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E ~ mc^2
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Living on Earth may be expensive, but it includes an annual free trip around the Sun.
Living on Earth may be expensive, but it includes an annual free trip around the Sun.
i'm not a physicist, but... (Score:1, Interesting)
Re:Even if he was off.. (Score:3, Interesting)
can someone explain to me (Score:3, Interesting)
If it's relative to a "given thing" then doesn't that hint toward Ether theory? The further we go in AP Physics the more I realise that my school is imprepared to answer anything that comes up and that modern theories (String theory and the like) seem reminescant of the old ones like Ether theory.
Re:gravity effects are instantaneous (Score:2, Interesting)
Since it is impossible to "transport" an object in that sence, no one has yet to be able to say that it is instantanius.. and Magnatism is definitely not the same way.. I believe its logical to assume that Gravity is Not Instantanious.. Example.. The stars as we see them in the universe are not actually where we see them.. we see them as they were several to hundreds to Thousands of years ago.. Yet if we calculate where gravity is interacting, its where we see it..
There is a study being done now I believe that is designed to find out if gravity travels instantaniously or if its trackable.. but as a logical person, I find it much more likely that at best it travels faster than we can track, not instantaniously. Much the way Light was thought to travel instantaniously before it was clocked at really really fast.
-Slashdot, Add spell check!:)
Re:can someone explain to me (Score:5, Interesting)
If you are zooming past me at half the speed of light and both of us measure the speed of a particular photon at the same time, we'll both measure it's speed as c. What will be different about our two measurements is that you'll see a higher energy photon (bluer) than me if the photon is moving opposite to your motion relative to me and a lower energy photon (redder) if the photon is moving in the same direction as your motion relative to me.
No particular point in space is special. Once you identify where the observer is located, you can call that point in space an "origin" or "zero" and make all of your measurements from that point in space. The rest of the universe relative to that origin is called an "inertial reference frame", but it's just the same as any other reference frame. There's another trick. Behavior of things in inertial reference frames is time dependent because gravity pulls your frame around and changes everything around it slightly every moment. Besides that, two inertial reference frames may have a relative velocity but for a moment share the same point in space (the example above).
That's when tensor math starts to come in handy. Don't worry, I won't torture you with that.
Relativity, once you grok it, will bend your mind. From a metaphysical perspective, it emphasizes the reality that most of what we call facts are actually just high probability observations.
Remember, there is no spoon.
Regards,
Ross
Comment removed (Score:3, Interesting)
And just a stupid quibbling footnote (Score:3, Interesting)
String Theory, in part, seeks to explain the structure of the universe in such a way as to accomodate both gravitation and quantum effects. It does this by shifting the understanding of particles from a family of points that all have different properties (protons, electrons, quarks, what have you) toward a *truly* fundamental form of matter - a string - that displays different properties depending on its orientation and motion in space. One (and ONLY one) type of string, many configurations, all leading up to families of particles.
It's elegant, unproven, pretty damn keen, and possibly wrong, but worth a look. The math involved makes *predictions* about the fundamental properties of matter, rather than being built off of measurements of those properties (as quantum theory and relativity are). That's an important step that cannot be underscored enough.
String Theory doesn't posit that there's a universal medium that everything travels through, as Ether theory does. Instead, it describes a configuration of space that strings wiggle around in to produce the world that we're used to looking at.
String Theory rocks. I hope it's right.
GMFTatsujin
Re:can someone explain to me (Score:1, Interesting)
you can't go faster than light because time acts like drag. that is your opposing force.
you can't go any faster than time can travel. maybe it shouldn't be called the speed of light, but the speed of time? for every tick in the universe you can only move so far. sort of like the 1 ghz duron sitting next to me...only so many operations can be done in a second.
FTL == Time Travel ? (Score:3, Interesting)
I do understand why you cannot ever reach or exceed the speed of light through normal acceleration. The closer you get to the speed of light, the more aparrent mass you get, and thus the more energy it takes to accelerate you. To hit the speed of light would take infinite energy (and you would have infinite mass when you hit it). Infinite energy and mass aren't really available, so you can't have a speeed >= C by accelerating, no matter how hard you try.
The part I don't understand:
I have been told that theory forbids any travel faster than light, no matter what the means ("warp drive", "hyperspace", "teleporter", whatever). My understanding is that if you could, some observers would see you traveling back in time, and this is forbidden.
I would appreciate any explanation of this, or even just a pointer to a reference I can understand. Thanks.
steveha
Re:You misunderstand completely (Score:1, Interesting)
By the nature of science, it is granted that theories and current "knowledge" may be overturned in light of future counter-evidence. However, evolutionists give the impression that they consider their views to be rock-solid, indisputable Truth that is impossible to disprove now and forevermore. Anyone who dares to disagree is dismissed out of hand as a kook. (See, I had to post as AC to even ask.)
Re:FTL == Time Travel ? (Score:5, Interesting)
Yes. One of the hypotheses of relativity is causality, that is, one event can possibly cause another only if the latter occurs at a later time than the former, and this must hold true for all possible observers whatever their frame of reference.
Now, as you know, the passing of time for an observer varies with his frame of reference (his speed, to put it simply). Hence, given two events, the interval of time from one to the other will not be the same for all observers. But if one is to cause another, it must always remain in its past; the sign of the time difference "t2-t1" must not change whatever the observer.
Unfortunately, my memories of relativity are too scarce to put this into equations, but if you could travel faster than light, you could, say, watch an asteroid smash into the Earth and warn your friend on the Centauri stock market to sell shares of all Terran businesses before anyone could "see" the flash of the impact.
And in a given frame of reference (maybe that of a traveler aboard a STL ship in-between), it would look as if you knew about it before it happened; stretching it further, it would be possible for the traveler (maybe through another FTL "jump") to warn Earth before the impact. Bye-bye causality.
If these situations are not to happen, information must not travel FTL.
Re:You misunderstand completely (Score:2, Interesting)
Actually, nobody has ever seen "evolution" happen in a way congruent with the theories proposed by Darwinian evolutionists. Their theories include rates of change that are so slow as to be unobservable.
Furthermore, no evolutionist has ever explained creatures like the Bombardier Beetle [owlkids.com] and its built-in flame thrower. This strange little insect has a defense mechanism based on the hypergolic reaction of two chemicals that it (obviously) stores in seperate sacks, mixing the two only in its rear-mounted "combustion chamber." The chemistry and mechanical complexity of the system is high enough I don't think simple evolutionary changes can account for it-- it must have been put in the beetle completely operational: how did it get two chemicals that are hypergolic into its body and learn to control them without blowing itself up? [talkorigins.org]
Later you rightfully mention Occam's Razor. I think that upon honest reflection, you will find that holding dogmaticly to Darwinian evoltion isn't nearly as satisfying and compelling as you previously thought compared to other, ultimately simpler, ideas.
Happy new yera!
Re:FTL == Time Travel ? (Score:1, Interesting)
Hm. That's assuming that what the law of causality describes as an 'observer' always uses his/her/its physical vision, which uses a speed-limited medium (light), and thus Causality's chain of events is defined by vision...
I don't think that Causality cares much about who's there watching, when things happens. I always figured an 'observer' as something close enough, or able, to be in the same space _and_ time referential as the event, and above all _remain in the same referential_. That is, the observer's time arrow doesn't make loops and knots and other not-fun thingies like trajectories using complexes (as in z=xi+y where sqr(i)=-1, what's the English term for those?), or if it _does_, then the event's has the _same_ loopies.
About FTL itself, the whole point is making the travel's duration approach zero. An ideal FTL travel would make us go from one side of the universe to the other in no time flat, whatever size the universe is. No time travel involved. You wouldn't be 15+ billions years in the past, or future, or whatever, but exactly at the same time than anyone who didn't travel. When you think about it, it's the same thing as supersonic vs. subsonic planes, only with a lot more numbers and funny characters, and a _lot_ higher speed limit.
So your exemple, while amusing, has no real effect on Causality; the 'flash' is just a by-product of the event, and not the event itself. Observing the flash is not really observing the event, since by the time you see it, the event could be over and done for billions of years, thus _quite_ leaving a human's referential. Exemple: we observed, not long ago, two galaxies colliding. Were we to be _there_, _now_, using FTL, what would we see? The billion-year old result of two galaxies colliding.
'Stretching it further' wouldn't change anything: the 'observer' (the FTL traveller) still doesn't stay in the same referential as the event during the whole incident (his time is 'compressed', while the event's is not). If he actually managed to find an intact Earth _after_ it blew up, then A) it's the same Earth, when warning authorities hadn't worked, or B) it's a parallel earth, so the original event wouldn't have any impact (so to speak) to that universe's Causality.
(Yes, I find it easier to believe in parallel universes, of which you can draw neat and simple mathematical representations, than time-travelling in a single timeline; not impossible, but not as simple nor realistic as
Well, all that is only my opinion, anyways. I only write about that stuff, don't ask me to actually _build_ the ship ^_^;
Nicolas Briche
nbriche@free.fr
============
"If you try to stay sane in life, it'll just drive you crazy. So, you may
as well go crazy now and have fun with life."
--MegaZone, of Eyrie Productions
===========
"Outside! What's it like?"
"Well... It's sort of big"
--Terry Pratchett
Examine your assumptions (Score:4, Interesting)
Re:You misunderstand completely (Score:2, Interesting)
Then you have to consider that photons created by different orbitals are different wavelength. Where does that fit in to the theory? It's called different "energy" photons. This energy can't make the photon go faster, so it bounces more? Doesn't that make it go faster along the wave? If so, then does the theory mean you can't travel in a straight line faster than c? Then the theory falls apart for any peice of the wave.
The cesium chamber experiment alone proves that either the cesium chamber was moving at phenominal speeds without us seeing it, c ~ infinity, or the chamber is shorter than was measured. Some experiments actually get photons out before they go in. According to everything I've read about the theory, "all calculations of the speed of light will be the same to any observer." This clearly isn't true in the cesium condensate experiment.
Really now... Occam's Razor tells me that it would be much easier to believe that we can't measure the speed of light properly with our equipment, and it could be possible to travel faster than light. This is especially true considering that c is the speed of light in a ray at an ungiven wavelength instead of the speed of a photon along a wave.
There are more complications caused by the theory of relativity than those it sought to fix. I would rather go back to the original failures of the "classic" equations and fix whats wrong than fix a theory that seems to generate loop holes every month. It would be easier to scrap it and solve the original problems than make a patchwork theory.
Re:Only two things are infinite (Score:1, Interesting)
Quick review (Score:4, Interesting)
Please don't forget your subscripts! As everyone learns in basic special relativity, total energy, which is kinetic + potential, is
where gamma = 1 / sqrt( 1-v^2/c^2 ) and m0 is the rest mass.At v = 0, gamma = 1 and E = m0 c^2, Einstein's famous formula for rest energy. Kinetic energy is given by KE = E - m0 c^2, or
To see any appreciable effect of velocity, consider the situation where you are going fast enough to double your effective mass (gamma = 2). Solving for velocity gives v = c sqrt(3/4) = 86.6% of the speed of light. Not gonna happen with current technology (outside of atom smashers).As v -> c, gamma -> infinity and this is Einstein's rationale for saying it's impossible to accelerate any matter up to the speed of light, since doing so would require an infinite amount of kinetic energy. On the other hand, the formula for photons is
where p is momentum, h is Planck's constant, lambda is wavelength, and c / lambda = nu is the frequency. Since photons are never at rest (remember the constant speed of light?), you won't see any m's make an appearance here. And just for the record, this last formula explains the photoelectric effect, which is what won Einstein his Nobel, not E = m c^2.