Antimatter Antistars In The Milky Way

in STEMGeeks12 days ago

The Universe has a problem. It’s missing a lot of antimatter. But there may be more antimatter than we think. French astronomers tracked down 14 objects that radiate gamma-rays while being candidates for antistars.


Image by WikiImages from Pixabay

Antimatter is still matter. It’s just made from anti-particles. These are just like the regular particles you know but with an opposite charge. That seems simple. The problem is that according to our models about the creation and evolution of the Universe the same amount of matter and antimatter was created. But when you look around all you will see is matter. You may see some occasionally but only in the most extreme of places such as particle accelerators, storms, cosmic rays, or black hole and pulsar mass ejections, and always only in tiny amounts.

So, where exactly is all the original antimatter? We assume most of it was destroyed in annihilations with regular matter and some of it just managed to remain? This seems to be the case. But it is also a possibility that the discrepancy between matter and antimatter is not as big as we think. Theoretically, there is nothing stopping antimatter from making up whole antiplanets, antistars, antigalaxies, or even antilife. But it should be hard to find because from a distance it would look just like regular things made from matter.

But not all is lost. There are still some possibilities. We can assume that anything made from antimatter moves through the Universe just like things from matter. And sometimes, they should meet regular matter. When that happens annihilation takes place and that’s hard to miss. Bursts of gamma radiation should be created during annihilations allowing us to track antistars.

That’s exactly the approach Simon Dupourqué and his collegues from the Recherche en Astrophysique et Planétologie (IRAP) took to find antistars. They analyzed data coming from the Fermi Gamma-ray Space Telescope gathered over 10 years. In the data, they researched 5,787 gamma-ray sources that could possibly be antistars.

Though, many things can produce gamma radiation. Thus, the researchers narrowed their selection to objects that produce radiation from a point source while having a spectrum similar to what we’d expect to see from radiation created by matter-antimatter annihilations. This led them to 14 potential objects that are in different places in the Milky Way.

What needs to be stressed that this doesn’t necessarily mean we found antistars. It is much more likely that these are just gamma-ray sources we have already seen before. Pulsars or black holes can behave similarly. Nonetheless, it is still an exciting possibility.


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