[Tycho?]

Its not like this guy actually has a valid weapon design. Its just some crackpot idea. Oh, it is valid? Then prove it.

Its highly likely they travel at c. If they dont, then some shit is going down. But not a lot is known about gravitons, they've never been observed and I dont think there is a consensus on how exactly they work. Wikipedia it.

I think dirty bombs would be useful as psychological weapon, not so much a practical one. The bomb used to disperse the radioactive material would have to be powerful enough to spread it over a decent area. But a powerful bomb would just kill everyone nearby with the shock wave, then cause everyone else to run away, away from the radiation. Getting any kind of nuclear material in sizable quantities is extremely difficult, any terrorist orginization would find it far more efficient to just make a whole bunch of easy to build conventional bombs if they wanted to cause death and descrution. But hearing that a radioactive weapon went off in some city would cause a panic, which is really the whole point of terrorism. But it wouldn't be a high death toll attack.

Yeah thats an interesting question. They've been pretty rigorous in trying to explain whats causing it, but so far nothing has come up. And its been observed in other probes as well, making it unlikely it has to do with the construction of the probe.

Uh huh. Because you think so? And have absolutely zero evidence to make anyone else think so?

I have never heard of such a thing, although its possible I do it without realizing it. I'll check next time I walk somewhere. But this may be based in instinct. Animals identify eachother largely by smell; just look at cats or dogs meeting something, one of the first things they do is smell it. This sniff could be a left over reaction from when the smell of a person was more important than it was now. It would make sense that humans also have this insticnt to identify others via smell. Just an idea though, who knows.

Gamma rays, usually. This info is incredibly easy to find in other posts on these forums, and indeed on the net in general.

Its not like you even need physics to answer that question, a dictionary would allow for an accurate guess.

Fire emits infrared mostly, some visible light. Negligible amounts of radiation in higher and lower parts of the spectrum.

http://gristmill.grist.org/story/2006/5/17/15336/5459 WHAT. THE. ****. Watch these ads. I dont even know how to respond to them. I cannot understand that 1) somebody actually wrote an ad like that and 2) people thought that producing and airing these ads would be a good idea. Please please tell me that the average person will realize how stupid these ads are? That commentary site is right, this looks exactly like satire.

I dont think anyone can give a definative answer for that. How causality works in quantum mechanics is still being debated, and how the universe in general works is still too much of a mystery to be able to ask such a broad question like that.

How do they not cope now? I can read books just fine, and I can read things on a computer screen just fine.

Yes you can add on later. However, I would recomend looking around these forums for a few days. Topics like relativity are very common, and you can learn a lot just by passively reading. SR and GR do not imply a finite universe. They just dont. For the time dilation thing, yes it applies to both. Each would see the effect occuring to the other. There have been numerous threads on exactly this subject in the relativity forums. I'm not really sure what you're asking for the quantum one, but as far as I know the uncertainty principle is based aroung the uncertainty of individual particles; ie you can apply the principal in a one particle system.

Supernovae, look it up on wikipedia.

I was wondering about that oddity actually, I just figured it was something I had yet to learn.

I wouldn't be suprised if this was correct; ie that the universe is in fact a lot older than we think. But I also wouldn't be suprised if everything in the article is wrong. As has been mentioned, the cosmological constant isn't exactly a good base for a theory, there is serious debate as to whether or not it even makes sense to have such a thing, and nobody has any idea what actually causes it.

If for example a comet was coming close to a planet, the planet's gravity would have an effect on the comets path. So if the path was altered in a very precise way the result could be a fairly circular orbit around the sun- but much closer than the kuiper belt. Note that there are no circular orbits, they are all elipises, some of which are more circular than others.

Negative mass? I'm not sure if this even has a definition in modern physics, but that is how I've heard it reffered to for these anti gravity things. And what has negative mass? Well "exotic matter". And whats that? Well, .... its exotic. Is there any reason to believe this "exotic matter" (whether it is possible or not) could actually have such an effect? If negative mass exists, would it have an opposite effect to normal gravity?

For me, billions of years is way, way too large a number to even make guesses about the level of technology possesed by humanity. I figure that by that time too many things will be fundamentally different. Who knows what humanities motives and abilities will be like then.

Are you guys sure that GR doesn't allow for anti-gravity? The original idea of mass that curves space in the "opposite" way is something I have heard before. Are you sure this sort of curvature cannot yeild an effect opposite to normal gravity?