[Tycho?]

Huh, its not moving too quickly. Chances of it hitting Earth is around 1/45 according to http://space.com/scienceastronomy/asteroid_risk_041224.html Small, but not the sort of small we are used to dealing with. Its over a 2% chance, which makes this more more of a concern than any previous asteroid. Further observations will be carried out soon, so we will soon have a better idea on what the chances actually are. And remember, it will probably miss.

I get "No" for the first one, because friction and force caused by gravity are equal. I get 0.36 as the coefficient of friction between the two blocks. And yeah, just draw a free body diagram. I've never done a question like this either, but its not that hard. edit: Well its not hard if I get it right.

Depends on how high you fall from.

For some info on what methods of propulsion may be used, look at this http://en.wikipedia.org/wiki/Space_propulsion Whenever I read science fiction, the drives are almost always fusion drives, so I always kinda think from that perspective.

Exactly. Niven's stuff, like Ringworld, or Clarke's stuff, like Rendezvous with Rama are hard science fiction. Lots of well grounded science things. Star Trek or something similar would be in the middle; some use of science, but ignores it on some aspects. Something like star wars is very soft science fiction. Science terms arn't used at all, it becomes little more than fantasy involving space and robots.

Bloodhound has already outlined how to combat this on the previous page. Not perfect of course, but you can increase your chances, and then guess.

Oh certainly. Laser light on an enemy telescope would make it impossible for them to see anything out of that one. If you can bathe the whole ship in laser light, even if it may lack destructive power it could effectively blind them on that frequency. The counter would be to have sensors over a wide variety of EM frequencies, so you can see in regular light, infra red, microwave, x-rays etc. The counter to this counter would be to try to blind those sensors as well....

Ender's Game was very good, and I agree that Ringworld was also excellent, thats the book that got me started on hard SF. Also excellent books: Dune and its sequal. Neuromancer. I could give you more, but these are keystones in sciencfiction writing, both amazing books.

Yes, this of course assumes you have enough laser weapons to shoot at all possible places for the variables of that situation. At long distance, big v and potentially big a, there very well could be too many places to shoot at once with limited weapons. Weather your hit would be guarunteed or not doesn't really matter, you would have to do this or something very similar if you wanted a chance at hitting your target.

Oh I didn't get the mu, didn't know the question wanted it, oops.

1)Yes, the beam does indeed diverge, but as lasers get more advanced they diverge by less and less. If we are at a point when we are using giant lasers to shoot at eachother across huge distances in space, laser technology will be a lot better. This is of course always a problem though, and does give the laser a maximum effective range, no matter how good it is (unless its possible for a perfectly parallel beam) 2)Well to aim you need good telescopes and good computers. You have to be able to see the direction the target is moving (including towards and away from you) and know his velocity/acceleration. The calculations could be hard to do in real time, especially in a gravity well, which is why good computers are needed for this. This becomes a larger problem as laser accuracy increases. If you can only shoot a fairly short distance, you can just aim the beam right at your target and unless he's moving .1c or something it will hit him. For more accurate beams you will have to actually lead the target at long ranges. Presumably the target would not like getting shot at, and so he would vary his thrust, so you end up shooting in the wrong place. At this point it becomes a gussing game of shooting in the general area where the target will be, and hope you hit him. Bigger distances, the harder this gets.

Its 10 I think.

Yeah. With a several megaton fusion bomb you could hit close to the ship, but yeah with no atmosphere its tricky to do damage in that way. What is a zero-point manipulator?

For weapons in space, you've got: Lasers, or other focused EM radiation weaponry, masers, x-ray lasers, or whatever. move at c, effective at huge ranges, very high accuracy. Projectiles: a big gun, probably magnetically fired. powerful if it hits, but only really effective at very close ranges as it would be easy to dodge at long ranges. guided missiles: ...guided missiles. They seek their targets. Long range, but you'd probably be able to see them coming from radiation from their propulsion. Nuclear warheads would probably be used. particle beam: fire a coherent beam of atomic nuclei or any other particles at a target. Plasma: charged particles, but not in beam form, could be fired from engines if a fusion drive was being used. wide area of effect, but tricky to employ, and not a surgical weapon.

What. Of course it could. Endless, meaning something with no end. It isn't startless, or beginingless. It just can't end.

No, TV's dont need chips to opperate, TV's were invented before computer chips were. If they were monitering us they would do it by basic radio first, even if they didn't know it was sound waves they would probably guess that pretty quickly. TV would come next, and be trickier to get a visual component in the same way that we see it, but since they must be pretty advanced just to get here they should be able to figure this out. Messages that are encoded are those that are digitally sent, like satellite TV.