Two Black Holes Merge into One
Why Physics Stack Exchange recommends it
Physics Stack Exchange answerers and askers link it as a ready visual reference for what a black hole merger looks like when discussing event horizons, merger orbits and lensing.
Recommended by 0 people across 0 different months, 2016 to 2024.
What it is
A 35-second numerical-relativity simulation from the LIGO Lab at Caltech and MIT showing two roughly 30-solar-mass black holes spiraling together and merging, as inferred from the first gravitational-wave detection. It shows gravitational lensing of background stars and an Einstein ring, with time slowed about 100 times.
Cited in 2 Wikipedia articles, including Black hole, Outline of black holes.
What people said
Cites Bob Bee · 2016-10 · Physics Stack Exchange · on “On the existance of black holes”
No, the universe is unaware of the existence of the BH, nor of any of the space inside the horizon -- actually all the spacetime the BH occupies is disconnected casually from the rest of the universe. A perpetual BH always existed and always will, and the spacetime it occupies (and all 'within' the horizon) is just not part of our universe. A real (non perpetual) BH is almost the same, we actually can't note a difference, except it is in an infinite process (from our point of view, due to time dilation) of forming. For all 'practical' purposes they are the same. We just cannot see the spacetime inside. The first part, as Benjimin said clearly, Alice's time is very limited. The falls towards
Cites Bob Bee · 2017-06 · Physics Stack Exchange · on “How do Black Hole event horizons grow?”
Yes they grow as mass or energy is added in. It's not complicated, and well understood, within General Relativity. With one caveat. The caveat if that a body that almost reaches the horizon gets so close to it even as time slows down infinitely (theoretically) that for all practical purposes you can cconsider it to have been absorbed into the black hole (BH). That deals with the confusing issue of time slows infinitely at the horizon. It's dealt with in other questions on this site The horizon radius of a Schwarzschild BH is (first reference at bottom) $R_h = 2GM/c^2$ There's an equation for rotating and charged BHs also, with the the charge and angular momentum entering in. The details are
Cites Paul · 2018-04 · Physics Stack Exchange · on “Variability of the orbital inclination of a black hole merger?”
How variable should we expect the orbital inclination of a typical black hole merger to be, relative to the galactic plane? The LIGO simulation [this video] seems to give the impression that the orbital inclination doesn’t change, but wouldn’t general relativity predict that there would be a very large precession of the perihelion? And wouldn’t the orbital inclination also precess due to the gravitational pull from the surrounding galaxy? Asked a different way, what would the merger look like from an outside observer watching over billions of years? Would the orientation of the orbital inclination become extremely erratic, switching from horizontal to vertical and everywhere in between?
Cites mmesser314 · 2024-02 · Physics Stack Exchange · on “Black Hole Ripped Apart”
First, a black hole between two black holes has two places where two black holes are near each other. This is much like two black holes merging. The two do not rip each other apart. You have probably seen videos showing two black holes circling each other until - blip - there is one black hole. If not, here is one from CalTech. Two Black Holes Merge into One [this video] Here is a numerical simulation from CalTech that shows the final moment of the first merger detected in 2019. You can see the shape is distorted, but not ripped apart. GW190412: Binary Black Hole Merger [LINK] [LINK]