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Gaia's first black hole discovery: GAIA-BH1 (2022)

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11–20 of 44 posts

Re: Gaia's first black hole discovery: GAIA-BH1 (2022)

#11
post #2

Exactly how terrified should I be at this news? Really super terrified, right?

I recently read "A Brief History of Black Holes" by Dr. Becky Smethurst and I recommend it if you're interested in these things. She wrote that the math indicates you have no reason to fear a black hole consuming you, or this solar system.

Black holes are just massive objects, no different from any other "massive object" in the universe. It's pretty easy / common for stuff to orbit massive objects, rather than fall into them. Furthermore I vaguely remember her mentioning another force involved with pushing things away from black holes, such that physicists of today aren't able to reach consensus on the idea that maybe one day all mass in the universe will be in one black hole or another, it seems there's other forces involved that may prevent that from happening (though there are hypothesis around that time is a cycle of all things falling into a universal singularity which then explodes into a big bag and the cycle continues).

In short though, no, you shouldn't be terrified. There has been an ongoing theory for a while that there's a micro black hole somewhere near pluto causing our predictions for its orbit to be just ever so slightly off. https://www.newscientist.com/article/mg24933280-100-is-there... If it's there, it's been there basically forever, and its event horizon, if it's a micro black hole, is hilariously small.

https://www.goodreads.com/en/book/show/61324554

Also as others have said, if it's coming directly for earth, it would take at least 1500 years to get here, which is plenty of time for humans to do something about it. Almost certainly you'll already be dead anyway.

Re: Gaia's first black hole discovery: GAIA-BH1 (2022)

#12
post #2

Exactly how terrified should I be at this news? Really super terrified, right?

Your reaction should be "astronomy fun fact, that will have no direct effects on anyone's life." This black hole is so dim and distant that it required a super powerful telescope to even notice it exists. It will have no effect on life on earth, except by adding to scientific understanding of the cosmos.

Moreover, black holes aren't death machines or anything. This black hole puts out much less light and energy than an equivalent-mass star. It's quite safe.

Re: Gaia's first black hole discovery: GAIA-BH1 (2022)

#14
post #5
post #2

Exactly how terrified should I be at this news? Really super terrified, right?

The closest one has 10 solar masses. Gravitationally there is zero difference between a black hole and a regular star except that the black hole has a way smaller radius. So for us it doesn't matter _at all_.

Yes. If the Sun somehow instantly collapsed into a 1 solar mass black hole, it would have no effect on Earth's orbit. The Schwarzschild radius of a 1 solar mass black hole is a bit under 3km, so the event horizon would be 3km in radius. For comparison, the Sun's current equatorial radius is about 696,000km.

To fall into the former Sun black hole would be much more difficult than falling into the Sun as it is now. You'd pretty much have to make a deliberate effort to "land" on the event horizon.

Re: Gaia's first black hole discovery: GAIA-BH1 (2022)

#17
post #12
post #2

Exactly how terrified should I be at this news? Really super terrified, right?

Your reaction should be "astronomy fun fact, that will have no direct effects on anyone's life." This black hole is so dim and distant that it required a super powerful telescope to even notice it exists. It will have no effect on life on earth, except by adding to scientific understanding of the cosmos. Moreover, black holes aren't death machines or anything. This black hole puts out much less light and energy than…

A lot of people seem to have the impression that black holes are like vacuum cleaners, sucking up anything that comes near.

If the Sun were replaced with a black hole of equal mass, apart from the heat and light going out, we wouldn't notice anything. All the planets would still orbit more-or-less the same.

Re: Gaia's first black hole discovery: GAIA-BH1 (2022)

#18
post #8
post #2

Exactly how terrified should I be at this news? Really super terrified, right?

Well, if it had choosen our planet as a direct destination for (providing it has means to travel at light speed) collision, we'd only have 1560 years to escape. There are a couple of comically improbable conditions that would happen only in fantasy to start threating us

On the other hand, if it had chosen our planet as its destination 1559 years ago, then we would have no way of being aware of this fact until next year

Re: Gaia's first black hole discovery: GAIA-BH1 (2022)

#19
post #18
post #8

Earlier quoted context omitted.

Well, if it had choosen our planet as a direct destination for (providing it has means to travel at light speed) collision, we'd only have 1560 years to escape. There are a couple of comically improbable conditions that would happen only in fantasy to start threating us

On the other hand, if it had chosen our planet as its destination 1559 years ago, then we would have no way of being aware of this fact until next year

But then we wouldn't be seeing it at a distance of 1560 ly right now.

Re: Gaia's first black hole discovery: GAIA-BH1 (2022)

#20
post #12
post #2

Exactly how terrified should I be at this news? Really super terrified, right?

Your reaction should be "astronomy fun fact, that will have no direct effects on anyone's life." This black hole is so dim and distant that it required a super powerful telescope to even notice it exists. It will have no effect on life on earth, except by adding to scientific understanding of the cosmos. Moreover, black holes aren't death machines or anything. This black hole puts out much less light and energy than…

Sorry. I can't hear you over all the panic screaming.
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