One of the most remarkable aspects of physics is that Newtonian gravity calculations are quite spot on for all the parts of black holes layfolk consider important.
1. Both predict the same critical radius, now called the Schwarzschild radius.
2. Both predict a central singularity with formally infinite density in idealised collapse.
3. Both predict exactly the same finite time to fall into the singularity under equivalent idealised conditions.
4. Both give the same equation for radial free fall, using different definitions of time.
What GR added was meaning to these things (and of course precise calculations outside of very idealised scenarios and symmetric conditions).
Both have finite time falling in to the singularity. If you use a point test particle Newton and GR agree on that finite time.
That's proper time I.e. the infalling particles wristwatch time.
In GR, external observers would never see the infalling particle cross the event horizon but that's a coordinate artifact. If using our wrist watch time for that particle.
What I find really interesting is that black holes don't really "require" infinite density; the mass density inside the event horizon never exceeds neutron star levels, and becomes in fact lower the heavier the black hole gets (=> event horizon enclosed volume grows faster than mass).
For large blackholes of course. And this actually makes other interesting property. Our universe is in fact giant blackhole with our own event horizon outside it. This also support cyclic big bang theory.
Once entire universe will collapse to singularity, the smallest possible particles shatters, leaving pure energy. Pure energy doesnt have "static" mass so no gravity => kaboom, we have new iteration. Theory of multiverse (multiple black holes aka universes) is out of scope here because we will never be able to escape ours.
One of the most remarkable aspects of physics is that Newtonian gravity calculations are quite spot on for all the parts of black holes layfolk consider important.
1. Both predict the same critical radius, now called the Schwarzschild radius.
2. Both predict a central singularity with formally infinite density in idealised collapse.
3. Both predict exactly the same finite time to fall into the singularity under equivalent idealised conditions.
4. Both give the same equation for radial free fall, using different definitions of time.
What GR added was meaning to these things (and of course precise calculations outside of very idealised scenarios and symmetric conditions).
Newtonian gravity gives infinite time to fall into black hole?
I thought you need at least special relativity for time dilution.
Both have finite time falling in to the singularity. If you use a point test particle Newton and GR agree on that finite time.
That's proper time I.e. the infalling particles wristwatch time.
In GR, external observers would never see the infalling particle cross the event horizon but that's a coordinate artifact. If using our wrist watch time for that particle.
What I find really interesting is that black holes don't really "require" infinite density; the mass density inside the event horizon never exceeds neutron star levels, and becomes in fact lower the heavier the black hole gets (=> event horizon enclosed volume grows faster than mass).
For large blackholes of course. And this actually makes other interesting property. Our universe is in fact giant blackhole with our own event horizon outside it. This also support cyclic big bang theory. Once entire universe will collapse to singularity, the smallest possible particles shatters, leaving pure energy. Pure energy doesnt have "static" mass so no gravity => kaboom, we have new iteration. Theory of multiverse (multiple black holes aka universes) is out of scope here because we will never be able to escape ours.
I'd use a camera, personally
make sure you set the exposure to a negative value
f/0 should work ? :)
First you'll need a camera that can detect mathematical equations.
Is it just me, or could they have added a, say, picture of a black hole?
It's the one in your head that you picture, as not many have been taken:
https://www.si.edu/newsdesk/releases/astronomers-reveal-firs...
Why does it look like it's moving to me?
I remember times when the best available photo of Pluto looked like this.
This is a transcript of a 60-minute podcast. Would you like that TIFF in Zmodem format? Or they could read it out in base64?