Question on the speed of light and black holes!

Hi everybody hope your weekend is good,

I am under the impression that the speed of light is a mathematical constant of 299 792 458 m / s. Scientist say that no matter how fast you are going the speed of light remains the same.

If I was traveling close to the speed of light wouldn't the actual speed of light have to change and increase for me to observe it as being constant.

If this was true then surely the speed of light isn't constant.

Unless they mean that the speed of light can change but always appears constant.

Also it is true that light cannot escape a black whole because basically it is not quick enough to overcome the massive amount of gravity that the black hole exerts.

Does this mean that anything traveling into a black hole, including light, is actually traveling quicker than the speed of light?

Any enlightenment would be welcome because I'm a little confused.

Cheers

That's the reason it's called 'relativity'!
Check out thislink for some great info on how amazing physics really is, including the answer to your question.

reply to post by el.rebelde

Hi el.rebelde,

Closead is correct, the question you raise is a common one when trying to get your head around light and space-time.

In the standard model of cosmology light travels at a constant 299792458 meters per second, that is to say that the individual quanta of light called Photons travel at that speed relative to the source.

It cannot travel faster but has been recorded at much slower speeds in ion traps the foundation of optical quantum computing (basically very dense clouds of ionised gas to slow down the propagations of light).

So to answer your question…

Image two spaceships floating stationary relative to you. Now both space ships set off at 50% light speed in exactly the opposite directions.

Now you have two perceptions of reality to consider here.

1. Your view would be stationary relative to the two ships, so from your point of view you would see both ships set off at the exact same speed. The reason is that the light would take exactly the same length of time travelling at 299792458 meters per second from each ship to you.

2. The people on the spaceship however have a very different view of reality, from their point of view they would see you travelling away from them at 50% the speed of light 149896229 meters per second ), but their perception of the other ship would be very different. From their point of view they would see the other ship disappear. This is because the time it would take light to get from the ships to each other is equal or more than the total time it would take the light to travel the distance covered between the ships.
Time/space is to be considered as a single entity as they are intrinsically connected; there could not be one without the other.

When considering a black hole you can think of it as an area of space where space-time is so dense that everything within a radius around it (the event horizon) has to travel more than 299792458 meters per second to escape the gravitational pull.

I hope this answers some questions.

All the best,

NeoN HaZe

reply to post by Neon Haze


Yea, thanks guys.

Both of your post have shed some 'light' on the matter lol, the post regarding the black hole and light was really well explained so thanks

all the best!

[edit on 5-4-2009 by el.rebelde]

The speed of light is constant, but don't drop the words "in a vacuum". Otherwise, the speed of light changes.

The speed of light is relative to the speed in which you are traveling. Trying to explain special relativity without them knowing physics is like trying to explain music to someone who was born deaf. That is why it gets confusing so quickly and easily.

As for the black holes. Once light (or any other object with mass) crosses the event horizon of a black hole, it cannot escape. But it still does not travel faster than the speed of light because of the same mass that attracted it into the black hole.

Things do not "directly" fall into a black hole. They first are ripped apart violently and spin around a black hole for years.

reply to post by el.rebelde


Watch this:


[edit on 6-4-2009 by Protector]

Originally posted by Shadow_Lord
Things do not "directly" fall into a black hole. They first are ripped apart violently and spin around a black hole for years.

Except for the biggest black holes with a very large Event Horizon. Objects as large as humans can cross the Event Horizon without getting ripped apart or even 'feeling' any tidal effects. Of course once an object crosses the event horizon, we have have very little idea what happens to them because they can no longer be observed.

From what I have been led to believe, strange and interesting things happen as soon as you get close to the speed of light.

Let's take the wonderful Steven Wright question:
"If you are in a spaceship that is traveling at the speed of light, and you turn on the headlights, does anything happen?"

If the headlights consisted of white light, the lights would indeed turn on and you would be able to see the beams of light but you would see it in a way that you hadn't previously imagined. The light would be white to a point and then you would be able to see the different wavelengths of light spread out like a rainbow. This is due to different wavelengths traveling at different speeds. It would be white to red then orange, yellow, green, blue, indigo, then finally violet.

This could be wrong because no one really knows what would really happen, but I imagine one day we will all know because we will see it with our own eyes as we actually perform the experiment. Some say this is impossible, but it was also thought to be impossible to fly or travel to the moon.

Some even say that there is no proof at all of black holes. My physics teachers in college all told be black holes were complete BS. May favorite black hole concepts has humans eventually using black holes as communication devices. By placing a small black hole and a stasis field, you could use the field to vibrate the black hole so that gravity waves could be sent across the galaxy to convey information.

Will it ever occur? Who knows.

Ive never qutie understyood this one either.
Lets say you could travel to the speed of light & beyond, would it just be black as you are going faster than the light from any object could reach you? if that makes sense?

You would need a damn good navigation system as well

(lets face it no one knows if faster than light speed is impossible as its just a theory based on current physics)

The speed of light is attached to the observer. When you factor in time dilation it makes sense.

Like say you were in a spaceship and you were going faster and faster... you'd be traveling into the future quite a bit relative to those back home. Get close to a black hole and the same thing happens. You fly into the future but everyone else sees you slow down and stop. Time dilation.

reply to post by Kruel


Kruel is correct, and to add to his (her?) post. Time dilation can also be construed as warping of the space time continuum. So think of it this way:

The space time continuum is a bed. You put a bowling ball on the bed (anything with mass) and the bowling ball will sink into it. This is what people refer to as warping the space time continuum. This very same effect occurs not only with mass but also with speed. The faster you go, relative to an observer, the more you warp the bed. If you shine a light from the bottom part of your warped bed the light would have to travel around the curvature of the warp.

So essentially, the speed of light is a constant. Its the universe the light has to travel through that is fracked up.

Good questions, keep thinking.

Obsidience

I'm not sure I'm wrapping my head around this concept, but would these theories about space time and relative observation be discussing the perception of distance and not time?

If we warped space time, we'd be changing the distance between two points which might cause us to take longer or less time to travel between.

Time itself has not changed in this concept, only the relative distance traveled in the movement and the observer?

So at a faster speed or shorter path I arrive ahead of you. Which means I reach a relative point sooner, not specifically time travel.

At a slower speed or a greater warping of the space time theory, as in a black hole or gravity well, I would arrive much later.

From point a to point b takes a relative amount of time that can be compared to the distance between the two. If I warp that space I can effect the distance thereby lessening or lengthening the amount of time invested in the journey.

I don't think this is time travel solved.