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Πέμπτη 9 Μαρτίου 2017

Are There Antimatter Galaxies?

                        

Are There Antimatter Galaxies?



Δημοσιεύτηκε στις 9 Ιουν 2016
One
of the big mysteries in astronomy is what happened to all the
antimatter? Is it possible that it’s actually still out there, in huge
antimatter galaxies?

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Team: Fraser Cain - @fcain
Jason Harmer - @jasoncharmer
Chad Weber - weber.chad@gmail.com

Created by: Fraser Cain and Jason Harmer
Edited by: Chad Weber
Music: Left Spine Down - “X-Ray”
https://www.youtube.com/watch?v=4tcoZ...

One
of the biggest mysteries in astronomy is the question, where did all
the antimatter go? Shortly after the Big Bang, there were almost equal
amounts of matter and antimatter. I say almost, because there was a tiny
bit more matter, really. And after the matter and antimatter crashed
into each other and annihilated, we were left with all the matter we see
in the Universe.

You, and everything you know is just a mathematical remainder, left over from the great division of the Universe’s first day.

We did a whole episode on this mystery, so I won’t get into it too deeply.

But
is it possible that the antimatter didn’t actually go anywhere? That
it’s all still there in the Universe, floating in galaxies of
antimatter, made up of antimatter stars, surrounded by antimatter
planets, filled with antimatter aliens?

Aliens who are friendly
and wonderful in every way, except if we hugged, we’d annihilate and
detonate with the energy of gigatons of TNT. It’s sort of tragic,
really.

If those antimatter galaxies are out there, could we detect them and communicate with those aliens?

First, a quick recap on antimatter.

Antimatter
is just like matter in almost every way. Atoms have same atomic mass
and the exact same properties, it’s just that all the charges are
reversed. Antielectrons have a positive charge, antihydrogen is made up
of an antiproton and a positron (instead of a proton and an electron).

It
turns out this reversal of charge causes regular matter and antimatter
to annihilate when they make contact, converting all their mass into
pure energy when they come together.

We can make antimatter in
the laboratory with particle accelerators, and there are natural sources
of the stuff. For example, when a neutron star or black hole consumes a
star, it can spew out particles of antimatter.

In fact,
astronomers have detected vast clouds of antimatter in our own Milky
Way, generated largely by black holes and neutron stars grinding up
their binary companions.

But our galaxy is mostly made up of
regular matter. This antimatter is detectable because it’s constantly
crashing into the gas, dust, planets and stars that make up the Milky
Way. This stuff can’t get very far without hitting anything and
detonating.

Now, back to the original question, could you have an
entire galaxy made up of antimatter? In theory, yes, it would behave
just like a regular galaxy. As long as there wasn’t any matter to
interact with.

And that’s the problem. If these galaxies were out
there, we’d see them interacting with the regular matter surrounding
them. They would be blasting out radiation from all the annihilations
from all the regular matter gas, dust, stars and planets wandering into
an antimatter minefield.

Astronomers don’t see this as far as
they look, just the regular, quiet and calm matter out to the edge of
the observable Universe.

That doesn’t make it completely
impossible, though, there could be galaxies of antimatter as long as
they’re completely cut off from regular matter.

But even those
would be detectable by the supernova explosions within them. A normally
matter supernova generates fast moving neutrinos, while an antimatter
supernova would generate a different collection of particles. This would
be a dead giveaway.

There’s one open question about antimatter
that might make this a deeper mystery. Scientists think that antimatter,
like regular matter, has regular gravity. Matter and antimatter
galaxies would be attracted to each other, encouraging annihilation.

But
scientists don’t actually know this definitively yet. It’s possible
that antimatter has antigravity. An atom of antihydrogen might actually
fall upwards, accelerating away from the center of the Earth.

Physicists at CERN have been generating antimatter particles, and trying to detect if they’re falling downward or up.

If
that was the case, then antimatter galaxies might be able to repel
particles of regular matter, preventing the annihilation, and the
detection.
ANAΡΤΗΣΗ ΑΠΟ ΤΟ YOUTUBE 9/3/2017














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