Tag: science

A blob in space

9:47 am

A blob in space
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope of the dwarf galaxy NGC 5238.

Its unexciting, blob-like appearance, resembling more an oversized star cluster than a galaxy, belies a complicated structure which has been the subject of much research by astronomers. Here, the NASA/ESA Hubble Space Telescope is able to pick out the galaxy’s countless stars, as well as its associated globular clusters — the glowing spots both inside and around the galaxy that are swarmed by yet more stars.

NGC 5238 is theorised to have recently — here meaning no more than a billion years ago! — had a close encounter with another galaxy. The evidence for this is the tidal distortions of NGC 5238’s shape, the kind produced by two galaxies pulling on each other as they interact. There’s no nearby galaxy which could have caused this disturbance, so the hypothesis is that the culprit is a smaller satellite galaxy that was devoured by NGC 5238.

Astronomers are hoping to use this image to detect the two different populations of stars within this blob that come from those once interacting galaxies.

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Webb infrared spectroscopy detects differences between morning and evening on tidally-locked exoplanet

9:36 am

Webb spectroscopic data
Click for original image.

Astronomers using Webb Space Telescope’s infrared spectroscopy have now detected distinct differences in the morning and evening atmosphere of a tidally-locked gas giant exoplanet.

The graph, cropped, reduced, sharpened, annotated to post here, shows the differences. From the caption:

Researchers using NASA’s James Webb Space Telescope have finally confirmed what models have previously predicted: An exoplanet has differences between its eternal morning and eternal evening atmosphere. WASP-39 b, a giant planet with a diameter 1.3 times greater than Jupiter, but similar mass to Saturn that orbits a star about 700 light-years away from Earth, is tidally locked to its parent star. This means it has a constant dayside and a constant nightside—one side of the planet is always exposed to its star, while the other is always shrouded in darkness.

Using Webb’s NIRSpec (Near-Infrared Spectrograph), astronomers confirmed a temperature difference between the eternal morning and eternal evening on WASP-39 b, with the evening appearing hotter by roughly 300 Fahrenheit degrees (about 200 Celsius degrees). They also found evidence for different cloud cover, with the forever morning portion of the planet being likely cloudier than the evening.

The actual temperatures of each terminator are quite hot, approximately 1,150 and 1450 degrees Fahrenheit respectively. Computer modeling suggests “the prevailing winds are likely moving from the night side across the morning terminator, around the dayside, across the evening terminator and then around the nightside,” with wind speeds thousands of miles per hour.

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A penguin and egg, as seen by Webb and Hubble

11:32 am

A penquin and egg compared
Click for original images.

Cool image time! The two pictures to the right, cropped, reduced, and sharpened to post here, were taken by both the Webb and Hubble space telescopes of the same unusual galactic object, officially called Arp 142 but nicknamed by astronomers the Penquin and the Egg.

Both of these objects are galaxies. The Penquin’s strange shape is caused by the presence of the Egg, which is an elliptical galaxy that is twisting and distorting the Penquin’s original spiral galaxy whirlpool as it flies past. From the caption:

Like all spiral galaxies, the Penguin is still very rich in gas and dust. The galaxies’ “dance” gravitationally pulled on the Penguin’s thinner areas of gas and dust, causing them to crash in waves and form stars. Look for those areas in two places: what looks like a fish in its “beak” and the “feathers” in its “tail.”

Surrounding these newer stars is smoke-like material that includes carbon-containing molecules, known as polycyclic aromatic hydrocarbons, which Webb is exceptional at detecting. Dust, seen as fainter, deeper orange arcs also swoops from its beak to tail feathers.

In contrast, the Egg’s compact shape remains largely unchanged. As an elliptical galaxy, it is filled with aging stars, and has a lot less gas and dust that can be pulled away to form new stars. If both were spiral galaxies, each would end the first “twist” with new star formation and twirling curls, known as tidal tails.

Another reason for the Egg’s undisturbed appearance: These galaxies have approximately the same mass or heft, which is why the smaller-looking elliptical wasn’t consumed or distorted by the Penguin.

The differences between the two pictures also reveal many aspects of the Penguin. The Hubble optical image at the top captures the lanes of dust in the foreground, while the Webb infrared image at the bottom looks right through this dust to better trace the now-distorted spiral arms where star formation is presently taking place.

Astronomers estimate that these two galaxies are about 100,000 light years apart, comparable to the width of the Milky Way. In comparison, the Andromeda galaxy is around 2.5 million light years away, and will not begin interacting with our galaxy in this manner for an estimated four billion years. The Egg and Penguin however began their warped dance about 50 million years ago.

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Europa Clipper mission threatened by faulty transistors

9:31 am

Engineers have learned that transistors installed on NASA’s Europa Clipper mission were not built to the right specifications and could fail in the harsh environment surrounding Jupiter.

The issue with the transistors came to light in May when the mission team was advised that similar parts were failing at lower radiation doses than expected. In June 2024, an industry alert was sent out to notify users of this issue. The manufacturer is working with the mission team to support ongoing radiation test and analysis efforts in order to better understand the risk of using these parts on the Europa Clipper spacecraft.

Testing data obtained so far indicates some transistors are likely to fail in the high-radiation environment near Jupiter and its moon Europa because the parts are not as radiation resistant as expected. The team is working to determine how many transistors may be susceptible and how they will perform in-flight. NASA is evaluating options for maximizing the transistors’ longevity in the Jupiter system. A preliminary analysis is expected to be complete in late July.

This issue could be disaster for the mission, which has a launch window that opens on October 10, 2024. If it is impossible to replace the bad transistors, NASA will be faced with two choices, neither great. It could launch regardless and hope for the best. It could delay the mission to fix the problem, which might involve a delay of years waiting for a new launch window.

This story appears to illustrate once again the decline in quality control that appears to be happening across much of American industry. The technology for building radiation-hardened equipment has been standard for decades. For a company to deliver equipment below standard now suggests incompetence or fraud, neither of which speaks well for it and the entire industry.

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Archeologists find the musket balls fired in the first shots of the Revolutionary War

9:33 pm

Archeologists digging at Concord discover what they think are five musket balls fired in the first shots of the Revolutionary War.

Archeologists believe five musket balls unearthed in Concord’s Minute Man National Historical Park were fired by colonial militia in the famed battle moments that sparked the Revolutionary War. The 250-year-old musket balls were discovered in an area inside the park where historians believe British troops faced colonial forces at the North Bridge.

Analysis of the artifacts indicates they were fired by colonial militia members from across the river, and not dropped from British weapons when troops were reloading.

Since the Minute Men fired over a period of time, routing the British troops, there is no way to know if these musket balls were the first fired, or among the later rounds. Nonetheless, these artifacts are an actual piece of a moment of history that literally changed all of human history.

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A ridge that runs right over a Martian mesa

2:42 pm

A dike in a mesa
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on April 5, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have cropped it to focus on the geological feature that likely attracted the interest of the scientists who requested this photo, the mesa that has a ridgeline running over it as if the mesa was not even there.

The mesa is about 80 feet high on its west side, but on its east the ground continues to drop away more than 500 feet as you move 2.5 miles to the east. Based on how the MRO science team interprets the colors [pdf] in the color strip, the orange areas are likely dust while the greenish surface suggests coarser sand and boulders. This conclusion is reinforced if you look at the parallel dunes south of the mesa. The dunes are yellow-orange (dust) while the ground between is yellow-green (sand), exactly what you expect with the larger coarser material settling in lower elevations.

The overview map provides the context, which might help explain the ridgeline.
» Read more

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Reanalysis of Apollo seismic data finds 22,000 previously undetected quakes

2:50 pm

By taking a new look at the data from the seismometers placed on the lunar surface by the Apollo missions during the 1970s, Keisuke Onodera of the University of Tokyo was able to find approximately 22,000 previously undetected quakes, almost tripling the rate of seismic activity on the Moon. From the paper’s abstract:

In the 1970s, two types of seismometers were installed on the nearside of the Moon. One type is called the Long-Period (LP) seismometer, which is sensitive below 1.5 Hz. The other is called the Short-Period (SP) seismometer, whose sensitivity is high around 2–10 Hz. So far, more than 13,000 seismic events have been identified through analyzing the LP data, which allowed us to investigate lunar seismicity and its internal structure.

On the other hand, most of the SP data have remained unanalyzed because they include numerous artifacts. This fact leads to the hypotheses that (a) we have missed lots of high-frequency seismic events and (b) lunar seismicity could be underestimated.

To verify these ideas, I conducted an analysis of the SP data. … I discovered 22,000 new seismic events, including thermal moonquakes, impact-induced events, and shallow moonquakes. Among these, I focused on analyzing shallow moonquakes—tectonic-related quakes. Consequently, it turned out that there were 2.6 times more tectonic events than considered before. Furthermore, additional detections of shallow moonquakes enabled me to see the regionality in seismicity. Comparing three landing sites (Apollo 14, 15, and 16), I found that the Apollo 15 site was more seismically active than others. These findings can change the conventional views of lunar seismicity.

The data also suggests the northern hemisphere is more active than the southern.

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Astronomers: A black hole weighing 8,200 solar masses likely sits at the center of the Milky Ways’ largest globular cluster

2:39 pm

Omega Centauri
Click for original image.

By analyzing the motion of seven fast moving stars at the center of the globular cluster Omega Centauri, the largest such cluster in the Milky Way and located about 18,000 light years away, astronomers now think they have detected evidence of an intermediate-sized black hole weight at least 8,200 solar masses.

You can read the published paper here. [pdf] The picture of Omega Centauri to the right, reduced and sharpened to post here, was created from more than 500 images taken over two decades by the Hubble Space Telescope. The inset, figure 1b of the paper, shows those seven fast-moving stars in pink, each having an arrow indicating the distance they are expected to move in a 100 years. The dashed circle marks the region where the black hole is believed to reside, with the dark blue cross in its upper left quadrant the most likely position of the black hole based on calculations.

From the caption for the larger Omega Centauri Hubble image:

Omega Centauri is visible from Earth with the naked eye and is one of the favourite celestial objects for stargazers in the southern hemisphere. Although the cluster is 17 700 light-years away, lying just above the plane of the Milky Way, it appears almost as large as the full Moon when seen from a dark rural area.

Though such intermediate-sized black holes have been theorized as existing inside globular clusters, I think this is the first real evidence of one.

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Radar movie produced of 500-foot-wide asteroid

9:44 am

Movie of asteroid

Cool image time! Astronomers have created a movie of radar images of a 500-foot-wide asteroid, dubbed 2024 MK, as it flew past the Earth on June 30, 2024 only 184,000 miles away, using two different radar dishes that are part of NASA’s Deep Space Network normally used for communications with planetary missions.

That movie is to the right.

The Deep Space Network’s 230-foot (70-meter) Goldstone Solar System Radar, called Deep Space Station 14 (or DSS-14), was used to transmit radio frequency signals to the asteroid, and the 114-foot (34-meter) DSS-13 received the reflected signals. The result of this “bistatic” radar observation is a detailed image of the asteroid’s surface, revealing concavities, ridges, and boulders about 30 feet (10 meters) wide.

This is not the first time an asteroid has been observed in this manner using radar, but it illustrates how the technique is becoming increasingly sophisticated, capable of producing images of surprising resolution.

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Webb: An exoplanet in the habitable zone with a possible nitrogen/CO2 atmosphere and water ocean

8:51 am

Using the Webb Space Telescope, astronomers have obtained new transiting spectroscopy of a “mini-Neptune-sized” exoplanet that circles in the habitable zone a red dwarf star about 48 light years away and have concluded that it appears to have a nitrogen/carbon dioxide atmosphere and even a water ocean.

While it is still only a tentative result, the presence of a nitrogen-rich atmosphere on LHS 1140 b would suggest the planet has retained a substantial atmosphere, creating conditions that might support liquid water. This discovery favors the water-world/snowball scenario as the most plausible.

Current models indicate that if LHS 1140 b has an Earth-like atmosphere, it would be a snowball planet with a vast “bull’s-eye” ocean measuring about 4,000 kilometers in diameter, equivalent to half the surface area of the Atlantic Ocean. The surface temperature at the centre of this alien ocean could even be a comfortable 20 degrees Celsius [68 degrees Fahrenheit]. [emphasis mine]

You can read the preprint of the paper here [pdf].

The highlighted phrase must be noted. These results contain a lot of uncertainties and assumptions. However, the data is tantalizing, to say the least, and justify more observations using Webb. The scientists argue in their paper that because there are only about eight transits of the exoplanet per year — requiring several years of observations to pin down this data more precisely — and because Webb has a limited life expectancy as an infrared observatory, this star should get observational priority.

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A jumble of blocks in the middle of a Martian flood lava plain

11:25 am

A jumble of blocks on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on March 18, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

This is one of what I like to call “What the heck?” images. The broken up blocks resemble ice floes on the edge of the Arctic ice cap that have broken off and have begun floating away.

The problem with this theory is many fold. First, this is on Mars and not on Earth. Second the “sea” these blocks are supposedly “floating” in is actual solid lava. There is no water or ice here, on the surface or even underground. This is in the dry tropics of Mars, where little or no near-surface ice has so far been detected.

The overview map below provides some context, and possibly an explanation.
» Read more

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Webb: Hot Jupiter exoplanet has atmosphere with the smell of rotten eggs

9:20 am

Using spectroscopy from the infrared Webb Space Telescope, astronomers have measured some of the molecules in exoplanet HD 189733 b, one of the first hot Jupiter exoplanets ever discovered, and found it has an atmosphere rich in hydrogen sulfide, which emits a smell like rotten eggs.

In addition to detecting hydrogen sulfide, the team analyzed the planet’s oxygen and carbon content, pinpointing water, carbon dioxide and carbon monoxide as major components of the planetary atmosphere. Measuring these heavy elements allows astronomers to compare the composition of exoplanets to that of gas giants in our solar system like Jupiter and Uranus.

The exoplanet, about 64 light years away, has an orbit lasting only about two Earth days, with atmospheric temperatures has hot as 1,700 degrees Fahrenheit.

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