speed of light

Originally posted by sonhouse
For him, it's true only if god says so, and of course we all know who we are talking about there.....

Please, have you seen anyone do that, travel at that speed and
come back? If not your imagination is running wild and reality and
you have parted company.
Kelly

Originally posted by twhitehead
And in practice so far - unless you know of an exception?

I'm sorry, let me see the documentation on when you did it please,
or point me to the team that managed to pull that off so we can
settle this, is this a theory or something done in practice.
Kelly

Originally posted by eamon o
not so fast, he forgot to factor-in time spent turning his ship around 😉

No, don't worry about it, there are some here who have suggested that
it is not a theory, but someone has actually done this and they can
show us the data I guess. I'm waiting on their documentation now,
as soon as they show it was done we can take the word theory out of
this subject and assign it to the reality we live in.
Kelly

Originally posted by sonhouse
That represents a time dilation of almost 500,000 to 1. That would be tricky to get to the velocity so close to C in such a short distance of 4 LY. If you had the thrust available, you might do it for a distance of a few thousand LY. That must be within one millimeter per second of the speed of light!

True. It can be done if the technology is available. Neither the laws of Universe, nor Einstein's relativity, forbids it.

So even theoretically, I can traverse the whole universe in my lifetime. But when I'm back, perhaps the Universe is not still there...

Originally posted by twhitehead
I cant make sense of what you are saying. However, I can assure you that time is most definitely distorted and as was pointed out earlier in this thread, GPS would not work if we didn't take that fact into account. Clocks on satellites go measurably slower than clocks on the surface of the earth.

Do you understand the doplar effect on sound?

My example was intended to describe this effect in terms of light and not sound. In the dopplar effect, the originating sound source is constant, but its perception by a stationary listener is changed.

I would be curious to know what the time problem on a satellite is attributed to. I understand clearly why accurate time is necessary on satellites, particularly GPS satellites. But I was unaware that keeping time on a satellite was unusual to keeping time on Earth.

Originally posted by KellyJay
I'm sorry, let me see the documentation on when you did it please,
or point me to the team that managed to pull that off so we can
settle this, is this a theory or something done in practice.
Kelly

As usual, since you chose to simple make a disparaging remark without explanation, I could not tell whether your simple statement of "in Theory" was referring to traveling to a star and back at near light speed or Einsteins Theory of General Relativity in general. I took it to mean that you disagreed with Einstein and my comment made it quite clear that that is what I was addressing. I then gave you a concrete example.
The fact that you are now asking for more tells me that you either are too stupid to understand what I am saying (I doubt that) or you intentionally don't want to understand it.
Which is it?

GPS is certainly a very good example of that the relativity works. My little thingy works perfectly. It wouldn't if relativity was not understood.

Originally posted by KellyJay
I'm sorry, let me see the documentation on when you did it please,
or point me to the team that managed to pull that off so we can
settle this, is this a theory or something done in practice.
Kelly

So we have two major areas in science you vociferously disagree with, at least two anyway, evolution and now GR. So are you saying time dilation has not been proved and you want proof? Are you willing to actually read such proof if thats what you are asking? What part of GR do you disagree with? I assume you have a Phd in physics and have done some papers on the subject? I would be very interested in those papers. What part of relativity do you not think true?

Originally posted by FabianFnas
True. It can be done if the technology is available. Neither the laws of Universe, nor Einstein's relativity, forbids it.

So even theoretically, I can traverse the whole universe in my lifetime. But when I'm back, perhaps the Universe is not still there...

Have you read any of the sci fi books about spacefaring civilizations that don't have some magical jump drive or whatever, to go faster than light and therefore are limited to regular spacecraft (a lot more advanced than anything we have on earth for sure, like antimatter contained in magnetic bottles, enough of it to get within a Klick of light, which puts a good size portion of space available to play in, like maybe 100 ly or so, and the people going out come back 100 years later and all the laws have to change, like you can't just put 10,000 bucks in stocks that may rise a thousand times in 100 years and you come back, still young and retire. In the books I read, the laws were changed so you give up the right to huge bank accounts and such. Can you think of any other conundrums of such a civilization? Like a guy inherits but he is on a spacecraft and won't be back for 50 years, now what?

Originally posted by sonhouse
Have you read any of the sci fi books about spacefaring civilizations that don't have some magical jump drive or whatever, to go faster than light and therefore are limited to regular spacecraft (a lot more advanced than anything we have on earth for sure, like antimatter contained in magnetic bottles, enough of it to get within a Klick of light, which puts ...[text shortened]... tion? Like a guy inherits but he is on a spacecraft and won't be back for 50 years, now what?

Well, we are talking of a far more superior technology than we have today. When this kind of technology is in our hand, I think money has no meaning anymore.

Science fiction is what it says - science fiction. What you read there is not neccesary sciencd facts. The SciFi authors don't have to write within science. Their imagination is very superior ours.

Originally posted by twhitehead
As usual, since you chose to simple make a disparaging remark without explanation, I could not tell whether your simple statement of "in Theory" was referring to traveling to a star and back at near light speed or Einsteins Theory of General Relativity in general. I took it to mean that you disagreed with Einstein and my comment made it quite clear that t ...[text shortened]... at I am saying (I doubt that) or you intentionally don't want to understand it.
Which is it?

As usual? Everything you have talked about not just the trip falls into
to the word theory not just the trip! I said in theory because no one
has done those things to see if they are true, I point that out then
the crying began and I get grief. I am not disagreeing with Einstein,
what good would it do, I cannot disprove the statement about light
travel anymore than you could prove it, so it remains in theory. As I
pointed out you cannot make that trip to prove it, in your imagination
you may think about all the cool things you could do it if were true,
but we have in the past seen a lot of theories fall apart for some
strange reason. For me I think it is due to raality is a lot complex
than we give it credit for otherwise someone would have come up with
the proper theory for everything.
Kelly

Originally posted by sonhouse
So we have two major areas in science you vociferously disagree with, at least two anyway, evolution and now GR. So are you saying time dilation has not been proved and you want proof? Are you willing to actually read such proof if thats what you are asking? What part of GR do you disagree with? I assume you have a Phd in physics and have done some papers o ...[text shortened]... ct? I would be very interested in those papers. What part of relativity do you not think true?Im

I'm keeping the word theory in place, if you want to call your theories
facts in that they are true beyond doubt you and I part company. I
disagree with people who think they have a lock on reality by the
use of their imagination not the scince.
Kelly

Originally posted by KellyJay
I'm keeping the word theory in place, if you want to call your theories
facts in that they are true beyond doubt you and I part company. I
disagree with people who think they have a lock on reality by the
use of their imagination not the scince.
Kelly

Relativistic effects have been measured and observed, thus its not an in theory as you like to put it. Observed data 100%, without exception agree with the "theory" at the velocities we can attain. Therefore it is perfectly valid to project the values onward. Your disparaging remarks are misplaced here KJ. It;s becoming clearer and clearer that you have little if any grounding in a scientific discipline. Yet you remain perfectly capable of commenting on subjects which at best you've skimmed over the basics of, as if your an expert on the topic. Honestly to fully understand the proofs both theoretical and experimental of Relativity you'd need a PhD in physics. I studied them for 2 years in college, gained only a very basic understanding, dropped physics and studied geology.

Originally posted by Mexico
Relativistic effects have been measured and observed, thus its not an in theory as you like to put it. Observed data 100%, without exception agree with the "theory" at the velocities we can attain. Therefore it is perfectly valid to project the values onward. Your disparaging remarks are misplaced here KJ. It;s becoming clearer and clearer that you have littl ...[text shortened]... ars in college, gained only a very basic understanding, dropped physics and studied geology.

You and I part ways there, "...it is perfectly valid to project..." by all
means project. Bottom line, you don't know, but you are willing to
claim knowledge you don't have and dismiss me, because I am not.
I said in theory it is correct, if you are willing to call that something
more than theory go ahead, I don't care, half of your universe is what
you project it to be, it only changes when you have to deal with reality.
Kelly

Well, tonight I was watching "The Universe" again, and of course, black holes and speed of light came up. I got to thinking--okay, I know light can be bent, and that light cannot escape the gravity of a black hole. What I wonder is, how much would the speed of light be slowed down to as it approached something massive enough to affect it (like a black hole)? And suppose we could see it. Imagine looking up at night and seeing one of those searchlight beams? Now, suppose there was a black hole nearby. Would we see the searchlight beam start to "recede" down to a simgle point (if the black holw was behiund the light source)? What if the beam were projected right at the Black Hole--would the immense gravity actually speed up the light beam's approach to the event horizon of the big black nasty?

I guess I'm just wondering how many different speed's of light there can be--and couldn't there be a point where a light beam could be brought to a halt by these supermassive black holes? {now that would be something to see--a frozen photon}