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Photon as a bullet. A newtonian question..

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Adrian
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Re: Photon as a bullet. A newtonian question..

#11 Post by Adrian » Sat Jul 28, 2018 6:45 pm

Where did you take that part with infinite gravity? A black hole has finite mass (huge usually for stellar black holes, but measurable and finite).

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timkb4cq
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Re: Photon as a bullet. A newtonian question..

#12 Post by timkb4cq » Sat Jul 28, 2018 7:17 pm

TauTsar wrote:
Fri Jul 27, 2018 5:32 am
A bullet and a photon are simultaneously fired from a gun. The bullet falls to the ground at x distance from the gun. Question, how wide would earth need to be before the photon hit the ground?
That's a pretty straightforward calculation. The situation is impossible, but assuming a sufficiently wide flat surface with 1g gravity we can get an answer. I'll stick to just a couple digits of precision
d = 1/2a*t^2
We'll figure a shot from 1 meter high (shooting from the hip ;) )
So 1=4.9*t^2
so t^2 = 0.204
so t = 0.45 seconds
Speed of light is 186,000 miles/sec, so in .45 seconds the photon would travel 83,000 miles.

You couldn't construct such a plane, and an object large enough to have less than 1m curvature per 135,000 km couldn't possibly have a 1g gravity, so it's a nonsense question - but if you could you have answer!
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Stevo
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Re: Photon as a bullet. A newtonian question..

#13 Post by Stevo » Sat Jul 28, 2018 7:21 pm

Adrian wrote:
Sat Jul 28, 2018 6:45 pm
Where did you take that part with infinite gravity? A black hole has finite mass (huge usually for stellar black holes, but measurable and finite).
Would the gravity gradient increase without limit the closer one got to the singularity?
Last edited by Stevo on Sat Jul 28, 2018 7:22 pm, edited 1 time in total.

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oops
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Re: Photon as a bullet. A newtonian question..

#14 Post by oops » Sat Jul 28, 2018 7:21 pm

colin_b wrote:
Sat Jul 28, 2018 6:39 pm
...
My guess is a black hole is a star with gravity which is strong enough to prevent light escaping, i.e. incomprehensibly strong, but its gravity is not infinite.
I think so too ... its gravity is not infinite, its mass not infinite too ... because it continues to catch some mass, light, stars, planets, etc. ... until when ? it's an other and good question?
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Re: Photon as a bullet. A newtonian question..

#15 Post by Stevo » Sat Jul 28, 2018 7:27 pm

oops wrote:
Sat Jul 28, 2018 7:21 pm
colin_b wrote:
Sat Jul 28, 2018 6:39 pm
...
My guess is a black hole is a star with gravity which is strong enough to prevent light escaping, i.e. incomprehensibly strong, but its gravity is not infinite.
I think so too ... its gravity is not infinite, its mass not infinite too ... because it continues to catch some mass, light, stars, planets, etc.
The way current physics has it, we don't know any way to prevent a collapse to a singularity once the neutron degeneracy pressure in a neutron star is overcome.

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Re: Photon as a bullet. A newtonian question..

#16 Post by oops » Sat Jul 28, 2018 7:30 pm

Stevo wrote:
Sat Jul 28, 2018 7:27 pm
...The way current physics has it, we don't know any way to prevent a collapse to a singularity once the neutron degeneracy pressure in a neutron star is overcome.
By singularity you mean another fractal universe?
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Re: Photon as a bullet. A newtonian question..

#17 Post by Stevo » Sat Jul 28, 2018 8:55 pm

oops wrote:
Sat Jul 28, 2018 7:30 pm
Stevo wrote:
Sat Jul 28, 2018 7:27 pm
...The way current physics has it, we don't know any way to prevent a collapse to a singularity once the neutron degeneracy pressure in a neutron star is overcome.
By singularity you mean another fractal universe?
The equations don't say anything about that--just that there is nothing that prevents gravity from pulling the star into a point mass of infinite density. Or course, since higher gravities slow down time, for an outside observer, the star would never fully collapse,it would just appear to shrink and turn black as it the surface approaches the event horizon. ( if you ignore all the other energies from the accompanying supernova--the Russian term is "frozen star" instead of the obscene "black hole".)

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Re: Photon as a bullet. A newtonian question..

#18 Post by colin_b » Sat Jul 28, 2018 11:00 pm

Stevo wrote:
Sat Jul 28, 2018 7:27 pm

The way current physics has it, we don't know any way to prevent a collapse to a singularity once the neutron degeneracy pressure in a neutron star is overcome.
This is what I see as providing the conundrum. A singularity is a minute point which has infinite gravity, so how can a supermassive object form around it?

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Adrian
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Re: Photon as a bullet. A newtonian question..

#19 Post by Adrian » Sat Jul 28, 2018 11:42 pm

A singularity is a minute point which has infinite gravity
Infinite density, not infinite mass or gravity (what does infinite gravity even mean?), you cannot have a beginning of understanding about anything even much simpler than the subject at hand if you start from facts that are clearly wrong.

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Re: Photon as a bullet. A newtonian question..

#20 Post by colin_b » Sat Jul 28, 2018 11:50 pm

I'm not trying to cause problems, I'm just the curious type.

I'll leave things here.

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