Giant magnetic spirals in the sky could explain why there is something rather than nothing in the universe, according to an analysis of data from NASA's Fermi space telescope.
Our best theories of physics imply we shouldn't be here. The Big Bang ought to have produced equal amounts of matter and antimatter particles, which would almost immediately annihilate each other, leaving nothing but light.
So the reality that we are here – and there seems to be very little antimatter around – is one of the biggest unsolved mysteries in physics.
Monopole monopoly
In 2001, Tanmay Vachaspati from Arizona State University offered a purely theoretical solution. Even if matter and antimatter were created in equal amounts, he suggested that as they annihilated each other, they would have briefly created monopoles and antimonopolesMovie Camera – hypothetical particles with just one magnetic pole, north or south.
As the monopoles and antimonopoles in turn annihilated each other, they would produce matter and antimatter. But because of a quirk in nature called CP violation, that process would be biased towards matter, leaving the matter-filled world we see today.
If that happened, Vachaspati showed that there should be a sign of it today: twisted magnetic fields permeating the universe – a fossil of the magnetic monopoles that briefly dominated. And he showed they should look like left-handed screws rather than right-handed screws.
So Vachaspati and his colleagues went looking for them in data from NASA's Fermi Gamma ray Space Telescope. As gamma rays shoot through the cosmos, they should be bent by any magnetic field they pass through, so if there are helical magnetic fields permeating the universe, that should leave a visible mark on those gamma rays.
All of a twist
Lo and behold, that's just what they found – well, maybe. "What we found is consistent with them all being left-handed," says Vachaspati. "But we can't be sure." He says there's less than a one per cent chance that what they see in the Fermi data happened by chance. "That's being conservative," he says.
They also found that the twists in the field are a bit bigger than they predicted. "So there is some mystery there," says Vachaspati. He says more data from Fermi, which is expected this year, will help narrow down the odds.
Nicole Bell from the University of Melbourne in Australia warns that magnetic fields could have been caused in other ways, including from inflation. What's more, for CP-violation to provide enough matter in the universe you usually need "new physics" – stuff beyond the standard model of particle physics – which hasn't been confirmed experimentally yet. "But it is a very interesting idea," she says.
Intergalactic magnetic field spectra from diffuse gamma-rays
Abstract
Non-vanishing parity-odd correlators of gamma-ray arrival directions observed by Fermi-LAT indicate the existence of a helical intergalactic magnetic field with strength B ∼ 10−14 G on ∼10 Mpc scales. We successfully test this hypothesis using more stringent cuts of the data, Monte Carlo simulations with Fermi-LAT time exposure information, separate analyses for the Northern and Southern galactic hemispheres, and confirm predictions made in Tashiro & Vachaspati. With some further technical assumptions, we show how to reconstruct the magnetic helicity spectrum from the parity-odd correlators.
I always thought the apparent anti-matter/matter imbalance in the universe was a combination of early physical laws causing matter and anti-matter to actually repel each other (meaning the other side of the universe is anti-matter), and anti-matter and matter giving off the same electromagnetic and gravity signature.
I've been asked why I still follow a few of the people I know on Facebook with 'interesting political habits and view points'.
It's so when they comment on or approve of something, I know what pages to block/what not to vote for.
No, there is an actual very slight breakage of the otherwise perfect symmetry in the laws of physics as applied to matter and anti-matter. It's not much, but it does skew things so that once the early universe settles down a bit, anti-matter is pretty much completely absent on a large scale. It's still created all the time particle by particle in high-energy events, but there aren't any chunks of anti-matter floating around out there anywhere.
“Despite rumor, Death isn't cruel — merely terribly, terribly good at his job.”
Terry Pratchett, Sourcery
SpottedKitty wrote:No, there is an actual very slight breakage of the otherwise perfect symmetry in the laws of physics as applied to matter and anti-matter. It's not much, but it does skew things so that once the early universe settles down a bit, anti-matter is pretty much completely absent on a large scale. It's still created all the time particle by particle in high-energy events, but there aren't any chunks of anti-matter floating around out there anywhere.
But...WHY, dammit?!
Yeah yeah, I know we don't know yet. I'd never have the patience to be a physicist...
Yeah, I've always taken the subtext of the Birther movement to be, "The rules don't count here! This is different! HE'S BLACK! BLACK, I SAY! ARE YOU ALL BLIND!?
- Raw Shark
Destiny and fate are for those too weak to forge their own futures. Where we are 'supposed' to be is irrelevent.
SpottedKitty wrote:No, there is an actual very slight breakage of the otherwise perfect symmetry in the laws of physics as applied to matter and anti-matter. It's not much, but it does skew things so that once the early universe settles down a bit, anti-matter is pretty much completely absent on a large scale. It's still created all the time particle by particle in high-energy events, but there aren't any chunks of anti-matter floating around out there anywhere.
There's no experimental evidence for a CP symmetry violation sufficient to explain the baryon/antibaryon imbalance. If you can show some, there's a Nobel prize in it for you.
Having matter and antimatter repel each other gravitically is a competing hypothesis, but comes with its own problems, that being that it would contradict some of the implications of CPT invariance.
