Re:When a black hole and a neutron star merge
by deepsun on Monday April 08, 2024 @08:21AM
(#39968940)
Nitpick: you will not feel acceleration in a freefall.
Re:When a black hole and a neutron star merge
by cheela on Monday April 08, 2024 @08:51AM
(#39969177)
You’ll feel the tides, however.
Re:When a black hole and a neutron star merge
by SoftTalker on Monday April 08, 2024 @10:36AM
(#39970185)
These analogies always fall apart for me because you'll be burnt to nothing long before you reach the surface of the sun.
Re:When a black hole and a neutron star merge
by onetimeuse92304 on Tuesday April 09, 2024 @03:48AM
(#39977057)
Your analogy falls apart, too. Sun does not have a surface to be reached. It just sort of gets more and more dense and that's all.
Re:When a black hole and a neutron star merge
by onetimeuse92304 on Monday April 08, 2024 @01:03PM
(#39971668)
What is "feeling"? If my senses can register changing spectra of the stars around me then yes, I will "feel" the acceleration.
Re:When a black hole and a neutron star merge
by abhpro on Monday April 08, 2024 @01:14PM
(#39971771)
I didn't think you could accelerate at all in a freefall (which is why you wouldn't feel it), you are just following a geodesic
Re:When a black hole and a neutron star merge
by medstrom on Monday April 08, 2024 @06:13AM
(#39968145)
So yea, this lets you equate standing on the surface of a given star of X radius, with hovering the same X distance away from a neutron star or black hole of the same mass.
The takeaway is that the cellophane dimple is more warped around the center point, but if, say, our Sun were to suddenly turn into a black hole it wouldn't change anything about our orbit.
Re:When a black hole and a neutron star merge
by philipov on Monday April 08, 2024 @10:29AM
(#39970103)
However, when you're 5 miles away from the surface of a black hole, you would be inside the sun, so the shape will be different. We are not comparing equal distances from the center of mass, but equal distances from the surface; which are different distances! Only if you are the same distance from the sun as from a black hole, what you say is correct. But then you will be much farther away from the black hole than in this example.
Re:When a black hole and a neutron star merge
by onetimeuse92304 on Tuesday April 09, 2024 @02:19AM
(#39976612)
Distance from the body I have defined as distance from its center.
Black hole does not have a surface. At least not that we know of. Event horizon is a surface, but it is not the surface of the BH in conventional sense. If you were falling into BH nothing special would happen as you crossed event horizon.
And neither does the Sun. Just like Earth's atmosphere, we can only talk about some arbitrary altitudes or pressures, but reality is that the atmosphere of the Sun or Earth does not have any firm beginning or end. And Sun is all atmosphere.
The shape of gravitational field only differs within the body. The shape outside of the perfectly spherical body will be exactly the same regardless of how the mass is distributed (whether it is all on the surface or all in the middle of it).
Or in other words, if you are on the surface of the sun, you will feel exactly the same acceleration as if entire mass of the sun was concentrated in its center.
The only time you feel the difference is if you dip into the sun. As you go deeper and deeper, the pull from all the mass that is further from the center than you are will perfectly nullify each other. As you go deeper and deeper into the sun you will feel less acceleration.