Tag: science

Galaxies without end

8:55 am

Galaxies without end
Click for original.

Cool image time! The picture to the right, reduced and enhanced to post here, was taken by the Hubble Space Telescope as part of a monitoring program studying the two supernovae that have occurred in this galaxy previously.

Hubble has turned its attention toward NGC 1309 several times; previous Hubble images of this galaxy were released in 2006 and 2014. Much of NGC 1309’s scientific interest derives from two supernovae, SN 2002fk in 2002 and SN 2012Z in 2012. SN 2002fk was a perfect example of a Type Ia supernova, which happens when the core of a dead star (a white dwarf) explodes.

SN 2012Z, on the other hand, was a bit of a renegade. It was classified as a Type Iax supernova: while its spectrum resembled that of a Type Ia supernova, the explosion wasn’t as bright as expected. Hubble observations showed that in this case, the supernova did not destroy the white dwarf completely, leaving behind a ‘zombie star’ that shone even brighter than it did before the explosion. Hubble observations of NGC 1309 taken across several years also made this the first time the white dwarf progenitor of a supernova has been identified in images taken before the explosion.

The image however carries a far more philosophic component. Except for the star near the top (identified by the four diffraction spikes), every single dot and smudge you see in this picture is a galaxy. NGC 1309 is about 100 million light years away, but behind it along its line of sight and at much greater distances are innumerable other galaxies, so many it is impossible to count them. And each is roughly comparable in size to our own Milky Way galaxy, containing billions of stars.

The scale of the universe is simply impossible to grasp, no matter how hard we might try.

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One of NASA’s two Tracers satellites just launched has an issue

10:17 am

During the commissioning phase shortly after their launch earlier this week, one of NASA’s two Tracers satellites designed to study the solar wind and its interaction with the Earth’s magnetic field has had an as yet unnamed issue.

During the commissioning process, the team made routine adjustments to the power subsystem on both vehicles. While the adjustments achieved the desired results on one satellite, the other satellite requires further investigation by the team. Commissioning operations are temporarily paused while the team analyzes the situation and determines the appropriate response.

Though the press release provides no other information, it appears the satellite is having a problem producing the power expected.

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Mars and its two moons seen in the infrared by Europa Clipper

10:37 am

Mars and its two moons
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Cool image time! The infrared image to the right, cropped, reduced, and enhanced to post here, was taken by Europa Clipper on February 28, 2025 just before it flew past Mars on its way to Jupiter.

Deimos is in the upper left corner, while Phobos is close to Mars.

When the image was taken by the mission’s Europa Thermal Emission Imaging System (E-THEMIS), the spacecraft was about 560,000 miles (900,000 kilometers) from the Red Planet. The image is composed of 200 individual frames, part of a continuous scan of 1,100 frames taken roughly a second apart over a period of 20 minutes. Scientists are using the tiny, point-like images of the moons to check the camera’s focus.

As this is an infrared image (measuring heat), it shows Mars’ northern polar cap as the dark oval at the top of the planet. The bright (and thus warmer) oval to the lower left is the shield volcano Elysium Mons.

This data suggests Europa Clipper’s thermal instrument is working as intended, which is essential for observing the ice content (if any) on Europa once it enters Jupiter orbit in 2030.

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The journal Science retracts 15-year-old paper that proposed arsenic as basic element of life

10:15 am

The death of science: Though numerous later research had rejected the conclusions of a 2010 research paper that had suggested a bacteria found at Mono Lake in Californa was using arsenic instead of phosphorus in its DNA, the journal Science that published that paper has now retracted it.

In a blog post accompanying this week’s retraction notice, Science’s current Editor-in-Chief Holden Thorp and Valda Vinson, executive editor of the Science family of journals, emphasize there is no suggestion of foul play in the GFAJ-1 paper. Instead, pointing to subsequent commentary and research that suggest some of the paper’s findings stem from contamination, not arsenic use by bacteria, they write: “Science believes that the key conclusion of the paper is based on flawed data.”

Speaking with Science’s News team, which operates independently from its research arm, study co-author and Arizona State University geochemist Ariel Anbar says the team disputes that assessment and has already addressed the referenced criticisms. “We stand by the data,” he adds.

Anbar added this in this report at Nature:

By contrast, one of the paper’s authors, Ariel Anbar, a geochemist at Arizona State University in Tempe, says that there are no mistakes in the paper’s data. He says that the data could be interpreted in a number of ways, but “you don’t retract because of a dispute about data interpretation”. If that’s the standard you were to apply, he says, “you’d have to retract half the literature”.

This action underlines the decline in open-mindedness in the academic field. It did not suffice to simply demonstrate in later papers that the paper’s conclusions were questionable. It was necessary to cancel it entirely, to airbrush it from history.

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The glaciers on Mars are almost pure ice with only a thin cover of dust and debris

9:55 am

A map of glaciers on Mars
A map of glaciers on Mars.

According to new research, scientists now think that the glaciers on Mars are almost pure ice, protected from sublimation by a thin cover of dust and debris.

Work over the last 20 years has demonstrated that at least some of these glaciers are mostly pure ice with only a thin cover of rock and dust, but according to a new paper published in Icarus, glaciers all over the planet actually contain more than 80% water ice, a significant finding. Ultimately, this means that Mars’s glacial ice deposits are nearly pure across the globe, providing a clearer understanding of Mars’ climate history and a possible resource for future utilization.

The researchers analyzed mid-latitude glaciers at five different locations in both the north and south hemispheres, and found that at every location the data suggested almost pure ice.

The map to the right, from earlier research, shows the prevalence of near-surface ice once you get above 30 degrees latitude. From the poles to the mid-latitudes it appears there is an ice sheet or “ice table” just below the surface. In the mid-latitudes glaciers dominate, as this appears to be the region where that ice is beginning to dissipate. In the equatorial regions little or no near-surface ice has been detected, though there has been some evidence in some places of ice at deeper depths.

This data once again demonstrates that Mars is not a desert like the Sahara, as we once believed. Instead, it more resembles Antarctica, where there is ice everywhere that simply needs to be processed for use.

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Study identifies range of interference produced by Starlink satellites

8:58 am

In analyzing about 76 million radio images produced by the new Square Kilometer Array (SKA) in Australia scientists have found within them signals produced by SpaceX’s Starlink satellites.

PhD candidate and study lead Dylan Grigg said the team detected more than 112,000 radio emissions from 1806 Starlink satellites, making it the most comprehensive catalogue of satellite radio emissions at low frequencies to date. “Starlink is the most immediate and frequent source of potential interference for radio astronomy: it launched 477 satellites during this study’s four-month data collection period alone,” Mr Grigg said. “In some datasets, we found up to 30 per cent of our images showed interference from a Starlink satellite.”

Mr Grigg said the issue wasn’t just the number of satellites, but the strength of the signals and the frequencies they were visible at. “Some satellites were detected emitting in bands where no signals are supposed to be present at all, such as the 703 satellites we identified at 150.8 MHz, which is meant to be protected for radio astronomy,” Mr Grigg said. “Because they may come from components like onboard electronics and they’re not part of an intentional signal, astronomers can’t easily predict them or filter them out.”

The researchers were careful to note that SpaceX has been following all international regulations, and that these signals are not a violation of any law or regulation. Further, they emphasized that “Discussions we have had with SpaceX on the topic have been constructive.”

Because many other such constellations are now being launched — with several from China that normally does not negotiate these issues like SpaceX — the scientists want new international regulations imposed to protect their work.

More and more it seems astronomers should simply move their operations into space or the Moon, where such issues will not exist. Getting above the atmosphere and away from our modern technological society provides so many benefits for research the move should be a no-brainer. That it is now also much cheaper to do it (thanks to SpaceX) makes the move even more practical.

For some reason however the idea seems too difficult for many astronomers to fathom.

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Curiosity amid the boxwork

12:13 pm

Curiosity amid the boxwork, looking uphill
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Overview map
Click for interactive map.

Cool image time! The panorama above, cropped to post here, was taken on July 20, 2025 by the left navigation camera on the Mars rover Curiosity. It looks uphill to the south into the canyon that Curiosity will eventually travel, with the white chaotic upper flanks of Mount Sharp on the horizon. The mountain’s peak itself is out of view, about 25 miles away.

The overview map to the right provides the context. The blue dot marks Curiosity’s present position, on the northern edge of the large patch of very distinct boxwork ridges visible from orbit. You can see these ridges in the foreground of the panorama above.

The yellow lines indicate the approximate area covered by the panorama. The red dotted line roughly indicates the rover’s future travels. At the moment, however, it is going nowhere, as the science team is focused on studying these boxwork ridges in the hope they can determine their origin. Such features are usually associated with cracking later filled with lava, with the polygon-shaped cracking usually associated with a formerly wet environment drying.

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First Hubble images of interstellar comet 3I/Atlas released

5:03 pm

Comet 3I/Atlas, taken by Hubble
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An undergraduate student has just released the first pictures taken by the Hubble Space Telescope of the interstellar object 3I/Atlas, confirming that it is a comet as indicated by the earlier image taken by the Gemini North telescope.

One of those images, taken only hours ago, is the inset on the map showing the comet’s route through the solar system to the right. The streaks on the image are either stars or cosmic rays. Though this image is of significantly lower quality than the Gemini North picture, it once again shows both the comet’s nucleus and developing coma.

A preprint [pdf] of a new research paper based on data from both telescopes further confirms this conclusion:

[T]hese results suggest that 3I/ATLAS hosts a coma containing large water ice grains, and that its dust continuum is stable over at least week-long timescales. The spectral characteristics further distinguish 3I from known ultrared trans-Neptunian objects and align it more closely with active Jupiter-family comets.

The last conclusion is very significant. Though the path and speed of this interstellar object says it must come from beyond the solar system, its cometary make-up more resembles comets that reside in the inner solar system. These facts strongly imply that there is at least one other solar systems not very different from our own.

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Astronomers detect exoplanet shaping the protoplanetary disk surrounding a baby star

9:41 am

Star with disk
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Astronomers using two different instruments on the Very Large Telescope (VLT) in Chile have now directly detected what they think is an exoplanet as it shapes the spiral arms of a baby star’s protoplanetary disk.

In the case of HD 135344B’s disc, swirling spiral arms had previously been detected by another team of astronomers using SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch), an instrument on ESO’s VLT. However, none of the previous observations of this system found proof of a planet forming within the disc.

Now, with observations from the new VLT’s Enhanced Resolution Imager and Spectrograph (ERIS) instrument, the researchers say they may have found their prime suspect. The team spotted the planet candidate right at the base of one of the disc’s spiral arms, exactly where theory had predicted they might find the planet responsible for carving such a pattern.

The newly detected object however might be a brown dwarf and not an exoplanet. More observations are required to reduce the uncertainty.

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Have astronomers observed a black hole twice gobble from the same star?

9:23 am

Astronomers have now observed identical flares 700 days apart and coming from the same supermassive black hole, suggesting that a star was partially disrupted both times as it orbited the black hole.

Both flares produced less energy than predicted, based on calculations that assumed the complete destruction of a star. From the paper’s [pdf] abstract:

Here we present the optical-ultraviolet tidal disruption event AT 2022dbl, which showed a nearly identical repetition 700 days after the first flare. Ruling out gravitational lensing and two chance unrelated disruptions, we conclude that at least the first flare represents the partial disruption of a star.

…Since both flares are typical of the optical-ultraviolet class of tidal disruptions in terms of their radiated energy, temperature, luminosity, and spectral features, it follows that either the entire class are partial rather than full stellar disruptions, contrary to the prevalent assumption, or some members of the class are partial disruptions, having nearly the same observational characteristics as full disruptions. Whichever option is true, these findings could require revised models for the emission mechanisms of optical-ultraviolet tidal disruption flares and a reassessment of their expected rates.

Assuming the star wasn’t completely destroyed during the second flare, a third flare should occur about two years from now, as the star swings around and makes its next close approach. If so it will confirm this theory. If not, we will be left with the simple uncertainty of science.

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A galaxy surrounded by galaxies

11:12 am

A galaxy surrounded by galaxies
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Cool image time! 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 galaxies where Type 1a supernovae have occurred, in order to better refine the precise brightness of these explosions.

What makes this galaxy most interesting are the hundreds of other galaxies that appear to surround it. And that ain’t an illusion.

NGC 3285B is a member of the Hydra I cluster, one of the largest galaxy clusters in the nearby Universe. Galaxy clusters are collections of hundreds to thousands of galaxies that are bound to one another by gravity. The Hydra I cluster is anchored by two giant elliptical galaxies at its centre. Each of these galaxies is about 150,000 light-years across, making them about 50% larger than our home galaxy, the Milky Way. NGC 3285B sits on the outskirts of its home cluster, far from the massive galaxies at the centre.

As for the survey program, Type 1a supernovae are the measure cosmologists have used to discover the unexpected acceleration of the universe’s expansion rate at the largest scales, something they dub “dark energy” because they really don’t understand what they have discovered. That discovery however hinges entirely on the assumed intrinsic brightness of Type 1a supernovae. Astronomers have assumed these supernovae all have the same approximate brightness, and extrapolate their distance by that brightness.

The problem are the assumptions. We really don’t know if all Type 1a supernovae are approximately the same brightness. And even if they are equally bright, we also do not have a firm grasp of what that brightness should be.

This survey is an attempt to narrow or eliminate these uncertainties.

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Update on eye research at ISS

10:03 am

Link here. The NASA update provides a nice overview of the research, beginning with this overview:

When astronauts began spending six months and more aboard the International Space Station, they started to notice changes in their vision. For example, many found that, as their mission progressed, they needed stronger reading glasses. Researchers studying this phenomenon identified swelling in the optic disc, which is where the optic nerve enters the retina, and flattening of the eye shape. These symptoms became known as Space-Associated Neuro-Ocular Syndrome (SANS).

The research suspects the changes are due to the fluid shifts in the body that take place due to weightlessness, with blood shifting from the legs to the head. Various projects have studied a number of solutions, including wearing leg cuffs, administering vitamin B, and possibly using centrifuge-created artificial gravity to mitigate the condition. The problem has also generated new work in developing better equipment for to studying the eye, including improved imaging and techniques for measuring the eye’s stiffness.

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