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BedrockFarmer t1_ixramsi wrote

Reply to comment by momentum77 in Hubble Telescope Observes Surreal Galactic Collision | The merging galaxies, heavily distorted by gravity, have formed an unusual celestial ring. by chrisdh79

What else is there to think but “We’re fucked.” when two super massive black holes start spiraling towards each other and wreaking havoc on everything in the newly merging galaxy?

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sticklebat t1_ixrby1d wrote

Why would we think that? Most individual star systems are completely unaffected during galaxy collisions and mergers. Compared to the vast space between them, stars and their planetary systems are minuscule.

And the black holes wouldn’t “wreak havoc” on anything but the very small fraction of stars on their immediate neighborhood.

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turningpoint84 t1_ixrcopy wrote

And in 100 years or a human lifetime, almost nothing would actually happen.

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BedrockFarmer t1_ixrd2l2 wrote

I guess if you are very solipsistic, sure, don’t worry. I was using “we” in the species-level plural.

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BedrockFarmer t1_ixrcldy wrote

Maybe I am misunderstanding what is being shown here then. Because it looks like stars that used to orbit the galactic plane of on or the other galaxy have been flung out into a huge horseshoe hoop while close to the galactic cores the gasses are even hotter with a huge jet of superheated gas shooting “down” from them.

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sticklebat t1_ixrg1lm wrote

Yes, some stars are out in the tidal arms, some have or will even be ejected from the galaxies, but so what? If our solar system suddenly found itself alone in the universe, it would have no practical effect on our existence whatsoever. We’d be just fine.

> while close to the galactic cores the gasses are even hotter with a huge jet of superheated gas shooting “down” from them.

You’re reading way too much into the image. There’s no superheated gas, and certainly not jets of it. It’s all just stars and dust. It’s just that their regular orbits are disrupted.

Galaxies are mostly nothing. Their densities are tiny (on the order of 10^-29 g/cc), about 10^26 times less than earth’s atmosphere. Stars are so sparse that the chance of even one collision between stars is nearly zero. And collisions between galaxies occur over hundreds of millions of years. Such collisions are disruptive to the orbits of stars and such, but they aren’t destructive in any sense.

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Tutorbin76 t1_ixt5sh4 wrote

But surely it would seriously screw up our horoscopes.

"Gemini are morphing into a bus and Scorpio's tail is descending into Capricorns left foot. Bad luck will find you today"

Could you imagine the chaos?

/s

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sticklebat t1_ixt7dxb wrote

That’s actually a problem with astrological signs even without galaxies colliding! Our astrological signs are discernibly different than they were a couple thousand years ago and, due to Earth’s precession, no longer correspond to the same times of year as they did originally.

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BedrockFarmer t1_ixriaaq wrote

Interesting. I wonder what happens when the event horizons from the two black holes touch.

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sticklebat t1_ixrn932 wrote

They merge into one black hole in a process that is very much non-destructive.

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BedrockFarmer t1_ixrorom wrote

Just read the short ESA post and the answer seems to be no one knows, but they have to projects planned to try and detect both gravitational waves and x-rays that are expected from such a merger.

I suppose as long as you are not in the path of the x-ray blast, there isn’t much to be concerned about.

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sticklebat t1_ixrsphd wrote

Well we know that when black holes meet they merge. We’ve observed black hole mergers and know that they release a huge amount of energy as gravitational waves, which are pretty harmless unless you’re right there.

Also, it’s believed that x-rays would be emitted, but that isn’t because of the event horizons touching, which is what you originally asked, but from the interactions of the black holes’ accretion disks and other nearby matter with each other and with the complex gravitation on the region around two merging black holes.

But yes even those x-ray bursts would be highly collimated and would only effect a small region directly in their path.

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Somebody_Forgot t1_ixrg4mz wrote

Yup! And the planets orbiting those stars are completely unaffected, safe within the heliosphere created by their parent star.

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Welpe t1_ixsmzsj wrote

…what? Why do you think a galactic merger would leave planets in solar systems “fucked”?

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