h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

For the record, relativity has been proven many times, in different ways. For example, they once took some atomic clocks on airplanes, and these clocks ticked a little bit slower than atomic clocks on the ground. Oh, and if you get your power for a nuclear power plant, you've got evidence for E=mc^2 right now, as you use your computer. That's what nuclear power is: gaining energy from a slight loss in mass that takes place during nuclear reactions.

Relativity may fail when it comes to describing sub-atomic distances, but it works when discussing matters of normal scale.

Oh, and if you wanted to, you could fly your spaceship with a constant acceleration of 1 g. But when you got near the speed of light, you wouldn't be continuously adding 9.8 m/s to your velocity. At relativistically high speeds, velocities aren't additive; if you walk forward down the aisle of your near-lightspeed ship, your velocity isn't velocity of ship + velocity of person in ship. I don't remember the formula offhand, but the upshot is that nothing can go faster than the speed of light in a vacuum.

Wait...I didn't realize that there was a second page of posts...ignore previous posting...

But I will reply to comments made on that second page. Yes, our perception of time may be relative to our species (with insects having a different perception of time), but the passage of time itself is only relative to our velocity or acceleration. There is no precongnisance.

Oh. I'm pretty sure they did the airplane experiment someone mentioned earlier as a test of relativity, and the numbers conformed to the theory. Which means that they found that c is where time stops.

And the person who thinks we came from Mars based on our internal clocks? You need to get out more. (j/k)

I have not taken physics yet but have read numerous books relating to the subject we have at hand. I will be a senior in high school and yet I know already that I will be a physicist when I get out of college. This is because I find this mini-conversation the most important issue on the grand scheme of life. For if we solve problems with physics, we can finally deal with everything else.

As for the post just before my own, it is not obvious that light must travel faster for information because we have no concrete evidence about alien species of any kind in existence. Believe me if there were any proof of this it would be the biggest story ever to be broadcasted to the world.

As for light having momentum, the simple equation above shows that if there is no mass, that any velocity multiplied to it would create a zero momentum. HOWEVER, light does not behave as a particle or a disturbance. Thus no one really seems to know what it is. It's not just a photon, because it has no mass, it causes momentum, yet it has no substance to create it. As for the scientist mentioning the 300 times thing, the person responding to it a few posts above seems to be completely right. Hmm, 186,000 * 300 = well, a big number, yet still miles/sec, or 90,000,000 km/sec. Just another number, right? It seemed at first glance that time could then not be jumped but just traversed faster by this faster-than-light speed. However, to maintain einstein's theory, this would travel time. Simply put, it seems either one is wrong. Either it did travel time and einstein is right yet time travel breaks his theory in the process, OR einstein is wrong and light is not a constant at all. Of course, a third option seems more probable, did this experiment turn up in the end as bunk?

It has been conjectured that light moving faster than the constant speed would go back in time because it would reach the source before it left it. This is to maintain einstein's theory. How about this tunneling idea? When did light jump through space without TRAVELING through it. That is amazing, and if it's already being utilized in physics, why isn't there more information to back this seemingly warp like capability up? Then again, this is a light-only feature it appears. Thus matter would again need infinite energy to gain this capability. It is starting to bother me when people continue to say "we have never gone light speed so how can we examine it". Huh? Have you ever read a linear graph? How about an exponential one? You can tell where it's going to intercept, and you can tell how much energy is required to bring normal matter to light speed, infinite.

The only exploit to this I've ever heard of is the FTL particle, dubbed the tachyon. Supposedly since it always moves ftl, it perfectly relates to the theories of the ein-man. Still doesn't give us propulsion. In the meantime of this circle of ideas, at least we all can find solitude and peace in H2G2, the book form, and if they make a movie out of it, I'll feel both happy and sad. Happy that H2G2 will apply to the masses and sad that it ruins the inner imagination of the pages. Harry Potter the movie did that to me. Bah, Douglas Adams rocked, I truly wish that there really was an afterlife for him to live on within. Because I agree with DNA himself that none of that really does exist, we must contain his spirit on this message board. I almost got scared when I didn't see "Don't Panic" written on the home page, and then I saw it. Phew. Let's talk more about light!

Let me clarify quickly, I missed the next page button, stupid me. It's funny how I like to feel that since I care about the universe unlike so many mindless people I feel exist on the streets of humanity that I am more intelligent than them. I have the same DNA, I have the same book written by DNA, I am a member of the world, and I make mistakes, and intelligence, just like time/space/light/love/life is relative .

This is in reply to the comments about light having mass because of the simple equation E=mc^2, so that everything with energy has mass.

The problem with this argument is that this simple equation isn't nearly so simple. The equation above is the everyday form quoted because most things people deal with have mass. The actual, relativistic equation is: E^2=(mc^2)^2+(pc)^2. When you take into account how minimal the momentum is compared to the speed of light, the second term essentially drops out for anything with mass and you get E^2=(mc^2)^2, but if you have no mass, then it becomes E=pc, so momentum is proportional to energy for photons and other massless particles.

If any of this is misleading, confusing, or possibly downright incorrect, I apologize as it's been quite a while since I took physics. But please, look up relativistic equations before you're tempted to quote E=mc^2 again.

I've been reading most of these posts, and one thing that puzzles me is that idea that max speed of light is not constant. I does makes sense, if this wang dude says he accelerated light speed up to 300x its normal speed, then some of the information like distance of far galaxies and stars could be all wrong, making me believe that certain stars that (might) have died millions of years ago are still intact, due to wrong calculations using a fixed light speed. Or that distances are wrong as well.

But then again, i'm probably the person that least knows about this topic.

Can anybody also help me on this:
If one object is at two points at the same time (beggining and end), when travelling at light speed or greater speeds, wouldn't it be everywere on diferent momentums along the traveling trajectory? (just like your computer mouse trail on the screen)

Rudy the Scotchguese