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2 years ago

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Observations suggest that the intergalactic gas in our universe is a little hotter than it should be. Recently, a team of astrophysicists have used sophisticated computer simulations to propose a radical solution: an exotic form of dark matter known as “dark photons” could be heating the place up.

These strange particles would be the carriers of a new, fifth force of nature that normal matter does not experience, but occasionally these dark photons can flip their identities to become regular photons, providing a source of heat.Feeling neutral

We could find such dark photons by observing the intergalactic gas using what’s known as the Lyman-alpha forest. When we observe light from a distant, bright object, like a quasar (glowing objects powered by black holes at the centers of distant galaxies), there is a series of gaps in an otherwise smooth spectrum of light from that faraway object. 

Here’s why: that light has to filter through billions of light-years of gas to reach us. Occasionally that light will pass through a relatively dense clump of neutral hydrogen — a type of hydrogen that consists of one proton and one neutron, and which permeates gas clouds throughout the universe. 

Most of that light will pass through unaffected, but a very specific wavelength of light will get absorbed. This wavelength corresponds to the energy difference needed to bump an electron from its first to its second energy level inside the hydrogen atoms.

When astronomers look at the light coming from that object, it will look otherwise unremarkable except for a gap at the wavelength of that specific energy transition, known as the Lyman-alpha line.

The light from the distant object will pass through multiple clouds and clumps of neutral hydrogen. The expansion of the universe causes the gaps to redshift to different wavelengths, with a new gap appearing at a different wavelength depending on the distance to the particular gas clouds.. The end result of this is the “forest”: a series of lines and gaps in the spectrum. Getting hot in here

These Lyman-alpha gaps can also be used to measure the temperature of each gas cloud. If the neutral hydrogen were perfectly still, the gap would appear as an incredibly thin line. But if the individual molecules are moving, then the gap will widen because of the kinetic energy of those molecules. The hotter the gas, the more kinetic energy the molecules have, and the wider the gap.

In a paper appearing in November in the journal Physical Review Letters, a team of astrophysicists have pointed out that by using this method, it seems that the clouds of gas that scatter between galaxies are a little too hot. Computer simulations of the evolution of those gas clouds predict them to be just a little bit colder than we observe, and so perhaps something is heating up those clouds that isn’t currently accounted for in our astrophysical simulations.

One possible explanation for this discrepancy is the presence of “dark photons” in our universe, the study authors claim. This is a very hypothetical form of dark matter, the mysterious, invisible substance that accounts for roughly 80% of all the mass in the universe, yet doesn’t seem to interact with light.

Since astronomers do not currently understand the identity of dark matter, the field is wide open with possibilities as to what it could be. In this model, instead of the dark matter being made of invisible particles (like a phantom version of electrons, for example), it would instead be made of a new kind of force carrier — that is, a type of particle that mediates interactions between other particles.A warm and fuzzy darkness

The familiar photon is the force carrier of electromagnetism – it’s what creates electricity, magnetism, and light. Dark photons would be a force carrier for a new force of nature that does not operate at the usual scales in the usual scenarios (for example, in our laboratories or within the solar system, where we otherwise would have already observed it).

According to the study authors, the dark photons would still have a tiny bit of mass, and hence they could still account for the dark matter. Plus, because they’re force carriers, they may also interact amongst themselves and with other potential dark matter particles. In the models investigated by the team of astrophysicists, the dark photons are capable of one more trick: they can occasionally turn into a regular photon.Related stories—From Big Bang to present: Snapshots of our universe through time

—The 18 biggest unsolved mysteries in physics

—The 15 weirdest galaxies in the universe

In physics terms, the dark photons can “mix” with regular photons, very rarely swapping identities. When they do, the newly created photon goes on to do what regular photons always do: heat things up. The researchers performed the first ever simulations of the evolution of the universe, including the effects of these sneaky shapeshifting dark photons. They found that a particular combination of dark photon mass and the probability of changing into a regular photon could explain the heating discrepancy.

This result is a very far from a slam-dunk case for the existence of dark photons. A range of possibilities could also explain the Lyman-alpha results, like inaccurate observations or a poor understanding of (normal) astrophysical heating between galaxies. But it is an intriguing clue, and the results can be used as a springboard to continue exploring the viability of this exotic idea. 

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Mark Carney’s Liberal Party wins Canada election, according to Canadian broadcasters

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28 mins ago

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April 29, 2025

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Mark Carney's Liberal Party wins Canada election, according to Canadian broadcasters

Mark Carney’s Liberal Party has won the election in Canada, according to Canadian broadcasters, but it is too soon to say whether they will form a majority government.

Mr Carney, who took over as prime minister after Justin Trudeau stepped down earlier this year, has beaten the leader of the Conservative Party Pierre Poilievre, according to CBC and CTV News projections.

However, it is too soon to say whether the Liberals will form a majority government, they added. The party has not yet secured the 172 electoral districts it needs for a majority.

FILE PHOTO: Conservative Party of Canada leader Pierre Poilievre speaks at an election campaign event in Brampton, Ontario, Canada April 9, 2025. REUTERS/Carlos Osorio/File Photo
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Conservative leader Pierre Poilievre. Pic: Reuters

The election initially appeared to be a clear-cut race for the opposition Conservatives, who were enjoying a double-digit lead over the Liberals before Mr Trudeau resigned, and an intervention by Donald Trump led to a surge in support for Mr Carney’s party.

Mr Trump has repeatedly called for Canada to become the 51st US state since he was elected president for a second time and has imposed sweeping tariffs on Canada.

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Trump on why he wants Canada to be 51st state

Mr Carney has vowed to take a tougher approach with Washington over its tariffs and has said Canada will need to spend billions to reduce its reliance on the US.

Liberal supporters react after Canadian broadcasters project their party has retained power. Pic: Reuters
Liberal supporters react after Canadian broadcasters project their party has retained power. Pic: Reuters
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Liberal supporters celebrate after Canadian broadcasters project their party has retained power. Pics: Reuters

If Mr Carney’s party only captures a minority of the House’s 343 seats, he will be forced to negotiate with other parties in order to stay in power.

Such minority governments rarely last longer than two-and-a-half years in Canada.

Canadians went to the polls after 11 people were killed in a deadly attack at a Vancouver street fair over the weekend that led to the suspension of campaigning for several hours.

Police have ruled out terrorism and said the suspect is a local man with a history of mental health issues.

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Mr Carney previously ran Canada’s central bank and later became the first non-Briton to become governor of the Bank of England.

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Sports

Lightning’s Hagel leaves G4 loss after high hit

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36 mins ago

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April 29, 2025

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Lightning's Hagel leaves G4 loss after high hit

  • Greg Wyshynski

Apr 28, 2025, 09:30 PM ET

Tampa Bay Lightning forward Brandon Hagel left his team’s 4-2 loss to the host Florida Panthers in Game 4 of their Eastern Conference first-round series on Monday night after a high hit from defenseman Aaron Ekblad that wasn’t penalized.

With less than 9 minutes left in the second period, Hagel played the puck out of the Tampa Bay zone near the boards. Ekblad skated in on him and delivered a hit with his right forearm that made contact with Hagel’s head, shoving him down in the process.

The back of Hagel’s head hit the ice. He was pulled from the game for concussions concerns. Ekblad did not receive a penalty on the play.

The Lightning trailed the Panthers 1-0 at the time of the hit, but Mitchell Chaffee and Erik Cernak scored two goals in 11 seconds after Hagel left the game to give Tampa Bay a 2-1 lead. When the teams returned for the third period, Hagel was not on the bench.

The Panthers rallied in the third, as Ekblad, Seth Jones and Carter Verhaeghe scored to give Florida a 3-1 series lead. Game 5 is in Tampa on Wednesday.

Game 4 saw Hagel return to the Tampa Bay lineup after he served a one-game suspension for interference on Florida captain Aleksander Barkov in Game 2. The NHL ruled the Barkov wasn’t eligible to be hit and that Hagel made head contact with him. It was the first suspension of this career.

Hagel was one of the best two-way wingers in the league this season, with 35 goals and 55 assists in 82 games for the Lightning.

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Nimmo matches Mets franchise record with 9 RBIs

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56 mins ago

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April 29, 2025

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Nimmo matches Mets franchise record with 9 RBIs

  • ESPN News Services

Apr 28, 2025, 08:07 PM ET

WASHINGTON — Brandon Nimmo hit a grand slam and matched a franchise record with nine RBIs, helping the New York Mets past the Washington Nationals in a 19-5 rout on Monday.

Nimmo also hit a three-run drive in his seventh career multihomer game. The 32-year-old outfielder had four hits and scored four times after beginning the day with a .192 batting average.

All of Nimmo’s damage came in a three-inning span. According to ESPN Research, he became only the third player to pull off that feat in that time frame since the RBI became an official stat in 1920.

The win came a day after New York let a six-run lead slip in an 8-7 loss to the Nationals. The matinee bounce-back earned the club split of the four-game series. The Mets have won nine of 11 overall to improve to a major league-best 20-9.

“Really proud of the guys for flushing yesterday, coming back today and really going out there and work on all sides of the ball,” Nimmo said. “It was really fun to play today.”

Jeff McNeil and Mark Vientos also homered for New York, which finished with 21 hits. Vientos connected for a three-run drive against Washington infielder Amed Rosario in the ninth.

James Wood and Nathaniel Lowe homered for Washington in the eighth.

The Mets had a 3-0 lead when Colin Poche replaced Nationals starter Trevor Williams (1-3) with two on in the sixth. Nimmo greeted the left-hander by ripping a 2-0 fastball deep to right-center.

An inning later, the Mets had the bases loaded when Nimmo sent Cole Henry‘s fastball into the right-field seats for his second career grand slam.

Nimmo added a two-run double in the eighth to tie the franchise record for RBIs set by Carlos Delgado in the first game of a doubleheader against the New York Yankees on June 27, 2008.

“Tomorrow is a new day as well,” Nimmo said, quickly turning the page from the win. “And we’re just going to have to take it a day at a time, and treat it like it is its own.”

McNeil, who made his season debut Friday after sitting out 25 games because of a right oblique strain, hit the first pitch of the fifth deep to right for his first home run of the year.

“One hundred percent,” Mets manager Carlos Mendoza said, when asked if McNeil’s start has been good to see. “When you see him pulling the ball like that, and going deep? That’s a good sign. It’s good to see him continue with that approach.”

Griffin Canning (4-1) pitched five innings of four-hit ball for New York. He has won four consecutive starts for the first time in his six-season career.

Jose Urena earned his first save of the season. He gave up five runs in three innings in his Mets debut.

Williams yielded five runs in a season-high 5⅓ innings.

The Associated Press contributed to this report.

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