[Wired] Astronomers Discover Millions of New Black Holes and a Rare Type of Galaxy - Page 9

Technically that is not true. Light always moves at the same speed, it's just the rate of transmission is much slower through certain materials. Light is constantly being absorbed and re-emitted by atoms all around us.

In the end, for this purpose most scientific articles state "speed of light in a vacuum" to avoid that issue.

Speed is measured using time, time is the non-constant.

It's hasn't been theoretical for about 90 years, it's been proven using countless experiments and is now part of our daily lives. The thing that makes it different from say, gravity, is that it is difficult for the common person to perceive it in their daily lives, even though it's always occurring around you. Atomic clocks for example, are so accurate that when they are transported, like via an airplane, they have to be re-synchronized with the clocks that remain on the surface. Atomic clocks at a higher altitude have to account for the altitude, as they're further from the center of the Earth. People living at higher altitudes will age faster. Again, like I said this is always happening around you, but when you're talking about speeds that are the same scale as the speed of light, anything speed less than a significant portion of the speed of light and it will be difficult to notice the effects without measurements.

Just so we're clear, you likely know more about relativity and physics than I do, considering my education in both stops at the high-school level. My knowledge of things like special relativity is self-taught. I'm more than willing to be corrected on any mistakes I've made, in fact, I welcome those corrections so that I may discuss them and learn from them. My last response to you was meant to basically say that I've been trying to keep things simple, since we're talking with people that are skeptical of relativity/time dilation in itself.
Edited by lordikon - 8/30/12 at 6:39am

speed = distance / time

As time approaches zero, then
either
speed approaches infinity
or
distance also approaches zero.

Since speed of light (in a vacuum) is constant, it means that as time decreases, distance must also decrease.

If we move things around a bit (bear in mind your original formula isn't entirely correct):

time = speed / distance

As speed approaches infinity (the speed of light can be thought of as infinity in this case since the formulas aren't entirely correct), time will approach zero. As something enters a black hole it would appear to stop moving as time slows down for it (as it speeds up). I'm not entirely positive on this though.

this helps

http://www.youtube.com/watch?v=V7vpw4AH8QQ

Also, given the formula you gave, as time decreases, speed increases, given a constant distance traveled. It is however, true that if both distance and time increased at the same rate, that speed would remain constant, but that should be obvious, if I'm traveling at 60 miles (distance), per hour (time), then that's the same speed as traveling 30 miles (distance), per half-hour (time). Same speed, distance and time were both halved.

Sorry for the self-response, I meant to edit my last post, and accidentally hit reply.

I agee with much of that video, but I am not convined about the "light travels further" explanation for time dilation.

Here is the same man claiming he can build a time machine (which uses a circulating light beams) that will allow time travel back to the moment when the machine was turned on.
He thinks his machine will be able to accelerate light (and any objects inserted into the machine) to move faster than c.
Therefore, time will run backwards inside his machine.
There is a serious flaw somewhere in his understanding of physics.
http://www.youtube.com/watch?v=xanDxgqg-oU&feature=player_detailpage#t=35s
Edited by Partol - 8/30/12 at 9:46am

The "time runs backwards when you move faster than C" is absolutely pure theory with zero proof, a theory based on the logic that if time slows down to a stop at C then faster than C must make it go backwards. But that's all there is to the theory, it's nothing more than hot air because general relativity doesn't allow for ANYTHING with mass to travel at the speed of light (because it would take an infinite amount of energy to accelerate said object to C), therefore traveling backwards through time is impossible if we are to go according to Einstein's rules.

The two exceptions to this rule are:
1) Wormholes. General relativity allows for wormholes to connect two different regions of spacetime, but again they are nothing more than theory at the moment with zero detected proof.
2) Black Holes. General relativity (and newtonian law, and all other laws) pretty much all go out the window in a black hole because of it's "infinite density in zero volume" property which makes NO SENSE because when something has zero volume, it shouldn't even exist (let alone have mass). Matter falling towards a black hole gets accelerated to C (or near C) with ease due to this property.
Edited by Tippy - 8/30/12 at 10:40am

Maybe just a little helper post for those confused by all the non sense. Correct me if I'm wrong but:

1. Time is not a constant. Why? Because space and time are connected in something called the space-time (think of it as a sheet of paper). A planets (or star's) gravity warps the space-time so someone really close to something with a ton of gravity will age slower than someone really far away from a source of gravity. (Seriously tests have been done on this kind of stuff)
2. The speed of light IS a constant but light gets affected by gravity as well, and gets distorted in the space-time.
3. Nothing can go faster than the speed of light because of Einsteins equation (E=mc^2) because in order to get the amount the energy required to surpass it the mass would increase and therefore slow it down. (Think of graph curves / parabolas)
4. You can not go back in time BUT you can theoretically let time "pass" you then end up in the "future". This ties into the first bullet. If you stay really close to an incredible source of gravity (such as a black hole) you will age very slow while everything else will age faster. Therefore, when you the leave the orbit of the black hole, you will end up in the "future". Pretty interesting stuff but all theory.
5. In order to travel huge distances across the universe, you would have to bend the space-time, which is called a wormhole). Think of this as folding the piece of paper in half and then poking a pencil through the two sides. The amount of energy required to create this is so incredibly out of reach its not even funny. All theory again.

I saw someone saying something about how the universe is expanding and Galaxies moving away from each other, but it sounded as if they were assuming that the galaxies are specifically moving away from Ours. We do not have the frame of reference as to where they started from, and when when and where they began to move away from X position.

So what I am saying, is this 10 billion Light Year away Galaxy, could potentially be moving towards us, away from us, along with us etc. How fast IS that Galaxy even moving?


as far as vast distance traveling our only chance would be the wild world of wormholes. or Space Fold technology. This would be extremely scary to me.. think about it, lets say we wanted to Exit betelgeuse which is 500-600 Lightyears out, we would have to do some calculations to determine where that star is Actually going to be, 500 year ahead of us.

Thats when Space gets fun to me, We are Orbiting our Son, But our star isnt stationary its moving right along with everything else spinning around our galaxy. (which our Sun suposedly orbits the galaxy every 220+ million years at a relatively unknown rate of speed ive read upwards of 500,000 Miles per hour)

I Dont have the slightest Idea how fast Betelguese is moving. One wrong calculation and You could exit the wormhole right into the giant and well game over.

You tell me if your that eager to visit distant planets and systems whyen you have No idea what you will find when you get there. If of course, we can at all. Cus even if we could go speed of Light, it woul dbe pointless if we couldnt get to anything in a humans life span. We would have to Master Crygenics first, freeze the team, Set ship to autopilot and 500 years later you have hopefully arrived at planet earth2