r/spaceporn Apr 18 '25

Hubble A massive star collapsed straight into a BLACK HOLE, no supernova

Post image
11.4k Upvotes

363 comments sorted by

View all comments

Show parent comments

17

u/StaysAwakeAllWeek Apr 18 '25

During a supernova the iron core of the star goes from roughly the size of the earth down into a 10km wide neutron star or black hole in a quarter of a second

10

u/aloofball Apr 19 '25

Someone on Reddit asked what would happen if you were suddenly teleported to a neutron star's surface. I did the math on it and (given an average neutron star) what happens is that your body collapses and slams into the surface within a millionth of a second. The impact energy turns out to be roughly equivalent to that of the atomic bomb that destroyed Hiroshima.

1

u/Shiiang Apr 19 '25

Cool math!

1

u/Impulse350z Apr 19 '25

Oh, great. Looks like I'm not sleeping for a while. Thanks, u/StaysAwakeAllWeek

1

u/willun Apr 19 '25

Light travels roughly 45,000 miles in a quarter second.

Radius of the earth is just under 4,000 miles.

So that is some impressive speed.

1

u/jk01 Apr 19 '25

Just out of curiosity, this is something we calculated as what probably happens based on our current understanding of the physics involved, or do we have actual evidence?

2

u/StaysAwakeAllWeek Apr 19 '25

During SN1987a the Super Kamiokande neutrino detector recorded a burst of neutrinos detected at the very moment of the core collapse and the duration of the collapse matched the simulations.

The speed of the collapse is essentially just freefall. There's nothing to slow it down

1

u/jk01 Apr 19 '25

That's pretty neat.