Tag: science

Land of dust devils

2:17 pm

Land of dust devils
Click for original image.

Today’s cool image to the right demonstrates that the atmosphere and climate of Mars is truly different in different places. The picture, rotated, cropped, reduced, and sharpened to post here, was taken on July 22, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled simply as a “terrain sample”, it was likely taken not as part of any specific research project but to fill a gap in the camera’s schedule in order to maintain its proper temperature.

I post it today almost to illustrate the difference between this location and the spot where the lander Insight landed on Mars. Earlier this week the MRO camera team released a short movie created by images of the lander taken over six years, showing how the dust around it had changed over time. I noted further how those images showed a very small number of dust devil tracks, which explained why no dust devil every crossed over the lander’s solar panels to clean them of dust.

For the picture on the right, however, there are a lot of dust devil tracks, so many near the bottom that they almost completely darken the ground.
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Curiosity looks down and across Gale Crater

10:43 am

Curiosity looks down across Gale Crater
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was part of a panorama created by 24 photos taken by the right navigation camera on the Mars rover Curiosity on December 16, 2024.

The view looks west at the foothills that fill the lower slopes of Mount Sharp. In the far distance, about 20 to 30 miles away, can be seen the western rim of Gale Crater, obscured by the dust in the Martian atmosphere.

Curiosity is presently contouring west along the mountain slope. As it goes it will pass a series of canyons coming down the mountainside. The goal is to eventually reach the canyon the science team has chosen to take for climbing that mountain.

Note the rocky ground. One of the surprises found as Curiosity left the crater floor and started climbing Mount Sharp about four years ago is the rockiness of the terrain. Unlike Earth, Mars’s atmosphere and environment does not have the activity to smooth out this landscape. While science data suggests flowing water was once present here, it wasn’t here long enough to smooth things out. And the atmosphere is just too thin.
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Astronomers discover 1st binary star system orbiting Milky Way’s central supermassive black hole

9:40 am

The stars orbiting Sag A*
The stars orbiting Sag A*. Click for original image.

Using infrared spectroscopic data gathered from 2005 to 2019 by the Very Large Telescope in Chile, astronomers have identified the first known binary star system to orbit Sagittarius A* (pronounced “A-star”), the Milky Way’s central supermassive black hole.

You can read their science paper here [pdf]. The white dot at the center of the map to the right marks the location of Sagittarius A*, while the red dot marks the present location of the binary star, dubbed D9. The other objects are the stars previously identified orbiting the central black hole, all of which are now believed to be single stars. The binary D9 has an estimated orbit around Sagittarius A* of 432 years and is thought to be less than three million years old. The two stars have approximate masses of 3.86 and 2.8 solar masses, with the smaller orbiting the larger every 372 days.

There is a lot of uncertainty in these numbers, but the data identifying the binary is quite firm. This discovery, as well as the many other stars now known to orbit Sagittarius A*, show that star formation so close to a supermassive black hole is not only possible, it is common, something astronomers a decade ago thought impossible.

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New computer simulations suggest Saturn’s rings are not young but formed at the same time as the solar system

9:12 am

A bright spot in Saturn's rings
Click for original source.

The uncertainty of science: Scientists doing computer simulations now posit that Saturn’s rings are not young, between 100 to 400 million years old as has been believed for the last few decades, but formed instead when Saturn formed, 4.6 billion years ago.

You can read their paper here [pdf].

The young age had been based on data from the Cassini orbiter, which showed the ring particles to be very bright and clean. If old those particles would have been darker as they accumulated dust over time on their surface. The new computer simulations suggest a process whereby those particles get “cleaned,” thus making it possible for the rings to be very old, possibly as old as Saturn itself.

Must I point out the uncertainties? The paper itself admits in its abstract “uncertainties in our models that assume no porosity, strength, or ring particle granularity.” Seems these assumptions make the conclusions very uncertain indeed.

Then again, the previous young estimates of the age of the rings had many similar assumptions and uncertainties. Essentially, we don’t have enough information to make any definitive determinations.

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A galactic eye in heaven

12:30 pm

A galactic eye in space
Click for original image.

Cool image time! The picture to the right, reduced and sharpened to post here, was taken by the Hubble Space Telescope as part of a project to study the star formation processes over time in this galaxy, located about 76 million light years away.

A prominent bar of stars stretches across the centre of this galaxy, and spiral arms emerge from each end of the bar. Because NGC 2566 appears tilted from our perspective, its disc takes on an almond shape, giving the galaxy the appearance of a cosmic eye.

As NGC 2566 gazes at us, astronomers gaze right back, using Hubble to survey the galaxy’s star clusters and star-forming regions. The Hubble data are especially valuable for studying stars that are just a few million years old; these stars are bright at the ultraviolet and visible wavelengths to which Hubble is sensitive. Using these data, researchers will measure the ages of NGC 2566’s stars, helping to piece together the timeline of the galaxy’s star formation and the exchange of gas between star-forming clouds and stars themselves.

To get the full picture, astronomers have also obtained infrared data from the Webb Space Telescope and millimeter/submillimeter radio wavelength data from the ALMA telescope.

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The Insight lander on Mars as seen from orbit over six years

12:07 pm

Insight as seen by MRO over six years
Click for movie.

Using photos taken by Mars Reconnaissance Orbiter (MRO) from 2018 to 2024, researchers have compiled a short movie showing how the dust around the Mars lander Insight changed over time.

This video shows images taken by HiRISE between Dec. 11, 2018, just a couple weeks after InSight landed on Mars, and Oct. 23, 2024. In the images, InSight often appears as a bright, blue dot due to its reflection of sunlight. A dark halo was scorched into the ground by the spacecraft’s retrorocket thrusters; this halo fades away over time. Dark stripes that can be seen on the surface are tracks left by passing dust devils. [emphasis mine]

You can see the movie here. The image to the right was the first picture taken by MRO only three weeks after landing.

Insight eventually shut down because this dust accumulated on its solar panels, and the lander never was blessed with having a dust devil cross over it to blow that dust away. This video illustrates why. Out of the seven images making up the short movie, only three show dust devil tracks, and in each case only a few tracks are seen. No other tracks are detected.

In other words, over six years this region simply did not get a lot of dust devils. The odds of one crossing over InSight was thus quite low. Ironically, the image to the right shows that a dust devil crossed very close to the lander about the time it landed in 2018, probably just beforehand since the dark scorch created by the lander’s thrusters cover the track. No dust devil ever got that close again.

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Juno spots changes on Io’s surface in just a two-month span

10:57 am

Before and after images by Juno of volcanic ring on Io
Click for original image.

New photos taken just two months apart by Juno of a region dubbed Nusk Patera on the Jupiter moon Io showed the appearance of a distinct ring that had hardly been there before.

The pictures, taken during two recent fly-bys of the moon, are above, and show the change. From the caption:

A red ring formed around Nusku Patera in the two months between the spacecraft’s 58th flyby on Feb. 3, 2024, and its 60th on April 9, 2024. The ring obscures some nearby features like Creidne Patera. This ring, 683 miles (1,100 kilometers) wide is likely from a Pele-type plume rich in sulfur. Similar transient red rings were observed by NASA’s Galileo mission around Grian Patera and Surt and were associated with intense but short-lived thermal “outburst” eruptions.

In other words, sulfur from eruption from the central vent/caldera was flung into the sky enough that when it eventually settled back down it landed in a ring about 340 miles away from the center.

Other data from Juno, also released this week here and here, detected fresh lava flows at another volcanic region of Io dubbed, Zal Patera.

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Perseverance reaches top of Jezero Crater rim

1:41 pm

The view west out of Jezero Crater
Click for high resolution panorama. For original images, go here and here.

Overview map
Click for interactive map.

After spending more than three and a half years exploring the floor of Jezero Crater, the rover Perseverance has finally reached the top of the crater’s western rim, and is about to begin exploring the mountainous and potentially rich mining region to the west.

The panorama above, created from two pictures taken by Perseverance’s right navigation camera on December 11, 2024 (here and here), has been cropped, reduced, enhanced, and annotated to post here. It looks west into that mountainous region, with the yellow lines on the overview map to the right indicating the approximate view. The blue dot on that map marks Perseverance’s present position, on top of Lookout Hill, the name the rover team has given to that spot on the rim.

The low resolution of the region beyond the grey strip is unexplained. For some reason the rover team has not yet updated the interactive map showing Perseverance’s travels with the many high resolution pictures that Mars Reconnaissance Orbiter (MRO) has taken of this region, in anticipation of Perseverance’s travels there. I expect however this will change shortly.

Witch Hazel Hill is the first target beyond the rim, where there is an outcrop 330-feet-high with many layers. The rover will then head downhill and south to check out a spot that the scientists believe might show features existing from before Jezero Crater was formed. The rover will then head back up to the rim further south to look at an outcrop of blocks that might actually be ejecta from another much larger Martian impact.

These blocks may represent ancient bedrock broken up during the Isidis impact, a planet-altering event that likely excavated deep into the Martian crust as it created an impact basin some 745 miles (1,200 kilometers) wide, 3.9 billion years in the past.

Jezero sits on the northwestern rim of Isidis.

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Curiosity begins to round the corner out of Gediz Vallis

11:37 am

Curiosity looks ahead
Click for original image.

According to an update yesterday from the rover team, the Mars rover Curiosity has finally begun to round the corner of the northern nose of the long ridge dubbed Texoli that forms the western wall of Gediz Vallis, the slot canyon that the rover has been exploring since August 2022.

The picture to the right, reduced, sharpened, and annotated to post here, was taken on December 10, 2024 and shows the view looking west. The red dotted line indicates the planned route. As the rocky ground indicates, travel forward in the near term will be interesting. As noted in the update:

While we want to head southwest, we had to divert a bit to the north (right of the image shown) to avoid some big blocks and high tilt. The path is very constrained in order to avoid driving over some smaller pointy rocks, scraping wheels along the sides of blocks, or steering into the side of blocks that might cause the steering to fail. And we also needed to worry about our end-of-drive heading to be sure the antenna will be clear to talk to Earth for the next plan. We ended up relying on the onboard behavior to help us optimize everything by implementing a really interesting and curvy 24-meter path (about 79 feet).

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Land of knobs

12:53 pm

Land of knobs
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 17, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it was likely taken not as part of any specific research project, but to fill a gap in the camera’s schedule in order to maintain its proper temperature.

When the camera team does this, they try to pick interesting targets. In this case, they targeted this 400-foot-high pointy-topped hill. The smoothness of its slopes suggest this hill is made up largely of packed dust, possibly a hardened former dune. This hypothesis seems strengthened by the erosion on the eastern slopes, which appears to be areas where that packed sand has worn or blow away.

Think of sandstone in the American southwest. It is made of sand that has hardened into rock, but wind and water and friction can easily break it back into dust particles, resulting often in the spectacular and weird geological shapes that make the southwest so enticing.

But is this sand?
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Io’s volcanoes get their lava from separate magma chambers, not a global underground ocean of magma

11:11 am

Io's interior as presently theorized
Click for original animation.

Using data collected from Juno’s multiple fly-bys of the Jupiter moon Io, scientists now hypothesize that the moon does not have a global underground ocean of magma, feeding its many volcanoes, but that instead each volcano is fed its lava from a separate magma chamber.

The graphic to the right illustrates the present conclusion. You can read the paper here [pdf]. From the press release:

The Juno team compared Doppler data from their two flybys with observations from the agency’s previous missions to the Jovian system and from ground telescopes. They found tidal deformation consistent with Io not having a shallow global magma ocean.

“Juno’s discovery that tidal forces do not always create global magma oceans does more than prompt us to rethink what we know about Io’s interior,” said lead author Ryan Park, a Juno co-investigator and supervisor of the Solar System Dynamics Group at JPL. “It has implications for our understanding of other moons, such as Enceladus and Europa, and even exoplanets and super-Earths. Our new findings provide an opportunity to rethink what we know about planetary formation and evolution.” [emphasis mine]

The highlighted words indicate the significance of this data. It possibly suggests that the underground oceans of water that have been theorized for these other moons — where life could possibly exist — might be mistaken. Instead, they might have smaller pockets of water, similar to Io’s many magma chambers.

Everything here however is uncertain, including these new conclusions about Io. We just don’t have enough data from any of these moons to make any definitive conclusions.

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A review of the last half century of major ice calving events in Antarctica detects no trend

11:58 am

47-year trend of large iceberg calving events in Antarctica
Click for original image.

The uncertainty of science: A review by scientists of major ice calving events in Antarctica that have occurred in the last 47 years has detected absolutely no trend either up or down, despite decades of predictions that human caused global warming would cause huge sections of the icecap to break off and catastrophically change the Earth’s climate.

The graph to the right comes from figure 4 of the paper, and illustrates the lack of trend. Note how the actual observations, the blue dots, show no increase in large calving events. From the abstract:

We use 47 years of iceberg size from satellite observations. Our analysis reveals no upward trend in the surface area of the largest annual iceberg over this time frame. This finding suggests that extreme calving events such as the recent 2017 Larsen C iceberg, A68, are statistically unexceptional and that extreme calving events are not necessarily a consequence of climate change.

The researchers of course genuflect to human-caused global warming in their conclusion by stating that the shrinkage predicted in the Antarctic ice cap (but not yet seen in any significant amount) could instead be occurring due to an increase in small calving events.

The lack of an upward trend in annual maximum iceberg area could be attributed to an overall increase in the number of smaller calving events, which may inhibit the development of extremely large calving events. As such, small calving events pose the greatest threat to the current stability of Antarctic ice shelves.

Since there is no detailed or reliable data of the number of smaller calving events, this hypothesis is entirely made up, and carries no weight. It is simply a fantasy created to maintain the fiction of global warming. A more open-minded look at these results would say that the larger events provide an excellent guide to the overall trend, and that the icecap simply isn’t shrinking as predicted.

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