A Question About Black Holes in Passing

[OneAngryDemocrat]

Obviously, black holes can (and will) consume anything that gets too close to the object's event horizon.

However, like all celestial objects, black holes move, and the strength of the object's gravity varies depending on the distance from the object's singularity.

Could a larger black hole in motion pull flat the gravity well of a smaller black hole while in passing, or possibly even invert it - without consuming the smaller body?

What would happen to the singularity of the smaller black hole, in the case that the smaller object's gravity well were ever to be pulled flat or inverted?

Could the gravity well of a smaller black hole facing a larger one in passing be flattened or inverted by the larger black hole without immediately affecting the smaller black hole's gravity well that is not facing the larger body?

And what would be the effect on the smaller body's singularity in THAT case? Would the gravity well of the smaller body NOT facing the larger black hole deepen?

Could it 'snap'?

[longship]

1. I don't know what this post is about. However...

Black holes are not magic vacuum cleaners. They are just dense objects with mass. You could replace the Sun with a black hole of the same mass and the planets would all revolve around it basically the same way they do now.

Where things get messy is when an object gets close to the Schwarzchild radius, the distance from the center of the black hole where the escape velocity equals the speed of light. Anything that goes in there doesn't come out, theoretically anyway. (Hawking radiation is an exception.) If the object is another black hole, I would expect a pretty messy outcome.

I am no cosmologist (nor a cosmetologist) so I cannot respond to your question beyond my basic physics education.

[OneAngryDemocrat]

4. In Short...

What I am asking is, is it possible for a larger object to exert gravitational force on a smaller object, rendering the smaller object's own gravitational force null, without swallowing up the smaller object?

Think of the rings of Saturn for a moment, and assume that one or more of the rings were, at one time, a single object (a moon).

If a moon can be shredded by the planet Saturn and it's constituent parts scattered, couldn't a large black hole do the same to a smaller black hole?

[jeff47]

6. The rings were caused by tidal forces

Gravity pulled harder on one side of the moons, and tore them apart.

Or so one theory says. We really don't know have enough information to conclusively say.

Theoretically, a large black hole could break up a smaller black hole via tidal forces, but the small black hole would have to get close to the large one - like inside the event horizon.

[longship]

7. Wrong on Saturn.

The rings are substantially within the Roche limit, IIRC. No moon would or could be stable there. Saturn has an extraordinarily large number of moons, some of which are shepherd moons which orbiting in the ring plane, help stabilize them. They are quite small, but their influence is enough.

That's the way I understand it.

Gravity is a bit more in my expertise.

No object can nullify the gravity on another. The theory of gravity is fairly simple. If an object has mass it has a gravitational field. The gravitational force is calculated as if all the mass of each object is at the center point (due to symmetries, there is no difference). As long as the two bodies don't contact one another they can be treated as point sources as far as calculating things.

The Sun is as much in orbit around the Earth as vice-versa. The Sun's orbit due to the Earth is smaller than its radius due to the huge mass difference. That's how telescopes detect extra-solar planets: the star jiggles which can be detected with spectral analysis.

This is first year physics stuff, probably all I can handle these days, 32 years after my BS degree.

[TheMadMonk]

14. Short answer no.

A moon breaks up under the influence of gravity, because the difference in gravitational forces on the near and far side of the is enough to overcome the mechanical strength of that moon. Quite literally it falls apart.

The mechanical strength of a black hole can be considered to be effectively infinite.

[jeff47]

2. Gravity isn't a field.

To be "pulled flat", you'd have to have something like a field of gravity. It doesn't work that way. Gravity of a black hole is more like a point mass. With a lot of mass.

Black holes are often depicted as funnel-like 'gravity wells', but that's not how they really work.

[OneAngryDemocrat]

3. Understood, but...

I intentionally used the term 'gravity well' because - not being a physics major - I don't have the math skills to describe what I am envisioning. I fully understand that a black hole is NOT a 'funnel-like' gravity well, but is, instead, a four dimensional hole in space, with gravity exerting it's force in all directions.

My question still remains valid however, with that cleared up.

I see no reason why a greater gravitational force from a super massive black hole couldn't "unpucker" the puckered up gravity well of a smaller black hole, pulling it flat, or even flattening it in passing, without consuming the smaller object.

[jeff47]

5. It's not a hole in space.

It's a really, really, really, really, really heavy rock.

I see no reason why a greater gravitational force from a super massive black hole couldn't "unpucker" the puckered up gravity well of a smaller black hole

Again, a 'pucker' requires a field. There is no pucker. There is no hole. There's a hunk of matter that is so heavy that escape velocity exceeds the speed of light.

[DreamGypsy]

8. Binary black holes

Perhaps this will help, from Wikipedia:

A binary black hole is two black holes in close orbit around each other. Although only a theoretical idea, they are important in astrophysics in that they would be the strongest known gravitational wave source in the universe. As the orbiting black holes give off these waves, the orbit decays, and the orbital period decreases. This stage is called binary black hole inspiral. The black holes will merge once they are close enough. Once merged, the single hole goes through a stage called ring down where any distortion in the shape is dissipated as more gravitational waves.

<snip>

The final-parsec problem

The natural separation of two, supermassive black holes at the center of a galaxy is a few to a few tens of parsecs (pc). This is the separation at which the two black holes form a bound, binary system. In order to generate gravitational waves at a significant level, the binary must first shrink to a much smaller separation, roughly 0.01 - 0.001 pc. This is called the "final-parsec problem". A number of solutions to the final parsec problem have been proposed; most involve the interaction of the massive binary with surrounding matter, either stars or gas, which can extract energy from the binary and cause it to shrink. For instance, gravitational slingshot ejection of passing stars can bring the two black holes together in a time much less than the age of the universe.

...and remember, a parsec is 30.9 trillion kilometres (19.2 trillion miles) or 3.26 light-years, so these puppies aren't particularly close.

The wikipedia article has a discussion of modeling binary black holes.

And then there's ...

Shape

One of the problems to solve is the shape or topology of the event horizon during a black-hole merger. In numerical models, test geodesics are inserted to see if they encounter an event horizon. As two black-holes approach each other, a duckbill shape protrudes from the two event horizons towards the other one. This protrusion extends longer and narrower until it meets the protrusion from the other black-hole. At this point in time the event horizon has a very narrow X-shape at the meeting point. The protrusions are drawn out into a thin thread. The meeting point expands to a roughly cylindrical connection called a bridge. Simulations as of 2011 had not produced any event horizons with toroidal topology, although others suggested that it would be possible, for example if several black-holes orbiting in the same circle coalesce.

Black hole merger recoil

An unexpected result can occur with binary black holes that merge in that the gravitational waves carry momentum and the merging black hole pair accelerates seemingly violating Newton's third law. The center of gravity can add over 1000 km/s of kick velocity. The greatest kick velocities (approaching 5000 km/s) occur for equal-mass and equal-spin-magnitude black-hole binaries, when the spins directions are optimally oriented to be counter-aligned, parallel to the orbital plane or nearly aligned with the orbital angular momentum. This is enough to escape large galaxies. With more likely orientations a smaller effect takes place, perhaps only a few hundred kilometers per second. This sort of speed will eject merging binary black holes from globular clusters, thus preventing the formation of massive black holes in globular cluster cores. In turn this reduces the chances of subsequent mergers, and thus the chance of detecting gravitational waves. For non spinning black holes a maximum recoil velocity of 175 km/s occurs for masses in the ratio of five to one. When spins are aligned in the orbital plane a recoil of 1300 km/s is possible with two identical black holes.

Below is a CalTech simulation of the inspiral of a binary black hole.

Note, the model shows 'gravity wells' for the two black holes. As should be clear from other comments, gravity wells are ONLY REPRESENTATIONS of the strength of the gravitation attraction for masses approaching from particular directions - there is no funnel! The uniformity of the 'gravitational well' of the Earth, for example, is obvious because the escape velocity is essentially the same everywhere on the surface of the earth (depending only on altitude and local fluctuations in the mass of materials in the crust.

[OneAngryDemocrat]

9. Thank You!

[byronius]

12. That is so cool. Thank you.

[lastlib]

10. take a look:

http://www.universetoday.com/13002/what-happens-when-supermassive-black-holes-collide/

[Xipe Totec]

11. Lagrangian Points

the five positions in an orbital configuration where a small object affected only by gravity can theoretically be part of a constant-shape pattern with two larger objects (such as a satellite with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to orbit with them.

Lagrangian points are the constant-pattern solutions of the restricted three-body problem. For example, given two massive bodies in orbits around their common center of mass, there are five positions in space where a third body, of comparatively negligible mass, could be placed so as to maintain its position relative to the two massive bodies. As seen in a rotating reference frame matching the angular velocity of the two co-orbiting bodies, the gravitational fields of two massive bodies combined with the satellite's acceleration are in balance at the Lagrangian points, allowing the third body to be relatively stationary with respect to the first two bodies.

http://en.wikipedia.org/wiki/Lagrangian_point

[Gore1FL]

13. If I understand what you are asking

Matter tells space how to curve.
Space tells matter how to move.

Black holes are made of matter.
The more matter you have crammed into a black hole, the stronger the curve (this is true with fleas. This is true with Jupiter. This is true with galaxies. more matter = more curve)

If you have two black holes close to one another, they will not nullify each other's warping of space, but add to the distortion and probably create some interesting effects between them.

I really should have said spacetime where I said space above.