Hypothetically, can an outside observer ever see an object fall into a black hole?

Question

The object that's falling into the black hole will see the outside observer moving at a fast rate, way into the future. So could the outside observer see the object in the black hole falling at all? It would be still? You wouldnt be able to see it descend at all, it would look frozen. Is it impossible for an outside observe to see anything move in a black hole? That sounds creepy.

Dumb question I know.

Answer 1

Yes : depending on how much they are separated, (frame of reference) and Back hole type.

In the case of a Supermassive Black Hole :

A person a* separated from person b* : by (for instance) 20 metres, both free_fallinginto a SMBH, b* behind a* would observe each other cross the apparent Event Horizon.

Both would free_fall ( floating) without any discomfort both experiencing their own normal passage of time (heart beats etc)



Simply : Within similar reference frame, communication takes place as normal.



All the best. ( my view : not recommended as a homework answer.)



"If the truth declares black to be white - then let it be so." ©

Answer 2

For a modest sized Black Hole an external observer would see the falling object accelerate down (and emit radiation), tear apart (tidal stress) and emit a LOT of radiation as it falls to the event horizon. The falling material (reduced to quarks and leptons) undergoes time dilation but this is not visible to the external observer.



Now, if you have a LARGE Black Hole and nothing else falling in to complicate matters we see a different process. The falling body still emits radiation as it accelerates but lower intensity, also tidal forces are much weaker so the falling body stays intact for a long time. If the falling body has a radio transmitter the external observer notes that the frequency is dropping as the transmitter approaches the Black Hole - the gravity well of the Black Hole is dominating and time dilation is taking place - observe for a long time and the transmitter never stops transmitting but the frequency keeps dropping until the external observer can no longer hear it.



AT the event horizon time has stopped and all of the photns falling in have arrested one plank length above the event horizon. They will remain there until Hawking radiation removes them.

Answer 3

Not dumb at all. This type of thing is totally outside of our range of experience and is very difficult for us to relate to unless you do it mathematically.



But to answer your question, yes an object would appear to freeze as it approaches the event horizon even though it will pass through the event horizon in a finite (and short) amount of it's own time. The easiest way to resolve this is to understand that it takes an infinite amount of time for the information that the object crossed the event horizon to reach us if we are an external observer. The object merrily crosses the event horizon we just can't get the information (e.g. visual cue) that it has done so in a finite time. You have to be very careful with comparisons of anything between an external observer and something at the event horizon. Things are generally not directly comparable. For instance, there is a very rigorous mathematical process for comparing vectors at two different points in a gravitational field due to a rather nasty effect that vectors will change direction when moved over a curved surface and you have to account for that curvature to do a comparison. Throw in the fact that the amount the vector changes depends on the path that you take and you can start to see the difficulty in comparisons.

Answer 4

in a way yes. To an outside observer, time is traveling at a constant speed. When an object meets the event horizon, its time will "stop" because time is retaliative. When the object meets this point, to an outside observer it would appear to freeze while i reality the object would have been stretched, shredded and compacted into the black hole's singularity.

Answer 5

Time continues at a normal rate for the outside observer.

Light rays from the falling object would be red shifted as it neared the event horizon, but they would reach the observer at the speed of light.

The falling object's colour would change rapidly towards the red end of the spectrum until the light passed from the visible spectrum at which point it would disappear from the observers view. This would occur shortly before it reached the event horizon.



It cannot appear to "freeze" at the event horizon. This is impossible as the event horizon would then be full of images from millions of years ago until now and the light from millions of frozen images would be brighter than the sun. Where do the people think the light from a frozen image comes from? Anyone thinking otherwise better do their maths again. Light is energy.

Answer 6

technically you cant see an object actually fall into it



You can see it "falling" into it - and the radiation it emits as it falls into it, but you cant see tha actual object fall into it