Tag: science

The remnant of the supernova from 1181, as seen in multiple wavelengths

9:44 am

Supernova remnant as seen in multiple wavelengths
Click for original image.

Using a number of different telescopes and observing in many wavelengths outside the visible spectrum, astronomers have produced a new composite image of the remnant of a supernova that was detected in the year 1181 and remained visible to the naked eye for about six months.

That composite picture is to the right, cropped and reduced to post here. From the press release:

X-ray observations by ESA’s XMM-Newton (blue) show the full extent of the nebula and NASA’s Chandra X-ray Observatory (cyan) pinpoints its central source. The nebula is barely visible in optical light but shines bright in infrared light, collected by NASA’s Wide-field Infrared Space Explorer (red and pink). Interestingly, the radial structure in the image consists of heated sulfur that glows in visible light, observed with the ground-based Hiltner 2.4 m telescope at the MDM Observatory (green) in Arizona, USA, as do the stars in the background by Pan-STARRS (white) in Hawaii, USA.

Because the remnant is so dim in visible light, it has taken years of searching to locate it.

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SLIM survives its second lunar night, re-establishes contact

9:33 am

SLIM's view after surviving its 2nd night on the Moon
Click for original image.

According to Japan’s space agency JAXA, the SLIM lunar lander has successfully survived its long night on the Moon, re-establishiing contact with ground controllers yesterday.

Last night, we received a response from #SLIM, confirming that the spacecraft made it through the lunar night for the second time! Since the sun was still high and the equipment was still hot, we only took some shots of the usual scenery with the navigation camera

One of those pictures is to the right, reduced slightly to post here. It looks west across the floor of Shioli Crater, with the far rim about a thousand feet away. The picture is identical to previous images, tilted because the spacecraft landed on its side and has limited scientific capabilities, being primarily an engineering test mission.

That this engineering test has now survived two lunar nights speaks well for its design. It tells us that future Japanese lunar landers (and rovers) will have a good chance of surviving for a long time on the Moon.

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Scientists release detailed geological map of the landing site for Europe’s Franklin rover

10:01 am

Low resolution cropped section of map
Click for original image.

Scientists today released a new high resolution and very detailed geological map of the landing site for Europe’s Franklin rover, produced using orbital data from the U.S.’S Mars Reconnaissance Orbiter and Europe’s Trace Gas Orbiter.

A very low resolution version of the map is to the right.

The work was divided into 134 one-square-kilometre areas, so that the [80-person] team could fully cover the estimated landing area. Scientists used a web-based system that allowed everyone to work on the map in parallel. The software was provided by NASA’s Jet Propulsion Laboratory and set up at ESA [European Space Agency]. Data came from the Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter and several instruments on NASA’s Mars Reconnaissance Orbiter (MRO), including the HiRISE camera, which returns images from Mars orbit at 25 cm per pixel.

The mapping leads then pieced together the information on all the areas to form a coherent map that shows the geology of the landing site in unprecedented detail. The map includes the main types of bedrock, and structures with distinct shapes like ridges and craters. It even features the material that rests on top, for example blown by the wind, or thrown long distances when meteorites impacted the surface.

The result is the highest resolution map of Oxia Planum yet, created at a scale of 1:25 000, by which every centimetre equals 250 metres on the martian surface. An average drive of 25 to 50 metres a day for Rosalind Franklin would be one to two milimetres on the map.

The team had the extra time to compile this map because the launch of Franklin to Mars was delayed a number of times because of engineering issues and the Ukraine War, which ended the Europe’s partnership with Russia, requiring ESA to find other means to launch and land the rover.

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Data from Perseverance suggests the delta in Jezero Crater was formed by a wide variety of different “fluvial” events

9:43 am

Jezero Crater delta
Jezero Crater delta

Using data from the Perseverance rover in Jezero crater, scientists now conclude that the delta that poured through a gap in the crater’s rim was formed by a wide variety of different “fluvial” events, not a steady flow as previously assumed.

From the paper’s conclusions:

The origin of this variability as well as that of the high discharge represented by the boulder conglomerate is still unknown. Realistic hypotheses include seasonal variations due to melting of snow, glacial input with possible episodic surges punctuating more regular fluvial input, or arid climate type of flows with intense storms and related flash floods.

We do not speculate further about the nature of fluvial activity in this study. However, the variability and the presence of high discharge rates have important implications on the lake evolution. Firstly, previous modeling of Jezero delta formation used steady-state discharge rates to estimate the time required to form the delta, an assumption that we can no longer justify according to our observations. Secondly, estimates of discharge rates … may be used as upper limits for some of the peak discharge rates, although the number of flood events is still difficult to determine from the sparse outcrops and the ubiquitous presence of scree.

In other words, the delta was not formed by a single event or a long stream of liquid flowing into the crater to form the lake that scientists believe once filled the crater. Instead, that flow varied, involved numerous distinct and different events over time, and likely included glacial ice transport as well.

Not that this is a surprise, but as always, the closer we get to a planet and the more detailed our data about it, the more complicated we find its nature and origins.

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The spiraling magnetic field surrounding the Milky Way’s central supermassive black hole

9:19 am

The magnetic field lines surrounding Sagittarius A*
Click for original image.

Astronomers have now produced the first detailed image of polarized light surrounding the Milky Way’s central supermassive black hole, dubbed Sagittarius A* (pronounced “Sagittarius A-star”) which in turn maps out the spiraling field lines of that black hole’s magnetic field.

The image to the right, reduced to post here, shows that image. From the press release:

“What we’re seeing now is that there are strong, twisted, and organized magnetic fields near the black hole at the center of the Milky Way galaxy,” said Sara Issaoun, CfA NASA Hubble Fellowship Program Einstein Fellow, Smithsonian Astrophysical Observatory (SAO) astrophysicist, and co-lead of the project. “Along with Sgr A* having a strikingly similar polarization structure to that seen in the much larger and more powerful M87* black hole, we’ve learned that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them.”

Light is an oscillating, or moving, electromagnetic wave that allows us to see objects. Sometimes, light oscillates in a preferred orientation, and we call it “polarized.” Although polarized light surrounds us, to human eyes it is indistinguishable from “normal” light. In the plasma around these black holes, particles whirling around magnetic field lines impart a polarization pattern perpendicular to the field. This allows astronomers to see in increasingly vivid detail what’s happening in black hole regions and map their magnetic field lines.

Despite this similarlity, it still remains a mystery why the much larger M87 black hole is very active while Sagittarius A’ remains generally quiet.

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Engineers resolve issue on IXPE space telescope

9:01 am

Engineers have resolved the issue on the IXPE (Imaging X-ray Polarimetry Explorer) space telescope that was jumbling the data it was sending to Earth, and expect to return it to full science operations shortly.

On March 26, using procedures developed following that previous interruption, the team initiated a spacecraft avionics reset to address the issue, which put IXPE into a planned safe mode. The team has confirmed that IXPE is once again transmitting valid telemetry data and is now working to resume science operations, in as rapid and safe a manner as possible. The spacecraft is in good health.

The “previous interruption” was in 2023. In both cases it appears that simply rebooting the telescope’s software fixed the problem.

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Bursting bubbles of water gas on Mars

12:41 pm

Bursting bubbles on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on January 12, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Because of a technical issue that leaves a blank strip down the center of recent high-res MRO images, I have filled in that gap using a MRO context camera photo taken on January 12, 2015. The resolution is much less, but by doing so we can see the ground features as a unit.

What are we looking at? According to the scientists, this picture shows “fresh-looking ruptures,” referring to the broken line of sharp tears inside that meandering canyon that almost resemble a fresh wound in flesh. As this location is at 28 degrees south latitude, it lies on the edge of dry equatorial regions, where orbital images have sometimes found hints of a few remaining buried glaciers that are much more common closer to the poles.

In this case it appears the warmer equatorial climate has acted to heat up the buried ice so that it sublimated into gas. At some point the gas pressure caused the surface to burst, much like bubbles bursting on the surface of a pot of simmering tomato sauce, leaving behind these scars.
» Read more

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Intuitive Machines: Odysseus is dead

8:53 am

In a tweet on March 23, 2024 the company Intuitive Machines announced that the mission of its first lunar lander, Odysseus, is officially over with the spacecraft failing to come back to life after sunrise on the Moon.

As of March 23rd at 1030 A.M. Central Standard Time, flight controllers decided their projections were correct, and Odie’s power system would not complete another call home.

The engineers had begun listening for a signal on March 20th, when their computer models said enough sunlight would reach the solar panels to charge its communications system.

The failure of the lander to survive the lunar night is a disappointment, but it was never considered a strong possibility. Right now the company’s main task is to prevent the issues that caused Odysseus to land too fast and tip over, so that the next two missions, scheduled for either this year or next, each deliver their payloads properly on the Moon’s surface.

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The tangled view of astronomers

11:06 am

A protostar in formation
Click for original image.

The uncertainty of science: The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a survey of young stars surrounded by an edge-on dust disk. From the caption:

FS Tau is a multi-star system made up of FS Tau A, the bright star-like object near the middle of the image, and FS Tau B (Haro 6-5B), the bright object to the far right that is partially obscured by a dark, vertical lane of dust. The young objects are surrounded by softly illuminated gas and dust of this stellar nursery. The system is only about 2.8 million years old, very young for a star system. Our Sun, by contrast, is about 4.6 billion years old.

The blue lines on either side of that vertical dust lane are jets moving out from FS Tau B. The caption says their asymetrical lengths are likely due to ” mass is being expelled from the object at different rates,” but it just as easily be caused by the angle in which we see this object, making the nearer jet seem longer than the one behind.

That astronomers cannot move around such an object and see it from many angles explains the headline of this post. We can only see astronomical objects from one angle, and when they are complex objects such as this one, a large part of the research problem is disentangling the shapes we see into a coherent picture. Spectroscopy helps a lot, as it provides information about the speed and direction of different parts of the object, but even this can be enormously complicated and difficult to interpret.

Remember these facts when you read news reports about astronomical research. No matter how certain the press release sounds, its certainty is always tempered by many unknowns, some very pedestrian but fundamental.

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Antenna for joint NASA-ISRO radar satellite needs fix, delaying launch

8:50 am

The large deployable antenna for a joint NASA-ISRO radar satellite, dubbed NISAR, that was targeting a spring launch will require an extra coat of reflective material, thus delaying the satellite’s launch until the second half of this year.

In a March 22 statement, NASA said a new launch date for the NASA-ISRO Synthetic Aperture Radar (NISAR) mission will be set at the end of April because of work to protect the spacecraft’s reflector, an antenna that is 12 meters across when fully deployed, from temperatures when in its stowed configuration. “Testing and analysis identified a potential for the reflector to experience higher-than-previously-anticipated temperatures in its stowed configuration in flight,” NASA said in the statement. To prevent those increased temperatures, a “special coating” will be applied to the antenna so that it reflects more sunlight.

That work, NASA said, requires shipping the antenna, currently with the rest of the NISAR spacecraft in India, to a facility in California that can apply the coating. NASA did not state how long the process of applying the coating, as well as shipping the antenna to California and then back to India, will take.

It appears that the need for this additional coat was discovered during environmental testing by ISRO engineers in India as part of its preparation for launch on India’s GSLV rocket. Based on the JPL website for this mission, it appears this antenna system was built by JPL.

NASA is providing the mission’s L-band synthetic aperture radar, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem. ISRO is providing the spacecraft bus, the S-band radar, the launch vehicle and associated launch services.

Though the purpose of the final environmental testing prior to launch is specifically to find such issues and correct them, the question remains why this issue occurred. One can’t help wondering if the many management problems detailed at JPL in several reports (here, herej, here) might have contributed, including the organization’s total commitment since 2022 to Diversity, Equity, and Inclusion quotas, making skin color and sex the primary qualifications for hiring, rather than skill, education, or talent.

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Martian vent or sink?

11:37 am

A Martian vent or sink?
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on January 29, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Though the scientists label this image showing “channels”, what I see is either a vent or a sink, with the channels to the south indicating past flows either coming out of the depression or into it. The uncertainty exists because the surface grade in this region is essentially flat. There is a lot of small up and down variations, but overall it is very difficult to determine the general trend, suggesting that when the depression and channels formed the grade was different, and there is no way from this data to determine the angle at that time.

Were the flows that created the channels lava or water or ice? Knowing the grade when these channels formed would help answer this question, but other research now suggests the latter.
» Read more

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Some more “What the heck?” geology on Mars

2:00 pm

What the heck?
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 1, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small part of a region dubbed Iani Chaos, but what this geology shows is way beyond my pay grade.

Why there are those tiny aligned mounds, oriented at right angles to the slope, is not clear at all. Nor is it obvious what created the lighter chaotic terrain at the base of the slope.

The elevation difference between the low and high points is about 400 feet. The slope continues up to the west for another 600 feet to the top of a north-south ridgeline. The patterns here suggest vaguely some flows downhill, such as that widening east-to-west gap, but only vaguely.

The look at the overview map only compounds the mystery.
» Read more

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Citizen scientist project discovers 16 active asteroids

10:39 am

A project that has enlisted approximately 8,300 ordinary citizens to review more than 430,000 photos taken by a telescope in Chile has discovered sixteen asteroids that produce comae and tails like comets.

Identifying and tracking active asteroids whose activity specifically appears to be due to the sublimation of ice – known as main-belt comets – is a particular interest of the project team, as it is an essential part of understanding the abundance and distribution of volatile material like ice in the Solar System.

…The project, utilizing publicly available Dark Energy Camera (DECam) data from the Victor M. Blanco telescope in Chile, involved the examination of more than 430,000 images of known minor planets by 8,300 volunteers, where images identified by citizen scientists as being likely to contain active asteroids were then passed on to the science team for confirmation and additional analysis.

You can read the research paper here. If you want to participate, the Active Asteroids project is still on-going, and can be accessed here.

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Cracking terraces in Valles Marineris

3:27 pm

Overview map

Cracking terraces in Valles Marineris
Click for original image.

Inset

Today’s cool image returns us to the truly spectacular terrain found on the floor of West Candor Chasma, one of the giant side canyons that form Valles Marineris, the biggest canyon in the solar system, many times larger than the Grand Canyon on Earth.

The picture to the right, cropped, reduced, and sharpened to post here, was taken on January 5, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). On the overview map above its location is indicated by the red dot in the inset. The two green dots mark previous cool images from August 2022 and February 2024.

All three images show the same wild alternating dark and light terracing, suggesting many sedimentary layers like those seen in our Grand Canyon, but enhanced by the different erosion processes of the thin Martian atmosphere and its one-third Earth gravity.

The second image to the right zooms in on the area indicated by the rectangle. What makes this area doubly interesting are the cracks that appear to cut through the terraces. In the north-south crack it also appears that the terraces are now offset on each side of the crack.

Apparently, some event, likely an earthquake that occurred after the terraces formed, caused the ground to rip apart, with the earth shifting sideways on either side. Though the seismometer on the InSight lander detected no major quakes in this region, this image suggests they have occurred here, sometime in the past.

To give you a sense of scale, the canyon’s nearby rim to the west is about 14,000 higher, making that canyon wall two to three times taller than the walls of the Grand Canyon.

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A relatively dim star is expected to become one of the brightest in the sky later this year

9:49 am

As it has done twice before at intervals of 80 years, a relatively dim star is expected to go nova later this year, becoming for a short time one of the brightest stars in the sky.

Located in the Northern Crown constellation, T Coronae Borealis (T CrB) is a pretty average looking star, most of the time. With a brightness of about magnitude +10, it’s right on the limits of what you could see with a pair of binoculars, and even if you do go looking there’s not much to see.

At least, that’s the case for about 79 out of 80 years. But on that 80th year, the star suddenly brightens drastically up to around magnitude +2, which puts it on par with the north star Polaris. That makes it one of the brightest stars in the night sky, easily visible with the naked eye even when washed out by city lights. This once-in-a-lifetime outburst last occurred in 1946, and before that 1866.

And lucky for stargazers, T CrB seems to be about two years ahead of schedule, with astronomers predicting it will flare up again between March and September 2024. It’ll appear as a bright ‘new’ star for a few days with the naked eye, and a little over a week with binoculars, before it settles down again for another few decades. Astronomers noticed last year that T CrB had started to dim, which data from 1945 showed preceded the last brightening event.

The star is actually a binary, made up of a white dwarf and a red giant. The white dwarf is pulling material from the red giant, and as that new material piles up, it eventually gathers enough mass to go critical and produce a thermonuclear explosion. The result is a nova, a smaller version of a supernova that unlike supernovae occurs repeatedly.

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ESA: Euclid vision cleared after being fogged by ground ice, after launch

9:13 am

The European Space Agency (ESA) today announced that engineers have successfully “de-iced” the optics of its new Euclid space telescope that developed after it was launched in July 2023.

It was always expected that water could gradually build up and contaminate Euclid’s vision, as it is very difficult to build and launch a spacecraft from Earth without some of the water in our planet’s atmosphere creeping into it. For this reason, there was an ‘outgassing campaign’ shortly after launch where the telescope was warmed up by onboard heaters and also partially exposed to the Sun, sublimating most of the water molecules present at launch on or very near Euclid’s surfaces. A considerable fraction, however, has survived, by being absorbed in the multi-layer insulation, and is now being slowly released in the vacuum of space.

After a huge amount of research – including lab studies into how minuscule layers of ice on mirror surfaces scatter and reflect light – and months of calibrations in space, the team determined that several layers of water molecules are likely frozen onto mirrors in Euclid’s optics. Likely just a few to few tens of nanometres thick – equivalent to the width of a strand of DNA – it’s a remarkable testament to the mission’s sensitivity that it is detecting such tiny amounts of ice.

While Euclid’s observations and science continue, teams have come up with a plan to understand where the ice is in the optical system and mitigate its impact now and in the future, if it continues to accumulate.

It appears this new process has worked, according to a short update at the link.

Normally spacecraft are vented both on the ground during thermal testing, as well as when they reach orbit. It appears some of these normal procedures were either insufficient for Euclid’s needs, or threatened its optics if done as usual. This press release suggests that Euclid required very targeted venting processes that would not harm its sensitive optics, and that the procedures have worked.

I must admit I am suspicious of these claims. During development and after launch Euclid has had a number of problems. First, back in 2017 the NASA instrument on the telescope had to be completely rebuilt when it was found to be defective. Second, after launch engineers discovered unexpected light leaks on the mirror that now limit where it can look. Third, the telescope required a software patch to fix its pointing system, which was confusing cosmic rays for guide stars, causing it to shift positions randomly.

I can’t help wondering if this icing on the mirrors was also due, not to actual planning as suggested by ESA’s press release, but to poor ground testing and engineering that missed what is a common problem on spacecraft and thus required a post-launch improvised fix. I admit I might be wrong, but I still wonder.

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China launches communications orbiter towards the Moon

8:19 pm

Using its Long March 8 rocket lifting off from its coastal Wenchang spaceport, China today launched its second Quequiao communications satellite to the Moon, designed to relay data from its landers on the far side back to Earth.

The Queqiao 2, or Magpie Bridge 2, satellite was lifted atop a Long March 8 carrier rocket that blasted off at 8:31 am from a coastal launch pad at the Wenchang Space Launch Center in China’s southernmost island province of Hainan.

After a 24-minute flight, the satellite was released from the rocket and then entered into a lunar transfer trajectory. At the same time, the solar wings and communication antennas smoothly unfolded.

This satellite is in preparation for the May launch of China’s Chang’e-6 lunar mission to grab samples from the Moon’s far side and bring them back to Earth. In the meantime it will test its capabilities by relaying data from the Chang’e-4 lander and its Yutu-2 rover, still in operation on the far side after landing there in January 2018.

The leaders in the 2024 launch race:

27 SpaceX
11 China
3 Russia
3 Rocket Lab

American private enterprise still leads the rest of the world combined in successful launches 31 to 20, while SpaceX leads the entire world, including American companies, 27 to 24.

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Gehrels Swift space telescope now in safe mode

9:33 am

The Gehrels Swift space telescope, used to get real time observations of gamma ray bursts and other high energy deep space events, is presently in safe mode due to the failure of one of its three gyroscopes.

On March 15, NASA’s Neil Gehrels Swift Observatory entered into safe mode, temporarily suspending science operations due to degrading performance from one of its three gyroscopes (gyros), which are used to point the observatory for making observations. The rest of the spacecraft remains in good health.

Swift is designed to successfully operate without one of its gyros if necessary; however, a software update is required. The team is working on the flight software update that would permit the spacecraft to continue science operations using its two remaining gyros.

The telescope has been operating in orbit for nearly twenty years, far longer than originally planned. Its observations were crucial in discovering that gamma ray bursts occur at vast distances and involve either the core collapse of a star or the merger of two neutron stars.

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India’s Vikram lander disturbed the lunar surface the least of all landers

9:29 am

According to an analysis of images taking before and after landing, engineers have concluded that India’s Vikram lander disturbed the lunar surface the least of all landers, due to its use of multiple smaller landing engines.

Presenting the new findings at LPSC on Monday, [ISRO scientist Suresh K] attributed the intriguingly short dust plume to the lack of a central engine on the spacecraft, which resulted in a lower engine thrust during descent. Starting its “rough braking phase” at an orbit of 18.6 miles (30 kilometers) above the lunar surface, when the spacecraft reached 0.4 miles (0.8 kilometers) above its targeted landing area, it switched off two of its four 800-newton engines such that two diagonal engines remained operational all the way until touchdown. The mission used the “least powerful engine till date,” [Suresh] K said. “We’ve observed very less disturbance on the surface.”

You can read their paper here [pdf].

Finding ways to reduce the dust kicked up during landings will be critical for the early missions to the Moon, before landing pads can be constructed. This research suggests that when Starship lands, it should use only its outer engines, and gimbal them sideways, in order to reduce the dust thrown up around it.

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Scientists: DART impact of Dimorphos changed its orbit and reshaped the asteroid

9:18 am

Dimorphos shape change
Click for original graphic.

According to a new study, the DART impact of Dimorphos in September 2022 not only shortened its orbit around the larger asteroid Didymos, it reshaped the asteroid itself, warping its widest point sideways from its equator.

You can read the paper here.

More important, the scientists found that the changes evolved over time.

Over the following weeks, the asteroid’s orbital period continued to shorten as Dimorphos lost more rocky material to space, finally settling at 11 hours, 22 minutes, and 3 seconds per orbit – 33 minutes and 15 seconds less time than before impact. This calculation is accurate to within 1 ½ seconds, Naidu said. Dimorphos now has a mean orbital distance from Didymos of about 3,780 feet (1,152 meters) – about 120 feet (37 meters) closer than before impact.

Similarly, the reshaping of the asteroid into its present shape took time. As the scientists noted in their conclusion, “it takes time for a binary system to settle after a kinetic impact event.”

Because of Dimorphus’s rubble pile nature, its shape and orbit should continue to evolve over the coming decades, as more of the ejecta from the impact slowly falls back onto its surface and the asteroid surface adjusts over time. This in turn should also effect the orbit, though by only very tiny amounts.

I continue to wonder if the entire solar orbit of this asteroid binary system was impacted at all by these changes. Any changes would likely be tiny, but it is important to know to see if such an impact can actually do such a thing. To find out will take several more years, as ground telescopes continue to track the asteroid.

In October 2024 the European probe Hera will launch on a mission to this asteroid binary, with its arrival expected in December 2026. At that time we will get a much better look at both asteroids and how the impact affected them.

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The vast Martian plains of lava

3:49 pm

The vast Martian lava fields
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 31, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled “Lava Embaying Highlands Ridge”, it shows an alcove along a ridgeline that appears filled with material, in this case solid lava.

If you look closely at the ridgeline, you can see several dark streaks on its southern slopes. These streaks could be one of two unique Martian features that remain unexplained. They could be slope streaks, which occur randomly through the year and fade with time, or recurring slope lineae, which occur seasonally at the same locations. In either case, though the streaks look like avalanches, they don’t change the topography, have no debris piles at their base, and even sometimes flow uphill for short lengths. Though there are a number of theories for their formation, many involving dust, none has been accepted as confirmed.

This location and its lava however are the stars of this picture, for a number of reasons, all revealed by the overview map below.
» Read more

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Mapping the layered geology of Mars

12:16 pm

Mapping the layers on Mars
Click for original image.

Today’s cool image is an update of a previous cool image from July 2021. Then, I posted a captioned high resolution Mars Reconnaissance Orbiter (MRO) photo of the many terraced layers within a 13-mile-wide crater dubbed Jiji and located in Arabia Terra, the largest transition zone between the Red Planet’s northern lowland plains and the southern cratered highlands. At that time the caption noted that research was on-going to see if the same layers could be identified in two other nearby craters, Banes and Sera, and thus use that data to extrapolate the long term geological history of this region on Mars.

Today’s cool image to the right, rotated, cropped, reduced, and enhanced to post here, was taken on January 4, 2024 as part of this research, and shows the layers in 18-mile-wide Sera crater, located only about ten miles to the east of Jiji crater. The highest mesa near the bottom of the picture is about twenty feet high on its southern side, but about 140 feet high to the north. The difference is because the crater floor under the mesa is sloping downward to its lowest point to the north.
» Read more

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Betelgeuse dimming again

10:00 am

Betelqeuse
An optical image of Betelgeuse taken in 2017 by a ground-based
telescope, showing its not unusual aspherical shape.
Click for original image.

It appears that the red giant star Betelgeuse is once again dimming, as it did in 2019-2020.

Betelgeuse, located in Orion’s right shoulder, ordinarily shines at magnitude +0.4, a close match to neighboring Procyon in Canis Minor. But since late January it’s lost some of its luster — at least a third of a magnitude’s worth. That may not sound like much especially given the star’s variable nature, but the red supergiant star is currently the faintest it’s been in the past two years.

Betelgeuse is less like a stable star and more like a gasbag in weightlessness, its shape bouncing in and out as convection bubbles from within push their way to the surface. In some cases, as in 2019-2020, a burst of a bubble releases dust and material, which scientists believe acted to block the star’s light at that time. The dimming now could be for the same reason. Or it could be because the star’s brightness is fundamentally variable. For years it reliably pulsed every 400 days, though that variation pattern now seems to have vanished since 2020.

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Engineers report progress in restoring proper communications with Voyager-1

9:51 am

According to a NASA update yesterday, software engineers for the Voyager-1 spacecraft now beyond the edge of the solar system have managed to decipher the garbled data the spacecraft’s computers have been sending back to Earth since November 2023, and are in the process of analyzing that data with the hope of restoring full understandable communications.

The source of the issue appears to be with one of three onboard computers, the flight data subsystem (FDS), which is responsible for packaging the science and engineering data before it’s sent to Earth by the telemetry modulation unit.

On March 3, the Voyager mission team saw activity from one section of the FDS that differed from the rest of the computer’s unreadable data stream. The new signal was still not in the format used by Voyager 1 when the FDS is working properly, so the team wasn’t initially sure what to make of it. But an engineer with the agency’s Deep Space Network, which operates the radio antennas that communicate with both Voyagers and other spacecraft traveling to the Moon and beyond, was able to decode the new signal and found that it contains a readout of the entire FDS memory.

This new readable data was the result of a command sent two days before, suggesting that engineers are on the right track. Because Voyager-1 is so far away, 15 billion miles, it takes 22.5 hours for any command to be sent to the spacecraft, and another 22.5 hours for ground controllers to get a response. This long lag time has slowed the effort to fix the problem, but this new success suggests that a full recovery is possible.

That recovery is going to be relatively short-lived, no matter what. The nuclear-powered power sources for both Voyager spacecraft, flying since 1977, are expected to finally run out of power sometime in 2026, after almost a half century of operation. Moreover, the computers on both Voyagers are the longest continuously running computers in history.

The engineering achievement of both is astonishing.

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Scientists: Mars’ mysterious slope streaks and seasonal recurring lineae are caused by dust

1:08 pm

Massive flow on Mars
A typical Martian slope streak.

On Mars there are two mysterious features that are somewhat similar but entirely unique to the Red Planet, and for years have baffled planetary geologists as to their origins.

One feature is called slope streaks, which appear randomly year-round as either dark or bright streaks on slopes. They resemble avalanches, except that they do not change the topography, have no debris piles at their base, and sometimes travel along that topography, sometimes even going uphill for short distances. Over time these streaks then fade.

The other feature is called recurring slope lineae, because though they look like slope streaks, they are not random but appear seasonally at the same places each year. Lineae are also always dark.

Scientists have proposed many theories to explain both, with most theories involving some form of water process, either the seepage of brine from below or water vapor causing the Martian surface dust to flow, like droplets on a car windshield. None of these theories has been confirmed, or entirely accepted.

Two studies at this week’s 55th annual Lunar and Planetary Science Conference in Texas have both concluded that water is not a factor in the formation of either phenomenon. Instead, both papers propose a much simpler explanation: Wind and blowing dust interact to cause small dust avalanches.
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Lucy’s first encounter with an asteroid produced surprises

12:39 pm

Dinkinesh, with Salam

At the 55th annual Lunar and Planetary Science Conference presently being held in Texas, the science team for the Lucy asteroid mission presented their first papers outlining what they learned during the spacecraft’s first asteroid encounter, flying past the main belt asteroid Dinkinesh on November 1, 2023.

To the right is the the best image taken at closest approach, at about 270 miles distance, annotated to include the analysis of Dinkinesh’s shape by scientists. As noted in the summary paper [pdf], the asteroid is about a half mile in diameter, and appears to have an equatorial ridge, similar to the ridges found on the near-Earth rubble-pile asteroids Bennu or Ryugu. Dinkinesh is not a rubble pile, however. Though boulder-strewn, it appears more solid, and even has what the scientists call a longitudinal trough, as indicated in the picture.

The ridge overlays the trough implying that it is the younger of the two structures. However, there is as yet no information to better constrain their relative ages, and thus they could potentially have formed in the same event. Indeed, Dinkinesh’s ridge and trough are likely the result of mass failure and the reaccretion of material, and may both be linked to the formation of Selam.

That flyby had produced one major surprise, the existence of a smaller satellite asteroid orbiting Dinkinesh, now dubbed Selam. It is shown in the lower left, as it appeared from behind the main asteroid as Lucy flew past. A later picture however revealed an even greater surprise.
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There likely is little or no ice in the Moon’s permanently shadowed craters

11:47 am

Shadowcam-LRO mosaic
The floor of Shackleton Crater showing no obvious ice deposits,
as seen by Shadowcam. The black cross marks the south pole.
Click for original image.

This week the 55th annual Lunar and Planetary Science Conference is being held in Texas. The conference was originally established in connection with the Apollo missions to allow scientists to release their Moon research results. It quickly morphed into an annual event covering research from the entire planetary research community.

I have reviewed the abstracts for this year’s meeting, and culled what I think are the most significant new results from the conference, which I will report on in the next few posts.

We begin however with possibly the most important result from the conference, given by the science team for the ShadowCam instrument on South Korea’s Danuri lunar orbiter. That low-light camera was designed to take high resolution pictures of the permanently-shadowed craters of the Moon, to see if there was any visible or obvious ice hidden there. Though the science team presented a number of papers, the summary paper [pdf] by the instrument’s principal investigator, Mark Robinson of Arizona State University, gave the bottom line:

The data so far is finding very little evidence of water ice in these dark regions.
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A Martian tadpole

3:01 pm

Overview map

A Martian tadpole
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on December 28, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The white dot on the overview map above marks the location, with the rectangle in the inset marking the area covered by the picture. The science team labels this “inverted features,” a more vague way to describe the feature geologists dub “inverted channels.” The flow of a river or glacier acts to harden and increase the density of the channel bed. Later, the water or ice disappears, leaving just the canyon.

Even later, erosion begins to wear away the surrounding terrain. Because the canyon floor is now harder than that surrounding terrain, that floor is more resistent to erosion, and eventually becomes ridge following the exact same path as the long gone river or glacier.

This is what we have here, with this inverted channel, which is about five miles long, once draining into the deeper eroded valley to the south.

The location is at 38 degrees north latitude and inside the 2,000-mile-long mid-latitude region I dub glacier country, because almost every image shows evidence of glaciers or ice flows on the surface. This picture however is a rare exception. The features in this picture instead appear to be bedrock, something that is rarely seen in the canyons and craters in glacier country. It is beyond my pay grade however to explain why this spot lacks such features. Or it could be the near surface ice here looks so much like bedrock I am misinterpreting the picture.

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Sunspot update: The Sun continues what appears will be a weak maximum

10:30 am

As I have done each month since 2011, I am now posting an annotated version of NOAA’s monthly graph, tracking the solar sunspot activity on the Earth-facing hemisphere of the Sun. The NOAA updated graph was posted at the start of March, covering activity through the end of February, so this report is a little later than normal.

That graph is below. In February sunspot activity remained essentially steady, only slightly higher than the activity from the month before. Those numbers also hovered at about the same level seen since August 2023.
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The strange surface of the perennial dry ice cap at Mars’ south pole

4:40 pm

The strange surface of Mars' dry ice cap
Click for original image.

Cool image time! The picture to the right, cropped to post here, was taken on January 24, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a region about 180 miles from the south pole of Mars.

This terrain is intriguing because is the pattern of ridges that cover it entirely. I have simply cropped the original image to show these ridges in highest resolution. The full image shows them covering a region much larger than this.

What are we looking at? Because it is near the pole, it is likely that the black splotches are caused by carbon dioxide gas breaking through the winter mantle of dry ice that covers the poles during the winter months and then sublimates away, from the bottom, each spring. As the dry ice turns to CO2 gas that gas is trapped, until it can find a weak spot in the overlying mantle. When the pressure builds enough, the mantle breaks, the gas escapes, and as it does so it deposits the dark dust around the breakage. That dust fades as the mantle disappears.

Sounds good, eh? Not so fast.
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