# If photon is mass-less why can it be pulled into blackhole?

Discussion in 'Physics & Math' started by Saint, Aug 7, 2017.

1. ### DaveC426913Valued Senior Member

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Because you are under a misapprehension.
It is simply not true.

Capture requires a third body to alter the potential energy (gravitational versus kinetic), changing its path from hyperbolic to elliptical.

Bodies captured our solar system are captured only when they have a close encounter a planet or other orbiting mass. If they do not, they will fly right on through and out the other side, continuing on their hyperbolic trajectory.

Same with ejection. (Which is identical to capture, but time-reversed).
No body can be ejected from the SS without having an encounter with one of the sun's children. It needs to alter its elliptical path to hyperbolic in order to escape.

Last edited: Aug 20, 2017
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3. ### The GodValued Senior Member

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Again...

1. How do you think Apollo 11, started orbiting moon ?

You are confusing small magnitude of angle on account of large distances involved. Initial condition involves position also with respect to central mass along with velocity vector. This could be any Point above the physical surface of the central mass. In Newtonian mechanics in principle the Gravitational well extends up to infinity, so your sticking with some 11000 or 10999 or 1.5 is your choice. An object even at 100 Meters height can escape and exit if velocity vector is just ok.

I will see how long you continue with your straw man.

5. ### The GodValued Senior Member

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Looks good to read, but incorrect.

Which third body is assisting Andromeda and Milky Way when they meet in few million years?

A body or an object cannot get out of Gravitational influence of any of our planet's or sun's, if it does not have required escape velocity and away from the trajectory of strike.

7. ### DaveC426913Valued Senior Member

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By doing a decel burn to alter its long period Earth orbit to a nearly circular lunar orbit.

The fact that the Moon cannot capture the capsule is something they counted on . If something went terribly wrong on the trip out, and they lost all propulsion, the capsule would loop around and come right back to Earth. That was a critical safety factor in their mission plan.

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A natural body cannot start out heading away from the surface of a body with more than escape velocity. Only objects with propulsion can do that.
This is not related to escape and capture of natural bodies.

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8. ### DaveC426913Valued Senior Member

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And someone was just speaking of straw men....

The sun cannot capture or (eject) a body without a third body in the mix.

9. ### The GodValued Senior Member

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Think louder.

What kind of propulsion you gave it?

You are rattled. Relax.

10. ### The GodValued Senior Member

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The sun is ejecting so many Photons every moment without any third body of your in mix.

A black hole can capture a photon in its photonsphere (1.5 Rs) without any third body in mix.

PS: now pl do not say that photon is not a natural body.

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12. ### DaveC426913Valued Senior Member

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And so the goalposts get moved willy nilly all over the playing field.

This is the sign of someone who has been challenged to back up their erroneous assertions, and cannot. So they change em.

13. ### The GodValued Senior Member

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I will let you go. Be happy.

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15. ### The GodValued Senior Member

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To mods,

This is where your role becomes crucial. Not to side with any of contesting posters but to ensure that the clear science is put on record.

Otherwise many of the occasional visitors will be confused or stressed in the jungle of multiple, many of them useless, posts. Many other posters who are following this thread, will be left to conclude on their own which could be erroneous or influenced by the unnecessary rhetorical nonsense used in the posts by both the sides.

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16. ### James RJust this guy, you know?Staff Member

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Thanks for the invitation, The God.

It threw out some matter in front of it, and so slowed down as it approached the moon. The exhaust gases are the required third body, along with the capsule and the Moon.

Dave had it right, as usual:
And that's what exactly what Apollo 13 did.

Photon's are massless particles, so they always travel at the speed of light. They don't require "propulsion".

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Is that science clear enough for you, The God?

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17. ### The GodValued Senior Member

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• Throwing a temper tantrum and hurling insults simply because you are proven wrong is not the way to debate science.
You are acting like a spoilt child who knows some science and undeservingly given the mod position.

I did not invite a mod to come and write such pathetic shit, but to put the science in right perspective.

And as far as science is concern, it has always been quite clear to me, James R, what I am waiting to see is when will so called pretentious teachers and preachers of this forum learn. With this you have successfully joined that gang of shallow pretenders.

18. ### exchemistValued Senior Member

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Spoilt child behaviour? Surely that would be you?

19. ### originIn a democracy you deserve the leaders you elect.Valued Senior Member

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While your ideas may seem quite clear to you, they are not science and they are not correct.

Why do you refuse to learn??

20. ### The GodValued Senior Member

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Exchemist ( to lesser extent), Origin and DaveC,

Thoroughly confused W4U and miserably failed in clarifying gravity assist to him. Got stuck in 2 body 3 body nonsense. Making incorrect statement after statement And now James R comes after his self imposed periodic off and makes some stray assertion supporting DaveC and lo two of you (Origin and Exchemist) rush to the podium shouting eureka.

21. ### The GodValued Senior Member

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That's what all those who are ignorant feel.

22. ### birchValued Senior Member

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So simply it bends space by displacement/mass and time by obstructing straight-line trajectory due to resulting curvature. Is this right in laymen's terms?

Only because it can't be measured due to it's velocity and the subsequent changes in mass, right?

Last edited: Aug 20, 2017
23. ### KittamaruAshes to ashes, dust to dust. Adieu, Sciforums.Valued Senior Member

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This would explain why your typical response to being proven wrong is to lash out at those who do so, insulting them an basically blowing copious amounts of smoke...

Let me make it abundantly clear - this kind of behavioral pattern will stop, one way or another - either through your own volition, or through infractions.

Is that understood?

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