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One of physicist Stephen Hawking’s most famous paradoxes may finally be solved: Black holes may in fact hang onto information about the massive stars that created them, new research indicates. 

This information may lurk in the radiation around black holes – colloquially known as “quantum hair” – and could, in theory, be retrieved to retell the origins of those black holes, the research suggests. 

These findings, published March 6 in the journal Physics Letters B. (opens in new tab) , may finally resolve a thorny problem that Hawking was working on in his last years. 

Related: Stephen Hawking’s final book says there’s ‘no possibility’ of God in our universe

According to Hawking’s work, radiation slowly “leaks” out of black holes in the form of thermal energy, which has come to be known as “Hawking radiation.” But because of its thermal nature, this radiation can’t carry information. That means that as black holes evaporate, they methodically destroy all information about the stars that created them. This is contrary to the laws of quantum mechanics, which say that information cannot be destroyed and that an object’s final state can reveal clues about its initial state. This problem has troubled cosmologists for decades and is known as the “Hawking information paradox.” 

“[This research] is the final nail in the coffin for the paradox because we now understand the exact physical phenomenon by which information escapes a decaying black hole,” lead study author Xavier Calmet (opens in new tab) , a professor of physics at the University of Sussex, told Live Science via email. He suggests a modification to Hawking radiation that makes it “non-thermal” and thus capable of carrying information with it away from the final fate of the black hole. 

Physicist Stephen Hawking in his office in 1989. (Image credit: Jean-Regis Rouston/Roger Viollet via Getty Images) The black hole problem

Black holes are objects so massive that nothing can escape the pull of their gravity, not even light. They form when enormous stars run out of fuel and collapse in on themselves.

In classical physics, black holes are “very simple objects,” Calmet said. “So simple that they can be characterized by three numbers: their mass, angular momentum, and electric charge.”

Famous physicist John Wheeler described this lack of distinguishing characteristics by saying “black holes have no hair.” But, Calmet explained, while the final black hole is very simple, the original star that birthed it is a complex astrophysical object, consisting of a complicated amalgam of protons, electrons, and neutrons which come together to form the elements that build the chemical composition of that star. 

While black holes carry no “memory” of the stars they once were, the rules of quantum physics say that information can’t simply be erased from the universe. In 1976, Hawking introduced a fly to this cosmic ointment by showing this information couldn’t dwell indefinitely within black holes sealed away from the outside universe either. Applying the rules of quantum mechanics to black holes, Hawking suggested they emit a type of thermal radiation, later called Hawking radiation. Over immense periods of time, the leaking of this radiation causes black holes to completely evaporate, leaving only a vacuum behind. In this way, information is irretrievably lost.

“This is however not allowed by quantum physics, which posits that the movie of this black hole’s ‘life’ could be rewound,” Calmet said. “Starting from the radiation we should be able to rebuild the original black hole and then eventually the star.”Finding the black hole’s ‘hair’

Along with his colleague Steve Hsu (opens in new tab) , a professor of theoretical physics at Michigan State University, Calmet has been working since 2021 to crack Hawking’s paradox. In a previous study, published in March 2022, the team argued that black holes do indeed have “quantum hair,” in the form of a unique quantum imprint in the gravitational fields that surround them

In their new research, the team reassessed Hawking’s 1976 calculations, but this time accounted for the effects of “quantum gravity”  —  the description of gravity according to the principles of quantum mechanics  —  something Hawking hadn’t done. Related stories— The 12 Strangest Objects in the Universe

— The 18 Biggest Unsolved Mysteries in Physics 

— 11 Fascinating Facts About Our Milky Way Galaxy 

“While these quantum gravitational corrections are minuscule, they are crucial for black hole evaporation,” Calmet said. “We were able to show that these effects modify Hawking radiation in such a way that this radiation becomes non-thermal. In other words, factoring in quantum gravity the radiation can contain information.”

While the quantum hair suggested in Calmetand Hsu’s previous work was an abstract mathematical concept, the team has now identified the exact physical phenomenon by which information escapes the black hole via Hawking radiation, and how it could be retrieved by an outside observer. This is currently not possible, as it would require an instrument sensitive enough to measure Hawking radiation, which currently is purely theoretical. 

Currently there is no real way for astrophysicists to measure the effect the researchers propose, as it is minuscule, Calmet acknowledged. Instead, he suggests one way to progress this theory would be by studying simulations of black holes in labs on Earth. The team’s mathematical modeling of Hawking radiation and black holes could prove invaluable in these simulations. 

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Trump criticises Putin after potentially ‘historic’ meeting with Zelenskyy before Pope’s funeral

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Trump criticises Putin after potentially 'historic' meeting with Zelenskyy before Pope's funeral

Donald Trump has criticised Vladimir Putin and suggested a shift in his stance towards the Russian president after a meeting with Volodymyr Zelenskyy before the Pope’s funeral.

The Ukrainian president said the one-on-one talks could prove to be “historic” after pictures showed him sitting opposite Mr Trump, around two feet apart, in the large marble hall inside St Peter’s Basilica.

The US president said he doubted his Russian counterpart’s willingness to end the war after leaving Rome after the funeral of Pope Francis at the Vatican.

Follow live updates: 200,000 mourn at Vatican

In a post on his Truth Social platform, he said “there was no reason” for the Russian president “to be shooting missiles into civilian areas, cities and towns, over the last few days”.

The two leaders held talks before attending the Pope's funeral
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The two leaders held talks before attending the Pope’s funeral

He added: “It makes me think that maybe he doesn’t want to stop the war, he’s just tapping me along, and has to be dealt with differently, through ‘Banking’ or ‘Secondary Sanctions?’ Too many people are dying!!!”

The meeting between the US and Ukrainian leaders was their first face-to-face encounter since a very public row in the Oval Office in February.

Mr Zelenskyy said he had a good meeting with Mr Trump in which they talked about the defence of the Ukrainian people, a full and unconditional ceasefire, and a durable and lasting peace that would prevent the war restarting.

Other images released by the Ukrainian president’s office show Sir Keir Starmer and French President Emmanuel Macron were present for part of the talks, which were described as “positive” by the French presidency.

Mr Zelenskyy‘s spokesman said the meeting lasted for around 15 minutes and he and Mr Trump had agreed to hold further discussions later on Saturday.

The world leaders share a moment before the service
Image:
The world leaders shared a moment before the service

Trump and Zelenskyy meet in the Basilica
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Donald Trump and Volodymyr Zelenskyy meet in the Basilica

But the US president left Rome for Washington on Air Force One soon after the funeral without any other talks having taken place.

The Ukrainian president’s office said there was no second meeting in Rome because of the tight schedule of both leaders, although he had separate discussions with Mr Starmer and Mr Macron.

The French president said in a post on X “Ukraine is ready for an unconditional ceasefire” and that a so-called coalition of the willing, led by the UK and France, would continue working to achieve a lasting peace.

There was applause from some of the other world leaders in attendance at the Vatican when Mr Zelenskyy walked out of St Peter’s Basilica after stopping in front of the pontiff’s coffin to pay his respects.

U.S President Donald Trump attends the funeral Mass of Pope Francis, at the Vatican, April 26, 2025. REUTERS/Kai Pfaffenbach
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Donald Trump and the Ukrainian president met for the first time since their Oval Office row. Pic: Reuters

Sir Tony Brenton, the former British ambassador to Russia, said the event presents diplomatic opportunities, including the “biggest possible meeting” between Mr Trump and the Ukrainian leader.

He told Sky News it could mark “an important step” in starting the peace process between Russia and Ukraine.

Professor Father Francesco Giordano told Sky News the meeting is being called “Pope Francis’s miracle” by members of the clergy, adding: “There’s so many things that happened today – it was just overwhelming.”

The bilateral meeting comes after Mr Trump’s peace negotiator Steve Witkoff held talks with Mr Putin at the Kremlin.

They discussed “the possibility of resuming direct negotiations between Russia and Ukraine”, Kremlin aide Yuri Ushakov said.

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Russia and Ukraine have not held direct talks since the early weeks of the war, which began in February 2022.

Mr Trump has claimed a deal to end the war is “very close” and has urged Mr Zelenskyy to “get it done” in a post on his Truth Social platform.

He has previously warned both sides his administration would walk away from its efforts to achieve a peace if the two sides do not agree a deal soon.

Meanwhile, the Polish armed forces said a Russian military helicopter violated its airspace over the Baltic Sea on Friday evening.

“The nature of the incident indicates that Russia is testing the readiness of our air defence systems,” they said in a post on X.

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What we learn from remarkable photos of Trump-Zelenskyy meeting

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What we learn from remarkable photos of Trump-Zelenskyy meeting

On an extraordinary day, remarkable pictures on the margins that capture what may be a turning point for the world.

In a corner of St Peter’s Basilica before the funeral of Pope Francis, the leaders of America and Ukraine sit facing each other in two solitary chairs.

They look like confessor and sinner except we cannot tell which one is which.

Leaning forward hands together in their laps, Donald Trump and Volodymyr Zelenskyy stare at each other in one photo.

In another, the Ukrainian president seems to be remonstrating with the US president. This is their first encounter since their infamous bust-up in the Oval Office.

The two leaders held talks before attending the Pope's funeral
Image:
The two leaders held talks before attending the Pope’s funeral

Other pictures show the moment their French and British counterparts introduced the two men. There is a palpable sense of nervousness in the way the leaders engage.

We do not know what the two presidents said in their brief meeting.

But in the mind of the Ukrainian leader will be the knowledge President Trump has this week said America will reward Russia for its unprovoked brutal invasion of his country, under any peace deal.

Mr Trump has presented Ukraine and Russia with a proposal and ultimatum so one-sided it could have been written in the Kremlin.

Kyiv must surrender the land Russia has taken by force, Crimea forever, the rest at least for now. And it must submit to an act of extortion, a proposed deal that would hand over half its mineral wealth effectively to America.

The world leaders share a moment before the service
Image:
The world leaders shared a moment before the service

Afterwards, Zelenskyy said it had been a good meeting that could turn out to be historic “if we reach results together”.

They had talked, he said, about the defence of Ukraine, a full and unconditional ceasefire and a durable and lasting peace that will prevent a war restarting.

The Trump peace proposal includes only unspecified security guarantees for Ukraine from countries that do not include the US. It rules out any membership of Ukraine.

Ukraine’s allies are watching closely to see if Mr Trump will apply any pressure on Vladimir Putin, let alone punish him for recent bloody attacks on Ukraine.

Or will he simply walk away if the proposal fails, blaming Ukrainian intransigence, however outrageously, before moving onto a rapprochement with Moscow.

If he does, America’s role as guarantor of international security will be seen effectively as over.

This could be the week we see the world order as we have known it since the end of the Second World War buried, as well as a pope.

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Crypto sentiment recovers, but weekend liquidity risks remain

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Crypto sentiment recovers, but weekend liquidity risks remain

Crypto sentiment recovers, but weekend liquidity risks remain

Crypto investor sentiment has seen a significant recovery from global tariff concerns, but analysts warn that the market’s structural weaknesses may still result in downside momentum during periods of weekend illiquidity.

Risk appetite appeared to return among crypto investors this week after US President Donald Trump adopted a softer tone, saying that import tariffs on Chinese goods may “come down substantially.”

However, the improved investor sentiment “does not guarantee that Bitcoin will avoid volatility over the weekend,” analysts from Bitfinex exchange told Cointelegraph:

“Sentiment improvements reduce fragility, but they do not eliminate structural risks like thin weekend liquidity.” 

“Historically, weekends remain vulnerable to sharp moves — especially when open interest is high and market depth is low,” the analysts said, adding that unexpected macroeconomic news can still increase volatility during low liquidity periods.

Related: Trump fought the bond market, the bond market won: Saifedean Ammous

Bitcoin (BTC) staged a near 11% recovery during the past week, but its rally has previously been limited by Sunday liquidity dynamics.

Crypto sentiment recovers, but weekend liquidity risks remain
BTC/USD, 1-year chart. Source: Cointelegraph

Bitcoin fell below $75,000 on Sunday, April 6, despite initially decoupling from the US stock market’s $3.5 trillion drop on April 4 after US Federal Reserve Chair Jerome Powell warned that Trump’s tariffs may affect the economy and raise inflation.

The correction was exacerbated by the lack of weekend liquidity and the fact that Bitcoin was the only large liquid asset available for de-risking, industry watchers told Cointelegraph.

Related: US banks are ‘free to begin supporting Bitcoin’ — Michael Saylor

“While improved sentiment creates a more stable foundation, cryptocurrency markets are still susceptible to rapid movements during periods of reduced trading volume,” according to Marcin Kazmierczak, co-founder and chief operating officer of RedStone blockchain oracle firm.

“The sentiment recovery provides some cushioning, but traders should remain cautious as weekend liquidity constraints can still amplify price movements regardless of the current market mood,” he told Cointelegraph.

Crypto investors may have “maxed out on tariff-related fears”

Cryptocurrency markets may have priced in the full extent of tariff-related concerns, according to Aurelie Barthere, principal research analyst at crypto intelligence platform Nansen.

“It feels like we’ve maxed out on tariff-related fear,” she told Cointelegraph, adding:

“While many remain uncertain about where things are headed over the next month or so, it also seems like markets were just waiting for the slightest signal that we’re back in the game.”

“Whether the rally is sustainable depends on whether we can break through previous resistance levels, at least in isolation. It could have legs, as markets now seem to believe there’s a ‘Trump put’ under equities, the US dollar and US Treasurys,” Barthere added, warning of more potential volatility amid the upcoming negotiations.

Nansen previously predicted a 70% chance that crypto markets will bottom and start a recovery by June, but highlighted that the timing will depend on the outcome of tariff negotiations.

The tariff negotiations may only be “posturing” for the US to reach a trade agreement with China, which may be the “big prize” for Trump’s administration, according to Raoul Pal, founder and CEO of Global Macro Investor.

Magazine: Bitcoin’s odds of June highs, SOL’s $485M outflows, and more: Hodler’s Digest, March 2 – 8

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