The universe is slightly hotter than it should be. ‘Dark photons’ could be to blame.

Published

2 years ago

January 30, 2023

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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.

Entertainment

Russell Brand charged with rape and sexual assault

Published

3 hours ago

April 4, 2025

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Russell Brand has been charged with rape and two counts of sexual assault between 1999 and 2005.

The Metropolitan Police say the 50-year-old comedian, actor and author has also been charged with one count of oral rape and one count of indecent assault.

The charges relate to four women.

He is due to appear at Westminster Magistrates’ Court on Friday 2 May.

Police have said Brand is accused of raping a woman in the Bournemouth area in 1999 and indecently assaulting a woman in the Westminster area of London in 2001.

He is also accused of orally raping and sexually assaulting a woman in Westminster in 2004.

The fourth charge alleges that a woman was sexually assaulted in Westminster between 2004 and 2005.

Police began investigating Brand, from Oxfordshire, in September 2023 after receiving a number of allegations.

The comedian has denied the accusations and said he has “never engaged in non-consensual activity”.

He added in a video on X: “Of course, I am now going to have the opportunity to defend these charges in court, and I’m incredibly grateful for that.”

Metropolitan Police Detective Superintendent Andy Furphy, who is leading the investigation, said: “The women who have made reports continue to receive support from specially trained officers.

“The Met’s investigation remains open and detectives ask anyone who has been affected by this case, or anyone who has any information, to come forward and speak with police.”

Sports

O’s Henderson off IL; will make ’25 debut vs. KC

Published

3 hours ago

April 4, 2025

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O's Henderson off IL; will make '25 debut vs. KC

Field Level Media

Apr 4, 2025, 04:36 PM ET

Baltimore Orioles All-Star shortstop Gunnar Henderson was activated from the 10-day injured list and will make his season debut Friday night against the Kansas City Royals.

Henderson has been sidelined with a right intercostal strain and missed the first seven games of the big league campaign.

The 23-year-old Henderson will lead off and play shortstop against the host Royals.

Henderson was injured during a spring training game Feb. 27. He was fourth in American League MVP voting last season when he batted .281 and racked up career bests of 37 homers and 92 RBIs.

Henderson completed a five-game rehab stint at Triple-A Norfolk on Wednesday. He batted .263 (5-for-19) with two homers and four RBIs and played four games at shortstop and one as the designated hitter. He did commit three errors.

“I think everybody’s looking forward to having Gunnar back on the team,” Baltimore manager Brandon Hyde said Thursday. “The rehab went really, really well. I talked to him a couple days ago, he feels great swinging the bat. The timing came, especially the last few days. He just had to get out there and get some reps defensively and get some games in, and it all went well.”

Baltimore optioned outfielder Dylan Carlson to Triple-A Norfolk to open up a roster spot. The 26-year-old was 0-for-4 with a run and RBI in two games this season.

Politics

‘Will the PM side with parents or tech bros?’: Labour peer demands action on children’s smartphone safety

Published

3 hours ago

April 4, 2025

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'Will the PM side with parents or tech bros?': Labour peer demands action on children's smartphone safety

Sir Keir Starmer needs to choose between parents who want stronger action to tackle harmful content on children’s phones, or the “tech bros” who are resisting changes to their platforms, Baroness Harriet Harman has said.

Speaking to Beth Rigby on Sky News’ Electoral Dysfunction podcast, the Labour peer noted that the prime minister met with the creators of hit Netflix drama Adolescence to discuss safety on social media, but she questioned if he is going to take action to “stop the tech companies allowing this sort of stuff” on their platforms where children can access it.

Sir Keir hosted a roundtable on Monday with Adolescence co-writer Jack Thorne and producer Jo Johnson to discuss issues raised in the series, which centres on a 13-year-old boy arrested for the murder of a young girl, and the rise of incel culture.

Politics latest: Could the UK retaliate against Trump?

The aim was to discuss how to prevent young boys being dragged into a “whirlpool of hatred and misogyny”, and the prime minister said the four-part series raises questions about how to keep young people safe from technology.

Sir Keir has backed calls for the four-part drama to be shown in all schools across the country, but Baroness Harman questioned what is going to be achieved by having young people simply watch the show.

“Two questions were raised [for me],” she said. ” Firstly – after they’ve watched it, what is going to be the discussion afterwards?

“And secondly, is he going to act to stop the tech companies allowing this sort of stuff to go online into smartphones without protection of children?

“Because if the tech companies wanted to do this, they could actually protect children. They can do everything they want with their tech.”

She acknowledged there are “very big public policy challenges” in this area, but added of the prime minister: “Is he going to side with parents who are terrified and want this content off their children’s phones, or is he going to accept the tech bros’ resistance to having to make changes?”

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Can parliament keep up?

The Labour peer backed the Conservative Party’s call for a ban on smartphones in schools to be mandated from Westminster, saying it would “enable all schools not to have a discussion with their parents or to battle it out, but just to say, this is the ruling” from central government, which Ofsted would then enforce.

“I’m sensitive to the idea that we shouldn’t constantly be telling schools what to do,” she continued. “And they’ve got a lot of common sense and a lot of professional experience, and they should have as much autonomy as possible.

“But perhaps it’s easier for them if it’s done top down.”

Baroness Harman also questioned the speed with which parliament is actually able to legislate to deal with the very rapid development of new technologies, and posits that it could “change its processes to be able to legislate in real time”.

She suggested that a “powerful select committee” of MPs could be established to do that, because “otherwise we talk about it, and then we’re not able to legislate for 10 years – by which time that problem has really set in, and we’ve got a whole load more problems”.

On the podcast, the trio also discussed the 10% tariffs imposed on the UK by Donald Trump and the government’s efforts to strike a trade deal with the US to mitigate the impact of the levy.

The government has refused to rule out scrapping the Digital Services Tax, a 2% levy on tech giants’ revenues in the UK, as part of the negotiations with the Trump administration – a move Baroness Harman said would be “very heartbreaking”.

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