Using Black Holes for Terraforming?

[KASASpace]

No no, this isn't a problem. You don't just send them there. It's kind of like climbing tall mountains. You acclimatize. So, perhaps using an orbital centrifuge you could slowly get the humans to get used to the new gravity levels. And then do this on the way to Earth if they ever visit. You would be surprised how well the human body can adapt to new environments. And the air problem for the moon is more than gravity, but the amount required with that low gravity to get the proper pressure at sea level. Good luck with that.

If only Jupiter hadn't stolen some of Mars' mass before Mars even came to be.........

The Moon isn't a likely target for terraforming, but Mars is. Venus is, just, no.

Now, here's something.

Increase the mass. Perhaps breaking up asteroids and raining them slowly over Mars could eventually increase it's mass to have the Gravity required to hold in an atmosphere at, let's say at least half the pressure at sea level on Earth. The percentages of Oxygen to Nitrogen can vary. You now have other problems. So, stop with the Gravity thing and accept that we aren't masters of the universe. Leave some things alone.

[KASASpace]

Actually, according to our current knowledge, they're made out of nothing. It's the best we can do now.

Nothing doesn't exist. What does exist is the lack of something, which is still a thing. So, therefore they are made of something, the lack of it.

[ZetaX]

I'm not making assumptions about anything.

Yes you do:

If the universe is going to expand, it must expand FROM somewhere TO somewhere.

That's not how expansion of the universe works. I bet you did not check the wikipedia article on it.

[Seret]

I'm not doubting motion. I'm doubting expansion. Of the universe

If the universe contains more space than it used to, then it's expanded. It's not just that the matter in the universe is moving relative to each other, spacetime is actually stretching. This expansion isn't "into" anything, there's nothing to expand "into". It's just that the size of the universe continues to increase. The universe used to be very small. It used to only be the size of tennis court. Before that it was the size of you. Before that it was the size of an atom. Before that it was even smaller. That's the Big Bang. The Big Bang didn't fill an empty space with matter, it was when the universe started to increase in size. It continues to do so (in fact it's accelerating).

You don't have to believe this prima facie, that's not how science works. If you look into it you'll find it is a hugely well supported idea, and fundamental to modern cosmology

There is only evidence that the observable portion of the universe is in motion relative to a central place.

The Big Bang didn't happen at the centre of the universe, it happened at every point in the universe. It happened right where you are now. Every point in the universe is in motion relative to every other point, not to some central point. That's what's been observed.

Edited July 26, 2014 by Seret

[Chiboko]

Who says something has to get bigger in order to appear to expand?

-Everything inside the universe could just get smaller

-The speed of light could slow down making distances appear to be greater

-The 3D plane of the observable universe could be on the surface of a shape similar to this http://upload.wikimedia.org/wikipedia/commons/d/de/Menger_sponge_%28Level_0-3%29.jpg thus allowing an infinite surface area of 3D 'universe' within a finite 4D volume.

-Or the multiverse theory could be correct and the universe is expanding into a greater multiverse filled with other expanding universes moving away from each (similar to the expansion of our universe) meaning they never collide, this multiveres is in turn part of an even greater multiverse of multiverses, ad infitum.

[SargeRho]

1: No.

2: Neither.

3: Dunno.

4: If the universe is all there is, then there is nothing it is expanding into.

[Chiboko]

No one is claiming that the universe is all there is. It is simply all that we can observe, directly or indirectly.

[SargeRho]

The universe being all there is is however a possibility.

[xcorps]

No one is claiming that the universe is all there is. It is simply all that we can observe, directly or indirectly.

That's not the definition of universe.

all existing matter and space considered as a whole; all of space and everything in it; the totality of known or supposed objects and phenomena throughout space;

The Universe is all of spacetime and everything that exists therein, including all planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy;The size of the Universe is unknown; it may be infinite.

All different sources.

If one is to suggest that the Universe consists of only what is observed, then one is doomed to geocentrist folly. Assuming that the Dark Matter hypothesis is true, your definition excludes dark matter from the Universe.

Or the multiverse theory could be correct and the universe is expanding into a greater multiverse filled with other expanding universes moving away from each (similar to the expansion of our universe) meaning they never collide, this multiveres is in turn part of an even greater multiverse of multiverses, ad infitum

If the multiverse theory is correct, then there is no universe.

[lajoswinkler]

Nothing doesn't exist. What does exist is the lack of something, which is still a thing. So, therefore they are made of something, the lack of it.

That's semantics and philosophy you're now trying to divert to. Not science.

If the multiverse theory is correct, then there is no universe.

Multiverse is not a theory. It's a hypothesis at best. There are no evidence to support it, so it can't be a theory.

[Nuke]

I agree. The only question is, if you are going to build a giant centrifuge for gravity, why build on a planet/moon at all? Just build it in orbit, and mag-rail processed materials from surface. Presumably, workers would have to leave centrifugal habitats and work in low-G either way, and shuttling them back and forward is easy/cheap enough if there is no atmo to get in the way.

having a station out in space might serve a few purposes, but if you are mining materials for example, it helps to live close to the job site.

[Chris P. Bacon]

I'm not doubting motion. I'm doubting expansion. Of the universe

one word: Redshift

[livefree75]

They're made of unknown material. Something infinitely small, but still there.

From what I know, black holes are made of everything that has fallen in since its formation. This matter is condensed at an infinitely small point called the singularity, which is literally the black hole itself.

When you see a picture of a black hole, you see a black sphere. This is because the singularity is so dense, there is a point beyond which light cannot escape. This boundary is called the event horizon. The black sphere is the area within the event horizon. Since no light is coming from there, it appears black.

Within the event horizon, spacetime curvature is infinite. So the "space" within the event horizon is literally made of nothing, possibly not even space-time.

[Chris P. Bacon]

So the "space" within the event horizon is literally made of nothing, possibly not even space-time.

Correct, but calling it "nothing" is a bit like calling dark matter "matter".. we do not yet have a name or theory of physics to explain the state of matter/energy within a black hole, Newton and even Einstein start to fall apart here.

But back to OP's question, while totally possible in creating the result you wanted (assuming you could contain and sustain the tiny, short-lived black hole), it would have severe negative effects to any nearby bodies, and would require a technology so advanced that other methods of creating the same result (genetic engineering, grav plating, massive centrifuges or simple bone-regenitive medication) would be trivial in comparison.

[Kinglet]

Also, we still have no idea about the effects of low gravity on human health. ZERO gravity is bad, yes, but there has been NO research on long term exposure to low gravity. What is the minimum gravity to keep a human healthy? No clue. It might be 1g, it also might be much less.

Ugh, I almost scream when people say gravity instead of G-force. Orbits would be impossible if astronauts always are in zero gravity instead of zero g force.

[ThinkOutsideTheHangar]

Micro black holes aren't the most stable things, and hawking radiation makes them evaporate almost immediately. And besides, the energy needed to make them are in the GeV range.

Edited July 27, 2014 by ThinkOutsideTheHangar

[ZetaX]

What makes you think a black hole with several times the mass of the moon is "micro"¿

[K^2]

Actually, according to our current knowledge, they're made out of nothing. It's the best we can do now.

No. There is no theoretical or experimental knowledge to suggest that black hole is "made out of nothing". Black hole is a state of matter. Collapsing stellar core undergoes several phase transitions, transition to black hole being one of the final possibilities.

[lajoswinkler]

No. There is no theoretical or experimental knowledge to suggest that black hole is "made out of nothing". Black hole is a state of matter. Collapsing stellar core undergoes several phase transitions, transition to black hole being one of the final possibilities.

Event horizon is space, which is "nothing" by traditional sense of speaking (let's ignore particles foaming in vacuum), and the center is singularity, which could also be called nothing because it has zero dimensions. It's a point. According to our current knowledge, of course. Who knows what's the actual bussiness inside. I was always fond of hypothesis that it's still a kind of star, but a totally degenerated and very small.

So, curved space... that's not a state of matter.

[Nuke]

is it even possible to know how much of the volume of the event horizon is actually filled with 'black hole stuff' (for lack of a better term), and how much is empty?

[Seret]

is it even possible to know how much of the volume of the event horizon is actually filled with 'black hole stuff' (for lack of a better term), and how much is empty?

Size of the event horizon, innit? The singularity doesn't have any volume, because it's a singularity. So if you define the "black hole" as everything within the event horizon then the answer is 100%, and if you only include the singularity then have fun dividing by zero

Edited July 29, 2014 by Seret

[lajoswinkler]

is it even possible to know how much of the volume of the event horizon is actually filled with 'black hole stuff' (for lack of a better term), and how much is empty?

Only by scribbling on the paper. No information can reach us from inside of the event horizon. Current knowledge supports the notion that matter is totally crushed into a point because even neutron pressure is not enough to stop the contraction. By the time event horizon is formed, matter as we know it can't exist.

[Z-Man]

is it even possible to know how much of the volume of the event horizon is actually filled with 'black hole stuff' (for lack of a better term), and how much is empty?

For a classical black hole, all of the inside apart from the singularity is empty (curved) space. If quantum effects are allowed, they may reach out a bit outside of the horizon and fill the entire inside even for big holes. Nobody knows. As you may imagine, testability is somewhat of an issue here There is, for example, the Firewall hypothesis that has a radiation flash near the event horizon that fries you right as you enter.

[lajoswinkler]

Also, for all but very small black holes, crossing the event horizon of a lonesome black hole would be just a fancy visual display (if Firewall hypothesis isn't true). Horror of pulling stuff apart comes after that, close to the singularity where the gravity gradient is enough for human-sized objects to experience high tidal forces.

[Z-Man]

If stellar black holes are very small by your standards, then yes. Those still rip you apart long before you cross the horizon. You may just be able to make out their gravity lensing effect with the naked eye if you fly closely past one, the stars would twitch a little bit.