Tag: astronomy

The spiral galaxy M91

3:38 pm

spiral galaxy M91
Click for full release image.

Cool image time! The image to the right, reduced to post here, was released today by the Space Telescope Science Institute as part of a regular program using the Hubble Space Telescope to photograph galaxies.

This observation is part of an effort to build a treasure trove of astronomical data exploring the connections between young stars and the clouds of cold gas in which they form. To do this, astronomers used Hubble to obtain ultraviolet and visible observations of galaxies already seen at radio wavelengths by the ground-based Atacama Large Millimeter/submillimeter Array.

The galaxy is estimated to be about 55 million light years away, and is thought to have a supermassive black hole at its center with a mass somewhere between 9 and 38 million times the mass of the Sun.

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Webb’s coldest instrument reaches operating temperature

1:32 pm

The engineering team announced today that the mid-infrared instrument on the James Webb Space Telescope has now cooled to its operating temperature of -447 degrees Fahrenheit, less than 7 kelvin degrees above absolute zero.

On April 7, Webb’s Mid-Infrared Instrument (MIRI) – a joint development by NASA and ESA (European Space Agency) – reached its final operating temperature below 7 kelvins (minus 447 degrees Fahrenheit, or minus 266 degrees Celsius).

Along with Webb’s three other instruments, MIRI initially cooled off in the shade of Webb’s tennis-court-size sunshield, dropping to about 90 kelvins (minus 298 F, or minus 183 C). But dropping to less than 7 kelvins required an electrically powered cryocooler. Last week, the team passed a particularly challenging milestone called the “pinch point,” when the instrument goes from 15 kelvins (minus 433 F, or minus 258 C) to 6.4 kelvins (minus 448 F, or minus 267 C).

Before science operations can begin the instruments still need further calibration and testing. Expect the first infrared images sometime in the next month or so.

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Astronomers confirm comet with largest nucleus ever found

9:29 am

Using the Hubble Space Telescope astronomers determined that the nucleus of Comet Bernardinelli-Bernstein (C/2014 UN271) is about 80 miles wide, making it the largest comet on record.

The estimated diameter is approximately 80 miles across, making it larger than the state of Rhode Island. The nucleus is about 50 times larger than found at the heart of most known comets. Its mass is estimated to be a staggering 500 trillion tons, a hundred thousand times greater than the mass of a typical comet found much closer to the Sun.

The behemoth comet, C/2014 UN271 (Bernardinelli-Bernstein) is barreling this way at 22,000 miles per hour from the edge of the solar system. But not to worry. It will never get closer than 1 billion miles away from the Sun, which is slightly farther than the distance of the planet Saturn. And that won’t be until the year 2031.

The previous record holder is comet C/2002 VQ94, with a nucleus estimated to be 60 miles across. It was discovered in 2002 by the Lincoln Near-Earth Asteroid Research (LINEAR) project.

This measurement does have a great deal of uncertainty, as Hubble cannot yet resolve the nucleus, and thus its diameter was determined by computer models based on the size of the comet’s coma, or surrounding atmosphere.

The comet itself has an orbit 3 million years long, which means it has zipped into the inner solar system many many times. The reason its nucleus remains so large is because its orbit never gets that close to the Sun, so its material does not get burned off so much with each perihelion. That it exists suggests there could be many such large comets which never dip close to the Sun.

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Interstellar meteor impacted Earth in 2014

10:28 am

According to classified military data just released, it appears that an asteroid from interstellar space impacted the Earth in 2014, with some of its pieces possibly hitting the ocean in the south Pacific.

The meteor ignited in a fireball in the skies near Papua New Guinea, the memo states, and scientists believe it possibly sprinkled interstellar debris into the South Pacific Ocean. The confirmation backs up the breakthrough discovery of the first interstellar meteor—and, retroactively, the first known interstellar object of any kind to reach our solar system—which was initially flagged by a pair of Harvard University researchers in a study posted on the preprint server arXiv in 2019.

Amir Siraj, a student pursuing astrophysics at Harvard who led the research, said the study has been awaiting peer review and publication for years, but has been hamstrung by the odd circumstances that arose from the sheer novelty of the find and roadblocks put up by the involvement of information classified by the U.S. government.

The speed and angle in which the object hit the atmosphere are why the scientists believe it comes from outside the solar system.

Siraj is actually hoping to mount a mission to recover parts of this asteroid, something that is extremely unlikely. First, the meteor itself was small, so it likely all burned up in re-entry. Second, even if pieces survived, finding them on the bottom of the Pacific is likely impossible.

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Neptune’s cooling when it should be warming

9:45 am

Neptune since 2006

The uncertainty of science: Observations of Neptune during the past seventeen years using the Very Large Telescope have shown the planet mostly cooling during this time period, even though Neptune was moving into its summer season.

Astronomers looked at nearly 100 thermal-infrared images of Neptune, captured over a 17-year period, to piece together overall trends in the planet’s temperature in greater detail than ever before. These data showed that, despite the onset of southern summer, most of the planet had gradually cooled over the last two decades. The globally averaged temperature of Neptune dropped by 8 °C between 2003 and 2018.

The astronomers were then surprised to discover a dramatic warming of Neptune’s south pole during the last two years of their observations, when temperatures rapidly rose 11 °C between 2018 and 2020. Although Neptune’s warm polar vortex has been known for many years, such rapid polar warming has never been previously observed on the planet. “Our data cover less than half of a Neptune season, so no one was expecting to see large and rapid changes,” says co-author Glenn Orton, senior research scientist at Caltech’s Jet Propulsion Laboratory (JPL) in the US.

The sequence of photos above show that change over time. Lower latitudes generally get darker, or cooler, while the south pole suddenly brightens, getting hotter, in 2020.

The scientists have no idea why this has happened, though they have theories, ranging from simple random weather patterns to the influence of the Sun’s sunspot cycle.

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Astronomers discover a solar twin whose sunspot cycle changed into a grand minimum

9:19 am

Astronomers studying the sunspot cycle of several dozen stars that are twins of our Sun have identified for the first time a star whose 17-year cycle suddenly ceased, going into an extended grand minimum.

Comparing these stars to the Sun enables astronomers to better determine how typical – or not – the Sun is as a star. The Sun’s magnetic activity is defined by its 11-year sunspot cycle. Of the 59 stars that Baum’s team surveyed, 29 appeared to also have starspot cycles, and the period of those cycles could be measured for 14 of them.

“Of these 14 stars, the average length of their cycle is just under 10 years, which is similar to the Sun’s 11-year cycle,” Baum tells Physics World. However, not all the stars adhered to this time frame. One star that was surveyed has a cycle lasting less than four years, while another star, HD 166620, had a cycle 17 years long.

Note the past tense. Sometime between 1995 and 2004, HD 166620’s starspot cycle simply stopped.

When or if the star’s sunspot activity resume is unknown. The Sun’s last grand minimum, dubbed the Maunder Minimum, lasted 70 years during the 1600s.

No one yet understands why stars do this. This discovery however now shows that the Sun is not unique in this behavior.

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Astronomers directly image the orbital motion of Jupiter protoplanet 531 light years away

1:41 pm

AB Aurigae B's motion over thirteen years
Click for original image.

Astronomers, using a number of ground- and space-based telescopes, have now directly photographed the orbital motion of a Jupiter protoplanet orbiting a star 531 light years away over a thirteen year time span.

The image to the right, cropped to post here, shows images produced by two Hubble instruments. The caption:

Researchers were able to directly image newly forming exoplanet AB Aurigae b over a 13-year span using Hubble’s Space Telescope Imaging Spectrograph (STIS) and its Near Infrared Camera and Multi-Object Spectrograph (NICMOS). In the top right, Hubble’s NICMOS image captured in 2007 shows AB Aurigae b in a due south position compared to its host star, which is covered by the instrument’s coronagraph. The image captured in 2021 by STIS shows the protoplanet has moved in a counterclockwise motion over time.

From the paper’s abstract:

Using the Subaru Telescope and the Hubble Space Telescope, we find evidence for a Jovian protoplanet around AB Aurigae orbiting at a wide projected separation (~93 au), probably responsible for multiple planet-induced features in the disk. Its emission is reproducible as reprocessed radiation from an embedded protoplanet.

The accretion disk around AB Aurigae happens to lie face on to our line of sight, which facilitates these observations. The data also shows two additional potential proto-planets farther from the star.

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Astronomers think they have detected the most distant star ever

9:24 am

The most distant star ever detected?
Click for full image.

The uncertainty of science: Using the Hubble Space Telescope astronomers now think they have detected the most distant single star ever located, the light of which is estimated to have come from a time only less than a billion years after the Big Bang itself.

The star, nicknamed Earendel by astronomers, emitted its light within the universe’s first billion years. It’s a significant leap beyond Hubble’s previous distance record, in 2018, when it detected a star at around 4 billion years after the big bang. Hubble got a boost by looking through space warped by the mass of the huge galaxy cluster WHL0137-08, an effect called gravitational lensing. Earendel was aligned on or very near a ripple in the fabric of space created by the cluster’s mass, which magnified its light enough to be detected by Hubble.

The arrow in the image, cropped and reduced to post here, points to the theorized star. Note the arc that tiny dot lies along. This arc is the result of the gravitational lensing, and illustrates quite bluntly the large uncertainties of this discovery. We are not seeing the star itself, but the distorted light after it passed through the strong gravitational field of the cluster of galaxies. The scientists conclusion that this dot is thus a single star, must be view with great skepticism.

Nonetheless, the data is intriguing, and will certainly be one of the early targets of the James Webb Space Telescope, which could confirm or disprove this hypothesis.

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Sharpest radio image ever taken of newly discovered space object

9:11 am

The first known Odd Radio Circle (ORC)
Click for full image.

The uncertainty of science: Astronomers, using the MeerKat radio telescope in South Africa, have taken the best radio image yet of a newly discovered type of astronomical object, dubbed whimsically as an odd radio circle (ORC).

The photo to the right is that image. While it is reminiscent of the many planetary nebulae seen in visible light that astronomers have been studying since the 1800s, this weird shape is only seen in radio frequencies, and it is much much larger.

Odd radio circles are so named because they’re large, circular objects which are bright around the edges at radio wavelengths, but which can’t be seen with optical, infrared or X-ray telescopes – and at this stage, astronomers don’t really know what they are.

And they’re massive – about a million light years across, making them sixteen times larger than our own galaxy. But despite their gargantuan size, the objects are difficult to spot, hiding in plain sight.

Planetary nebulae are generally the size of solar systems.

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Alignment of segments in Webb’s primary mirror completed

3:06 pm

Alignment image
Click for full image.

Astronomers and engineers have now successfully completed the alignment of the eighteen segments in the primary mirror of the James Webb Space Telescope.

On March 11, the Webb team completed the stage of alignment known as “fine phasing.” At this key stage in the commissioning of Webb’s Optical Telescope Element, every optical parameter that has been checked and tested is performing at, or above, expectations. The team also found no critical issues and no measurable contamination or blockages to Webb’s optical path. The observatory is able to successfully gather light from distant objects and deliver it to its instruments without issue.

The picture to the right shows that alignment, focused on a single star. As noted in the caption:

While the purpose of this image was to focus on the bright star at the center for alignment evaluation, Webb’s optics and NIRCam are so sensitive that the galaxies and stars seen in the background show up.

After many years delay and an ungodly budget overrun, thank goodness Webb appears to be working better than expected.

It will still be several months before actual science observations begin. Further more precise alignment adjustments need to be done for all its instruments and mirrors.

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Supernova discovered in Cartwheel galaxy

8:54 am

Cartwheel Galaxy, before and after supernova
Click for full image.

Cool image time! In reviewing a December 2021 image of the Cartwheel Galaxy taken by the New Technology Telescope in Chile, astronomers noticed something that was not there in earlier images, a new supernovae.

The photo above, reduced to post here, compares a 2014 image, taken by the Very Large Telescope, with the 2021 photo. In the lower left of the new image is a bright object not in the previous photo.

This event, called SN2021afdx, is a type II supernova, which occurs when a massive star reaches the end of its evolution. Supernovae can cause a star to shine brighter than its entire host galaxy and can be visible to observers for months, or even years — a blink of an eye on astronomical timescales. Supernovae are one of the reasons astronomers say we are all made of stardust: they sprinkle the surrounding space with heavy elements forged by the progenitor star, which may end up being part of later generations of stars, the planets around them and life that may exist in those planets.

Cartwheel is about 500 million light years away, and because of its bright outer ring is one one of the more unusual nearby galaxies.

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Chandra’s camera remains in safe mode

12:12 pm

Though engineers have improvised a work-around that has allowed most of instruments on the Chandra X-Ray observatory to resume science operations, the power supply problem in the telescope’s high resolution camera (HRC) that occurred on February 9th remains unresolved, leaving that camera in safe mode.

The Chandra science instrument and engineering teams continue to analyze the cause of the HRC power supply issue, as well as potential approaches to enable the HRC again. The spacecraft is otherwise healthy and operating normally.

Chandra has been flying now for more than two decades, well past its original mission. For it to begin to have these problems is not surprising, though it will be a great tragedy if it fails just as the James Webb Space Telescope is about to go operational. Ideally astronomers want data from both, as well as Hubble, to cover a wide swath of the electromagnetic spectrum, from the optical to the infrared to X-rays.

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Have astronomers found an exoplanet with raining metal and gems?

9:33 am

The uncertainty of science: Using data from the Hubble Space Telescope, astronomers think they have detected on a hot Jupiter exoplanet 880 light years away the formation of clouds and rain made up metals and gems.

The exoplanet is tidally locked so that one side always faces its star, which also means the temperature difference between the two hemispheres is gigantic, 5,400 degrees Fahrenheit on the dayside and about 2,600 degrees on the nightside.

Previous Hubble data showed signs of metals including iron, magnesium, chromium and vanadium existing as gasses on the planet’s dayside. But in this study, the researchers have found that on the planet’s nightside, it gets cold enough for these metals to condense into clouds.

And, just as the strong winds pull water vapor and atoms around the planet to break apart and recombine, metal clouds will blow to the planet’s dayside and evaporate, condense back on the nightside and so on.

But metal clouds aren’t the only strange phenomenon these researchers spotted on this hot Jupiter. They also found evidence of possible rain in the form of liquid gems.

While tantalizing and alien, these results have many uncertainties. What the data suggests might not be the reality. To find out more, the astronomers hope to use the James Webb Space Telescope to do more infrared observations, once it becomes operational.

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Hugging galaxies

2:25 pm

Hugging galaxies
Click for full image.

Cool image time! The Hubble Space Telescope science team today released the photo to the right, cropped and reduced to post here, of the interaction of three galaxies, the larger two of which look like they are hugging each other.

This galaxy triplet is estimated to be about just under 700 million light years away. It was taken as part of a program aimed at producing high quality images of strange looking galaxies.

Using Hubble’s powerful Advanced Camera for Surveys, astronomers took a closer look at some of the more unusual galaxies that volunteers identified. The original Galaxy Zoo project was the largest galaxy census ever carried out and relied on crowdsourcing time from more than 100,000 volunteers to classify 900,000 unexamined galaxies. The project achieved what would have been years of work for a professional astronomer in only 175 days and has led to a steady stream of similar astronomical citizen science projects. Later Galaxy Zoo projects have included the largest ever studies of galaxy mergers and tidal dwarf galaxies, as well as the discovery of entirely new types of compact star-forming galaxies.

If you want to do some real science, you should definitely check out the Galaxy Zoo webpage. Anyone can join in, using images produced by the Victor Blanco 156 inch (4 meter) telescope in Chile to find cool stuff that needs closer examination using better telescopes like Hubble.

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Gehrels-Swift returns to science operations

2:13 pm

The Gehrels-Swift orbiting space telescope has returned to full science operations, after engineers determined the shut down on January 18th was caused by the failure of one reaction wheel and uploaded software allowing the telescope to function using only its remaining five gyroscopes.

In the last two decades satellite engineers have developed a range of software to allow spacecraft to point with acceptable accuracy using as few as two gyroscopes, even one in some circumstances. Thus, Gehrels-Swift has significant margin with five working reaction wheels.

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Chandra in safe mode

9:11 am

The Chandra X-ray Observatory last week experienced a loss of power that caused engineers to put the science instruments on the space telescope into safe mode while they investigate the problem.

No further information is presently available.

Chandra has been in orbit since 1999, and is now on an extended mission through 2025. It would be a great tragedy if it failed now, just as the infrared Webb telescope is about to begin operations. The two space telescopes are complementary.

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First image from IXPE

3:29 pm

Supernova remnant Cassiopeia A as seen by IXPE

NASA today released the first image produced from its new X-ray space telescope, the Imaging X-Ray Polarimetry Explorer (IXPE).

The photo to the right is that image, showing the intensity of X-rays coming from the supernovae remnant Cassiopeia A. From the caption:

Colors ranging from cool purple and blue to red and hot white correspond with the increasing brightness of the X-rays. The image was created using X-ray data collected by IXPE between Jan. 11-18.

Though Chandra also detects objects in X-rays, IXPE will also detect their polarization, or the way the rays are oriented as they travel through space.

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Astronomers form lobbying group to block development on Moon’s far side

9:14 am

Lunar zone reserved solely for astronomers
Lunar zone reserved exclusively for radio astronomers

In order to allow them to someday in the future maybe consider the idea of possibly building space-based radio telescopes on the Moon, astronomers have now formed a new lobbying group to advocate the creation of a zone more than a thousand miles wide on the Moon’s far side where all future development will be forbidden.

The new committee is chaired by Claudio Maccone, an Italian SETI (search for extraterrestrial intelligence) astronomer, space scientist and mathematician. Maccone supports creation of a Protected Antipode Circle or PAC, a large circular piece of lunar landscape about 1,130 miles (1,820 kilometers) wide that would become the most shielded area of the moon’s far side.

“PAC does not overlap with other areas of interest to human activity,” he said. “PAC is the only area of the far side that will never be reached by the radiation emitted by future space bases located at the L4 and L5 Lagrangian points of the Earth-moon system.”

In view of these unique features, Maccone believes the PAC should be officially recognized by the United Nations as an international protected area, where radio contamination by humans is curbed, now and into the future.

In other words, these astronomers want to be given, for free, full ownership of the region in the center circle on the graphic above for future radio telescopes, even though at present they have no plans or projects to build such things.

Though the idea of creating a region protected from radio signals so that good radio astronomy can be conducted has merit, no one should have the slightest sympathy for this request by astronomers. Why should anyone give them this vast amount of real estate when astronomers have shown so little interest in building any telescopes in space, anywhere?

Only after the astronomical community finally proposes an actual radio telescope for installation at this site should this request be given the slightest attention. Before that, it is merely a stupid power grab by elitists who deserve nothing from nobody.

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First image from Webb released

8:52 am

Webb's first released alignment image

It ain’t pretty, nor is it in optical wavelengths, but the first alignment image from the James Webb Space Telescope has been released by NASA.

That image, reduced slightly to post here, is to the right. It shows 18 different near-infrared images of the same star, each image taken by a different segment of Webb’s primary mirror. At the moment the mirrors are not perfectly aligned, so that each segment’s star image shows up at a slightly different place. The goal now will be to adjust those mirror segments so that future images will show only one star, all focused to the same spot.

This alignment process is expected to take about a month.

The image is significant however because it shows that each segment is producing a relatively sharp image, even though the telescope has not yet cooled to its operating temperature. It thus appears that, unlike Hubble, Webb’s mirror segments were ground correctly, and it will be able to take sharp images right off the bat.

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Earthlike exoplanet in habitable zone detected orbiting nearest star

9:21 am

The uncertainty of science: Astronomers think they have detected an Earthlike exoplanet, in habitable zone, orbiting Proxima Centauri, the nearest star to our solar system.

Astronomer João Faria and his collaborators detected Proxima Centauri d by measuring tiny shifts in the spectrum of the star’s light as the planet’s gravity pulled it during orbit. The team used a state-of-the art spectrograph called ESPRESSO at the Very Large Telescope, a system of four 8.2-metre telescopes at the European Southern Observatory in Cerro Paranal, Chile. The results were published on 10 February in Astronomy & Astrophysics.

This ‘wobble’ technique looks for changes in the star’s motion along the line of sight from Earth, and ESPRESSO can detect variations of just 10 centimeters per second. The total effect of the planet’s orbit, which lasts only five days, is about 40 cm/s, says Faria. “I knew that ESPRESSO could do this, but it was still surprised to see it showing up,” says Faria, who is at the Institute of Astrophysics and Space Sciences in Porto, Portugal.

Though the scientists are very confident about their results, the detection is at present only a candidate planet, as its existence has not been confirmed by an second independent method. Also, the method of detection cannot pin down the exoplanet’s mass very precisely, though it suggests the exoplanet has rocky planet mass, not too different than Earth’s.

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Have astronomers discovered an asteroid with three moons?

9:44 am

The uncertainty of science: According to a New York Times article published yesterday, astronomers have now discovered an asteroid with three moons, making it the first such asteroid ever discovered.

The asteroid, Electra, was first discovered in 1873, and orbits the Sun in the asteroid belt between Mars and Jupiter. It was already known that it had two moons. The new research thinks it has found a third.

In reading the researchers’ the actual paper describing this research, it appears that the Times is spinning the data, making it sound more certain than it is. This new result comes entirely from new software that was designed to better resolve archival images of the asteroid, and thus carries a lot of uncertainty. From the paper’s conclusion:

[There remain] a lot of uncertainties remain concerning the orbit of S3 [the new asteroid moon]. More data on S2 and S3, as well as a more thorough dynamical study are necessary to solve the problem of the motion of the satellites of Elektra. However, the discovery of the first quadruple asteroid system slightly opens the way for understanding the mechanisms of the formation of these satellites.

In terms of data processing, S3 is barely visible in the data reduced with the standard pipeline and processed with standard halo removal algorithms and it was missed until now.

The paper repeatedly notes that the orbital data for Electra and its moons is presently “poorly constrained” and needs significant refinement in order to confirm this result.

If true, however, these moons are probably pieces that broke off of Electra at some point in the past, and could provide good information about the long term history of asteroids in the asteroid belt.

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Astronomers organize lobbying group to block satellite constellations

10:13 am

The International Astronomical Union (IAU) has now created an office to lobby governments worldwide to block the coming commercial launch of numerous satellite constellations.

The IAU claims that the first goal of this new office will be to study the effects of these satellites on ground-based astronomy accompanied by an effort to work with industry to mitigate those effects.

That is a lie. This is the office’s real purpose:

Another role for the center will be to create national and international laws and norms for what regulators allow in orbit. “We need to codify these good intentions, to have some backup,” says Richard Green of the University of Arizona’s Steward Observatory. “We’ll take a two-pronged approach: Cooperate and develop legislation to apply if necessary.” IAU and other bodies are working to convince the United Nations’s Committee on the Peaceful Uses of Outer Space of the need for legislation. “We are confident that we will have guidelines that will have to be followed by companies in the near future,” Benvenuti says. Cosmologist Aparna Venkatesan of the University of San Francisco says it would be good if there were laws in the United States and elsewhere that echoed the influential U.S. Clean Air Act: “Many of us dream of a Clean Skies Act.”

Rather than realize that things are changing and Earth-based astronomy is becoming obsolete, the astronomers wish to use the force of law to block progress by others so that they can continue to live in the past.

The time to have moved all cutting edge astronomical research off the planet arrived more than three decades ago. The astronomers refused to recognize this, focusing instead on building giant telescopes on the ground that had less capability than the Hubble Space Telescope and were dogged by political and engineering challenges that hindered their success.

Had astronomers instead focused on building many small orbiting optical telescopes, the threat of satellite constellations now would be minimal. Instead, astronomers would be poised to build the bigger space-based telescopes they need. Instead, they are grounded, with the needed future space-based telescopes possibly decades away.

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Engineers determine failed gyroscope caused Gehrels-Swift shutdown

1:56 pm

Engineers have now determined that the failure of one of the six reaction wheels that point the orbiting Gehrels-Swift Observatory was the cause of its shutdown into safe mode on January 18th, and are now reconfiguring the space telescope to operate with only five gyroscopes.

The team is currently testing the settings for operating the spacecraft using the five operational reaction wheels. After the tests for these settings have been completed, they plan to upload them to the spacecraft next week.

Swift can fully carry out its science mission with five wheels. After careful analysis, the team has determined that the five-wheel configuration will minimally impact the movements necessary for Swift to make science observations. The team expects the change will slightly delay the spacecraft’s initial response time when responding to onboard gamma-ray burst triggers, but this will not impact Swift’s ability to make these observations and meet its original operational requirements.

Only after getting Gehrels-Swift operating again will the engineers then consider trying to recover the failed reaction wheel.

Gehrels-Swift was one of the key space telescopes that made it possible for astronomers to solve the mystery of gamma ray bursts. It is also used today to help identify the source of mysteries like fast radio bursts and other supernovae events. It was designed to quickly begin observing in multiple wavelengths any spot in the sky where a mystery burst or new supernova has occurred, thus getting astronomers the earliest new data possible.

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Webb mirror alignment begins with first photons detected by instrument

2:19 pm

With the detection by one instrument of the first photons traveling through all of the mirrors of the James Webb Telescope the alignment of its many mirror segments begins.

This week, the three-month process of aligning the telescope began – and over the last day, Webb team members saw the first photons of starlight that traveled through the entire telescope and were detected by the Near Infrared Camera (NIRCam) instrument. This milestone marks the first of many steps to capture images that are at first unfocused and use them to slowly fine-tune the telescope. This is the very beginning of the process, but so far the initial results match expectations and simulations.

The article at the link provides a very detailed description of the step-by-step process used by engineers to align the eighteen segments of the primary mirror.

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Astronomers confirm asteroid discovered in 2020 is an Earth Trojan

9:57 am

Astronomers have now confirmed that an asteroid discovered in 2020, dubbed 2020 XL5, is an orbit that makes it the second Earth Trojan asteroid discovered, orbiting the Sun in the same orbit as the Earth but 60 degrees ahead of us.

In December 2020, 2020 XL5 was spotted by astronomers with the Pan-STARRS 1 survey telescope in Hawaii and added to the International Astronomical Union’s Minor Planet Center database. Amateur astronomer Tony Dunn went on to calculate the object’s trajectory using NASA’s publicly-available JPL-Horizon’s software and found that it orbits L4, the fourth Earth-sun Lagrange point, a gravitationally balanced region around our planet and star. 2010 TK7, the first-confirmed Earth Trojan asteroid, is also at L4.

The confirmation that it is definitely a Trojan was then made using both new observations as well as a review of archival images, allowing the astronomers to not only refine the asteroid’s orbit, but determine that it is a C-type asteroid, dark with lots of carbon. The data also suggests that in about 4,000 years, 2020 XL5 will drift from its Trojan point.

There are certainly more such asteroids, but detecting them is difficult from Earth because they can only be seen in twilight.

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A galactic starship Enterprise

3:30 pm

A galactic starship Enterprise
Click for full image.

Cool image time! The image to the right, cropped and reduced to post here, was taken by cameras on the Hubble Space Telescope. From the caption:

The subject of this image is a group of three galaxies, collectively known as NGC 7764A. They were imaged by the NASA/ESA Hubble Space Telescope, using both its Advanced Camera for Surveys and Wide Field Camera 3. The two galaxies in the upper right of the image appear to be interacting with one another. The long trails of stars and gas extending from them give the impression that they have both just been struck at great speed, thrown into disarray by the bowling-ball-shaped galaxy to the lower left of the image. In reality, interactions between galaxies happen over very long time periods, and galaxies rarely collide head-on with one another. It is also unclear whether the galaxy to the lower left is interacting with the other two, although they are so relatively close in space that it seems possible that they are.

This galaxy group is estimated to be about 425 million light years away, though that number might be different for the galaxy in the lower left.

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Eta Carinae: The star that proved Hubble was fixed

1:02 pm

The Space Telescope Science Institute, which operates both the Hubble Space Telescope and the James Webb Space Telescope, today released a wonderful short video summarizing in images the decades of knowledge that Hubble has gleaned of the massive star Eta Carinae.

I have embedded that video below the fold. What makes Eta Carinae special is that when Hubble was pointed at it shortly after the first repair mission in 1993, that photo proved without a doubt that the telescope’s vision had been fixed. More important, the photo proved that Hubble was going to routinely show us things never before seen. In this case, we got our first sharp and unambiguous view of a massive star exploding.
» Read more

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Planetary scientists fight back: “Pluto is a planet!”

6:04 pm

A group of eminent and active planetary scientists have just published a new peer-reviewed paper documenting how moons and asteroids were routinely referred to as planets from Galileo until 2006 when a very small number of scientists at an International Astronomical Union (IAU) meeting decided arbitrarily that the definition must be changed.

That IAU definition, which required an object to have a solar orbit and the vague ability of the object to clear that orbit, somehow made Pluto a non-planet. It has also never been accepted by planetary scientists, who consider it inconsistent, vague, and useless in their research as well as in teaching students about planetary science. I know this attitude is real because of what planetary scientists have told me consistently in many interviews since 2006.

The new paper appears to be part of a new aggressive campaign by planetary scientists to get that IAU definition dumped, and replace it with the definition planetary scientists have been using forever, which is that if the object is large enough for gravity to shape it into a spherical shape, it is a planet. This is still the definition they routinely use when discussing large moons like the Moon or the large Galilean moons of Jupiter or the larger moons of Saturn or Pluto itself.

It also appears, based on information at the link, that this campaign is beginning to make headway. To that I say, Hallelajuh!

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Webb successfully inserted in final orbital position at the Sun-Earth Lagrange point

3:01 pm

The James Webb Space Telescope today successfully completed a five minute firing of its engines to place it at the Sun-Earth Lagrange point dubbed L2.

Webb’s orbit will allow it a wide view of the cosmos at any given moment, as well as the opportunity for its telescope optics and scientific instruments to get cold enough to function and perform optimal science. Webb has used as little propellant as possible for course corrections while it travels out to the realm of L2, to leave as much remaining propellant as possible for Webb’s ordinary operations over its lifetime: station-keeping (small adjustments to keep Webb in its desired orbit) and momentum unloading (to counteract the effects of solar radiation pressure on the huge sunshield).

Engineers will spend the next three months aligning the segments of Webb’s large primary and secondary mirrors, while they wait for the telescope to cool down to the ambient very cold temperatures required for it to detect the tiny infrared heat emissions from very faint very very very distant objects.

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Gehrels/Swift space telescope enters safe mode

3:57 pm

The Neil Gehrels Swift observatory ceased science observations and entered safe mode on January 18, 2021, when one of its six reaction wheels experienced a failure.

It appears the other five reaction wheels, which function as gyroscopes to point the telescope accurately, are working properly. If engineers can’t recover the lost wheel, the telescope will still be able to operate with no problems.

Swift was launch seventeen years ago in order to solve the mystery of gamma ray bursts, which it did most successful. The man who most made the observatory possible, its principal scientist, Neil Gehrels, passed away in 2017, and to honor his memory the telescope was then named after him.

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