/sci/ - Science & Math

>>10093007
it’s possible, yes. but unlikely, since most speculative theories of why matter dominates over antimatter attribute it to a global broken symmetry (basically broken CP symmetry) that made energy tend to condense into matter instead of antimatter not just here but everywhere.

but if we get contacted by aliens and they want to meet up, we would be wise to shoot an electron or two at their ship first, just to make sure shaking hands flat out doesn’t turn into the biggest nuclear explosion of all time

I like the idea that antimatter has both a real location and momentum, and I could appreciate that there are plenty of places in the universe energetic enough to be producing antimatter through collisions, like in the areas dominated by black holes. Maybe what we see as accelerating expansion of the universe is actually the distortion of radiation wavelengths by a super stretched spacetime in which the index of refraction of spacetime itself is determined by the sum of all local gravitational forces.

>>10093007
You'd see tons of shit like, exploding all the time

>>10093087
This but unironically.

>>10093166
>>10093087
And why would that be? You don't see things exploding all the time on our 'ordinary' matter dominated galaxy. Why should a galaxy dominated by antimatter behave differently?

>>10093007
>call dirac
>ask him
>???
>profit

>>10093177
Because by definition, our galaxy is not anti matter. Assuming an anti matter full region of space exists, it will be surrounded by a region of normal matter. Then, at the boundary we'd expect to see a large amount of radiation from the annihilation along that border.

>>10093648
dude, your explanation is super retarded

space is mostly empty. duh. if there are two galaxies separated by a few lightyears, and one were made of antimatter and the other made of matter, you really wouldn't be able to tell. nothing would be exploding in between them because the space between them is empty (or at least only populated by dark matter and photons and stuff that isn't going to do pair annihilation like positron-electron annihilation)

stop acting smart dude, you don't know your shit

>>10093657
Because the observable universe is homogeneous.
If there is a giant lump of antimatter in the middle of a matter dominated universe then it would have annihilated when the universe was still in a denser state.
Moreover, galaxies are connected to eachother by a web of cold plasma, these all flow together into super clusters of galaxy that are exchanging mater at an albeit slow rate, so you don't need an anti matter galaxy, you need an antimatter galaxy cluster in order for the constant annihilation of massive amounts of antimatter to not be something you could see glowing with gamma rays.

>>10093707
well first off, no, the reason antimatter galaxies don't exist is not because it would have annihilated during a denser state, it's because CP symmetry is a global symmetry, not a local one

second, your bullshit of cold plasma exchange would not result in anybody seeing anything like an "explosion". so your initial explanation is bullshit. and i don't even think it would solve the issue of antimatter galaxies. far too little plasma flows occur to neutralize an antimatter galaxy via that mechanism.

>>10093069
wouldn't it be immediately obvious they were made of anti-matter when looking at the light/em they gave off

>>10093657
>space is mostly empty

not really

food for thought

>>10094151
Well let us consider two galaxies far apart in an otherwise empty space, one made of antimatter and one of matter. The density of particles should decrease exponentially with distance from each galaxy, right? So if we regard the radiation from annihilation as a linear function of the product of matter and antimatter density and look at the plane that is the interface between these regions. We shall then find that even though the plane is infinite, it only grows as a power function which is weaker than an exponential function in the limit r -> infinity. Therefore we should not expect the radiation from this interface to be infinite, but rather finite.

>>10093657
>a few lightyears
kek
that's halfway the distance to Alpha Centauri

>>10094152
wats dat

>>10097844
seems there is a thing which eats light

>>10094149
Nope.

>>10097844
The final solution to the Fermi paradox.

>>10097893
>>10097879
is it dark matter?

>>10094152
fake

reminder that Dirac's models of cosmology failed horrendously

>>10097957
A swarm of hunter killer von neumanns. Until a few millennia ago there was a thriving civilization in that region, with laser beam propulsion links between a dozen star systems. Until the probes detected their radio chatter and swarmed .