Hubble Telescope sees spiral galaxy dancing through the Dorado constellation (image)

Samantha Mathewson
Wed, November 1, 2023 

A view of a spiral structure that has red specks, blue specks and a glowing yellowish core.

The Hubble Space Telescope has snapped a new view of a spirited galaxy dancing among the stars.

NGC 1566, also called the "Spanish Dancer" galaxy, lies about 60 million light-years from Earth in the southern constellation Dorado. This new Hubble Telescope photo shows the galaxy face-on, capturing its gorgeous and grand design.

The galaxy has two distinct and graceful spiral arms that span over 100,000 light-years; each arc half-turns from start to finish, resembling a dancer’s moving form. The spiral arms are traced by bright blue star clusters, pinkish star-forming regions and swirling interstellar dust, according to a statement from the European Space Agency (ESA).


Related: The best Hubble Space Telescope images of all time!


A view of a spiral structure that has red specks, blue specks and a glowing yellowish core.

A full view of the image at the top, of the Spanish Dancer galaxy. (Image credit: ESA/Hubble & NASA, D. Calzetti and the LEGUS team, R. Chandar

Observations suggest NGC 1566 is weakly-barred, making it an intermediate spiral galaxy. While the galaxy boasts a bright core, it lacks a distinct bar-shaped structure at its center.

NGC 1566 belongs to the Dorado galaxy group, which is a concentration of both spiral and elliptical galaxies bound together by gravity. The Dorado Group comprises an estimated 70 galaxies, making it much larger than the Local Group that houses our own Milky Way; the Local Group contains around 30 galaxies.

"[Galaxy] groups differ from galaxy clusters in size and mass: Galaxy clusters may contain hundreds of galaxies, whereas groups might contain several tens of galaxies," ESA officials said in the statement.

Galaxy clusters are the largest groupings of galaxies — and largest structures of any kind in the universe — to be held together by their own gravity. The Dorado Group approaches the size of a galaxy cluster, though there are differing opinions on the delineation between a galaxy group and cluster, according to the statement.

Members of the Dorado Group have changed over time as more sophisticated observation techniques enhance our view of the cosmos, adjusting our understanding of the relative sizes and proximities of galaxies along the same line of sight.

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"When working out members of a galaxy group, astronomers are not necessarily equipped with the knowledge of the size of the individual galaxies, and so have to work out whether galaxies really are relatively close together in space, or whether some of them are actually much closer or much further away," ESA officials said in the statement.

ESA released the new Hubble photo of NGC 1566 online on Oct. 30.

NASA's Lucy spacecraft successfully completes 1st flyby of asteroid 'Dinky'

Monisha Ravisetti
Wed, November 1, 2023 

A size comparison of Dinkinesh (shown in blue) and other main asteroid belt objects Bennu and (2867) Steins.


On Nov. 1, NASA confirmed its Lucy spacecraft successfully completed a flyby of asteroid Dinkinesh, a relatively small space rock located in the main belt between Mars and Jupiter. This marks a milestone in Lucy's journey, as Dinkinesh, or 'Dinky,' is the first of 10 asteroids the probe will visit over the next 12 years.

"Based on the information received, the team has determined that the spacecraft is in good health," NASA officials wrote in a blog post after the flyby occurred. "The team has commanded the spacecraft to start downlinking the data collected during the encounter."

In a nutshell, the Lucy mission is part of NASA's ambitious endeavor to unveil secrets of our solar system's past. Though Lucy will also be passing by a few relatively nearby asteroids like Dinky, the probe's main goal is to fly by a few more distant Trojan asteroids orbiting the sun alongside Jupiter like bundles of pebbles bound to the gravitational tides of a giant boulder. Scientists are interested in learning more about those Trojans because they're believed to be ancient relics of the solar system, like extra Lego bricks from the box that built the planets.

Related: NASA's LUCY mission snaps its asteroid targets for the 1st time

An illustration of NASA's Lucy spacecraft as it approaches the asteroid Dinkinesh.

An illustration of NASA's Lucy spacecraft as it approaches the asteroid Dinkinesh. (Image credit: Robert Lea/NASA)

Lucy's flyby of Dinkinesh can be thought of as a test-run in this regard, as many of the spacecraft's instruments have now been oiled while collecting data about this first asteroid encounter — including a color imager, high-resolution camera and infrared spectrometer.

According to the blog post, data from these tools will take about a week to be downlinked to Earth, and the team is "looking forward to seeing how the spacecraft performed during this first in-flight test of a high-speed asteroid encounter."

Related Stories:

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An animation showing two black and white images side-by-side. The right image has a yellow circle around the dot that is moving across the screen in both images.
The yellow circle represents Dinkinesh. This is a visual Lucy snagged of the asteroid far prior to the approach. (Image credit: NASA/Goddard/SwRI/Johns Hopkins APL)

Next, Lucy will head back to Earth for a gravity assist that'll help it zoom toward its second asteroid target: 52246 Donaldjohanson — named after co-discoverer of the Lucy fossil (representative of one the earliest human ancestors, for which the spacecraft is named), American paleoanthropologist Donald Johanson. And if you were wondering, "Dinkinesh" is just another title for the Lucy fossil.

It also means "you are marvelous," as you are, Lucy.

What astronomers learned from a near-Earth asteroid they never saw coming

Briley Lewis
Wed, November 1, 2023 

Haleakalā, Hawaii, is the site of one of the four telescopes that make up the Asteroid Terrestrial-impact Last Alert System.

In the summer, astronomers spotted an airplane-sized asteroid—large enough to potentially destroy a city—on an almost-collision course with Earth. But no one saw the space rock until two days after it had zoomed past our planet.

This asteroid, named 2023 NT1, passed by us at only one-fourth of the distance from Earth to the moon. That’s far too close for comfort. Astronomers weren’t going to let this incident go without a post-mortem. They’ve recently dissected what went wrong and how we can better prepare to defend our planet from future impacts, in a new paper recently posted to the preprint server arXiv.

We know from history that asteroids can cause world-shattering events and extinctions—just look at what happened to the dinosaurs. The study team estimated that, if NT1 hit Earth, it could have the energy of anywhere from 4 to 80 intercontinental ballistic missiles. “2023 NT1 would have been much worse than the Chelyabinsk airburst,” says University of California, Santa Barbara astronomer Philip Lubin, a co-author on the new work, referring to the meteor that exploded over a Russian city in 2013. As devastating as that would be, it’s “not an existential threat like the 10-kilometer hit that killed our previous tenants,” he adds.

The asteroid-monitoring system ATLAS, the “Asteroid Terrestrial-impact Last Alert System”—four telescopes in Hawaii, Chile, and South Africa—discovered NT1 after the rock flew by. ATLAS's entire purpose is to scour the skies for space rocks that might threaten Earth. So with this set of eyes on the sky, how did we miss it?

It turns out that Earth has what Brin Bailey, UC Santa Barbara astronomer and lead author on the paper, calls a “blindspot.” Any asteroid coming from the direction of the sun gets lost in the glare of our nearest star.” There’s another way for asteroids to sneak up on us, too: the smaller the asteroid, the harder it is for our telescopes to spot them, even when the rocks come from parts in the sky away from the sun.

[Related: NASA’s first asteroid-return sample is a goldmine of life-sustaining materials]

“Currently, there is no planetary defense system which can mitigate short-warning threats,” Bailey says. “While NT1 has no chance of intercepting Earth in the future, it serves as a reminder that we do not have complete situational awareness of all potential threats in the solar system,” they add. That leads to Lesson #1: We simply need better detection methods for planetary defense.

If we can manage to detect an asteroid with a few years’ warning, we might be able to redirect it with the technology recently tested by NASA’s Double-Asteroid Redirection Test (DART) mission.For a case with very little warning, such as NT1, though, we’d need a different approach—that’s Lesson #2. Bailey and colleagues propose a method they call “Pulverize It” (PI).

PI’s plan is exactly what it sounds like: break the asteroid into tiny pieces, small enough to burn up in the atmosphere or fall to the ground as much less dangerous little rocks. They’d do this by launching one or multiple rockets to send arrays of small impactors to space. The impactors—six-foot-long, six-inch-thick rods filled with explosives—would smash into the asteroid like buckshot, efficiently dismantling it. “Had we intercepted it [NT1] even one day prior to impact, we could have prevented any significant damage,” claims Lubin.

https://twitter.com/tony873004/status/1680662549791150080?

It sounds simple enough, but some astronomers aren’t quite convinced. “I think the PI method is impractical even though it does not violate the laws of physics,” says University of California, Los Angeles astronomer Ned Wright, who was not involved in the new work. “When a building is demolished by implosion using explosive charges, a weeks-long testing and planning phase is needed in order to place the charges in the right locations and set up the proper timing. The PI method seeks to do this measuring, planning, and placing the explosives all within a period of 1 minute or so just before the spacecraft hits the asteroid.”

[Related: NASA’s first attempt to smack an asteroid was picture perfect]

Whether we use PI or another line of defense, it’s clear that we need to plan ahead. Not only is there the hazy threat of an asteroid coming out of nowhere, there are two specific, extremely risky events headed our way: asteroid Apophis’ near flyby in 2029, and close approaches from the even larger Bennu (recently sampled by NASA’s OSIRIS-REx mission) in 2054, 2060, and 2135.

“Humanity now possesses the technology to robustly detect and defend the planet if we choose to do so,” says Lubin. “And a variety of people are working hard to ensure we can.”


"Scary Barbie" Black Hole Slurps Up a Star Like Spaghetti

Cassidy Ward
Wed, November 1, 2023 

"Scary Barbie" Black Hole Slurps Up a Star Like Spaghetti


When Oppenheimer and Barbie hit theaters at the same time, there was little reason to think they would compete with one another. They are very different movies intended for divergent audiences and yet they found a sort of bizarre companionship in the theaters, becoming the unexpected double feature dubbed "Barbenheimer."

Now, it turns out, the two cultural touchstones might have more in common than we realized. Thanks to a transient space object – an object which changes on short timescales of seconds, weeks, or years, as opposed to millions or billions of years – known as ZTF20abrbeie and dubbed "Scary Barbie" by astronomers, we now know that Barbie is packing the sort of power Oppenheimer could only dream of in the far reaches of deep space.

Scary Barbie Black Hole’s Appetite Lights Up the Sky

The object – a black hole in the process of gobbling up a star – wasn’t noticed when it was first observed back in 2020, but it was assigned a random designation. The ZTF at the beginning of its name refers to the Zwicky Transient Facility which made the observation, and the mishmash of letters at the end stuck out to astronomers. When combined with the raw power astronomers found when they took a closer look, the Scary Barbie moniker was born. Analysis of Scary Barbie was posted to the ArXiv preprint server and accepted for publication in The Astrophysical Journal Letters.

RELATED: Christopher Nolan's Oppenheimer Coming Home with 3 Hours of Bonus Features

“It's absurd. If you take a typical supernova and multiply it a thousand times, we're still not at how bright this is – and supernovas are among the most luminous objects in the sky. This is the most energetic phenomenon I have ever encountered,” said Danny Milisavljevic, an assistant professor of physics and astronomy in Purdue University’s College of Science, in a statement.

Despite the incredible energy on display, it wasn’t noticed at first because it’s far away and in a part of the sky that doesn’t get as much attention. It might have gone unnoticed a lot longer if not for a machine learning algorithm set loose on archival data. Researchers used the Recommender Engine For Intelligent Transient Tracking (REFITT) to do a first pass on the back catalog of astronomical observations and highlight candidate objects that look the most promising for additional analysis.

A black hole destroying a star.

A disk of hot gas swirls around a black hole in this illustration. The stream of gas stretching to the right is what remains of a star that was pulled apart by the black hole. A cloud of hot plasma (gas atoms with their electrons stripped away) above the black hole is known as a corona. Photo: NASA/JPL-Caltech

Once it was identified, the team was able to look for observations from other telescopes to start building a picture of what’s going on. When all the data came together, astronomers realized they were seeing a black hole rip a star to shreds.

“We think a very supermassive black hole pulled in a star and ripped it apart. The forces around a black hole, called tidal disruption, pull other objects apart in a process called ‘spaghettification.’ We think that’s what happened, but on extreme time scales: The most massive of black holes ripping apart a massive star. The duration is unlike anything we’ve ever seen before, and it produced the most luminous transient in the universe,” said Bhagya Subrayan, one of the study’s authors.

RELATED: Christopher Nolan's Oppenheimer Overtakes Bohemian Rhapsody as Highest-Grossing Biopic Ever

In addition to being brighter and more energetic than any transient object ever before discovered, Scary Barbie has demonstrated unusual staying power. Most of its peers fade out over the course of weeks or months but Scary Barbie has been going strong for more than two years. However, astronomers say the actual unspooling of the unfortunate prey star likely happened on a much shorter timescale. It appears to have played out more slowly from our perspective because the light got stretched out on its way from there to here. When we try to watch cosmic home movies like this one, relativity has a tendency to play fast and loose with the frame rate.

The identification of Scary Barbie is only the latest in a growing list of wins for machine learning in astronomy. Algorithms are increasingly doing the legwork of tromping through the uncharted swamps of archival astronomical data and lighting waypoints for human scientists along the way. Scary Barbie might have languished in data limbo for decades yet if not for a digital mole scouting the way.

Relive one half of the theatrical powerhouse that was Barbenheimer with Oppenheimer’s at-home release November 24.

Rare type of space explosion could leave Earth uninhabitable for 'thousands of years'

Robert Lea
Wed, November 1, 2023 

An illustration of two colliding neutron stars, a tremendously powerful event that could spell doom for life on Earth.

Scientists have determined the possible effects of a neutron star collision happening near Earth, finding that these so-called kilonovas could be real killers that would doom humanity. But don't worry, the collision would have to be really close to wreak havoc on our world. Nonetheless, here's what would probably go down.

"We found that if a neutron star merger were to occur within around 36 light-years of Earth, the resulting radiation could cause an extinction-level event," Haille Perkins, team leader and a scientist at the University of Illinois Urbana-Champaign, told Space.com.

Neutron star clashes that create bursts of light, called kilonovas, are considered the most violent and powerful events in the known universe. This is perhaps unsurprising, given that neutron stars are the collapsed remnants of dead stars and are made of matter so dense a teaspoon of one brought to Earth would weigh about 10 million tons. That's equivalent to 350 Statues of Liberty balanced on a spoon.

Not only do these dead star mergers create blasts of gamma rays and showers of charged particles moving at near-light speeds , known as cosmic rays, but they also generate the only environments we know of turbulent enough to forge elements heavier than lead, like gold and platinum. These elements can't even be created at the incredible ultra-high temperatures and pressures found in the hearts of massive stars.

Further, neutron star mergers set the very fabric of space "ringing" with ripples called gravitational waves, which can be detected here on Earth — even after traveling across billions of light years.

"Neutron stars can exist in binary systems, and when they merge, they produce a rare but spectacular event," Perkins said.

The team's research was based on observations of the neutron star merger behind gravitational wave signal GW 170817, picked up by Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2017, and gamma-ray burst GRB 170817A.

Occurring about 130 million light-years away, this is the only neutron star merger thus far seen in electromagnetic radiation and heard in gravitational waves, making it a natural choice for investigating these powerful events.
A killer-nova?

An illustration of two colliding neutron stars, a tremendously powerful event that could spell doom for life on Earth.

Neutron star merger gamma rays are arguably the most obviously threatening aspect of these events. That's because this type of radiation carries enough energy to strip electrons from atoms, a process called ionization. And these ionizing blasts of radiation could easily destroy the Earth's ozone layer, resulting in our planet receiving lethal doses of ultraviolet radiation from the sun.

Perkins and her colleagues determined gamma rays coming from neutron star mergers — in twin narrow jets from either side of the merger — would pretty much roast any living thing that falls directly in their path for a distance of about 297 light-years. Fortunately, however, that effect has an extremely narrow range. In other words, it really would take a "direct hit" from a jet to give rise to such dramatic effects. But, there's another issue.

These jets are cocooned with gamma radiation in general, which would also affect the ozone layer of Earth if our planet was in their wider path — within about 13 light-years of them. This "off-axis" gamma-ray cocoon's ozone damage would also take 4 years to recover from. All in all, the gamma-ray cocoon strike would leave the Earth's surface exposed to harmful ultraviolet light for nearly half a decade.

Though gamma-ray effects of neutron star mergers are relatively short-lived, there is also another form of ionizing radiation these emissions give rise to, which is less energetic but longer-lasting.

When the jets of gamma rays hit gas and dust around stars, called the interstellar medium, this creates powerful X-ray emissions called the X-ray afterglow. Such X-ray emission lives longer than gamma-ray emissions and could also ionize the ozone layer, the team says. This, therefore, is arguably more lethal. Earth would need to be quite close to this afterglow before we have to be concerned about our fate, however — within a distance of 16.3 light years to be exact.

And we haven't gotten to the worst part yet.

The most threatening effect of the neutron star smash-up that the team discovered comes from those highly energetic charged particles, or cosmic rays, that spread away from the event's epicenter in the form of an expanding bubble. Were these cosmic rays to strike Earth, they would strip the ozone layer and leave the planet vulnerable to being blasted by ultraviolet rays for a period of thousands of years.

This would qualify as an extinction-level event, and Earth could be affected even if our planet were around 36 light-years away.

"The specific distance of safety and component that is most dangerous is uncertain as many of the effects depend on properties like viewing angle to the event, the energy of the blast, the mass of material ejected, and more," Perkins continued. "With the combination of parameters we select, it seems that the cosmic rays will be the most threatening."
Again, don't panic just yet!

Before lamenting that the end is nigh, it is worth weighing the apocalyptic picture painted by the impact of neutron star mergers against some other factors surrounding these events.

"Neutron star mergers are extremely rare but quite powerful, and this, combined with the relatively small range of lethality, means an extinction caused by a binary neutron star merger should not be a concern of the people on Earth," Perkins assured.

To get a picture of this rarity, throughout the 100 billion stars in the Milky Way, scientists have thus far only found one potential kilonova progenitor system, CPD-29 2176, which is located about 11,400 light-years from Earth.

"There are several other more common events like solar flares, asteroid impacts, and supernova explosions that have a better chance of being harmful," Perkins continued.

She added that some of these other events have been associated with mass extinction events on Earth already, with the most striking example of this being the impact of a massive asteroid that wiped out the non-avian dinosaurs and three-quarters of life on Earth around 66 million years ago in the Cretaceous-Tertiary extinction event.

Where this research does have important connotations is in the search for life elsewhere in the universe, as it certainly gives us an idea of the systems that aren't likely to enjoy the conditions needed to support life. (Life as we know it, at least.)

"Their conclusion that kilonovas could have a similar lethality to supernovas, but are much less common, coincides with what I believe would be likely to be the case," Niels Bohr Institute Cosmic Dawn Center scientist Darach Watson, who also studies kilonovas and was not involved in this research, told Space.com. "So overall, this is likely to be more of a threat for planets in old galaxies where the star-formation has ended, not so much in the Milky Way."

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As for the team behind this research, Perkins explained that the next step is to observe more of these neutron star collision events.

"Currently, we only have one confirmed detection of a kilonova from a binary neutron star merger, so any more observations will constrain the unknowns," she concluded.

The team's research is published on the open-access paper repository arXiv.