Starmer & Lammy A Marriage Made In...
News8 mins ago
No best answer has yet been selected by kev100. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.By "USA" I presume you mean NASA? As I understand it NASA's mission is not to develop space travel but to improve our understanding of the cosmos. Sometimes this requires space travel (e.g. sending probes to other planets) but this should be regarded as the "means" rather than the "ends" and is not the goal of the whole venture.
Because you cannot paddle a canoe to New York doesn't mean you shouldn't go fishing across the bay!
The planetary science that we've been able to do with probes over the last half centuary has told us a gigantic amount about the Universe.
There is even the prospect of finding basic fossilised life on Mars.
Not to mention Hubble.
It's not about recreating Star Trek in real life
Or do you mean why do they spend so much on manned spaceflight?
The answer to that one is there is a lot of stuff that just can't yet be done by robots - repair of satellites etc. But most importantly it's major PR for NASA.
I think of it a bit like Formula 1 racing. Hugely expensive, debatable spin offs but necessary to keep interest levels (and funding) high for the important stuff.
NASA do spend money on "interesting" ideas for lightspeed and faster than light travel as part of their "breakthrough propulsion physics" program, but that program's budget isn't billions. NASA spend most of it's money on investigating the solar sytem, including earth, from space.
Relativity isn't the last word on the cosmos.
Well Einstein's theory was a theory when it was put forward since then there have been an awful lot of experiments validating it.
My two favorites for time dilation are the flying of an atomic clock around the world and comparing it's time with another one on earth
The second is that muons created in the upper atmosphere reach the earth when their half life is too short to let them survive the journey.
Both conveniently described here: http://www.physlink.com/Education/AskExperts/ae433.cfm
Physics is not like Maths. In Physics a theory is put forward and tends to retain the term theory even after vast amounts of evidence have supported it (eg Newton's theory of Gravitation) because unlike maths there can be no final proof, there is always the possibility of modification however remote.
However, and here's something to ponder, the time diletion equations do not prohibit something travelling faster than light. They prohibit something travelling at the speed of light in theory. Past the speed of light you get a negative square root. Whether or not that has meaning nobody knows - we've never found a tachyon.
http://scienceworld.wolfram.com/physics/Tachyon.html