Tag: science

Webb’s infrared view of the Tarantula Nebula

9:55 am

Two views of the Tarantula Nebula by Webb
Click for original image.

The two images to the right, reduced and annotated to post here, were released today by the science team of the James Webb Space Telescope, and show two different views of the Tarantula Nebula, located 161,000 light years away in the Large Magellanic Cloud.

It is home to the hottest, most massive stars known. Astronomers focused three of Webb’s high-resolution infrared instruments on the Tarantula. Viewed with Webb’s Near-Infrared Camera (NIRCam) [top], the region resembles a burrowing tarantula’s home, lined with its silk. The nebula’s cavity centered in the NIRCam image has been hollowed out by blistering radiation from a cluster of massive young stars, which sparkle pale blue in the image. Only the densest surrounding areas of the nebula resist erosion by these stars’ powerful stellar winds, forming pillars that appear to point back toward the cluster. These pillars contain forming protostars, which will eventually emerge from their dusty cocoons and take their turn shaping the nebula.

…The region takes on a different appearance when viewed in the longer infrared wavelengths detected by Webb’s Mid-infrared Instrument (MIRI) [bottom]. The hot stars fade, and the cooler gas and dust glow. Within the stellar nursery clouds, points of light indicate embedded protostars, still gaining mass. While shorter wavelengths of light are absorbed or scattered by dust grains in the nebula, and therefore never reach Webb to be detected, longer mid-infrared wavelengths penetrate that dust, ultimately revealing a previously unseen cosmic environment.

As with all images from Webb, these are false color, as the telescope views the infrared heat produced by stars and galaxies and interstellar clouds, not the optical light our eyes see. Thus, the scientists assign different colors to the range of wavelengths each instrument on Webb captures.

These photos once again illustrate Webb’s value. It will provide a new layer of data to supplement the basic visual information provided by the Hubble Space Telescope, allowing scientists to better understand the puzzles we see in the optical.

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Gullies and glaciers in a crater on Mars

4:46 pm

The gullies and glaciers in Avire Crater
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on July 10, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the floor of 4-mile-wide Avire Crater, located at about 41 degrees south latitude inside the much larger 185-mile wide Newton Crater.

This picture was taken as part of a long term monitoring program of the many gullies that flow down the slopes of the crater’s interior rim. In fact, the gullies of this crater have so interested scientists that one even proposed [pdf] this location as a potential future rover landing site.

Avire Crater, a small … gullied crater within Newton Crater, provides many aspects ideal to a future rover mission. It has been previously hypothesized to be the location of a former paleolake with multiple episodes of ponding and deposition. Gullies occur almost continuously on the southwest wall clockwise to the northeastern wall. Dark-toned dunes are present in the northern portion of the crater, in some places obscuring gullies while cut by gullies in others. No changes in the extent or appearance of the dunes have been observed since they were first imaged … in January of 2000. The dunes lack superimposed craters, indicating that the gullies that cut through them are geologically very youthful. Layered lobate features are present at the base of the gullies on the northern wall, seen in many other craters on Mars (not always in association with gullies), which have been suggested to have formed as terminal moraines of ice-rich flows; in Avire, these features have also been suggested to be paleolake deposits. The crater floor is obscured by mid-latitude “fill” material, hypothesized to be partially comprised of ice based on morphologic evidence that the material has been partially removed.

As gullies, dunes, and “fill” material occur in many places on Mars, a single rover mission to a site containing these features would provide valuable information applicable to thousands of other locations across the planet.

The curved ridgeline in the crater floor is thought to be a moraine. The “fill” material to the south is essentially glacial in nature. Both, as well as the gullies, appear to have been shaped either a paleolake that once existed in the crater or by cyclical glacier activity. By going to this one crater, scientists could study all these different geological features at one time.
» Read more

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Ingenuity’s flight plan for its next and 31st flight

10:22 am

Perseverance's location on September 2, 2022
Click for interactive map

The Ingenuity engineering team today released the flight plan for the helicopter’s next flight on Mars, its thirty-first since arrival.

The flight is scheduled for no earlier than September 6, mid-day on Mars, and will travel about one minute to the west for a distance of about 319 feet. The white dot on the overview map to the right shows the approximate landing spot, with the green dot marking Ingenuity’s present position. The blue dot marks Perseverance’s present position as it moves to the south and west after leaving the first delta cliff face it studied during the past few months.

The flight’s main goal is to reposition the helicopter to keep it close to the rover to facilitate communications. However, the engineering team has also now adjusted its goals to also practice hitting very precise landing spots. This goal is to develop the engineering and software that can be used on the helicopter that is not yet built that NASA and ESA intend to use to recover Perseverance’s core samples for return to Earth. That helicopter will not only have to very precisely land right next to those samples in a position allowing it to grab them, it must also land very precisely next to the sample return spacecraft to deposit them within it.

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Sunspot update: Solar activity continues to exceed sunspot predictions

3:50 pm

It is the beginning of September and time to post another update on the Sun’s ongoing solar cycle. Below is NOAA’s monthly graph tracking the number of sunspots on the Sun’s Earth-facing hemisphere, with the activity in August now added. I have also added some additional details to the graph to give the numbers a larger context.

Though sunspot activity dropped in August it remained significantly above the predictions of the panel of government solar scientists put together by NOAA. The predicted sunspot number for August, as indicated by the red curve, was supposed to be about 48. The actual number was 75.

» Read more

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On Mars you can find glaciers everywhere in the mid-latitudes

12:42 pm

Glacial material in Mars' rift zone
Click for full image.

Cool image time! If you ever decide to have some fun exploring the archive of images being sent back to Earth by the high resolution camera on Mars Reconnaissance Orbiter (MRO), always remember that the latitude of the image will almost immediately help to explain the strange features that you see in each picture.

The hi-res photo to the right, rotated, cropped, and reduced to post here, was taken on May 22, 2022 and provides us a great example. The jumbled features in the depression on the image’s right half surely look like the glacial features seen routinely in the 2,000-mile-long strip found in the 30 to 60 degree band in the chaos terrain of the northern lowland plains. In fact, it is likely that cycles of ebb and flow of those glaciers helped shape this chaos of buttes and mesas and cross-cutting canyons.

This picture however is nowhere near any chaos terrain, or that 2,000 long strip. In fact, it is instead in an area that appears mostly formed by tectonic and volcanic activity, as the overview map below shows.
» Read more

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Webb obtains first direct infrared images of exoplanet

9:49 am

Webb's first infrared images of an exoplanet
Click for original image.

Using four different infrared instruments on the James Webb Space Telescope, astronomers have obtained the first infrared images of a gas giant with a mass about six to twelve times larger than Jupiter and circling about 100 times farther from its sun.

The montage to the right shows these four images. The white star marks the location of this star, the light of which was blocked out to make the planet’s dim light visible. The bar shapes on either side of the planet in the NIRCam images are artifacts from the instrument’s optics, not objects surrounding the planet.

This is not the first direct image of an exoplanet, as the Hubble Space Telescope has already done so, and done it in the visible spectrum that humans use to see. However, Webb’s infrared images provide a great deal of additional detail about this planet and its immediate surroundings that optical images would not. For example, the MIRI images appear to show us the outer atmosphere of this gas giant.

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Experiment on Perseverance has successfully produced oxygen repeatedly

9:29 am

An engineering experiment on the Mars rover Perseverance, dubbed MOXIE, has now successfully produced oxygen from the carbon dioxide in the Martian atmosphere, and has done so seven different times. After filtering an air sample…

…the air is then pressurized, and sent through the Solid OXide Electrolyzer (SOXE), an instrument developed and built by OxEon Energy, that electrochemically splits the carbon dioxide-rich air into oxygen ions and carbon monoxide. The oxygen ions are then isolated and recombined to form breathable, molecular oxygen, or O2, which MOXIE then measures for quantity and purity before releasing it harmlessly back into the air, along with carbon monoxide and other atmospheric gases.

Since the rover’s landing in February 2021, MOXIE engineers have started up the instrument seven times throughout the Martian year, each time taking a few hours to warm up, then another hour to make oxygen before powering back down. Each run was scheduled for a different time of day or night, and in different seasons, to see whether MOXIE could accommodate shifts in the planet’s atmospheric conditions.

During each run, the instrument produced about six grams of oxygen per hour, though a recent run produced more than 10 grams per hour, about half what a human needs to survive.

MOXIE runs only for short times, because it uses so much power the rover can’t do other work during runs. It is also only a technology test, so its operation is given a lower priority. Nonetheless, it appears that this test has successfully demonstrated that future astronauts on Mars will have a system for producing an unlimited supply of breathable oxygen. The next step would be to scale this up to produce enough oxygen to also fuel the astronaut’s return rocket.

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Perseverance: Evidence of both past lava and liquid water on the floor of Jezero Crater

1:40 pm

Figure 6: Two models for geological history of Jezero Crater

Two new papers (here and here), published last week in Science and using data obtained during Perseverance’s first year of roving on Mars, strongly suggest that the floor of Jezero Crater was first formed by lava flows, either from impact or later flows from eruptions, followed by a period where liquid water interacted with these igneous materials to produce the chemistry seen today. From the first paper:

After emplacement of the igneous rocks on the crater floor, multiple forms of aqueous interaction modified—but did not destroy—their igneous mineralogy, composition, and texture. Evidence for alteration includes the presence of carbonate in the Séítah abrasion patches, the iron oxides in the Máaz formation abrasion patches (which we presume are due to iron mobilization and precipitation), and the deposition of salts including sulfates and perchlorate. More broadly, the appearance of possible spheroidal weathering textures suggests that aqueous alteration played a role in rock disintegration.

The graphic to the right, figure 6 in the first paper, shows two different models for the geological formation of the floor of Jezero Crater. “Basalt emplacement” are the lava flows.

According to the press release today [pdf], the first core samples that the rover gathered for later pickup and return to Earth will likely show the following:

The salts include sulfates, similar to Epsom salts, which are common on Mars. Most importantly, high levels of chlorine-containing salts are also present, such as chlorides (“table salt”) and perchlorates. These highly soluble salts reveal that the rocks were soaked in brines, and hence contain clear evidence of liquid water.

The on-going big geological mystery of Mars remains. The data suggests liquid water once existed as some form in Jezero Crater. Other data suggests liquid water existed elsewhere on Mars as well. Yet, no model exists that anyone accepts with any confidence that makes it possible for liquid water to exist on the Martian surface. Its atmosphere has always been either too cold or thin.

To underline this conundrum, note that in the graphic above, neither model includes a time period when liquid water sat on top of these layers. Though the evidence calls for liquid water at some time, the scientists do not feel confident enough to include it in these initial models.

One possible explanation that I sense some scientists are beginning to consider is the chemical interaction of melted ice at the base of past long gone ice glaciers. The ice would be frozen, but the glacier’s movement might create pockets of liquid water at its base, which over eons might result in these chemical reactions. If Jezero Crater had once been filled with glaciers, as many Martian craters in the mid-latitudes appear to be now, this could have provided the water necessary for the chemical modifications the scientists are finding.

This theory however is entirely speculative on my part, and has not yet been proposed by any scientists, though I have seen hints of it in a number of different research papers.

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Webb’s infrared view of a face-on spiral galaxy

9:44 am

M74, as seen by Webb and Hubble combined
Click for original image.

Using the James Webb Space Telescope, astronomers have produced a false-color infrared view of M74, a face-on spiral galaxy located 32 million light years away.

The montage above shows that image to the right, with a Hubble optical image to the left. In the center both images are combined.

The addition of crystal-clear Webb observations at longer wavelengths will allow astronomers to pinpoint star-forming regions in the galaxies, accurately measure the masses and ages of star clusters, and gain insights into the nature of the small grains of dust drifting in interstellar space.

Because infrared can see through cold dust, it provides a much sharper view of this galaxy’s central regions.

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Engineers fix problem that caused data to arrive garbled from Voyager-1

9:00 am

By switching computers on Voyager-1 — now in interstellar space and having recently celebrated its 45th anniversary since launch — engineers were able to prevent data from coming back garbled from the spacecraft.

Earlier this year, the probe’s attitude articulation and control system (AACS), which keeps Voyager 1’s antenna pointed at Earth, began sending garbled information about its health and activities to mission controllers, despite operating normally. The rest of the probe also appeared healthy as it continued to gather and return science data.

The team has since located the source of the garbled information: The AACS had started sending the telemetry data through an onboard computer known to have stopped working years ago, and the computer corrupted the information.

Suzanne Dodd, Voyager’s project manager, said that when they suspected this was the issue, they opted to try a low-risk solution: commanding the AACS to resume sending the data to the right computer.

The switch worked. The mystery now is figuring out why the AACS started using that long-decommissioned computer, which could indicate another computer or software issue elsewhere in the spacecraft.

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InSight power levels continue to hold steady

2:35 pm

InSight power levels through August 27, 2022

According to a new update posted today by the InSight science team, the power being generated by the lander’s dust-covered solar panels once again did not decline last week, holding at 400 watt-hours generated per day for the fifth week in a row.

The graph to the right shows the trends since May. The dust in the atmosphere is indicated by the red line, marking what scientists call the tau level. A normal level outside of the winter dust season should be between 0.6 and 0.7 tau. Even though that dust season has been ending, that level has remained high, thus cutting off more of the sunlight that the Mars lander could use to generate the electricity needed by its seismometer.

That the power generated continues to hold steady however suggests that InSight’s seismometer might be able to continue working into September, detecting Martian earthquakes. The scientists had predicted the spacecraft would die sometime around now. Without doubt they are thrilled their prediction appears wrong.

That the lander might last longer also increases the chance that it might experience a wind event, such as a dust devil, that could blow the solar panels clear of dust and save the lander entirely. All it needs is one such event, which sadly has not occurred since InSight landed on Mars in 2018.

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Martian auroras as seen by UAE’s Al-Amal orbiter

10:42 am

Aurora types on Mars
Click for full image.

Using data gathered by the Al-Amal orbiter (“Hope” in English), scientists have identified three types of aurora on Mars. The image to the right, figure 1 from their paper, shows these types, crustal field aurora, patchy aurora, and sinuous aurora. From the abstract:

We categorize discrete auroral patterns into three types: those near strong vertical crustal magnetic field, patchy aurora near very weak crustal fields, and a new type we call “sinuous,” an elongated serpentine structure that stretches thousands of kilometers into the nightside from near midnight in the northern hemisphere.

All three types generally occur during the Martian night, and evolve quickly over periods of less than 45 minutes. The first type, which is generally the brightest, forms over terrain where Mars’ residual magnetic field is strongest and vertically oriented, and was most often seen over the southern cratered highlands centered between the large impact basins Argyre and Hellas. The third type, sinuous aurora, was more unusual:

These we are calling “sinuous discrete aurora,” due to their thin, elongated, and sometimes serpentine shapes. They share several key traits: (a) they appear in the northern hemisphere away from strong crustal fields, (b) they usually connect to the dayside in the far north but also sometimes separately at lower latitudes, (c) they extend for thousands of kilometers into the night side, (d) they appear on both dusk and dawn sides, and (e) their shapes change moderately and brightnesses shift by factors of up to two over timescales of ∼20 min (i.e., the time between swaths, as shown in the differences between Figures 1j and 1k [in the figure above).

The existence of aurora on Mars has been known since the 2000s. These observations however are the first that show more details beyond a fuzzy patch.

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