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Astronomers witness energetic switch on of black hole

phys.org

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Re: Astronomers witness energetic switch on of black hole

#21

Post by willis936 »

ars wrote: post #16
treeman79 wrote: post #14

Earlier quoted context omitted.

It ate a star.

But that would take infinite time (as we perceive the event) because of time dilation. You would not see it "turn on", you would see a slowly, very slowly, changing signal.

You'd be hard pressed to ever directly observe something that is astronomically tiny and emits extremely low frequency radiation, if any at all.

When an accretion disk is actively ripping apart a celestial body the plasma is some of the hottest material in the current universe. It's extremely violent and bright. You're seeing a gravitational well converting a huge quantity of mass to energy.

Re: Astronomers witness energetic switch on of black hole

#23

Post by deepspace »

willis936 wrote: post #21
ars wrote: post #16

Earlier quoted context omitted.

But that would take infinite time (as we perceive the event) because of time dilation. You would not see it "turn on", you would see a slowly, very slowly, changing signal.

You'd be hard pressed to ever directly observe something that is astronomically tiny and emits extremely low frequency radiation, if any at all. When an accretion disk is actively ripping apart a celestial body the plasma is some of the hottest material in the current universe. It's extremely violent and bright. You're seeing a gravitational well converting a huge quantity of mass to energy.

Yes, as I understand it, the “turn-on” effect is from the plasma generated while the star is falling into the gravity well. The bit of the star that passes the event horizon would be tiny.

Moreover, I believe that the radiation from an object falling into a black hole is redshifted so rapidly, that it effectively disappears from view in a very short time. An outside observer would not see anything “lingering” near the event horizon.

Re: Astronomers witness energetic switch on of black hole

#24

Post by post-it »

drojas wrote: post #20
ars wrote: post #16

Earlier quoted context omitted.

But that would take infinite time (as we perceive the event) because of time dilation. You would not see it "turn on", you would see a slowly, very slowly, changing signal.

I think this is good evidence in favor the plasmoid model from Eric Lerner as a replacement for black holes. Some key differences. * Instead of a black hole eating a star, a plasmoid is having an increased load. * Black holes are "gravitational" machines while plasmoid are "electromagnetic" machines. * With the plasmoid model there is no time dilation * With the plasmoid model, the load is any source of plasma, not n…

> With the plasmoid model there is no time dilation

But there is time dilation, so the plasmoid model isn't very good at explaining observations.

Re: Astronomers witness energetic switch on of black hole

#26

Post by FredPret »

etra0 wrote: post #4
dathos wrote: post #2

“Very Large Telescope”, I love this name. Any better ones out there?

Now they're building the ELT –– Extremely Large Telescope. They're great with names haha.

They should build one ten times the size of the next largest one, and call it the Quite Sizeable Telescope

Re: Astronomers witness energetic switch on of black hole

#27

Post by floxy »

ck2 wrote: post #8
dathos wrote: post #2

“Very Large Telescope”, I love this name. Any better ones out there?

Go read about the solar gravitational lens telescope proposal by physicist Slava Turyshev It is the most mind blowing thing that could actually be built someday by humans imho, well if we decide to stop blowing all our budget on killing other people https://google.com/search?q=solar+gravitational+lens It would be able to image exoplanets, 10 square kilometers for objects 100 light-years away.

>solar gravitational lens telescope

Here is a great video about it:

https://www.youtube.com/watch?v=NQFqDKRAROI

...and a paper:

https://arxiv.org/abs/1802.08421

Re: Astronomers witness energetic switch on of black hole

#30

Post by pengaru »

moffkalast wrote: post #13
cyberax wrote: post #6

Earlier quoted context omitted.

Don't forget OWL: Overwhelmingly Large Telescope ( https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope ).

Still waiting for the Stupendously Gigantic Telescope.

What, no BFT?
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