Tag: astronomy

Italy awards Italian company contract to design constellation of radio telescopes orbiting the Moon

8:45 am

Capitalism in space: The Italian Space Agency has awarded the Italian company Blue Skies Space a contract to design a constellation of radio telescopes orbiting the Moon and designed to map the universe’s earliest radio emissions.

The project, named RadioLuna, aims to uncover whether a fleet of small satellites in a lunar orbit could detect faint radio signals from the universe’s earliest days—signals that are nearly impossible to pick up on Earth due to man-made radio interference. These signals, in the FM radio range, come from a time before the first stars formed, when the universe was mostly hydrogen gas. By listening from the far side of the Moon, free from Earth’s radio noise, scientists could use the satellites to uncover a missing piece of the puzzle in our understanding of the cosmic “dark ages.”

The study will establish the viability of operating simple and cost-effective CubeSats equipped with commercial off-the-shelf (COTS) components orbiting the Moon and will be led by Blue Skies Space Italia S.r.l., a subsidiary of UK-based Blue Skies Space Ltd. Project partner OHB Italia will be responsible for the definition of a viable platform in a Moon orbit.

The contract is another example of Italy (and Europe) shifting to private enterprise in space. Rather than design this project in-house, its space agency is contracting it out to private companies.

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Astronomers: Potentially dangerous asteroid 2024 YR4 originally came from main asteroid belt

12:26 pm

Using new data from ground-based telescopes, astronomers now believe that the potentially dangerous asteroid 2024 YR4 originally came from main asteroid belt and is a stony solid body, not a rubble pile.

The study reveals YR4 is a solid, stony type that likely originated from an asteroid family in the central Main Belt between Mars and Jupiter, a region not previously known to produce Earth-crossing asteroids. “YR4 spins once every 20 minutes, rotates in a retrograde direction, has a flattened, irregular shape, and is the density of solid rock,” said Bryce Bolin, research scientist with Eureka Scientific and lead author of the study.

You can read the paper here [pdf].

At present calculations suggest it has an almost zero chance of hitting the Earth in 2032, though during that close approach the chances of it hitting the Moon range from 2% to 4%, depending on which scientist you ask.

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White dwarf binary discovered only 150 light years away is a major supernova candidate in about 23 billion years

9:35 am

Astronomers have discovered only 150 light years away the most massive white dwarf binary system yet detected, that they believe is a major candidate for producing one type of supernova many billions of years in the future.

White dwarf stars in binary systems are thought to produce Type 1a supernova. The dwarf sucks material from the companion star, which eventually piles up on the surface of the dwarf until the extra mass, more than 1.4 times the mass of the Sun (dubbed the Chandrasekhar mass limit), causes the supernova explosion.

That’s the theory at least. Up to now astronomers have not yet observed this process, prior to the supernova. This newly discovered binary system however is a prime candidate, because its combined mass is already 1.55 the mass of the Sun. According to the researchers’ computer models, when these stars come close to merging the result will be a Type 1a supernova. From the peer reviewed paper:

The interaction of the accretion stream with the surface of the primary white dwarf ignites a helium detonation close to the point of interaction. The helium detonation then wraps around the primary white dwarf and sends a shock wave into its core that converges at a single point. This ignites a second detonation that completely destroys the primary white dwarf. When the shock wave of its explosion hits the secondary white dwarf, the double detonation mechanism repeats itself. The shock wave from the detonation of the primary ignites a helium detonation near the surface of the secondary which drives a shock wave into its core. It is sufficient to ignite the core detonation, destroying the secondary white dwarf as well.

These events won’t occur tomorrow however. The two stars orbit each other every 14 hours, but their high mass is causing gravitational waves to ripple outward from the system, robbing it of energy. The orbits of the stars are thus spiraling inward. In about 23 billion years they will be about to merge, which will be the moment when the above explosive events are predicted to occur.

If at that moment the binary system was still only 150 light years away, the explosion would do great harm to the Earth and likely cause a major extinction. In 23 billion years however the binary will no longer be so close, and could in fact be on the other side of the Milky Way.

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Webb infrared data increases odds asteroid 2024 YR4 will impact Moon in 2032

9:40 am

Asteroid 2024 YR4 as seen by Webb in the mid-infrared
Asteroid 2024 YR4 as seen by Webb in the
mid-infrared. Click for original image.

Using new infrared images and data from the Webb Space Telescope, astronomers have further refined the orbit and size of the potentially dangerous asteroid 2024 YR4.

The image of 2024 YR4 to the right was taken by Webb’s mid-infrared camera, and provides information on its thermal surface characteristics.

First, the Webb data narrowed the uncertainty about the asteroid’s size, suggesting it is about 200 feet in diameter. You can read the paper outlining this result here. The data also suggested nature of the asteroid’s surface, which is important in determining its future path. The pressure from sunlight can change the orbits of small asteroids, but figuring out how much is extremely difficult without knowing the rotation of the asteroid and the reflective qualities of its entire surface.

Second, based on this new data, other astronomers are increasingly certain 2024 YR4 will not hit the Earth in 2032, but the odds of it impacting the Moon have now increased to 4%.

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Twenty years of Hubble data map one long season on Uranus

9:09 am

Uranus over twenty years
Click for original image.

Astronomers using the Hubble Space Telescope multiple times since 2002 have now tracked the changes in its atmosphere during one quarter of its 84 year orbit around the Sun.

The image to the right, reduced and sharpened to post here, shows Hubble’s views across several electromagnetic wavelengths. Uranus’s rotational tilt or inclination is almost 90 degrees, so that it literally rolls on its side as it orbits the Sun. You can see this especially in the bottom two rows. From 2012 to 2022 one pole slowly shifted westward. From the press release:

The Hubble team observed Uranus four times in the 20-year period: in 2002, 2012, 2015, and 2022. They found that, unlike conditions on the gas giants Saturn and Jupiter, methane is not uniformly distributed across Uranus. Instead, it is strongly depleted near the poles. This depletion remained relatively constant over the two decades. However, the aerosol and haze structure changed dramatically, brightening significantly in the northern polar region as the planet approaches its northern summer solstice in 2030.

Since we have not yet observed Uranus over one full year, there are a lot of uncertainties in any conclusions the scientists propose. For one, we don’t know the general atmospheric patterns across all four seasons. For another, any changes seen now might simply be the planet’s weather, random events not directly related to long term climate patterns.

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Webb finds more elements not possible so soon after the Big Bang

11:19 am

A galaxy that shouldn't be there
Click for original image.

The uncertainty of science: Using the Webb Space Telescope, astronomers have now detected emissions of hydrogen from a galaxy that exists only 330 million years after the Big Bang that simply shouldn’t be possible, based on present cosmological theory.

The false-color infrared image of that galaxy is to the right, cropped to post here. At that distance, 13.5 billion light years away, all Webb can really see is this blurry spot. From the press release:

In the resulting spectrum, the redshift was confirmed to be 13.0. This equates to a galaxy seen just 330 million years after the big bang, a small fraction of the universe’s present age of 13.8 billion years old. But an unexpected feature stood out as well: one specific, distinctly bright wavelength of light, known as Lyman-alpha emission, radiated by hydrogen atoms. This emission was far stronger than astronomers thought possible at this early stage in the universe’s development.

“The early universe was bathed in a thick fog of neutral hydrogen,” explained Roberto Maiolino, a team member from the University of Cambridge and University College London. “Most of this haze was lifted in a process called reionization, which was completed about one billion years after the big bang. GS-z13-1 is seen when the universe was only 330 million years old, yet it shows a surprisingly clear, telltale signature of Lyman-alpha emission that can only be seen once the surrounding fog has fully lifted. This result was totally unexpected by theories of early galaxy formation and has caught astronomers by surprise.”

In more blunt terms, the theory that the haze would clear only one billion years after the Big Bang appears very wrong. This result is also similar to the story earlier this week about the detection of oxygen in a similarly early galaxy, oxygen that could not possibly be there only a few hundred million years after the Big Bang. Not enough time had passed for the number of star generations needed to produce it.

You can read the peer-reviewed paper here. While the Big Bang theory is hardly dead, the data from Webb continues to suggest it either needs a major rethinking, or there is something fundamentally wrong with it.

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Webb images in the infrared the aurora of Neptune

9:30 am

The aurora of Neptune
Click for original image.

Astronomers using the Webb Space Telescope have captured the first infrared images of the aurora of Neptune, confirming that the gas giant produces this phenomenon.

The picture to the right combines infrared data from Webb and optical imagery from the Hubble Space Telescope. The white splotches near the bottom of the globe are clouds seen by Hubble. The additional white areas in the center and near the top are clouds detected by Webb, while the greenish regions to the right are aurora activity detected by Webb.

The auroral activity seen on Neptune is also noticeably different from what we are accustomed to seeing here on Earth, or even Jupiter or Saturn. Instead of being confined to the planet’s northern and southern poles, Neptune’s auroras are located at the planet’s geographic mid-latitudes — think where South America is located on Earth.

This is due to the strange nature of Neptune’s magnetic field, originally discovered by Voyager 2 in 1989, which is tilted by 47 degrees from the planet’s rotation axis. Since auroral activity is based where the magnetic fields converge into the planet’s atmosphere, Neptune’s auroras are far from its rotational poles.

The data also found that the temperature of Neptune’s upper atmosphere has cooled significantly since it was first measured by Voyager 2 in 1989, dropping by several hundred degrees.

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Survey of protoplanetary disks finds their size varies significantly

9:02 am

Proto-planetary disks of all sizes
Click for original image.

A survey of the protoplanetary disks in a star-forming region about 400 light years from Earth has found that the size of the disks can vary considerably, with many much smaller than our own solar system.

Using ALMA [Atacama Large Millimeter/submillimeter Array in Chile], the researchers imaged all known protoplanetary discs around young stars in Lupus, a star forming region located about 400 light years from Earth in the southern constellation Lupus. The survey reveals that two-thirds of the 73 discs are small, with an average radius of six astronomical units, this is about the orbit of Jupiter. The smallest disc found was only 0.6 astronomical units in radius, smaller than the orbit of Earth.

…The small discs were primarily found around low-mass stars, with a mass between 10 and 50 percent of the mass of our Sun. This is the most common type of star found in the universe.

You can read the research paper here [pdf]. The image to the right, figure 1 from the paper, shows 71 of those disks, with two-thirds clearly much smaller than our solar system.

Because exoplanet surveys have found many small exoplanets around low-mass stars, this new data suggests that planets can also form from these small accretion disks, and that planet formation is also ubiquitous throughout the universe.

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New Webb infrared image reveals galaxy hidden behind outflow from baby star

10:22 am

Webb infrared image of baby star outflow
Click for original image.

Cool image time! The false-color infrared image to the right, cropped, reduced, and sharpened to post here, was taken by the Webb Space Telescope of the outflow from a baby star, dubbed Herbig-Haro 49/50, located about 625 light years away.

The picture was taken to get a better understanding of the flow itself. Earlier infrared images at much lower resolution by the Spitzer Space Telescope had left many features in this outflow unclear. For example, at the head of the outflow the Spitzer infrared image was unable to clearly identify the background spiral galaxy located there. In those earlier images it could have instead been a part of the outflow itself.

The galaxy that appears by happenstance at the tip of HH 49/50 is a much more distant, face-on spiral galaxy. It has a prominent central bulge represented in blue that shows the location of older stars. The bulge also shows hints of “side lobes” suggesting that this could be a barred-spiral galaxy. Reddish clumps within the spiral arms show the locations of warm dust and groups of forming stars. The galaxy even displays evacuated bubbles in these dusty regions

The actual source from which this flow comes remains unconfirmed, though astronomers think the source is one particular protostar about 1.5 light years away.

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New research finds cosmic rays hitting the atmosphere cause of the ignition of lightning

9:52 am

Two lightning flashes graphed
Click for original image.

New research has now found that the shower of energy produced when a cosmic ray hits the atmosphere could be a major cause for the ignition of lightning in thunderheads.

You can read the paper here. The two graphs to the right are taken from figure 3 of the paper, and show two different lightning events. The colors represent time, going from green (earliest) to blue to yellow and red (latest). The white dot marks the spot where the lightning flash started. From the article above:

We believe that that most lightning flashes in thunderstorms are ignited by cosmic ray showers,” says the study’s lead author Xuan-Min Shao, a senior scientist at the Los Alamos National Laboratory in New Mexico.

…One of the important things about cosmic ray showers is that they contain antimatter–positrons as well as ordinary electrons. The Los Alamos 3D lightning maps contained strong evidence for positrons. Electrons and positrons are bent in opposite directions by Earth’s magnetic field, so they leave opposite imprints on the lightning’s polarization, which BIMAP-3D also measured.

…Positrons clinched the case for cosmic rays. “The fact that a cosmic ray shower provides an ionized path in the cloud that otherwise lacks free electrons strongly favor the inference that most lightning flashes are ignited by cosmic rays,” the authors wrote.

It remains unclear if cosmic rays cause all lightning flashes or just some. Either way, it is a remarkable thing to consider: Cosmic rays are created in distant interstellar and even intergalactic events. The rays take millions, maybe billions of years to reach Earth. And when they do, they produce lightning in thunderstorms!

Hat tip reader Steve Golson.

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Oxygen found in the most distant known galaxy, too soon after the Big Bang

9:22 am

The uncertainty of science: Astronomers studying the most distant galaxy so far discovered, 13.4 billion light years away and existing only 300 million years after the Big Bang, have now detected the existence of oxygen, an element that simply should not have had the time to develop in such a short time span.

The new oxygen detection with ALMA, a telescope array in Chile’s Atacama Desert, suggests the galaxy is much more chemically mature than expected. “It is like finding an adolescent where you would only expect babies,” says Sander Schouws, a PhD candidate at Leiden Observatory, the Netherlands, and first author of the Dutch-led study, now accepted for publication in The Astrophysical Journal. “The results show the galaxy has formed very rapidly and is also maturing rapidly, adding to a growing body of evidence that the formation of galaxies happens much faster than was expected.”

Galaxies usually start their lives full of young stars, which are made mostly of light elements like hydrogen and helium. As stars evolve, they create heavier elements like oxygen, which get dispersed through their host galaxy after they die. Researchers had thought that, at 300 million years old, the Universe was still too young to have galaxies ripe with heavy elements. However, the two ALMA studies indicate JADES-GS-z14-0 has about 10 times more heavy elements than expected.

The spectroscopy that confirmed the oxygen also allowed the scientists to confirm the galaxy’s distance, which also confirmed the fact that there is something seriously wrong with the present theories of cosmologists about the formation of the universe. Present theory requires at least several generations of star birth followed by star death, with each forming heavier and heavier atoms. Such a process is expected to take far more than 300 million years.

Either that theory is very wrong, or the theory of the Big Bang has problems. The facts don’t fit the theories, and when that happens, it is the theories that must be abandoned.

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More surprises from the Wolf-Rayet star numbered 104 and known for its pinwheel structure

2:03 pm

Keck infrared data of WR104

Among astronomers who study such things, Wolf-Rayet 104 is one of the most well known OB massive stars in their catalog, with the infrared picture to the right illustrating why. The star is actually a binary of massive stars, orbiting each other every eight months. Both produce strong winds, and the collision of those winds results in a glorious pinwheel structure that glows in the infrared.

Such stars are also believed to be major candidates to go supernova and in doing so produce a powerful gamma ray burst (GRB) that would shoot out from the star’s poles. As the orientation of this pinwheel suggests we are looking down into the pole of the system, this star system was actually considered a potentially minor threat to Earth. Located about 8,400 light years away, this is far enough away to mitigate the power of the GRB, but not eliminate entirely its ability to damage the Earth’s atmosphere.

New research now suggests however that despite the orientation of the pinwheel, face-on, the plane of the binary star system is actually tilted 30 to 40 degrees to our line of sight. The press release asks the new questions these results raise:

While a relief for those worried about a nearby GRB pointed right at us, this represents a real curveball. How can the dust spiral and the orbit be tilted so much to each other? Are there more physics that needs to be considered when modelling the formation of the dust plume?

You can read the paper here. It is a quite refreshing read, not just because of its relatively plain language lacking jargon, but because of its willingness to list at great length the uncertainties of the data.

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Webb captures infrared images of five exoplanets orbiting two different stars

10:17 am

Four gas giants in infrared
Click for original image.

Using the Webb Space Telescope, astronomers have taken two different direct false-color infrared images of exoplanets orbiting the stars HR 8799 (130 light years away) and 51 Eridani (97 light years away.

The image of the four gas giants orbiting HR 8799 is to the right, cropped, reduced, and slightly enhanced to post here. From the caption:

The closest planet to the star, HR 8799 e, orbits 1.5 billion miles from its star, which in our solar system would be located between the orbit of Saturn and Neptune. The furthest, HR 8799 b, orbits around 6.3 billion miles from the star, more than twice Neptune’s orbital distance. Colors are applied to filters from Webb’s NIRCam (Near-Infrared Camera), revealing their intrinsic differences. A star symbol marks the location of the host star HR 8799, whose light has been blocked by the coronagraph. In this image, the color blue is assigned to 4.1 micron light, green to 4.3 micron light, and red to the 4.6 micron light.

The Webb false color infrared picture taken of one of the exoplanets orbiting the star 51 Eridani is also at the link, showing “a cool, young exoplanet that orbits 890 million miles from its star, similar to Saturn’s orbit in our solar system.”

The data from the HR 8799 image suggests these gas giants have a lot of carbon dioxide gas, and thus might be growing by pulling in material from the star’s accretion disk.

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Astronomers discover 128 more moons around Saturn

9:01 am

Using a ground-based telescope, astronomers have now identified 128 new moons circling Saturn, bringing its moon count to 274, more than the total moons around all the other planets in the solar system combined.

Edward Ashton at Academia Sinica in Taipei, Taiwan, and his colleagues found the new moons with the Canada-France-Hawaii Telescope, revealing dozens that have previously evaded astronomers. They took hours of images of Saturn, adjusted them for the planet’s movement through the sky and stacked them on top of each other to reveal objects that would otherwise be too dim to see.

All the new moons are between 2 and 4 kilometres in diameter and are likely to have been formed hundreds of millions or even billions of years ago in collisions between larger moons, says Ashton.

That Saturn has so many moons should surprise no one. Saturn actually has possibly millions, maybe even billions, of moons, if you count every particle in its rings. In fact, the gas giant poses a problem for astronomers in defining what a moon actually is. How small must an object be before you stop calling it a moon?

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Astronomers have discovered four sub-Earth-sized exoplanets orbiting Barnard’s Star

10:44 am

Based on data from several ground-based telescopes, astronomers now believe that Barnard’s Star, the nearest single star to our Sun at a distance of about six light years away, has a solar system of at least four sub-Earth-sized planets.

After rigorously calibrating and analyzing data taken during 112 nights over a period of three years, the team found solid evidence for three exoplanets around Barnard’s Star, two of which were previously classified as candidates. The team also combined data from MAROON-X with data from a 2024 study done with the ESPRESSO instrument at the European Southern Observatory’s Very Large Telescope in Chile to confirm the existence of a fourth planet, elevating it as well from candidate to bona fide exoplanet.

You can read the paper here. The scientists estimate the minimum masses of these exoplanets to range from 19% to 34% that of the Earth, with their maximum mass not exceeding 57% of the Earth. All are believed to be rocky planets orbiting just inside the star’s habitable zone.

Astronomers have been trying to detect exoplanets around Barnard’s Star for more a century. Several previous “discoveries” were later retracted. This result however appears somewhat firm though of course there are a lot of uncertainties in the result.

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A galactic ball and spiral interact

9:55 am

A galactic ball and spiral interact
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 of the star populations in these two interacting galaxies. From the caption:

Arp 105 is a dazzling ongoing merger between an elliptical galaxy and a spiral galaxy drawn together by gravity, characterized by a long, drawn out tidal tail of stars and gas more than 362,000 light-years long. The immense tail, which extends beyond this image from NASA’s Hubble Space Telescope, was pulled from the two galaxies by their gravitational interactions and is embedded with star clusters and dwarf galaxies.

The three blue objects on the outskirts of both galaxies are thought to be active star-forming regions. Whether all three are part of this collision is unclear, as the object on the lower right might simply be a foreground object based on the available data.

What makes this galactic pair so intriguing is that the two galaxies are so different with very different theorized histories. Elliptical galaxies (“the ball”) are thought to be very old, the result of the long term evolution of spirals. You would therefore not think an elliptical would normally interact with a spiral, as their ages are likely so dissimilar.

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Webb captures infrared view of a baby binary star system and its bi-polar jets

9:41 am

A baby binary in formation
Click for original image.

Cool image time! The infrared false-color picture to the right, reduced and sharpened to post here, was released today by the science team of the Webb Space Telescope. It shows the bi-polar jets spewing out from a newly formed binary of two very young stars as their interact during their formation process.

The two protostars responsible for this scene are at the center of the hourglass shape, in an opaque horizontal disk of cold gas and dust that fits within a single pixel. Much farther out, above and below the flattened disk where dust is thinner, the bright light from the stars shines through the gas and dust, forming large semi-transparent orange cones.

It’s equally important to notice where the stars’ light is blocked — look for the exceptionally dark, wide V-shapes offset by 90 degrees from the orange cones. These areas may look like there is no material, but it’s actually where the surrounding dust is the densest, and little starlight penetrates it. If you look carefully at these areas, Webb’s sensitive NIRCam (Near-Infrared Camera) has picked up distant stars as muted orange pinpoints behind this dust. Where the view is free of obscuring dust, stars shine brightly in white and blue.

To put it more simply, the accretion disk for the binary system lies at right angles to the much larger jets. The rotation of that disk as well as the stars causes those jets to flow up and down from the poles, with the existence of two stars producing the complex patterns in those jets.

As this image was focused mostly on studying the upper jet, it does not show the entire lower jet, which extends beyond the lower border.

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Is a supermassive black hole is hidden in the Large Magellanic Cloud?

11:45 am

Based on the motions of a number of runaway stars on the edge of the Milky Way that are moving so fast they will leave the galaxy, astronomers believe that many were accelerated not by the galaxy’s own central supermassive black hole but a previously undetected supermassive black hole at the center of the Large Magellanic Cloud, one of the Milky Ways nearby dwarf galaxies.

To make this discovery, researchers traced the paths with ultra-fine precision of 21 stars on the outskirts of the Milky Way. These stars are traveling so fast that they will escape the gravitational clutches of the Milky Way or any nearby galaxy. Astronomers refer to these as “hypervelocity” stars.

Similar to how forensic experts recreate the origin of a bullet based on its trajectory, researchers determined where these hypervelocity stars come from. They found that about half are linked to the supermassive black hole at the center of the Milky Way. However, the other half originated from somewhere else: a previously-unknown giant black hole in the Large Magellanic Cloud (LMC).

You can read the paper here [pdf]. This result was made possible by the very precise location and velocity data of over a billion stars measured by Europe’s Gaia satellite.

Based on the available data, the scientists estimate (with great uncertainty) the mass of this supermassive black hole, which the scientists have dubbed LMC* (pronounced “LMC star”), to be about 600,000 times the mass of the Sun, quite big but significantly less than the mass of the Milky Way’s central black hole, Sagittarius A* (pronounced “A-star”), which is estimated to be about 4.3 million times the mass of the Sun.

The mystery to solve now is why this super massive black hole is so quiet. It has literally emitted no obvious energy in any wavelength in the past seven decades, since ground- and space-based telescopes went into operation capable of detecting such emissions. Even the relatively inactive supermassive black hole at the Milky Way’s center, Sagittarius A* (pronounced “A-star”) emits distinct radio energy that the first radio telescopes were able to detect almost immediately.

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Scientists: X-rays from the Helix Nebula caused by the destruction of a planet

10:12 am

A composite image of the Helix Nebula
A composite image of the Helix Nebula, combining data
from multiple ground- and space-based telescopes.
Click for original image.

Using data collected by multiple ground-bases and space telescopes over decades, scientists now think the previously unexplained high energy X-rays coming from the white dwarf star at the center of the Helix Nebula are caused by the destruction of a Jupiter-sized exoplanet.

The besieged planet could have initially been a considerable distance from the white dwarf but then migrated inwards by interacting with the gravity of other planets in the system. Once it approached close enough to the white dwarf, the gravity of the star would have partially or completely torn the planet apart. “The mysterious signal we’ve been seeing could be caused by the debris from the shattered planet falling onto the white dwarf’s surface, and being heated to glow in X-rays,” said co-author Martin Guerrero of The Institute of Astrophysics of Andalusia in Spain. “If confirmed, this would be the first case of a planet seen to be destroyed by the central star in a planetary nebula.”

The study shows that the X-ray signal from the white dwarf has remained approximately constant in brightness between 1992, 1999, and 2002 (with observations by ROSAT, Chandra and XMM respectively). The data, however, suggests there may be a subtle, regular change in the X-ray signal every 2.9 hours, providing evidence for the remains of a planet exceptionally close to the white dwarf.

You can read the original paper here. The Helix Nebula is about 650 light years away, and is one of the most studied planetary nebula, believed to have formed when the central star collapsed into a white dwarf.

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A galaxy surrounded by clusters of hot massive stars

8:44 am

A galaxy surrounded by hot massive stars
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 the galaxy NGC 5042, located about 48 million light years away. The picture combines data from all of Hubble’s available wavelengths from the ultraviolet to the infrared. From the caption:

Perhaps NGC 5042’s most striking feature is its collection of brilliant pink gas clouds that are studded throughout its spiral arms. These flashy clouds are called H II (pronounced “H-two”) regions, and they get their distinctive colour from hydrogen atoms that have been ionised by ultraviolet light. If you look closely at this image, you’ll see that many of these reddish clouds are associated with clumps of blue stars, often appearing to form a shell around the stars.

H II regions arise in expansive clouds of hydrogen gas, and only hot and massive stars [indicated by blue] produce enough high-energy light to create an H II region. Because the stars capable of creating H II regions only live for a few million years — just a blink of an eye in galactic terms — this image represents a fleeting snapshot of life in this galaxy.

The image also includes one star (distinguished by its four diffraction spikes) and a few background galaxies in yellow, the most obvious found in the upper and lower right.

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Lucy takes first picture of its next target asteroid

9:12 am

Lucy's future route through the solar system
Lucy’s route to the asteroids. Click for original blink animation.

The asteroid probe Lucy, on its way to the orbit of Jupiter to study numerous Trojan asteroids, has taken its first picture of the the main asteroid belt asteroid Donaldjohanson, which it will pass within 600 miles on April 20, 2025.

The map to the right shows the spacecraft’s looping route to get to the Trojans, with that image of Donaldjohanson in the lower right. Though the asteroid is about two miles side, it will remain an unresolved point of light until the day of the fly-by. This image was taken from a distance of 45 million miles. As for the asteroid’s name:

Asteroid Donaldjohanson is named for anthropologist Donald Johanson, who discovered the fossilized skeleton — called “Lucy” — of a human ancestor. NASA’s Lucy mission is named for the fossil.

After this encounter, Lucy will head to the Trojans, where it will visit its first six asteroids (including two binaries) in 2027-2028.

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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

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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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