Is lightspeed the fastest ?

#1 23-05-2005, 12:03 AM

Coz I know you all loved my last question, here's another one I often wonder about. It has been said, and agreed upon by many that the nothing can travel faster than the speed of light, including of course light itself. Keep in mind it was believed once that if you exceeded 20 miles an hour in a horseless carriage you would die from untold pressure on your body.

Now here's the tricky bit, if nothing can travel faster than light, and black holes really exist, based on light not being able to escape the massive gravity, then wouldn't the velocity created by that gravity be faster than the speed of light? If it were the same as the speed of light then the light would stand still but we would still see it? Of course that means that any object (say a pebble) falling in to a black hole would travel faster than the speed of light once it passed the event horizon. That and my Chev. Personally, I like to belive that light speed is merely a number like KPH and therefore something could travel at many light speeds.

RAJAH235 · #2 23-05-2005, 02:03 AM

Nightshift, please explain,> 'the velocity created by that gravity...'.
Surely, the gravitational field is acting solely on the particles/waves which make up light in the first place.
By all accounts, the action of anything being caught & dragged into a black hole creates x-rays etc etc, but these apparently escape or are ejected thru the 'north & south poles', (weakest part), of the 'magnetic field'. These are much more energetic than light particles & as such are capable of 'escaping' or 'being squeezed out'. These are not able to be 'seen' by us directly, but we need detectors to do so.
As for 'seeing the light' inside a black hole, this goes against what is being told to us.
'If it were the same as the speed of light etc....', To my way of thinking, If it's 'standing still', how are we 'seeing it'? It's not travelling, so how is it getting to our eyes?
I just know that it's another interesting question. Something else to think about.
Goes back to the theory that as you approach the speed of light, your mass increases dramatically, & as such, the energy required to 'go faster' increases also. The end result being, that you will never be able to carry/generate, (at present), enough fuel/energy to exceed the 'speed of light'.
Thanks, you made me think again,(at 2.00 am & on my birthday).
Regards, L.

Quote/
Now here's the tricky bit, if nothing can travel faster than light, and black holes really exist, based on light not being able to escape the massive gravity, then wouldn't the velocity created by that gravity be faster than the speed of light? If it were the same as the speed of light then the light would stand still but we would still see it? /quote

iceman (Mike) · #3 23-05-2005, 06:31 AM

Great questions Nightspeed - that is what this forum is all about, pondering all things space and astronomy. Generating discussions and having healthy debate!

[1ponders] (Paul) · #4 23-05-2005, 08:25 AM

The often quoted speed of light is for light in a vacuum. From what I understand light can actually travel faster than "the speed of light" in a transparent solid. As for the black hole bit. The light speed doesn't change, its wavelength does. Almost like a doppler shift. And yes right at the very point of the event horizon light does (apparently stand still) Mind you that "point" is in fact a 2 dimensional field curvature. therefore it has no measureable thickness, so you wouldn't be ale to view it anyway.

slice of heaven · #5 23-05-2005, 08:42 AM

Its all theory.
At one stage during the expansion of the universe matter was travelling faster than the speed of light.
So no ,light speed is not the limit of speed.
Only the fastest speed of light is constant, light can be slowed.
Light travels slower through mediums like glass and crystals.

cahullian · #6 23-05-2005, 08:46 AM

I always thought that light was captured crossing the gravity field of a black hole. Not chased after overtaken and dragged back.The light gets bent and moves away fron our line of sight. Can we only see blackholes from the front? If we saw one from the back would it look ultra bright as we would be able to see light being dragged towards our line of sight?But I love the topic and also think that one day we will be able to travel at many times the speed of light.

[1ponders] (Paul) · #7 23-05-2005, 08:54 AM

Sorry your right Slice about the slowing. Must be having a black hole morning.

Quote from "Violence in the Cosmos"
Furthermore, contrary to normal intuition, the Theory of Relativity tells us that light always travels at the same speed relative to some observer, no matter what the relative motion of the observer. Thus, light emitted from a moving airplane does not travel with the speed of light plus the speed of the airplane, it travels with the "speed of light", no matter what the speed of the airplane! In a vacuum, light always travels at a speed of 299,792,458 meters per second, no matter how its speed is measured.

Although this seems strange, it has been confirmed in many experiments. These experiments show that it is our "common sense" that is wrong in this case!

To be precise, what we usually call the "speed of light" is really the speed of light in a vacuum (the absence of matter). In reality, the speed of light depends on the material that light moves through. Thus, for example, light moves slower in glass than in air, and in both cases the speed is less than in a vacuum. However, the density of matter between the stars is sufficiently low that the actual speed of light through most of interstellar space is essentially the speed it would have through a vacuum, so we don't make much error by ignoring the difference.

The preceding statements about the constant speed of light refer to the speed of light in a particular medium, such as a vacuum. Within such a medium, the speed is constant, but light changes its speed when it moves from one medium (say air) to another (say glass). This change of speed at the boundary between two different media is the principle that causes a lens in a telescope or eyeglasses to work.

end quote

cahullian · #8 23-05-2005, 09:02 AM

there is a good link to black holes at
http://www.bbc.co.uk/science/space/d...es/index.shtml

[1ponders] (Paul) · #9 23-05-2005, 09:03 AM

Another point about Nightshifts questions/statements. There is nothing to say that somewhere there are particles that travel faster than light. (eg the much discussed Tachyon) However for normal Baryon matter (electrons, neutrons and protons etc) it would take infinite energy to accellerate to the speed of light. As the velocity increases, its mass would increase, requiring more energy to accellerated it, requiring more energy to accellerate it, increasing its mass ..... ad infinitum. Therefore any Baryon object accellerated to the speed of light would gain infinite mass requiring infinite energy to keep it accellerating.

The same holds true for the theorized Tachyon. It would require infinite evergy to slow it down to the speed of light.

This is all according to theory of course

Does this apply to dark matter? Who knows. We can't even agree on what it is.

Robby · #10 23-05-2005, 10:26 AM

I've always been confused by the "twins paradox". One twin leaves earth travelling at close to the speed of light. He returns some years in the future and due to relatively the twin the reamined on earth has aged alot more than the travelling twin.

I can understand half of it, based on the clock explanation...
If we travel away from a clock at close to the speed of light, the time on the clock will appear to run slower. This is fine. This must mean that when you head back towards the clock, the clock will appear to run faster. Therefore when you return to the clock the same amout of time will have elapsed for both the traveller and the clock.
This seems to contradict the "twins paradox". Sure when the traveller is travelling away from home time for the traveller is slower (reletive to earth), but on return time is faster. Surely these would cancel each other out and the twins should have aged by the same amount.

I'm probably missing something here??
Cheers
Rob

ving (David) · #11 23-05-2005, 10:55 AM

Quote:

Originally posted by slice of heaven
Its all theory.
At one stage during the expansion of the universe matter was travelling faster than the speed of light.
So no ,light speed is not the limit of speed.
.

light would only be the highest measured (or measurable) speed i am guessing.
think of the highest number... now because that is the highest number you can think of doesnt mean there arent numbers after it... there would be speeds infinitely faster than light. we just havent measured them probably

i hate thinking on monday mornings... I have only had one coffee

toetoe (Peter) · #12 23-05-2005, 12:03 PM

Is it a "gravity pull" faster than light speed as mentioned above, or is it in fact a "vacume" sucking at the speed of light.?
I am not up to scratch with any black hole theory, this is why i ask the question within this thread. Could it be possible for a vacume in space to be faster than the speed of light.?

slice of heaven · #13 23-05-2005, 12:13 PM

Its actually the gravity of the blackhole warping the space-time around it that traps the light.

Which reminds of my favourite object that I cant see in my scope.
Einsteins cross.
Its a quasar that is behind a galaxy and because of the gravitational lensing the quasar shows up as 4 quasars surrounding the galaxy. A good example of space-time being warped by gravitation. The Hubble took a great pic of this.

rowena · #14 23-05-2005, 05:51 PM

I think we will be able to go faster then the 'speed of light' in a vacuum (or space), but not in an atmosphere someday.

also haven't there been experiements conducted at Sian? mountain, where they have lasers going faster then the speed of light? ahuh found an article on it... http://physicsweb.org/articles/news/4/7/8/1

ohh i found this cool experiment with choclate to supposedly measure the speed of light! http://physics.about.com/cs/opticsex...s/a/290903.htm

even if it doesnt work... you still get to eat the warm yummy choclate!

slice of heaven · #15 23-05-2005, 06:11 PM

Nice links.Especally the chocky one.
Einstein liked choccies too, his famous formula E=mc2 translated is
Energy = Milk Chocolate squared

Striker (Tony) · #16 23-05-2005, 07:04 PM

I thought my old GTR Torana went faster then light speed....but I could be wrong.....lol

rowena · #17 23-05-2005, 10:05 PM

Striker, no that was just the girls running away from your car at faster then light speed!

teehee

*note... this is all in jest people!*

The interesting thing with that above article is that it was done 5 years ago. I haven't heard anything since if they have been able to push anything else faster then light. I wonder if 'Beyond Tomorrow' will go to it... I loved Beyond 2000 when I was a kid!!!

ballaratdragons (Ken) · #18 23-05-2005, 10:13 PM

Gee what a flashback Rowena! Beyond 2000. That was a great show. Towards 2000 was excellent as well.

rowena · #19 23-05-2005, 10:24 PM

I don't remember seeing Towards 2000.. but i loved beyond 2000!

I remember in year 8, my teacher held up a diagram of the human body but the picture was a temperature signature of the human body. I got the answer right, and he was kinda amazed that TV teaches you something!

I hope the next one, Beyond Tomorrow is just as good! looks interesting some of the stuff they have coming up.

#20 23-05-2005, 10:59 PM

Actually, the real answer is Beer, beer warps light at light speed, that's where the phrase Beer goggles comes from, everyone looks 10 times better after a certain volume of beer due to warping of visible light, I am experementing on this theory as often as possible and the results are always the same. It does however take more than 4 litres to make Judge Judy look like Elle McPherson..........It doesn't seem to work on Steve "the idiot" Irwin.