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inscrutable interiors — Probing the mysteries of neutron stars with a surprising earthly analog Ultracold gases in the lab could help scientists better understand the universe.

Katie McCormick – Jul 9, 2023 11:34 am UTC Enlarge / Spectral analysis indicates that silica is present in this supernova remnant, Cassiopeia A.NASA/JPL-Caltech/ O. Krause (Steward Observatory) reader comments 28 with

Ever since neutron stars were discovered, researchers have been using their unusual properties to probe our universe. The superdense remnants of stellar explosions, neutron stars pack a mass greater than the Suns into a ball about as wide as San Francisco. A single cup of this star matter would weigh about as much as Mount Everest.

These odd celestial bodies could alert us to distant disturbances in the fabric of spacetime, teach us about the formation of elements, and unlock the secrets of how gravity and particle physics work in some of the most extreme conditions in the universe.

Theyre at the center of a lot of open questions in astronomy and astrophysics, says astrophysicist Vanessa Graber of the Institute of Space Sciences in Barcelona.

But to accurately interpret some of the neutron stars signals, researchers must first understand what goes on inside them. They have their hunches, but experimenting directly on a neutron star is out of the question. So scientists need another way to test their theories. The behavior of matter in such a superdense object is so complicated that even computer simulations arent up to the task. But researchers think they may have found a solution: an earthly analog.

Though young neutron stars can have temperatures in the millions of degrees in their interior, by one important energetic measure neutrons are considered cold. Physicists think that is a characteristic they can exploit to study the inner workings of neutron stars. Instead of looking to the sky, researchers are peering into clouds of ultracold atoms created in laboratories here on Earth. And that might help them finally answer some longstanding questions about these enigmatic objects. Advertisement Space oddities

The existence of neutron stars was first proposed in 1934, two years after the discovery of the neutron itself, when astronomers Walter Baade and Fritz Zwicky wondered if a celestial body made entirely of neutrons might remain after a supernova explosion. Though they didnt get all the details right, their general idea is now widely accepted.

Stars power themselves by fusing the nuclei of lighter atoms into those of heavier atoms. But when stars run out of those lighter atoms, nuclear fusion stops and there is no longer an outward pressure to fight against the inward force of gravity. The core collapses and the stars outer layer races inward. When this layer hits the dense core, it bounces off and explodes outward, producing a supernova. The dense core that remains afterward is a neutron star. Enlarge / The remains of a supernova witnessed in the year 1054, the Crab Nebula contains a rapidly spinning neutron star known as a pulsar.CREDIT: NASA: X-RAY: CHANDRA (CXC), OPTICAL: HUBBLE (STSCI), INFRARED: SPITZER (JPL-CALTECH)

It wasnt until the 1960s that Zwicky and Baades hypothetical neutron stars were finally detected. Radio astronomer Jocelyn Bell Burnell noticed a strange, regularly pulsed radio wave signal from space while working as a graduate student at the University of Cambridge. She was detecting something that had never been seen before: a special kind of neutron star called a pulsar, which flashes beams of radiation at regular intervals as it spins, like a lighthouse. (Her adviser, along with the director of the observatorybut not Bell Burnelllater received the Nobel Prize for the discovery.)

Since then, thousands of neutron stars have been detected. As some of the densest, highest-pressure objects in the universe, neutron stars might help us learn about what happens to matter at extremely high densities. Understanding their structure and the behavior of the neutron matter composing them is of paramount importance to physicists. Advertisement

Scientists already know that the neutrons, protons, and other subatomic particles that compose a neutron star arrange themselves differently depending on where in the star they are. In certain sections, they pack rigidly like water molecules in a block of ice. In others, they flow and swirl like a frictionless fluid. But exactly where the transition happens and how the different phases of matter behave, physicists arent sure.

A superdense star born of a nuclear fireball seems, on its face, to have very little in common with a dilute cloud of ultracold particles. But they can share at least one useful characteristic: They are both below a threshold known as the Fermi temperature that depends onand is calculated based onthe matter each system is made of. A system that is well above this temperature will largely behave according to the laws of classical physics; if it is well below, its behavior will be ruled by quantum mechanics. Certain ultracold gases and neutron star material can both be well below their Fermi temperatures and consequently can act in similar ways, says Christopher Pethick, a theoretical physicist at the Niels Bohr Institute in Copenhagen and coauthor of an early overview of neutron stars in the 1975 Annual Review of Nuclear Science.

Matter that is below its Fermi temperature can obey remarkably universal laws. This universality means that, while we dont have easy access to several-million-degree neutron star matter, we could learn about some of its behavior by experimenting with ultracold gases that can be created and manipulated in laboratory vacuum chambers on Earth, says theoretical astrophysicist James Lattimer of Stony Brook University in New York, author of a summary of the science of nuclear matter in the 2012 Annual Review of Nuclear and Particle Science.

Of particular interest to Lattimer is a theoretical state called a unitary gas. A gas is unitary when each of its particles sphere of influence becomes infinite, meaning that they would influence each other no matter how far apart they are. This is impossible to have in reality, but ultracold atom clouds can get closeand so can the matter inside of neutron stars. Its similar to a unitary gas, Lattimer says, but its not a perfect unitary gas. Page: 1 2 Next → reader comments 28 with Advertisement Channel Ars Technica ← Previous story Next story → Related Stories Today on Ars

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NASCAR suspends Hill 1 race for intentional crash

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NASCAR suspends Hill 1 race for intentional crash

CHARLOTTE, N.C. — NASCAR on Tuesday suspended Austin Hill for one Xfinity Series race for intentionally crashing Aric Almirola at Indianapolis Motor Speedway.

Richard Childress Racing said Cup Series driver Austin Dillon will replace Hill in the Xfinity Series race at Iowa this weekend.

The suspension also stripped Hill of the 21 playoff points he has earned in 2025 and prohibits him from earning points ahead of the playoffs under a new rule made before the start of the 2025 season. Hill will have to apply for a waiver to retain his playoff eligibility.

Prior to the suspension, Hill’s playoff points trailed only Connor Zilisch (29) and Justin Allgaier (22). But that count resets to zero, making his margin of error during the first playoff round virtually none.

Hill is ranked seventh in the Xfinity Series standings with three victories. He will likely lose position in the standings with the suspension, and only drivers ranked in the top 12 make the Xfinity playoffs.

Hill argued the contact with Almirola on Saturday was not intentional but NASCAR gave him a five-lap penalty. Hill went into an expletive-filled tirade after being told he was penalized.

The two were in the top-five at Indy when Almirola made contact to move Hill up the race track. Hill corrected his car and then turned left to hook Almirola in the right rear.

Almirola spun and crashed into the outside wall. Hill finished 34th and five laps down. Almirola finished 35th.

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Starmer’s plan to recognise Palestinian state labelled ‘appeasement towards jihadist terrorists’ by Netanyahu

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Starmer's plan to recognise Palestinian state labelled 'appeasement towards jihadist terrorists' by Netanyahu

Sir Keir Starmer’s plan to recognise Palestine as a state has been attacked as “appeasement towards jihadist terrorists” by Israeli Prime Minister Benjamin Netanyahu.

The prime minister said the UK will recognise a Palestinian state by September unless Israel takes “substantive steps” to end the situation in Gaza, Israel agrees to a ceasefire, commits to a long-term sustainable peace, allows the UN to restart aid supplies and does not annexe the West Bank.

About 250 MPs from all parties – half of them Labour – had signed a letter last week calling for Sir Keir to immediately recognise a Palestinian state.

Politics latest: PM’s Palestine plan labelled ‘absurd’

Sir Keir said that by giving Israel a deadline of 9 September UN meeting, he hoped this would play a part “in changing the conditions on the ground, and making sure aid gets into making sure that there is hope of a two-state solution for the future”.

But Mr Netanyahu condemned the plan, saying Sir Keir “rewards Hamas’s monstrous terrorism and punishes its victims”.

“A jihadist state on Israel’s border today will threaten Britain tomorrow,” he wrote on X.

More on Israel

“Appeasement towards jihadist terrorists always fails. It will fail you too. It will not happen.”

The Israelis also accused Sir Keir of pandering to his MPs and France, after Emmanuel Macron committed to recognising a Palestinian state last week, and harming efforts to release Israeli hostages.

Benjamin Netanyahu
Image:
Benjamin Netanyahu was effusive in his condemnation

Lib Dems and Greens: ‘Bargaining chip’

Sir Keir also faced accusations of using Palestinian state recognition as a “bargaining chip” by both the Lib Dems and the Green Party.

Lib Dem leader Sir Ed Davey said a Palestinian state should have been recognised “months ago” and “far greater action” is needed to stop the humanitarian disaster in Gaza.

Jordanian military personnel prepare planes to deliver airdrops in Gaza on Monday
Image:
Jordanian military personnel prepare planes to deliver airdrops in Gaza on Monday

Green Party foreign affairs spokesperson Ellie Chowns, who wants immediate state recognition, said it was a “cynical political gesture”.

Humza Yousaf, Scotland’s former SNP first minister, who revealed a family member was killed in Gaza days ago, told Sky News statehood “shouldn’t be dependent” upon the conditions Sir Keir has set for Israel, but is the “inalienable right” of the Palestinian people.

The British Palestinian Committee, representing Palestinian interests in the UK, described conditions as “absurd and performative”.

UK Jewish groups seek clarity

The Board of Deputies of British Jews, the UK’s largest Jewish organisation, said it was “seeking urgent clarification” that the UK will not recognise Palestine as a state if Israeli hostages remain in Hamas captivity, or if Hamas keeps rejecting a ceasefire deal.

The Labour Friends of Israel group said it has “shared goals” with the government but state recognition “will be a merely symbolic act unless the UK uses its influence to establish the principles of a meaningful pathway to a Palestinian state”.

Read more:
What does recognising a Palestinian state mean?
Children ‘eating out of piles of garbage’ as time runs out for Gaza

Sarah Champion, Labour MP and chair of the international development committee, who started the MP letter calling for state recognition, said she was “delighted and relieved”.

However, she added: “I’m troubled our recognition appears conditional on Israel’s actions.”

When Foreign Secretary David Lammy announced the plan at a UN meeting, he received applause.

Not many other Labour MPs commented.

Tories accuse Starmer of appeasing MPs

Conservative leader Kemi Badenoch accused Sir Keir of being more focused on a “political problem for the Labour Party” than other issues facing the UK.

“Recognising a Palestinian state won’t bring the hostages home, won’t end the war and won’t get aid into Gaza,” she posted on X.

“This is political posturing at its very worst.”

Tory shadow foreign secretary Priti Patel said the announcement was “to appease his backbenchers” as “he knows that promises to recognise Palestine will not secure lasting peace”.

Pic: Reuters
Image:
Aid trucks were allowed into Gaza on Tuesday. Pic: Reuters

Trump did not discuss statehood with Starmer

Donald Trump said he and Sir Keir “never did discuss” the PM’s plan to recognise a Palestinian state during their meetings in Scotland the day before.

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Trump responds to Sky question on Israel

However, Tammy Bruce, spokeswoman for the US state department, said Sir Keir’s plan is a “slap in the face for the victims of October 7”, which “rewards Hamas”, the Telegraph reported.

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Environment

Tesla tops another ADAS test, Hyundai tops range tests, and Texas gets BESS

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Tesla tops another ADAS test, Hyundai tops range tests, and Texas gets BESS

On today’s test-acular episode of Quick Charge, it’s a new day and a new Chinese ADAS test for Tesla to conquer – but this one’s got a LOT more pedestrian carnage to parse through! We’ve also got some great e-bike deals from Retrospec and a bladder-busting Hyundai.

Today’s episode is brought to you by Retrospec – the makers of sleek, powerful e-bikes and outdoor gear built for everyday adventure! To that end, we’ve got a pair of Retrospec e-bike reviews followed up by the updated Hyundai IONIQ 6 with nearly 350 miles of range from its updated long-range battery. With that, Hyundai now has the longest range Korean EV on the market, while Texas is adding megawatts of battery energy storage to beef up its troubled grid, and it’s doing so faster and cheaper than ever before.

PlusQuick Charge listeners can get an extra 10% off the price of their next awesome e-bike by using code ELECTREK10 at retrospec.com!

Prefer listening to your podcasts? Audio-only versions of Quick Charge are now available on Apple PodcastsSpotifyTuneIn, and our RSS feed for Overcast and other podcast players.

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New episodes of Quick Charge are recorded, usually, Monday through Thursday (most weeks, anyway). We’ll be posting bonus audio content from time to time as well, so be sure to follow and subscribe so you don’t miss a minute of Electrek’s high-voltage daily news.

Got news? Let us know!
Drop us a line at tips@electrek.co. You can also rate us on Apple Podcasts and Spotify, or recommend us in Overcast to help more people discover the show.


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