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[Frumple]

Oh, there is, but only in the sense that at some point you stop having the lift capacity to get it out of atmo

If at some point we get some decent orbital industry going on, well... suddenly the new breakpoint starts when it starts having so much mass it's causing singularities, heh.

[Robot Parade Leader]

The voyager probe still somehow working gives me hope. I really don't get how it does, but I am glad it does. I guess they really built it right.

[Eric Blank]

Apparently the necessities of its function are all redundant; they've got backups. But not the science instruments. And the tape recorder.

I've been listening to the Event Horizons podcast on YouTube. The guy interviews a lot of scientists about various space topics. One of them concerned the voyager probes. I'll see if I can find it again later.

[MaxTheFox]

And, in galactic terms, it's right next door at about 2,000 light-years distant

Dear god, should we start panicking now or should we wait a bit then panic?

Nope. Even if it was moving at 99.999% lightspeed directly at us, it'd take 2000 years to reach us. And it definitely isn't. This is like being in Europe and worrying about having your city destroyed by a volcano in Hawaii.

[King Zultan]

And, in galactic terms, it's right next door at about 2,000 light-years distant

Dear god, should we start panicking now or should we wait a bit then panic?

Nope. Even if it was moving at 99.999% lightspeed directly at us, it'd take 2000 years to reach us. And it definitely isn't. This is like being in Europe and worrying about having your city destroyed by a volcano in Hawaii.

Sounds like a wait then panic situation, even if the wait is thousands of years.

Also I said as a joke.

[Starver]

This is like being in Europe and worrying about having your city destroyed by a volcano in Hawaii.

Probably less so.

Increased vulcanism in Hawaii could cause or provoke worldwide effects that concern us all (though perhaps we should worry more about Yellowstone, on that front[1]). The creation of a black hole might be a problem, but the discovery of one (already created) shouldn't have any additional effects[2].

In truth, even the sudden 'magical' transformation of the Sun into a stellar-mass black hole would not suck us into gravitational doom, as we'd still be orbiting the same mass at the same distance. Though we would have a big problem with no longer having our usual dose of sunlight. Unless there was enough other new mass to feed it, no new increase in 'hard' radiation, so even that might end up less. Perhaps a wonderful opportunity to try to understand  what Hawking Radiation might actually be (once we set aside who snapped their fingers to transform the Sun, in the first place, and dealt with the immediate issues of survival from the rapid cooling).

There are other subtle potential problems with extrasolar black holes, but a newly discovered (yet 'established') one at that distance (and not itself obviously heading this way, in any substantial manner) is more just an interesting thing to know about[3]. What I'd be more worried about is a more subtle one, not so large but perhaps actually travelling directly towards us (alone, so with no tell-tale glowing disc) still in a particularly empty/unstudied slot of sky (where any lensing hasn't yet been realised for what it is). And even that probably isn't as 'immediately' likely to cause us problems as a rogue planet/failed-brown-dwarf looming up out of the cosmic-biege, which probably number far greater than 'stealth' black holes in our local neighbourhood.

(Though, of course, there's always a chance. Or "sufficiently advanced aliens" intervening. Or probably many other things that science just doesn't know about yet. And, of course, humorous (as well as humourless?) hyperbole.)


[1] Not sure about the potential Krakatoa-like issues of extremely ready seawater, though, on top of even a 'smaller' mega-eruption. Loads of variables there.

[2] There's black hole 'ejection flares', from a glut of accretion material being forced away from the rotational poles of the new material, but that's a rather aimed effect, and to be hit (eventually) by the maximum possible effects of one (over any interstellar distance) is extremely unlikely.

[3] Instead of "Second-biggest black hole in the Milky Way found", I would have said "Black hole is second-biggest found in the Milky Way", or similar. And, for scale, we're talking Sagittarius A* at ~4 million solar masses, this one at ~32, Cygnus X1 at ~15 and then other candidates at ~12 (but could be up to 26, from the manner of its discovery), ~11, ~10, ~9s, an ~8, ~7s, ~6s, a ~5, (no obvious ~4s), ~3s and ~2s, numbering to 20 examples. And Gaia BH3 is the second closest discovered (Gaia BH1 is at ¾ the distance, with a high 9-stellar-mass size). In truth, BHs are hard to find/pin down, unless they're quite close or very large.

edit(s): I just couldn't get "Sagittarius" spelt correctly first(/second/third) time!

[Egan_BW]

And, in galactic terms, it's right next door at about 2,000 light-years distant

Dear god, should we start panicking now or should we wait a bit then panic?

Nope. Even if it was moving at 99.999% lightspeed directly at us, it'd take 2000 years to reach us. And it definitely isn't. This is like being in Europe and worrying about having your city destroyed by a volcano in Hawaii.

Well, it could have spectacularly exploded 1999 years ago and we just haven't observed the light from that event yet. Still pretty unlikely to affect us.

[Bralbaard]

Black holes can't explode. Nothing can escape from them.

Not counting cheating by Hawking radiation.

[Robsoie]

related interesting article from a few years ago about why scientists are often losing their hairs after repeatedly scratching their head from the amount of contradictions coming in theoretical or established physic laws, all because of those black holes and particles not willing to cooperate with them

https://www.scientificamerican.com/article/escape-from-a-black-hole/

[Starver]

That aside, it could merge with another black hole, sufficient to increase the resulting Schwarzschild radius to the best part of that 2kly distance that it needs to touch us...

(But then the problem wouldn't really lie with the 32-sol BH, any more, just the added presence of the... hmmm... 6 quadrillian-sol one? Outweighing the whole Milky Way by a factor of nearly 4000 (and Sag A* by 1.4bil), if I've done my sums right. And, even if I haven't, it'd probably be still 'significant', with BH3 barely the thinnest icing on the resulting cake.)

Luckily, it's a leap year, which gives us some additional breathing space! 

[Egan_BW]

Black holes can't explode. Nothing can escape from them.

Not counting cheating by Hawking radiation.

What if every single particle inside the event horizon happens to tunnel out at the same time? What then huh?

[Eric Blank]

Then the black hole wouldnt exist anymore.

My question would be, can we still detect the gravitational waves of two blackholes orbiting each other once one has passed within the schwartzchild radius of the other, but has not yet fallen into the singularity. The merger of the singularities shouldnt be instantaneous, right? and they can't travel faster than light towards each other. The effect of their gravity, separately, should still be detectable on objects outside the event horizon, right?

We'd need two sufficiently ginormous black holes about to merge, though, and instrumentation that allows us to tell at what point they enter one-another's event horizons.

[Starver]

"I'll huff, and I'll puff and I'll blow off your spin..."

(Three little pigs meets rocket science...)

[Eric Blank]

That's an interesting technique. I wonder if they would attempt to fully deorbit something by doing the same. Or grab it, slow it down to an unstable low orbit, then push off it, fully deorbiting it and sending their capture vehicle back up to catch another.

[Starver]

My reading is that this is the "we haven't built the bit that can grab the other object" yet. But by using up some propellant[1], they can refine their ability to get (and stay) in close enough proximity to try these tricks.

Once they have an appropriate gripper, magnetetic grapple, tethered throw-net or harpoon system then probably much more efficient to just make actual firm contact[2] and then do whatever it is they do next (attach thruster packs and/or keep attached as you drag it along to de-orbit, graveyard-orbit, the 'recycling space station' or even just the next target in a list of objects[3]).

But they've got to get used to how to get close (but not dangerously close), and it would be interesting to see how effective a bit of judicious and coordinated thruster-plume can be (a bit like the Double Asteroid Redirection Test's impactor was just an emperical try-out of how much could be done).


(And I find that part at least as fascinating as the more 'practical' (or at least currently presumed as more useful) operational modes.)



[1] Twice, probably, some directed onto the target, whilst the opposing thrusters make sure that the forces balance and the testing craft doesn't zoom off...

[2] For spinning objects, this will probably be propellent-intensive to match the frame of rotation whilst converging, and not getting side-swiped by extended bits of the target in the process. But I'm sure the "waft it stationary" method will use even more fuel.

[3] Takes more delta-v to do multiple targets, and drag around more stuff to be useful when finding the targets, but might be cheaper than dedicating a single 'disposal drone' to each item of interest, given that you have to avoid dumping more awkward booster-stuff along the way, beyond the point of immediate/easy deorbiting. But perhaps a few low-hanging fruit could be rounded up for the cost of one disposal-bot deplyment.