is only one gas giant, of what we now know must be millions and millions throughout the galaxy.

If we have the nerve and daring, the human race has the opportunity to go out there and never be bored. There will always be something unknown to discover.

All that still applies. We have only just begun our journey exploring the universe.

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Cave pits in the Martian northern lowlands

1:22 pm

New pits in Hephaestus Planitia

I could call this my monthly Martian Pit update. Since November 2018 I have each month found from two to five new and interesting cave pits in the monthly download of new images from the high resolution camera on Mars Reconnaissance Orbiter (MRO). My previous posts:

All except the last August 12 post were for pits on the flanks of Arsia Mons, the southernmost in the line of three giant volcanoes to the southeast of Olympus Mons, and were thus almost certainly resulting from lava flows.

The August 12 post instead showed pits found in Utopia Planitia, one of the large plains that comprise the Martian northern lowlands where scientists think an intermittent ocean might have once existed. All of these pits are found in a region of meandering canyons dubbed Hephaestus Fossae.

In the most recent MRO release scientists once again focused on the pits in or near Hephaetus, imaging four pits, two of which have been imaged previously, as shown in my August post and labeled #2 and #4 in this article, and two (here and here) that appear new. The image on the right, cropped to post here, shows the two new pits, dubbed #1 and #3. In the full image of #1, it is clear that this pit lines up nicely with some other less prominent depressions, suggesting an underground cave. Pit #3 however is more puzzling. In the full image, this pit actually runs perpendicular to a long depression to the west. There are also no other related features around it.

What makes all four of these pits intriguing is their relationship to Hephaestus Fossae and a neighboring rill-like canyon dubbed Hebrus Valles, as shown in the overview map below.
» Read more

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Russia and China to team up on lunar lander/orbiter missions

9:25 am

Russia and China have signed an agreement to cooperate on several future lunar lander and orbiter unmanned missions.

The agreements will see cooperation in Russia’s Luna-26 orbiter spacecraft and Chang’e-7 polar landing mission, according to Roscosmos, which could involve contributions of science payloads to the respective spacecraft. Both missions are currently scheduled for the early-to-mid 2020s.

The two sides also committed to previously announced plans to create a joint lunar and deep space data center, which will consist of hubs in both Russia and China.

How they will specifically cooperate on those specific space missions was not made clear. From what I can gather, the real heart of this agreement are those joint data centers for both missions.

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ESA asks NASA’s help on ExoMars rover parachute problems

8:58 am

The European Space Agency (ESA) has asked for help from NASA in trying to figure out the cause of the failures during testing of the parachutes they want to use to safely land their ExoMars 2020 rover, Rosalind Franklin.

So far the parachutes have been damaged on all previous tests. They plan two more tests in December and February.

Both tests, to be held at high altitude to simulate the Martian atmosphere, need to succeed in order for the parachutes to pass qualification. TheExoMars mission faces a final review scheduled April 2020, Francois Spoto, ExoMars program manager, told SpaceNews. “Now the situation is critical, of course, because we have limited time and no margin,” Spoto says.

If one of the tests fails, the ExoMars mission will miss the narrow July 25 to Aug. 13 launch window next year and slip to the next window, in late 2022. The lander and rover segments are meanwhile progressing well and ready for environmental testing.

They held a workshop on the previous failures, and obtained new analysis of the causes from JPL engineers.

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Yutu-2’s first close look at mysterious “gel-like” material

8:29 am

gel-like?
Click for full image.

Chinese scientists have released images showing their approach and first look at the mysterious “gel-like material they spotted inside a small crater using their lunar rover Yutu-2, presently exploring an area on the far side of the Moon.

The image to the right, cropped and expanded to post here, focuses on that location. As much as we might wish it, the rectangle is not the monolith from 2001, a Space Odyssey. It is merely a section where it appears they increased the exposure to see more details in the shadows. Also, as noted at the webpage:

The compressed, black-and-white shot comes from an obstacle-avoidance camera on the rover. The green, rectangular area and red circle within are suspected to be related to the field of view of the Visible and Near-Infrared Spectrometer (VNIS) instrument, rather than the subject matter itself, according to some lunar scientists.

Apparently they were unsatisfied with the data from this viewpoint, and moved the rover to get a second better view. The results from that second location however have not been released.

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Io’s shadow on Jupiter

1:05 pm

Io's shadow on Jupiter
Click for full image.

Citizen scientists Kevin Gill and Tanya Oleksuik have used raw images from Juno to create several really cool images of the eclipse shadow of Io moving across the face of Jupiter. The image above, by Gill, is what I think is the most dramatic. The other images are here, here, here, here, and here.

Oleksuik notes that the colors are not true, and are enhanced for drama. Also, the shadow in many of the images are much too large relative to the globe of Jupiter. The last link above gives a better sense of the true size of that shadow against Jupiter’s giant sphere. Io’s shadow only covers a tiny part of the surface. The reason it appears larger is that the whole image does not see the entire hemisphere.

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Fifty years of failed climate predictions

4:12 pm

Link here. From the abstract:

Modern doomsayers have been predicting climate and environmental disaster since the 1960s. They continue to do so today.

None of the apocalyptic predictions with due dates as of today have come true.

What follows is a collection of notably wild predictions from notable people in government and science. More than merely spotlighting the failed predictions, this collection shows that the makers of failed apocalyptic predictions often are individuals holding respected positions in government and science.

While such predictions have been and continue to be enthusiastically reported by a media eager for sensational headlines, the failures are typically not revisited.

Many of these doomsday predictions have been previously documented by Tony Heller at his Real Climate Science website.

Much of the fault of these failed predictions falls to the media, which blindly hawks these predictions as if they were solid science, when most were merely political activism falsely dressed up as science. Predictions like this should almost never make the news. What should count are actual results, and data, showing something that is actually happening.

Unfortunately, our mostly liberal press has since the 1980s instead decided to team up with climate activists to push their agendas. Worse, though the examples at the link end in 2014, this journalistic malpractice still goes on today. Only three weeks ago Heller posted this story, Greenland Propaganda Meltdown, noting the errors and false claims in an August 20, 2019 Los Angeles Times that claimed “Greenland’s glaciers are melting.”

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New findings from Rosetta: Bouncing boulders and collapsing cliffs

10:13 am

cliff collapse on Comet 67P/C-G
Click for full image.

In reviewing the large image archive taken by Europe’s Rosetta probe while it orbited Comet 67P/C-G from 2014 to 2016, scientists have found more evidence of changes on its surface during its closest approach to the Sun, including a bouncing boulder and the collapse of large cliff.

The image on the right, reduced to post here, shows both wide (top) and close-up (bottom) views of the cliff collapse.

“This seems to be one of the largest cliff collapses we’ve seen on the comet during Rosetta’s lifetime, with an area of about 2000 square metres collapsing,” said Ramy, also speaking at EPSC-DPS today. … “Inspection of before and after images allow us to ascertain that the scarp was intact up until at least May 2015, for when we still have high enough resolution images in that region to see it,” says Graham, an undergraduate student working with Ramy to investigate Rosetta’s vast image archive.

“The location in this particularly active region increases the likelihood that the collapsing event is linked to the outburst that occurred in September 2015.”

These finds are only a sample of a number of similar discoveries since the end of the mission, as scientists pore through the more than 76,000 images in the Rosetta archive.

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Hayabusa-2 completes rehearsal for MINERVA-II drop

9:58 am

Hayabusa-2 has successfully completed its rehearsal for its planned drop of its last MINERVA-II bouncer/rover, releasing two reflective targets in order to track how they spiral down to the surface of Ryugu.

Hayabusa 2’s cameras will track the movement of the two navigation aids as they fly in space around Ryugu over the next several days. Scientists expect Ryugu’s tenuous gravity will pull the target markers to the asteroid’s surface within a week.

The release of that last bouncer is now expected in about a month. After spending time obtaining the data from that drop, Hayabusa-2 will then head back to Earth by the end of the year.

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Scientists propose mission to interstellar comet Borisov

9:31 am

In a paper published on the Cornell arXIiv site for preprint science papers, scientists have posted a paper proposing sending an unmanned probe to the newly discovered interstellar Comet Borisov, arriving in 2045.

You can download the paper here. [pdf]

Their analysis found that we just missed the ideal and most efficient launch date using the Falcon Heavy. If it had launched in July 2018 a two-ton spacecraft could have reached Comet Borisov by next month.

The best alternative option is a launch in January 2030, flying past Jupiter, then the Sun, and arriving in 2045. Because of the mission’s close approach to the Sun to gain speed, the mission would require the type of shielding developed for the Parker Solar Probe. If the Space Launch System was used for launch, a six-ton spacecraft could be sent. With other available rockets the largest possible payload would be 3 kilograms (about 6 pounds), making the probe a cubesat. As they note,

Despite this very low mass, a CubeSat-scale spacecraft could be sent to the interstellar object. Existing interplanetary CubeSats (Mars Cube One) show that there is no principle obstacle against using such a small spacecraft to deep space.

In fact, having a decade and a half before launch guarantees that a cubesat will be able to do this job, because by 2030 the technology for using smallsats for this kind of planetary mission should be fully developed.

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The never-ending snowstorm circling Saturn

10:21 am

New data suggests that the water being spewed out of Enceladus’s tiger stripes is depositing so much snow and ice on Saturn’s three inner moons, Mimas, Enceladus and Tethys, that these moons, as well as Enceladus, are about twice as bright in radar than previously thought.

Dr Le Gall and a team of researchers from France and the US have analysed 60 radar observations of Saturn’s inner moons, drawing from the full database of observations taken by the Cassini mission between 2004 and 2017. They found that previous reporting on these observations had underestimated the radar brightness by a factor of two.

Unprotected by any atmospheres, Saturn’s inner moons are bombarded by grains of various origins which alter their surface composition and texture. Cassini radar observations can help assess these effects by giving insights into the purity of the satellites’ water ice.

The extreme radar brightness is most likely related to the geysers that pump water from Enceladus’s internal ocean into the region in which the three moons orbit. Ultra-clean water ice particles fall back onto Enceladus itself and precipitate as snow on the other moons’ surfaces.

Dr Le Gall, of LATMOS-UVSQ, Paris, explained: “The super-bright radar signals that we observe require a snow cover that is at least a few tens of centimetres thick. However, the composition alone cannot explain the extremely bright levels recorded. Radar waves can penetrate transparent ice down to few meters and therefore have more opportunities to bounce off buried structures. The sub-surfaces of Saturn’s inner moons must contain highly efficient retro-reflectors that preferentially backscatter radar waves towards their source.”

While the new results suggest that the surfaces of these moons are much brighter that expected, I find the circumstances they describe far more fascinating: a never-ending snow storm in the orbits around Saturn and landing continually on these moons.

My, isn’t the universe wonderful?

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Io volcano erupts like Ol’ Faithful

10:09 am

Having determined that Io’s largest volcano appears to erupt on a regularly schedule, scientists have predicted that a new eruption should occur sometime in the next week or so.

The volcano Loki is expected to erupt in mid-September, 2019, according to a poster by Planetary Science Institute Senior Scientist Julie Rathbun presented today.

“Loki is the largest and most powerful volcano on Io, so bright in the infrared that we can detect it using telescopes on the Earth,” Rathbun said. Based on more than 20 years of observations, Loki undergoes periodic brightenings when it erupts on a relatively regular schedule. In the 1990s, that schedule was approximately every 540 days. It currently appears to be approximately every 475 days. Rathbun discovered the 540-day periodicity, described in her 2002 paper “L. Loki, Io: A periodic volcano” that appeared in Geophysical Research Letters.

These same scientists successfully predicted Loki’s last eruption based on this data, but also warn that there is no guarantee the volcano will do what they say. As stock brokers are required to say, past performance is no guarantee of future results.

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New data cuts neutrino mass in half

9:54 am

The uncertainty of science: New data now suggests that the highest mass possible for the neutrino is about half the previous estimates.

At the 2019 Topics in Astroparticle and Underground Physics conference in Toyama, Japan, leaders from the KATRIN experiment reported Sept. 13 that the estimated range for the rest mass of the neutrino is no larger than about 1 electron volt, or eV. These inaugural results obtained earlier this year by the Karlsruhe Tritium Neutrino experiment — or KATRIN — cut the mass range for the neutrino by more than half by lowering the upper limit of the neutrino’s mass from 2 eV to about 1 eV. The lower limit for the neutrino mass, 0.02 eV, was set by previous experiments by other groups.

This lower limit does not tell us what the neutrino actually weighs, only reduces the uncertainty of the range of possible masses.

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New theory says evaporating exomoon explains Tabby’s Star

9:47 am

Astronomers have proposed a new theory for the random and inexplicable light variations that Tabby’s Star undergoes, a melting and evaporating exomoon.

The Columbia team suggests that Tabby’s Star abducted an exomoon from a now long-gone, nearby planet and pulled it into orbit around itself, where it has been getting torn apart by stronger stellar radiation than existed in its former orbit. Chunks of the exomoon’s dusty outer layers of ice, gas, and carbonaceous rock have been able to withstand the radiation blow-out pressure that ejects smaller-grain dust clouds, and the volatile, large-grain material has inherited the exomoon’s new orbit around Tabby’s Star, where it forms a disk that persistently blocks the star’s light. The opaqueness of the disk can change slowly, as smaller-grain clouds pass through and larger particles stuck in orbit move from the disk toward Tabby’s Star, eventually getting so hot that they melt and fall onto the star’s surface.

Ultimately, after millions of years, the exomoon orbiting Tabby’s Star will completely evaporate, the researchers suggest.

The article does not explain why the theory requires this exoplanet to have once been a moon to another exoplanet, now gone. It seems to me that this is adding unnecessary complexity to the solution, but I have not read the paper itself, so their might be reasons.

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More potential Starship landing sites on Mars

5:07 pm

Starship landing sites

On August 28, 2019 I broke the story that SpaceX is beginning to obtain images of candidate Starship landing sites from Mars Reconnaissance Orbiter (MRO).

Many news sources, skilled in their ability to rewrite press releases, saw my article and immediately posted stories essentially repeating what I had found, including my geological reasoning. Some did some more digging and, because they came out a few days later they were able to take advantage of the next MRO team image release, issued on August 30th, to find a few more candidate site images.

Those additional images included the remaining stereo images for all the images in my August post, indicated by the white boxes in the overview map above. They also included two new locations, indicated by the black boxes. One was of one more location in the easternmost hills of Erebus Montes. The other was a stereo pair for one entirely different landing location, farther to the west in the mountains dubbed Phlegra Montes, a location that SpaceX had previously been considering, but until this image had not been included in its MRO image requests.

The grey boxes in the map above show the approximate locations of images not yet officially released by MRO. Though unreleased, their existence is still public knowledge, as they are listed as already acquired images in the HiWish database. Below are links to the three upcoming new images (the second stereo images for locations #1 and #2 are not included)

Both the Phlegra Montes location and #3 above appear to be looking at soft slushy material that might have a lot of water just below the surface.
» Read more

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Stony-iron asteroid caused flash on Jupiter in August

11:26 am

According to an analysis of the data obtained from the light flash that occurred when an object hit Jupiter on August 7, scientists have estimated its probably make-up, mass, and size.

They estimate from the energy released by the flash that the impactor could have been an object around 12-16 metres in diameter and with a mass of about 450 tons that disintegrated in the upper atmosphere at an altitude of about 80 kilometres above Jupiter’s clouds. Sankar and Palotai’s models of the light-curve for the flash suggest the impactor had a density typical of stony-iron meteors, indicating that it was a small asteroid rather than a comet.

Their conclusions are strengthened because they were able to compare this flash with five other similar but not as bright flashes, all detected since 2010.

These recent detections, all by amateurs, are because of the higher quality equipment now available to ordinary people, including the use of computers and remote operation. This technology is making it possible for amateurs to discover things that once only professionals could find.

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Update on effort to save heat probe on InSight

8:38 am

Link here. The article, written in late August by one of the German scientists in charge of the heat probe on the Mars lander InSight, gives a detailed look at the effort to figure out what is blocking the Mole, the digging tool designed to pound the heat probe as much as 15 feet into the ground.

They had discovered previously is that the ground had collapsed around the drill shaft, creating a very wide hole. The Mole however needed the friction caused by the surrounding dirt to push downward, and thus didn’t have it.

They have since used InSight’s scoop at the end of the robot arm to push at the ground around the hole in an effort to fill the hole. As of mid-August this has managed to fill the hole about half way.

This report was written on August 27, just before contact with Mars was lost for two weeks because the Sun had moved between the Earth and Mars. Communications have now resumed, so I expect they will also resume their efforts to fill the hole enough that they might then try to resume the digging effort.

Hat tip to Doug Messier of Parabolic Arc, who by the way is right now running his annual fund-raising drive for the website. Please consider donating.

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