116
votes
Accepted
Is it worth sending a manned mission to a black hole?
What could be learned?
There are so many things you could study by looking at a black hole. There are lots of open or partially unsolved problems that surround them:
Does Hawking radiation exist? ...
- 98.4k
59
votes
Accepted
Protect a planet against a black hole attack
Physical Paradoxes
we do have FTL travel and communication, but other laws of physics are the same
They can't be the same, FTL breaks known physics. A lot.
The speed of light isn't really the speed ...
- 30.1k
53
votes
Black hole as a storage device?
I wasn’t sure how the weapon could be pulled back out, and I was thinking perhaps magnets?
Nothing can get out of the event horizon of a black hole, not even light. And light is made of ...
- 262k
52
votes
Accepted
Destroy a Planet inside a black hole?
You need to understand better how the event horizon works. It is a point of no return. Your implicit idea of it being a shell that destroys anything that passes is simply wrong.
From physicist Matt ...
- 68.9k
48
votes
Accepted
What would happen to a modern skyscraper if it rains micro blackholes?
would it triggers extinction level event?
Since they'd evaporate more or less instantaneously (known as Hawking radiation), releasing energy according to the famous equation beginning E=, the ...
- 23.7k
46
votes
Accepted
1 Light Year Diameter Planet
As mentioned, anti-gravity and or gravity generators will let you pull magic out of thin air, but let's try it without magic. I can't imagine why anyone would bother doing it, but I decided to see ...
- 6,303
43
votes
Accepted
How would one destroy a black hole?
Welcome to How to destroy a black hole for dummies
So, are you looking for a way to eliminate the right black hole, arent' you? Well, you're reading the right guide. But before beginning, it could be ...
- 1,280
40
votes
How to tell a blackhole from a neutron star covered entirely by Dyson sphere painted in vantablack?
I'm surprised no one has mentioned this.
Your ultra-black Dyson sphere is easily distinguishable from a quiescent black hole or unnaturally cold neutron star by one major thing, if you're close ...
- 44.4k
39
votes
Is it worth sending a manned mission to a black hole?
There is no point in sending a manned mission!
As @HDE22686 noted, there are many interesting phenomena associated with black holes. Given the opportunity to study one up close, it is likely that ...
- 20.5k
39
votes
Accepted
The Moon turns into a black hole of the same mass -- what happens next?
what practical differences would arise when compared to a normal moon (such as it affecting the atmosphere)
Almost none.
There'd be no moonlight under normal circumstances, which means that no life ...
- 67.3k
37
votes
Accepted
A planet illuminated by a black hole?
This scenario is quite problematic for two main reasons: evaporation and peak wavelength.
The black hole's lifetime is too short
We can make a rough estimate of the properties of the Hawking radiation ...
- 98.4k
37
votes
Accepted
How do you detect and defend against micro blackhole cannon?
Dont do anything.
1: a BH of that size would evaporate in 129 years (which surprised me I thought it would be shorter). This makes my point of it evaporating in microseconds moot so ignore point 1.
2: ...
- 43.1k
37
votes
How do you detect and defend against micro blackhole cannon?
We'd definitely notice.
A 365000 tonne black hole has a luminosity of $2.6*10^{15}$ watts. On the K-scale of civilizations this is about 0.95.
1.0 is roughly consuming all of the energy the Sun ...
- 13.9k
36
votes
Accepted
How to tell a blackhole from a neutron star covered entirely by Dyson sphere painted in vantablack?
When we “see” a black hole or neutron star, we don’t see the actual body itself — they’re much too small, as well as black holes being black. So there’s no point messing around with Dyson spheres and ...
- 19.7k
35
votes
Accepted
Black hole at the center of the planet
Your planet needs to be about 722500 times more massive than Earth for its core to undergo collapse into a black hole.
Leaving aside the small detail that at this point your "planet" would ...
- 8,497
32
votes
How would someone destroy a black hole that’s at the centre of a planet?
A black hole with a Schwarzschild radius of 4 feet would have a mass of 137.5 x Earth and the gravity to go along with it. Such a black hole would instantly liquefy the earth as it shreds it into an ...
- 3,837
30
votes
Accepted
What would happen if the black hole at the center of a galaxy was removed?
Not all that much
Sagittarius A* is big, but not that big. Its mass is estimated to be around 4,200,000 (four million two hundred thousand) solar masses. That's a lot of gravity! But consider the ...
- 130k
30
votes
Accepted
Is it safe to orbit HDE 226868?
X-ray radiation at the orbit of HDE226868
Cygnus X-1 is famous as one of the most powerful X-ray sources in the sky. According to the US Naval Observatory, the max flux of Cygnus X-1 (near the bottom ...
- 84.9k
30
votes
Black hole as a storage device?
Could this work in any scenario?
Unfortunately not.
If you are looking for a scientifically sound explanation, even in purely theoretical terms what you're asking just is not possible. As others have ...
- 6,212
30
votes
How to tell a blackhole from a neutron star covered entirely by Dyson sphere painted in vantablack?
Vantablack doesn't reflect light, but it'll still have black body radiation based on temperature. It may be far into the infrared, but the black body curve is a signature we can recognize from a ...
- 1,897
28
votes
How to annihilate an object completely?
I mean there’s a lot of ways to do this honestly. Humans are really good at destroying things. So there are a couple ways you can completely ”destroy” something. Let’s break it down.
Physical: ...
- 5,273
28
votes
Accepted
How would a space probe determine its distance from a black hole while orbiting around it?
I am neglecting the effect of tidal forces on the integrity of any object
Well, don't be doing that! Those forces can be used to answer your question.
Given a couple of bars of known length and mass, ...
- 67.3k
27
votes
Black hole at the center of the planet
No
A natural occurring black hole that comes into existence due to mass collapsing onto itself must have more mass than the Tolman–Oppenheimer–Volkoff limit, which has been estimated to be around 2.17 ...
- 131k
26
votes
Accepted
Reasons for time dilation to happen on a habitable planet with same g force and not orbiting a black hole
Time dilation comes from gravity and/or velocity.
Since the planet is not orbiting a black hole it would either have to orbit another super heavy mass or fly through space with a lorentz factor of 0....
- 6,829
26
votes
How to build a fail-safe system for an engine that can harness energy from a Black Hole?
Start with an 0.1% of Everest-mass black hole. Stuff it into a 0.001 meter radius (1 mm) containment device.
At the edge of the containment device, gravity is 0.01 m/s^2 from the black hole. This ...
- 13.9k
26
votes
What would happen to a modern skyscraper if it rains micro blackholes?
Black holes evaporate by emitting Hawking radiation
a 1-second-life black hole has a mass of $2.28 \cdot 10^5 \ \mathrm{kg}$
A grape has far less mass than that, thus the black hole would ...
- 262k
26
votes
Accepted
What happens if I shot a blackhole pellet point blank at someone?
I am NOT (not, not not) fluent in celestial mechanics, so if I'm wrong, let me know and I'll delete this answer. But...
Our favorite supervillain, Gru, has asked his most trusted scientist, Dr. ...
- 107k
25
votes
Accepted
How big a black hole is needed for this story?
That's some extreme time dilation.
It is possible, but the black hole needs to be insanely massive for your ship to orbit it without falling into the event horizon and have the proper amount of time ...
- 48.3k
25
votes
How to build a fail-safe system for an engine that can harness energy from a Black Hole?
You invented it, you decide
Sorry for coming off as boring but this question is of the sort:
I have invented Big Magic™ for my setting.
Now please tell me how this little aspect of Big Magic™ works.
...
- 39.9k
24
votes
Is a solar system around a black hole possible?
Yes.
You can take binary or trinary star systems and swap one of the stars for a black hole and nothing changes in the orbital dynamics.
Depending on the layout of the solar system planets can orbit ...
- 76.7k
Only top scored, non community-wiki answers of a minimum length are eligible