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why_can_t_we_go_faster_than_the_speed_of_light_can_we_ever_colonize_other_planets 2009/02/02 13:17 current
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 +**1. Is the the speed of light the maximum speed and why/why not?**
 +----
 +
 +For a particle which is created travelling slower than the speed of light,
 +the speed of light is the fastest possible speed. The reason is that,
 +in order to accelerate an object, you need to use energy. The more massive
 +(or "heavier") an object is, then the more energy it takes to accelerate
 +it. You understand this well, as it is easier to throw a ball at 50
 +kilometers per hour than it is to throw an automobile at 50 kilometers an
 +hour.
 +As an object moves faster, it appears to gain mass (or become
 +heavier). We don't notice this in everyday life, because this effect
 +really only becomes noticeable when you get very close to the speed of
 +light, but scientists have measured and verified this theory in laboratory
 +experiments. In fact, if an object gets very very close to the speed of
 +light, it's mass goes up so fast that it can seem to be infinitely heavy!
 +At this point, it is impossible to gain enough energy to accelerate the
 +object any further.
 +
 +**2. E.g. if you travel in a ship that are well protected from paticle hits
 +or are flying far from all material, would it be possible to gain
 +lightspeed (theoretically) ? and could you increase speed from there ?**
 +----
 +
 +No, for the reasons I describe above. It would require infinite energy
 +just to reach the speed of light, let alone accelerate beyond it!
 +
 +**3. If 2 photons emitts from the same source, are not their speed, compared
 +to each other, twice the light speed ?**
 +----
 +
 +No. This is a very strange thing about special relativity. Einstein's
 +theory states that, no matter whether you are moving or standing still,
 +light always moves at the speed of light. So, if you were on one photon
 +and looking at the other photon, it would appear to be moving at the speed
 +of light. This is very complicated, and I really cannot explain it via
 +email, but good books on special relativity should be able to help you
 +somewhat.
 +Mathematically, the ideas behind special relativity are very
 +simple, and can be understood with basic algebra. However, a physical
 +understanding of what special relativity means is very difficult to
 +achieve. I'm still not certain that I truly understand it; I just accept
 +it as true (since repeated experiments show these theories are true).
 +
 +** 4. In your oppinion, how far are we from common use of spacetravel,
 +collonization and space mining etc.? 50, 250 ...?**
 +----
 +
 +For colonization and mining of objects in the solar system, we have the
 +technology now to be able to accomplish these things. The major hurdles
 +are economics (space travel is very expensive, and it is hard to justify
 +sending people to an asteroid to mine iron when it is cheaper and safer to
 +mine iron on the Earth) and physiological (we don't know what will happen
 +to astronauts who are in space for years at a time, both physically and
 +mentally). In the next several decades we will probably begin to reach
 +out within our solar system, but it will take economic pressure to
 +establish permanent residences.
 +
 +As for colonizing other stars, I personally believe that it may take
 +thousands to millions of years, if ever, for us to reach out. The nearest
 +star is four light-years away, but at the speeds of modern rockets, it
 +would take us tens of thousands of years to get there. There are dreamy
 +designs for nuclear powered rockets that may be able to go as fast as 1/10
 +the speed of light, but even then it would take 40 years to get to the
 +nearest stars. And we have no clue if these stars have planets capable of
 +supporting life! Outer space is much larger than most people imagine, and
 +so I think it will be much longer than most people imagine before we are
 +able to bridge the gaps between stars.
 +
 +Thanks for writing!
 +
 +Sincerely,
 +Kurtis Williams
 
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