Tag: astronomy

New calculations now say asteroid 2024 YR4 will almost certainly not hit the Earth in 2032

9:49 am

According to an announcement from NASA yesterday, the chances of asteroid 2024 YR4 hitting the Earth in 2032 is now reduced to 0.004%, meaning that it almost certainly not a threat at that time.

There remains a 1.7% chance it will instead impact the Moon in 2032.

These refined calculations were likely achieved by looking not at the asteroid itself (it is now too far away), but at places where it might have been visible to ground-based telescopes in the past, assuming it had an orbit that will hit the Earth in 2032. Since those past observations did not see it, those orbits are thus eliminated, and the threat goes down.

Of course, the uncertainty remains. It also remains important that we obtain more detailed information about this asteroid, because it is still a potential threat to the Earth.

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Hubble takes a close look at one tiny part of the Veil Nebula

12:47 pm

A small section of the Veil Nebula
Click for original image.

Cool image time! The picture to the right, reduced and sharpened to post here, was taken by the Hubble Space Telescope of just one very tiny section of the supernova remnant known as the Veil Nebula, located about 2,400 light years away.

The white dot on the inset (showing the entire Veil Nebula) marks the area covered by this closeup, focused on the one bright section of nebula in the Veil’s southwest quadrant. From the caption:

This nebula is the remnant of a star roughly 20 times as massive as the Sun that exploded about 10 000 years ago. … This view combines images taken in three different filters by Hubble’s Wide Field Camera 3 instrument, highlighting emission from hydrogen, sulphur and oxygen atoms. This image shows just a small fraction of the Veil Nebula; if you could see the entire nebula without the aid of a telescope, it would be as wide as six full Moons placed side by side.

Astronomers have been using Hubble to take periodic pictures of the Veil Nebular since 1994 in order to track changes as these gaseous gossamer strands evolve over time.

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New observations reduce odds of asteroid 2024 YR4’s 2032 Earth impact to practically zero

9:26 am

The uncertainty of science: According to a short update from NASA late yesterday, new ground-based observations have now reduced the odds that asteroid 2024 YR4’s will hit the Earth in 2032 to only 0.28 percent.

Observations made overnight on Feb. 19 – 20 of asteroid 2024 YR4 have further decreased its chance of Earth impact on Dec. 22, 2032, to 0.28%. NASA’s planetary defense teams will continue to monitor the asteroid to improve our predictions of the asteroid’s trajectory. With this new data, the chance of an impact with the Moon increased slightly to 1%.

Expect these numbers to change again in March, when the Webb telescope tracks the asteroid. And do not assume Webb will confirm these numbers. There remains great uncertainty in all these calculations, especially because there is great uncertainty about the size, mass, and make-up of 2024 YR4. It could be anywhere from 130 feet to 320 feet in diameter, and that difference makes these calculations uncertain.

In other words, it remains essential that work should begin on putting together a mission to visit and study this asteroid, now. Though it isn’t large enough to cause a worldwide extinction, it is big enough to do very significant damage, depending on where it hits.

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The uncertainty of science: Astronomers keep changing the odds of asteroid 2024 YR4 hitting the Earth in 2032

8:53 am

In the past three days three different reports from both NASA and the European Space Agency have given three different percentages for the chances that asteroid 2024 YR4 will hit the Earth in 2032.

On Tuesday, NASA calculated that the space rock had a 3.1% chance of hitting Earth in 2032, while the European Space Agency’s risk assessment sits at 2.8%.

The narrow difference is due to the two agencies’ use of different tools for determining the asteroid’s orbit and modeling its potential impact. But both percentages rise above the 2.7% chance of collision once associated with an asteroid discovered in 2004 called Apophis, making 2024 YR4 the most significant space rock to be spotted within the past two decades.

However, another update shared by NASA on Wednesday showed that 2024 YR4 has a 1.5% chance of colliding with Earth in December 2032, based on new observations now that the full moon has passed. Astronomers have anticipated that such fluctuations are possible as they gather more observational data.

While the media has generally focused mostly on the higher numbers in their knee-jerk “We’re all gonna die” approach to everything, all these different numbers simply illustrate is the generally limited nature of our data about the asteroid’s orbit and its future path. For example because such asteroids are so small, it isn’t just gravity that influences their flight path through the solar system. The Sun’s light pressure can actually have an impact, but to determine how much you need to know the exact size, shape, and rotation of the object. Right now 2024 YR4’s size is estimated to range from 130 to 320 feet in width, determining this effect is presently impossible. Nor is this the only such variable.

At the same time, the data continues to suggest that the chances of this asteroid hitting the Earth are not trivial. The sooner we can find out everything about it the better. Getting a mission to it quickly would be the best way, but so far I have heard little from NASA or anyone about such an idea.

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New data from Webb shows the Milky Way’s central supermassive black hole flares multiple times per day

9:47 am

The magnetic field lines surrounding Sagittarius A*
The magnetic field lines surrounding Sagittarius A*,
published in March 2024. Click for original image.

Though past research had shown that the Milky Way’s central supermassive black hole, dubbed Sagittarius A* (pronounced A-star) is generally quiet and inactive, new data from the Webb Space Telescope gathered over a year’s time now shows that it flares multiple times per day.

Throughout the year, the team saw how the black hole’s accretion disk emitted 5 to 6 large flares per day, of varying lengths and brightnesses, plus smaller flares in between. “[Sagittarius A*] is always bubbling with activity and never seems to reach a steady state,” Yusef-Zadeh says. “We observed the black hole multiple times throughout 2023 and 2024, and we noticed changes in every observation. We saw something different each time, which is really remarkable. Nothing ever stayed the same.”

In their paper published in The Astrophysical Journal Letters, the team outlines two possible ideas for the processes driving these flares. The faint flickers may be caused by turbulent fluctuations in the accretion disk, which could compress plasma and trigger a burst of radiation. “It’s similar to how the sun’s magnetic field gathers together, compresses and then erupts a solar flare,” Yusef-Zadeh says. “Of course, the processes are more dramatic because the environment around a black hole is much more energetic and much more extreme.”

The larger and brighter flares, on the other hand, may be caused by two fast-moving magnetic fields colliding and releasing accelerated particles. These magnetic reconnection events also have a solar parallel.

You can read their paper here [pdf]. Though this research shows unexpected activity, that activity is still relatively mild compared to other central supermassive black holes in many other galaxies. Why this difference exists remains an unanswered question.

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A rose in space

10:02 am

A rose in space
Click for original image.

Cool image time! Using the Gemini South telescope in Chile, astronomers have taken a very beautiful picture, cropped, reduced, and sharpened to post here, of a nebula dubbed LH 88 that surrounds a star cluster and is located 160,000 light years away in the Large Magellanic Cloud.

The bright stars seen in the image are widely separated, but their motions through space are similar, indicating that they have a common origin. The layered nebulous structures in LH 88 are the remnants of stars that have already died. The delicate leaves of the rose were formed by both the shockwaves from supernovae and the stellar winds of the O and B stars.

The intense radiation of these super giant O and B stars — that burn fast and explode as supernova after only a few million years of life — not only shapes the nebula, it lights the nebula’s different atoms and molecules in different colors, with red/orange representing hydrogen and blue oxygen. The white areas indicate a mixture of both.

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Astronomers demand more regulations to prevent industry from ruining the Moon’s “environment”

9:33 am

According to two articles yesterday in the British press (here and here), both quoting extensively one astronomer, if strong regulation and control (given to them of course) isn’t imposed immediately, the space tourism of billionaires is going to ruin the Moon’s pristine environment, which on its far side is especially perfect for radio astronomy. From the first link:

“There’s a rush of companies and states who might want to get in on the act on the moon,” said [astronomer Martin Elvis, who added that there were also other concerns. “There’s a desire there from the billionaire class, ‘Oh I would love to spend a week on the moon’. And you don’t need many billionaires to start adding up. If they go without coordination, then it’s a mess. We could well lose these unique opportunities to do science on a scale that we couldn’t possibly imagine.”

One of the most exciting possibilities is the use of the far side of the moon for radio astronomy. As all signals from the Earth are blocked, telescopes would, Elvis said, have the sensitivity to see into the so called “dark age” of the universe, after the big bang but before stars had formed.

Elvis is based at Harvard and also co-chairs a working group at the International Astronomical Union (IAU) that wants astronomers to be given full legal control of the Moon, preventing anyone from building anything without their permission so they can instead build their telescopes there instead.

The problem is that the astronomical community has so far shown little interest in building telescopes in space. It has instead focused on building giant Earth-based telescopes while trying to get governments to restrict the launch of satellite constellations that might interfere with those telescopes. Now it wishes to restrict lunar development as well.

Elvis however admits “It’s a sort of first come, first served situation, which encourages people to rush in and do things without thinking too hard.” Let me translate: Everyone else is beating us to the Moon because we haven’t been interested in going, so now that we might be interested we want governments to shut down our competition.

It is long past time for astronomers and the IAU to stop trying to use government to squelch everyone else and get in the game. Initiate the building of telescopes both in space and the Moon. Not only are these better places to build telescopes than on Earth, it will give astronomers some credibility when they ask others to give them their own space.

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European underwater neutrino telescope detects most powerful neutrino ever

8:53 am

A European underwater neutrino telescope that is still under construction recorded evidence in February 2023 of most powerful neutrino particle ever detected.

KM3NeT’s two neutrino detectors — one off the coast of Sicily, the other near southern France — are still under construction but already collecting data. Both contain cables hundreds of meters tall, which are strung with bundles of light sensors anchored to the seafloor.

When cosmic neutrinos interact with matter in or near a KM3NeT detector, they spawn charged particles such as muons. As those muons careen through water, they give off feeble flashes of bluish light that KM3NeT’s sensors can pick up. Clocking when different sensors spot this light can reveal a particle’s path; the brightness of the blue hue reflects the particle’s energy.

On February 13, 2023, the detector near Sicily was run through by an extremely energetic muon traveling nearly parallel to the horizon. At the time, only 21 of the planned 230 sensor cables were in place. Based on the muon’s energy and trajectory, KM3NeT scientists determined it must have been spawned by a neutrino from space rather than a particle from the atmosphere.

Simulations suggest the neutrino’s energy was around 220 petaelectron volts. The previous record holder boasted around 10 petaelectron volts.

Tracking that trajectory backwards, astronomers say the particle came from a region of space where there are a lot of active galaxies, any one of which could be the source of the neutrino. It is also possible the neutrino came instead from an interaction of high energy cosmic rays and the photons from the faint microwave background left over from the Big Bang.

As noted very correctly by one scientist, “At this point, it’s very difficult to make conclusions about the origins,” says Kohta Murase, a theoretical physicist at Penn State not involved in the research. “It’s dangerous to rely on one event.”

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Astronomers catalog large ring systems surrounding 74 stars

11:32 am

74 rings surrounding stars
Click for original image.

Using a variety of ground-based telescopes in many wavelengths, astronomers have now produced a detailed catalog of 74 stars with large dust rings similar to the Oort cloud that is believed to exist at the very outer fringes of our own solar system.

The image to the right, reduced to post here, shows all 74 stars.

The new gallery shows a remarkable diversity of structure in the belts. Some are narrow rings, while others are wider and could be categorized more as “disks” than “belts”. Moreover, some of the 74 exocomet systems have multiple rings or disks and some of those are “eccentric,” meaning not a circular orbit but more like an oval. This provides evidence that yet undetectable planets or perhaps moons are present and their gravity affects the distribution of pebbles in these systems.

You can read the paper here [pdf].

The press release implies the discovery of “exocomets” but that is not true. The belts and rings mapped are likely to have comets in them, but no such comets have been found.

The scientists say that this database can be used to better understand the formation of solar systems, though they also admit that the “limited (although much improved) size of our sample” makes any conclusions based on it very uncertain. They hope however that over time that sample size will grow.

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Astronomers find galaxy with nine rings

11:15 am

The Bullseye Galaxy
Click for original image.

Using both the Hubble Space Telescope as well as the Keck telescope in Hawaii, astronomers have discovered a galaxy with nine rings, something never seen before.

The gargantuan galaxy LEDA 1313424 is rippling with nine star-filled rings after an “arrow” — a far smaller blue dwarf galaxy — shot through its heart. Astronomers using Hubble identified eight visible rings, more than previously detected by any telescope in any galaxy, and confirmed a ninth using data from the W. M. Keck Observatory in Hawaii. Previous observations of other galaxies show a maximum of two or three rings.

More information from Keck can be found here.

Keck Observatory and Hubble’s follow-up observations helped the researchers prove which galaxy plunged through the center of the Bullseye — a blue dwarf galaxy to its center-left. This relatively tiny interloper traveled like a dart through the core of the Bullseye about 50 million years ago, leaving rings in its wake like ripples in a pond. A thin trail of gas now links the pair, though they are currently separated by 130,000 light-years.

The Hubble picture is to the right, cropped, reduced, and sharpened to post here. The small blue dwarf galaxy to the left is believed to be the galaxy that plowed through LEDA 1313424 to create the rings. LEDA is itself thought to be two and a half times the size of the Milky Way, making one of the larger known galaxies.

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200-foot-wide asteroid has a 1-in-83 chance of hitting the Earth in 2032

10:12 am

New data that has refined the solar orbit of 200-foot-wide asteroid discovered in 2024, dubbed 2024 YR4, suggests it has a 1-in-83 chance of hitting the Earth on December 22, 2032.

“Odds have slightly increased to 1 in 83,” Catalina Sky Survey engineer and asteroid hunter David Rankin wrote on BlueSky. “This is one of the highest probabilities of an impact from a significantly sized rock ever.”

Amateur astronomer Tony Dunn shared a simulation of the asteroid approach on his X feed. “Recently-discovered #asteroid 2024 YR4 may make a very close approach to Earth in 8 years. It is thought to be 40-100 meters wide. Uncertainty is still high and more and more observations are needed confirm this.”

The asteroid is rated three on the Torino risk scale, which indicates a close encounter that warrants close attention from astronomers and an over 1% chance of impact.

Though most reports say the asteroid is about 200 feet across, there is great uncertainty in that number. It could also be as large as 320 feet, or as small as 130 feet.

At the moment the risk of impact is still small. If it does occur, there is a chance it could either cause a major airburst similar to the Chelyabinsk meteor impact in 2013 that injured more than 400 people, or even impact the ground or ocean. If it hits the ocean there is a considerable risk of tsunamis. At the moment it appears its path will cross from South America to Africa in the southern hemisphere, but this data remains very uncertain at this time.

Though there will be doom-sayers, overall this is not a world destroyer. It carries some risk, but we have eight years to refine our knowledge significantly, especially when it will make a close approach of five million miles in 2028. At that time scientists should be able to better measure its size as well as its future orbit, determining more precisely whether it will even hit the Earth in 2032.

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Fast radio burst unexpectedly traced to dead and old elliptical galaxy

10:12 am

Location of Fast Radio Burst
Figure 4 from this paper [pdf].

The uncertainty of science: Using several radio telescopes working in tandem, astronomers have been able to identify the source galaxy of a fast radio burst (FRB) that repeatedly erupted throughout 2024, and discovered it came from a dead and old elliptical galaxy, not a younger galaxy as predicted.

[W]hile most FRBs originate well within their galaxies, the team traced FRB 20240209A to the outskirts of its home — 130,000 lightyears from the galaxy’s center where few other stars exist. “Among the FRB population, this FRB is located the furthest from the center of its host galaxy,” said Vishwangi Shah, a graduate student at McGill, who led the effort to pinpoint the FRB’s origins. “This is both surprising and exciting, as FRBs are expected to originate inside galaxies, often in star-forming regions. The location of this FRB so far outside its host galaxy raises questions as to how such energetic events can occur in regions where no new stars are forming.”

The small ellipse to the upper left of the giant elliptical galaxy (in yellow) marks the location of the FRB relative to its galaxy. Why it is so far outside remains a puzzle. The scientists consider two options: First, that the magnetar was once inside the galaxy but was kicked out at some point, and second, it simply could be inside a globular cluster that is too small to detect at this distance, two billion light years away.

Both explanations have problems and really don’t work.

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Hubble’s biggest image yet, of Andromeda

12:14 pm

Andromedia as seen by Hubble
Click for original image.

The image above, cropped and reduced to post here, was taken by the Hubble Space Telescope and shows the Andromeda galaxy, the Milky Way’s nearest spiral galaxy neighbor. The picture however is not one photo, but hundreds taken over the past decade.

This is largest photomosaic ever assembled from Hubble Space Telescope observations. It is a panoramic view of the neighboring Andromeda galaxy, located 2.5 million light-years away. It took over 10 years to make this vast and colorful portrait of the galaxy, requiring over 600 Hubble overlapping snapshots that were challenging to stitch together. The galaxy is so close to us, that in angular size it is six times the apparent diameter of the full Moon, and can be seen with the unaided eye.

Andromeda is not just visible to the naked eye, it is one of the largest objects seen in the sky. If you ever can get to a really dark sky location when it is above and have someone point it out to you (it remains faint), you will be astonished to find that it stretches across the sky the length of about six to eight full moons.

Thus, Hubble literally can’t take a picture of it. Its field of view is much too small. It must take many pictures to assemble a mosaic.

The picture above also hides the data contained in all those images. At the full resolution of each individual picture, Hubble has literally mapped the entire galaxy. Combined with other spectroscopic survey data taken by Hubble, astronomers over time will be able to decipher the galaxy’s makeup to better understand its formation history.

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Hubble captures a nice example of intergalactic microlensing

9:56 am

Micro-lensing at is most distinct
Click for original image.

Cool image time! The picture to the right, cropped to post here, was taken by the Hubble Space Telescope and released this week. I have specifically cropped it to focus on this ringlike feature, as it one of the nicest examples of micro-lensing I have seen. From the caption:

This curious configuration is the result of gravitational lensing, in which the light from a distant object is warped and magnified by the gravity of a massive foreground object, like a galaxy or a cluster of galaxies. Einstein predicted the curving of spacetime by matter in his general theory of relativity, and galaxies seemingly stretched into rings like the one in this image are called Einstein rings.

The lensed galaxy, whose image we see as the ring, lies incredibly far away from Earth: we are seeing it as it was when the Universe was just 2.5 billion years old. The galaxy acting as the gravitational lens itself is likely much closer. A nearly perfect alignment of the two galaxies is necessary to give us this rare kind of glimpse into galactic life in the early days of the Universe.

I am generally a very big skeptic of most astronomical studies that rely on micro-lensing. I don’t deny it happens and has been detected, as in this case. The uncertainties — such as the unknown distance to intervening galaxy that is causing the lensing — always require too many assumptions that make any reliable conclusions difficult.

Nonetheless, this object illustrates the phenomenon perfectly. The light from the distant galaxy is bent around the intervening nearer galaxy so that we that distant galaxy as a ring.

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A fading supernova 650 million light years away

10:18 am

A fading supernova 650 million light years away
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 in March 2024, and shows the fading blue light of a supernova that was first discovered by another survey telescope six weeks earlier. The galaxy, dubbed LEDA 22057, is estimated to be about 650 million light years away.

The supernova is the bright spot in the galaxy’s southeast quadrant near the edge of the galaxy’s bright body. From today’s caption release:

SN 2024PI is classified as a Type Ia supernova. This type of supernova requires a remarkable object called a white dwarf, the crystallised core of a star with a mass less than about eight times the mass of the Sun. When a star of this size uses up the supply of hydrogen in its core, it balloons into a red giant, becoming cool, puffy and luminous. Over time, pulsations and stellar winds cause the star to shed its outer layers, leaving behind a white dwarf and a colourful planetary nebula. White dwarfs can have surface temperatures higher than 100,000 degrees and are extremely dense, packing roughly the mass of the Sun into a sphere the size of Earth.

While nearly all of the stars in the Milky Way will one day evolve into white dwarfs — this is the fate that awaits the Sun some five billion years in the future — not all of them will explode as Type Ia supernovae. For that to happen, the white dwarf must be a member of a binary star system. When a white dwarf syphons material from a stellar partner, the white dwarf can become too massive to support itself. The resulting burst of runaway nuclear fusion destroys the white dwarf in a supernova explosion that can be seen many galaxies away.

The rate in which this supernova fades will help astronomers untangle the processes that cause these gigantic explosions. Though the caption makes it sound as if we know how this happens, we really don’t. There are a lot of assumptions and guesses involved in the description above, based on the limited knowledge astronomers have gathered over the past few centuries looking at many supernovae many millions of light years away.

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Astronomers discover 1st binary star system orbiting Milky Way’s central supermassive black hole

9:40 am

The stars orbiting Sag A*
The stars orbiting Sag A*. Click for original image.

Using infrared spectroscopic data gathered from 2005 to 2019 by the Very Large Telescope in Chile, astronomers have identified the first known binary star system to orbit Sagittarius A* (pronounced “A-star”), the Milky Way’s central supermassive black hole.

You can read their science paper here [pdf]. The white dot at the center of the map to the right marks the location of Sagittarius A*, while the red dot marks the present location of the binary star, dubbed D9. The other objects are the stars previously identified orbiting the central black hole, all of which are now believed to be single stars. The binary D9 has an estimated orbit around Sagittarius A* of 432 years and is thought to be less than three million years old. The two stars have approximate masses of 3.86 and 2.8 solar masses, with the smaller orbiting the larger every 372 days.

There is a lot of uncertainty in these numbers, but the data identifying the binary is quite firm. This discovery, as well as the many other stars now known to orbit Sagittarius A*, show that star formation so close to a supermassive black hole is not only possible, it is common, something astronomers a decade ago thought impossible.

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A galactic eye in heaven

12:30 pm

A galactic eye in space
Click for original image.

Cool image time! The picture to the right, reduced and sharpened to post here, was taken by the Hubble Space Telescope as part of a project to study the star formation processes over time in this galaxy, located about 76 million light years away.

A prominent bar of stars stretches across the centre of this galaxy, and spiral arms emerge from each end of the bar. Because NGC 2566 appears tilted from our perspective, its disc takes on an almond shape, giving the galaxy the appearance of a cosmic eye.

As NGC 2566 gazes at us, astronomers gaze right back, using Hubble to survey the galaxy’s star clusters and star-forming regions. The Hubble data are especially valuable for studying stars that are just a few million years old; these stars are bright at the ultraviolet and visible wavelengths to which Hubble is sensitive. Using these data, researchers will measure the ages of NGC 2566’s stars, helping to piece together the timeline of the galaxy’s star formation and the exchange of gas between star-forming clouds and stars themselves.

To get the full picture, astronomers have also obtained infrared data from the Webb Space Telescope and millimeter/submillimeter radio wavelength data from the ALMA telescope.

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Reanalysis of Webb data discovers more than a hundred very small main-belt asteroids

11:42 am

Portrait of all 138 new asteroids
Click for original image.

Using data from the Webb Space Telescope in an unexpected way, astronomers have discovered 138 asteroids in the main asteroid belt, most of which are the smallest so far detected.

The picture to the right shows all 138 asteroids. The researchers had originally used Webb to study the atmospheres of the exoplanets that orbit the star TRAPPIST-1. They then thought, why not see if their data also showed the existence of asteroids in our own solar system. By blinking between multiple images they might spot the movement of solar system objects moving across the field of view. From the press release:

The team applied this approach to more than 10 000 [Webb] images of the TRAPPIST-1 field, which were originally obtained to search for signs of atmospheres around the system’s inner planets. By chance TRAPPIST-1 is located right on the ecliptic, the plane of the solar system where all planets and most asteroids lie and orbit around the Sun. After processing the images, the researchers were able to spot eight known asteroids in the main belt. They then looked further and discovered 138 new asteroids, all within tens of meters in diameter — the smallest main belt asteroids detected to date. They suspect a few asteroids are on their way to becoming near-Earth objects, while one is likely a Trojan — an asteroid that trails Jupiter.

The data is insufficient for most of these objects to chart their orbits precisely. Based on this one single study, however, it suggests that pointing Webb along the ecliptic in almost any direction will detect more such objects. Do this enough and astronomers might actually be able to get a rough census of the asteroid belt’s population.

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NSF punts on its two big telescope projects

10:50 am

Because it presently does not have sufficient funds to build both the Giant Magellan Telescope (GMT) in Chile and the Thirty Meter Telescope (TMT) in Hawaii, the National Science Foundation (NSF) asked an independent panel to look at both projects and give recommendations on which project it should go with.

That report [pdf] has now been released, and its conclusions essentially take the advice of former Yankee catcher Yogi Berra, “When you come to a fork in the road, take it.” From the report’s executive summary:

Both GMT and TMT have strong leadership, partnership and financial commitments but require $1.6 billion in NSF funding to proceed. Without this support, significant delays or project cancellations may result. The panel emphasized the critical need for congressional support, noting that without additional appropriations, NSF may face challenges balancing these projects with other national priorities, risking U.S. competitiveness in fundamental research. [emphasis mine]

If you dig into the report however you find that TMT is a far more uncertain project. GMT is already being built, while TMT is stalled because it has been unable to get political approval to build in Hawaii on Mauna Kea, even though it initially wanted to start construction almost a decade ago.

Clearly, this report was created simply as a lobbying ploy by the NSF to Congress. NSF didn’t want the report to make a choice. It wanted it to endorse both telescopes so that — rather than bite the bullet and fund one telescope with the money it has already been given by Congress — NSF could use the report to demand more funding so that it can fund both.

Though Congress is now controlled by more fiscally-minded Republicans, don’t expect them to be anymore responsible on this issue than Democrats. These guys really don’t understand basic economics, and think they have a blank check for anything they wish to do. I anticipate Congress will give NSF the extra cash for both telescopes.

The problems for TMT remain, however, and even with that cash it remains very doubtful the telescope will be built. But gee, that won’t be a problem for NSF. Who wouldn’t like getting an extra billion or two to spend as one wishes?

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Hubble takes a different look at quasar 3C 273

10:25 am

Hubble's different views of 3C 273
Click for original image.

One of the most studied objects in the sky is the quasar 3C 273, located about 2.5 billion light years away and the first quasar ever to be identified, in 1963. What makes it especially interesting is the 300,000-light-year-long jet that shoots out from it.

Astronomers have now used the Hubble Space Telescope to take a different view of 3C 273, using the telescope’s coronograph to block the central bright light so that the surrounding dimmer features can be seen. The two images to the right, reduced and sharpened to post here, show what this new image (bottom) reveals when compared to an earlier Hubble image (top).

The new Hubble views of the environment around the quasar show a lot of “weird things,” according to Bin Ren of the Côte d’Azur Observatory and Université Côte d’Azur in Nice, France. “We’ve got a few blobs of different sizes, and a mysterious L-shaped filamentary structure. This is all within 16,000 light-years of the black hole.”

Some of the objects could be small satellite galaxies falling into the black hole, and so they could offer the materials that will accrete onto the central supermassive black hole, powering the bright lighthouse.

What makes this observation even more outstanding is that the image was produced by using Hubble’s Space Telescope Imaging Spectrograph (STIS) as the coronograph to block the bright center of 3C 273. This improvisation of STIS has been done many times before, but it remains a great example of clever thinking by the astronomers who use Hubble.

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The uncertainty of science: Star refuses to erupt when predicted

9:48 am

Based on records of two past eruptions approximately eighty years apart, astronomers had predicted that the binary star system T Coronae Borealis would erupt sometime in September 2024, brightening from magnitude 10 to as much as magnitude 2, making it one of the sky’s brighter stars for a short while.

That eruption however has so far not taken place.

“We know it has to happen,” astrophysicist Elizabeth Hays, who is watching T CrB every day using NASA’s Fermi gamma-ray space telescope, told Space.com in a recent interview. “We just can’t pin it down to the month.”

The unpredictability stems partly from limited historical records of T CrB’s outbursts. Only two such eruptions have been definitively observed in recent history: on May 12, 1866, when a star’s outburst briefly outshined all the stars in its constellation, reaching magnitude 2.0, and again on February 9, 1946, when it peaked at magnitude 3.0. These events appear to follow the star’s roughly 80-year cycle, suggesting that the next outburst may not occur until 2026. [emphasis mine]

The eruptions are thought to occur because the system’s denser white dwarf star pulls material from the lighter orbiting red giant. Over time that material accumulates on the surface of the white dwarf until it reaches critical mass, triggering a nuclear explosion that we see as the star’s brightening.

Astronomers have assumed this process is predictable, but in truth it really is not. For example, the star has brightened at other times, in 1938 and again in 2015, though not as much. These other brightenings suggest a great deal of uncertainty in the rate in which material accumulates, as well as how much is needed to trigger a nuclear burst.

Because of the possibility however of a burst at any time, astronomers have been poised eagerly now for months, observing the star regularly with the many orbiting telescopes that can observe it not only in optical wavelengths but in gamma, X-rays, and infrared. The latter capabilities didn’t exist in previous eruptions, and are now able to tell them things about the system that was impossible for earlier astronomers.

Assuming the eruption occurs at all. Despite the certainty of the astronomer’s quote highlighted above, there is no certainty here. This star system will do whatever it wants, despite the predictions of mere human beings.

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New stars shaped by old stars

8:50 am

New stars shaped by old stars
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 as part of a study focused on looking at star formation in nearby galaxies. From the caption:

Evidence of star formation is scattered all around NGC 1637, if you know where to look. The galaxy’s spiral arms are dotted with what appear to be pink clouds, many of which are accompanied by bright blue stars. The pinkish colour comes from hydrogen atoms that have been excited by ultraviolet light from young, massive stars. This contrasts with the warm yellow glow of the galaxy’s centre, which is home to a densely packed collection of older, redder stars.

The stars that set their birthplaces aglow are comparatively short-lived, and many of these stars will explode as supernovae just a few million years after they’re born. In 1999, NGC 1637 played host to a supernova, pithily named SN 1999EM, that was lauded as the brightest supernova seen that year. When a massive star expires as a supernova, the explosion outshines its entire home galaxy for a short time. While a supernova marks the end of a star’s life, it can also jump start the formation of new stars by compressing nearby clouds of gas, beginning the stellar lifecycle anew.

This galaxy is one worth keeping an eye on for supernovae, since every one of those blue stars has the potential of erupting.

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Hubble vs Webb, or why the universe’s secrets can only be uncovered by looking at things in many wavelengths

11:15 am

Hubble view of Sombrero galaxy
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Time for two cool images of the same galaxy! The picture above shows the Sombrero Galaxy as taken by the Hubble Space Telescope in 2003. The picture below is that same galaxy as seen by the Webb Space Telescope in the mid-infrared using false colors. From the press release:

In Webb’s mid-infrared view of the Sombrero galaxy, also known as Messier 104 (M104), the signature, glowing core seen in visible-light images does not shine, and instead a smooth inner disk is revealed. The sharp resolution of Webb’s MIRI (Mid-Infrared Instrument) also brings into focus details of the galaxy’s outer ring, providing insights into how the dust, an essential building block for astronomical objects in the universe, is distributed. The galaxy’s outer ring, which appeared smooth like a blanket in imaging from NASA’s retired Spitzer Space Telescope, shows intricate clumps in the infrared for the first time.

Researchers say the clumpy nature of the dust, where MIRI detects carbon-containing molecules called polycyclic aromatic hydrocarbons, can indicate the presence of young star-forming regions. However, unlike some galaxies studied with Webb … the Sombrero galaxy is not a particular hotbed of star formation. The rings of the Sombrero galaxy produce less than one solar mass of stars per year, in comparison to the Milky Way’s roughly two solar masses a year. Even the supermassive black hole, also known as an active galactic nucleus, at the center of the Sombrero galaxy is rather docile, even at a hefty 9-billion-solar masses. It’s classified as a low luminosity active galactic nucleus, slowly snacking on infalling material from the galaxy, while sending off a bright, relatively small, jet.

In infrared the galaxy’s middle bulge of stars practically vanishes, exposing the weak star-forming regions along galaxy’s disk.

Both images illustrate the challenge the universe presents us in understanding it. Basic facts are often and in fact almost always not evident to the naked eye. We always need to look deeper, in ways that at first do not seem obvious. This is why it is always dangerous to theorize with certainty any explanation too soon, as later data will always change that explanation. You can come up with an hypothesis, but you should always add the caveat that you really don’t know.

By the way, this concept applies not just to science. Having absolute certainty in anything will almost always cause you to look like a fool later. Better to always question yourself, because that will make it easier for you to find a better answer, sooner.

We need only look at the idiotic “mainstream press” during the months leading up to the November election to have an example of someone with certainty who is now exposed as an obvious fool.

The Sombrero Galaxy as seen by Webb
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A new geologic map of one of the Moon’s largest impact basins

10:00 am

Orientale Basin on the Moon
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Using data from Lunar Reconnaissance Orbiter (LRO), scientists have now produced a high resolution geological map of Orientale Basin, one of the largest impact basins on the Moon — at about 600 miles across — and located just on the edge of the Moon’s visible near side.

That map is to the right, reduced and sharpened to post here. You can read the paper here [pdf]. From the press release:

Planetary Science Institute Research Scientist Kirby Runyon is a lead author on a paper published in the Planetary Science Journal containing a new high-resolution geologic map of Orientale basin that attempts to identify original basin impact melt. The hope is that future researchers use this map to target sample return missions and pin down impact dates for this and other impact basins.

“We chose to map Oriental basin because it’s simultaneously old and young,” Runyon said. “We think it’s about 3.8 billion years old, which is young enough to still have its impact melt freshly exposed at the surface, yet old enough to have accumulated large impact craters on top of it as well, complicating the picture. We chose to map Orientale to test melt-identification strategies for older, more degraded impact basins whose ages we’d like to know.”

The map’s prime purpose is to pin down locations where material from the actual impact exist and can be returned to Earth for precise dating, thus helping to create a more accurate timeline of the Moon’s formation as well as the entire solar system’s accretion rate.

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A spiral galaxy as seen from the side

9:36 am

A spiral galaxy seen from the side
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Cool image time! The picture to the right, reduced to post here, was taken by the Hubble Space Telescope of what is believed to be a spiral galaxy seen edge-on. The galaxy itself is estimated to be 150 million light years away, and this view highlights two major features, the dust lanes that run along the galaxy’s length and its distinct central nucleus, bulging out from the galaxy’s flat plain.

The way this image was produced however is intriguing on its own:

Like most of the full-colour Hubble images released by ESA/Hubble, this image is a composite, made up of several individual snapshots taken by Hubble at different times and capturing different wavelengths of light. … A notable aspect of this image is that the two sets of Hubble data used were collected 23 years apart, in 2000 and 2023! Hubble’s longevity doesn’t just afford us the ability to produce new and better images of old targets; it also provides a long-term archive of data which only becomes more and more useful to astronomers.

All told, four Hubble data sets were used to produce the picture.

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Astronomers call for the FCC to halt all launches of satellite constellations

9:50 am

In a letter [pdf] sent to the FCC on October 24, more than one hundred astronomers demanded a complete halt of all launches of low-Earth satellite constellations until a complete environmental review can be done.

The environmental harms of launching and burning up so many satellites aren’t clear. That’s because the federal government hasn’t conducted an environmental review to understand the impacts. What we do know is that more satellites and more launches lead to more damaging gasses and metals in our atmosphere. We shouldn’t rush forward with launching satellites at this scale without making sure the benefits justify the potential consequences of these new mega-constellations being launched, and then re-entering our atmosphere to burn up and or create debris This is a new frontier, and we should save ourselves a lot of trouble by making sure we move forward in a way that doesn’t cause major problems for our future.

Under this premise, Americans would forever be forbidden from doing anything without first having detailed environmental reviews by federal government agencies. Ponder that thought for a bit.

The astronomers’ argument of course is intellectually dishonest and disingenuous, on multiple levels. It is more than evident that these launches and satellites will cause little serious harm to the atmosphere or the environment. What the astronomers really want is to block these constellations so that their ground-based telescopes will be able to continue to see the heavens unhindered.

To hell with everyone else! We need to gaze at the stars and we are more important!

What these Chicken Littles should really do is give up on ground-based astronomy entirely, and start building space-based telescopes of all kinds, and fast. They would not only bypass the satellite constellations, they would get far better data as they would also bypass the atmosphere to get sharp images of everything they look at.

Whether the FCC listens to this absurd demand depends entirely on who wins the election. A Harris administration might easily go along, shutting down not only SpaceX’s Starlink constellation (thus getting political revenge on Elon Musk for daring to campaign against Democrats) but Amazon’s Kuiper constellation as well. Such an action would likely exceed the FCC’s statutory authority, but that won’t matter to these power-hungry thugs.

Trump in turn would almost certainly shut down much of the administrative state’s mission creep into areas of regulation it has no legal business.

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WISE/NEOWISE burns up in the atmosphere

9:22 am

NASA’s Wide-field Infrared Survey Explorer (WISE, later renamed NEOWISE) has ended its fifteen years in orbit, burning up in the atmosphere on November 1, 2024.

In its initial mission it did an infrared survey of the sky, discovering millions of black holes, many of the most luminous galaxies, and numerous brown dwarfs. It was then repurposed to survey the sky for near Earth objects, asteroids that have the potential to impact the Earth, discovering more than two hundred new asteroids while tracking more precisely another 3,000. It did this by repeating its survey over and over so that moving objects could be spotted.

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A 2017 supernova as spotted by Hubble

11:20 am

Before and after of galaxy with supernova
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Cool image time! The pictures to the right were both compiled from photos taken by the Hubble Space Telescope, with the bottom annotated to indicate the location of a 2017 supernova that was not visible in the earlier 2005 picture.

In this collage two images of the spiral galaxy NGC 1672 are compared: one showing supernova SN 2017GAX as a small green dot, and the other without. The difference between the images is that both have been created by processing multiple individual Hubble images, each taken to capture a specific wavelength of visible light, and combining them to make a full-colour image. In one of those filtered frames, taken in 2017, the fading supernova is still visible

NGC 1672 is considered a barred spiral galaxy. Located an estimated 52 million light years away, the 2017 supernovae was not the last detected within it. In 2022 a second supernovae occurred. That’s two supernovae within five years. Meanwhile the Milky Way has not seen a supernova in more than four centuries.

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Scientists use Hubble and Webb to confirm there are as yet no planets forming in Vega’s accretion disk

11:16 am

Hubble and Webb images of Vega's accretion disk
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Using both the Hubble and Webb space telescopes, scientists have now confirmed, to their surprise, that the accretioni disk that surrounds the nearby star Vega is very smooth with almost no gaps, and thus apparently has not new exoplanets forming within it.

The two pictures to the right, cropped and reduced to post here, come from two different papers. The Hubble paper is here [pdf] while the Webb paper is here [pdf]. From the press release:

Webb sees the infrared glow from a disk of particles the size of sand swirling around the sizzling blue-white star that is 40 times brighter than our Sun. Hubble captures an outer halo of this disk, with particles no bigger than the consistency of smoke that are reflecting starlight.

The distribution of dust in the Vega debris disk is layered because the pressure of starlight pushes out the smaller grains faster than larger grains. “Different types of physics will locate different-sized particles at different locations,” said Schuyler Wolff of the University of Arizona team, lead author of the paper presenting the Hubble findings. “The fact that we’re seeing dust particle sizes sorted out can help us understand the underlying dynamics in circumstellar disks.”

The Vega disk does have a subtle gap, around 60 AU (astronomical units) from the star (twice the distance of Neptune from the Sun), but otherwise is very smooth all the way in until it is lost in the glare of the star. This shows that there are no planets down at least to Neptune-mass circulating in large orbits, as in our solar system, say the researchers.

At the moment astronomers consider the very smooth accretion disk surrounding Vega to be rare and exception to the rule, with most debris disks having gaps that suggest the presence of newly formed exoplanets within them. That Vega breaks the rule however suggests the rule might not be right in the first place.

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Post-collision images of two galaxies

10:56 am

Post-collision imagery by Hubble and Webb
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Using both the Hubble and Webb space telescopes, astronomers have now produced multi-wavelength images of the galaxies NGC 2207and IC 2163, as shown to the right.

Millions of years ago the smaller galaxy, IC 2163, grazed against the larger, NGC 2207, resulting today in increased star formation in both galaxies, indicated by blue in the Hubble photo. From the caption of the combined images:

Combined, they are estimated to form the equivalent of two dozen new stars that are the size of the Sun annually. Our Milky Way galaxy forms the equivalent of two or three new Sun-like stars per year. Both galaxies have hosted seven known supernovae, each of which may have cleared space in their arms, rearranging gas and dust that later cooled, and allowed many new stars to form.

The two images to the left leaves the Hubble and Webb separate, making it easier to see the different features the different wavelengths reveal. From this caption:

In Hubble’s image, the star-filled spiral arms glow brightly in blue, and the galaxies’ cores in orange. Both galaxies are covered in dark brown dust lanes, which obscure the view of IC 2163’s core at left. In Webb’s image, cold dust takes centre stage, casting the galaxies’ arms in white. Areas where stars are still deeply embedded in the dust appear pink. Other pink dots may be objects that lie well behind these galaxies, including active supermassive black holes known as quasars.

The largest and brightest pink area in the Webb image, on the bottom right and a blue patch in the Hubble image, is where a strong cluster of star formation is presently occurring.

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