Tag: science

Another giant star undergoes dimming

9:51 am

The changes seen in RW Cephei
Click for original image.

Astronomers have detected another giant star dimming in a manner similar to the dimming that Betelgeuse experienced around 2019.

Old stars display light variations that are related to changes in their outer layers. The changes are usually small, so scientists were amazed when astronomers Wolfgang Vollmann and Costantino Sigismondi announced in 2022 that RW Cephei had faded dramatically over the previous few years. By December 2022, RW Cephei had faded to about one third of its normal brightness, an unprecedented drop.

You can read the published paper here. The researchers believe the dimming was caused by the release of dust from the star, blocking its light, much as what is believed happened with Betelgeuse.

RW Cephei, like Betelgeuse, is like a giant gas bag that fluctuates in shape like blob of water in weightlessness. This blob however so big that if placed where the Sun is its surface would be about the orbit of Jupiter. As shown in the two pictures to the right taken by this research team, the shape changed during this dimming.

The star however is much farther away, 16,000 light years compared to Betelgeuse’s 550 light years. Because of Betelgeuse’s size and nearness, until recently it was the only star outside of the Sun whose actual disk had been imaged. That astronomers can now get images of a star as far away as RW Cephei illustrates the incredible improvement in astronomical technology in the past three decades.

0 comments

The Surt volcano on Io

1:19 pm

The Surt volcano on Io in close-up
Click for original image.

Cool image time! The picture to the right, rotated, reduced, and sharpened to post here, was taken by Juno during its 57th close-fly of Jupiter on December 30, 2023. It shows of one of the many volcanoes that cover and continually recoat the surface of the Jupiter moon Io.

The picture was initially processed by citizen scientist Gerald Eichstädt. Thomas Thomopoulos then zoomed in and added additional enhancements to this particular area. (I thank Thomas for his additional help in making this post happen.)

The location is an active volcano named Surt, which has been observed to erupt several times since the 1970s, with its February 2001 eruption the most powerful yet observed on Io, though the pictures by the Jupiter orbiter Galileo taken before and after revealed few significant surface changes.

The picture itself shows a region where major changes have definitely occurred. The large arc of mountains across the photo’s center suggests the remaining half of a large caldera, its northern half now either buried or destroyed. The deep obvious hole inside that crescent appears to be the main vent from which the recent eruptions have spewed, as indicated by the light-colored apron surrounding it.

In the southwest section of that large mountain arc is a distinct ridgeline with a small circular curve in its middle that suggests a former volcanic cone, its northern half now gone.

To put it mildly, Io appears a very alien place, shaped entirely and continuously by endlessly volcanic eruptions that spread lava across its entire surface repeatedly.

2 comments

Layered volcanic vent on Mars

3:53 pm

Layered volcanic vent on Mars
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 31, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what the science team labels as a “vent near Olympica Fossae.”

The grade within the fissure is downhill to its center. Outside the vent the grade is downhill to the north and south, with the overall grade sloping to the west as well. Note the layers on each side of the depression. Each indicates another volcanic flood event that laid down another layer of lava. At some point this vent either blew up through those layers, or it had remained opened during all those many events, the lava flowing out and acting like water to erode the layers on the north and the south.

As always, the scale of Martian geology is daunting, as shown by the overview map below.
» Read more

0 comments

Scientists: Suspended iron minerals floating in Venus’s atmosphere explain dark UV streaks

9:37 am

Venus as seen in ultraviolet by Mariner 10, February 5, 1974
Venus as seen in ultraviolet by Mariner 10,
February 5, 1974

The uncertainty of science: Since the mid-1970s scientists have been trying to figure out the cause of the dark streaks seen in the atmosphere of Venus when photographed in ultraviolet. The image to the right was the first such UV image, taken by Mariner 10 during its fly-by on its way to Mercury. These streaks are caused by some unknown material that absorbs the UV light.

Researchers have now proposed that two different iron-bearing minerals, floating in Venus’s atmosphere, are what cause these dark UV streaks. From the absract:

Our results demonstrate that ferric iron can react with sulfuric acid to form two mineral phases: rhomboclase [(H5O2)Fe(SO4)2·3H2O] and acid ferric sulfate [(H3O)Fe(SO4)2]. A combination of these two mineral phases and dissolved Fe3+ in varying concentrations of sulfuric acid are shown to be good candidates for explaining the 200- to 300-nm and 300- to 500-nm features of the reported unknown UV absorber.

Iron has been detected in the atmosphere previously, and is theorized could come from volcanic eruptions on the planet’s million-plus volcanoes.

This new hypothesis explaining the dark UV absorber however remains unconfirmed, and joins a list of other candidates for that absorber, many of which propose either iron or sulfur in different combinations. Because so little data really exists about the atmosphere of Venus, with what is known also uncertain, it is presently impossible to solve this mystery with confidence. The problem is made even more difficult in that scientists understand almost nothing about the chemistry of materials under the conditions seen in Venus’s atmosphere, which is extremely hot (800 degrees Fahrenheit) and very thick and dense (100 times that of Earth).

1 comment

NASA: UAE to build airlock module for lunar station plus have astronaut fly there

9:20 am

According to a press release from NASA today, the United Arab Emirates (UAE) will build the airlock module for the Lunar Gateway space station plus have one astronaut fly a mission to the station after it is built.

Under a new implementing arrangement expanding their human spaceflight collaboration with NASA through Gateway, MBRSC will provide Gateway’s Crew and Science Airlock module, as well as a UAE astronaut to fly to the lunar space station on a future Artemis mission.

I strongly suspect that the UAE will mostly pay for this module to be built, hiring outside contractors from either the U.S. or Europe to do the work.

4 comments

Canyons formed from the giant crack that splits Mars

2:45 pm

Canyons formed by the giant crack that splits Mars
Click for original image.

Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken on September 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a complex of north-south trending canyons, with easternmost cliff about 400 feet high (though the full drop to the large canyon on its east is closer to 800 feet).

These canyons however have nothing to do with ice or water flow. They were formed by underground tectonic forces that pushed the ground upward, forced it to split and form cracks. Those cracks in turn produced these canyons. In some cases, such as the depression on top of the central ridge, the formation process probably occurred because fissures formed below ground, causing the surface to sag.

As always, the hiker in me wants to walk up the nose of that ridge and then along its western edge, with the western canyon on my left and that smaller depression on my right.

The larger context of this location is in itself even more spectacular.
» Read more

0 comments

Researchers propose method for removing toxic perchlorates from Martian water

9:55 am

Of the twelve research grants just awarded by NASA to develop a variety of new technologies for astronomy and future space exploration, one proposes a new method for removing the toxic perchlorates that are thought to exist in all Martian water.

What if we could make the perchlorates just vanish? This is the innovative solution we propose here, taking advantage of the reduction of chlorate and perchlorate to chloride and oxygen being thermodynamically favorable, if kinetically slow. This is the promise of our regenerative perchlorate reduction system, leveraging synthetic biology to take advantage of and improve upon natural perchlorate reducing bacteria.

These terrestrial microbes are not directly suitable for off-world use, but their key genes pcrAB and cld, which catalyze the reduction of perchlorates to chloride and oxygen, have been previously identified and well-studied. This proposed work exploits the prior work studying perchlorate-reducing bacteria by engineering this perchlorate reduction pathway into the spaceflight proven Bacillus subtilis strain 168, under the control of a robust, active promoter. This solution is highly sustainable and scalable, and unlike traditional water purification approaches, outright eliminates perchlorates rather than filtering them to dump somewhere nearby.

Essentially the researchers will try to engineer bacteria known to be able to survive space so that it carries genes from another microbe able of changing the perchlorate into chloride and oxygen.

This study as well as the other eleven are only in phase one of their contracts, with the award of later phases determined by their initial successes or failures.

3 comments

The mining potential on Mars

11:01 am

The mining potential on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled simply as a “terrain sample,” it was probably taken not as part of any specific research project but to fill a gap in the schedule in order to properly maintain the camera’s temperature.

Nonetheless, the larger region where this photo is located is one of great interest to scientists as well as to future explorers. First note the colors. The wide variations between the bright orange of that peak (only a few tens of feet high) and the light orange and aqua-green of the bedrock to the north and south suggest a terrain with a lot of different materials within it.

The location is in the dry equatorial regions, so the swirls visible on the plateaus north and south of that small peak are not related to near surface ice. Instead, this is warped bedrock, with those swirls also suggesting material of a varied nature, exposed to the surface by erosion processes.
» Read more

1 comment

Hubble detects changes in atmosphere of exoplanet

10:16 am

Using data from collected in 2016, 2018, and 2019 combined with computer simulations, scientists now believe they have detected changes in the atmosphere of the exoplanet WASP-121b, also nicknamed Tylos.

The Jupiter-sized planet orbits a star about 880 light years away.

WASP-121 b is so close to its parent star that the orbital period is only 1.27 days. This close proximity means that the planet is tidally locked so that the same hemisphere always faces the star, in the same way that our Moon always has the same side pointed at Earth. Daytime temperatures approach 3,450 degrees Fahrenheit (2,150 degrees Kelvin) on the star-facing side of the planet.

The team used four sets of Hubble archival observations of WASP-121 b. The complete data-set included observations of WASP-121 b transiting in front of its star (taken in June 2016); WASP-121 b passing behind its star, also known as a secondary eclipse (taken in November 2016); and the brightness of WASP-121 b as a function of its phase angle to the star (the varying amount of light received at Earth from an exoplanet as it orbits its parent star, similar to our Moon’s phase-cycle). These data were taken in March 2018 and February 2019, respectively.

A computer model was then used to fill in the gaps and provide a simulation of the hot temperatures of that exoplanet’s atmosphere over time. Two videos of that simulation are available at the link.

There of course is a lot of uncertainty in this result, though the fundamental discovery of changes is important. This data proves there is weather on such alien planets, even if that weather is so alien we really don’t understand it in the slightest based on the available data on hand.

2 comments

Sunspot update: Are we now in the next solar maximum?

9:57 am

Time for my monthly update on the Sun’s sunspot activity has it proceeds through its eleven-year sunspot cycle. NOAA has released its update of its monthly graph showing the number of sunspots on the Sun’s Earth-facing hemisphere, and I have posted it below, annotated with further details to provide a larger context.

In December sunspot activity increased slightly for the second month in a row, but only by a little bit. The number of sunspots for the month was still significantly below the highs seen in the summer, and continue to suggest that the Sun has already entered solar maximum (two years early), and like the previous two solar maximums in 2001 and 2013, will be double peaked.
» Read more

11 comments

Dunes on the floor of Valles Marineris

2:17 pm

Overview map

Dunes on the floor of Valles Marineris
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on September 26, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a field of scattered elongated dunes on a flat older surface with craters and what appear to be smaller ripple dunes (in the lower left). The large elongated dunes tend to be oriented in an east-west manner, while the older tiny ripple dunes appear to have a north-south orientation.

Very clearly the larger dunes appear to be traveling across that flat older surface, though whether there is any documented movement is unknown. Generally (though there are exceptions) scientists have found most of the dunes on Mars to be either inactive, or if they are moving because of the wind that movement is very tiny per year. In this case there is one dark spot on the dunes, near the center of the picture, where it appears a collapse might have occurred, suggesting recent change.

On the center right of the picture is the end point of a long ridgeline extending 10 to 12 miles to the east and rising about 7,300 feet, as shown in the overview map above. The small rectangle in the inset shows the area covered by the photograph.

At the base of that ridgeline can be seen a series of terraces descending to the west, suggesting that this hill might be volcanic in nature, with each terrace indicating a separate lava flow. The location is in the dry equatorial regions, so near-surface ice is likely not an explanation.

In the inset the mountain wall to the north is the large mountain chain that bisects this part of Valles Marineris. It overwhelms this small 7,300-foot-high ridge, rising more than 22,000 feet from these dunes with its high point still one or two thousand feet below the rim of Valles Marineris itself.

Once again, the grand scenery of Mars amazes. Imaging hiking a trail along that ridgeline, with the mountains rising far above you to the north and south.

0 comments

First Juno images of Io from December 30th fly-by

9:51 am

Io as seen by Juno on December 30, 2023
For original global image go here. For original of inset go here.

The first raw Juno images taken of the Jupiter moon Io during its close fly-by on December 30, 2023, the closest in more than twenty years, have been released by the science team and citizen scientists have begun processing them.

The global picture to the right, rotated and reduced to post here, was processed by Kevin Gill. The inset of the volcanic mountains near the terminator was processed by Thomas Thomopoulos. As he notes, to obtain better detail he enhanced the colors and image and then zoomed in.

In the inset, note the northeast flows coming off the two mountains near the center. With the lower mountain, this flow appears to lie on top of a larger flow that extended out almost to the mountain to the right.

Io is a planet of continuous volcanic activity. For example, when the global image above was taken, the plume of a volcano eruption was visible on the right horizon, as shown in this version, its exposure adjusted by Ted Stryk. Catching such eruptions on Io is not unusual, considering its continuous volcanic activity generated by the tidal forces the planet undergoes from its orbit around Jupiter. In fact, the very first plume was imaged in 1979 by Voyager 1 during its short fly-by, and proved a hypothesis of such activity that scientists had only published one week earlier.

2 comments
1 … 94 95 96 97 98 … 729