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BACKSTORY

I read today newspaper and made discovery of planet Cygnus (in news paper of course :v) that human can live there! The distance is 1400 Lightyear. Assuming I travel with the world fastest rocket in the planet earth how many days / year would it take me to travel (and rule da planet :v) If that is possible I will surely want to be an astronauts! Yay :v if its not I will consider what would I become.. XD

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I have read something about 'TIME DILUTION' that can make me survive the 'TRANSPORTATION'

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The question is how long is it to be exact in my iOS (and bricked android) timer app? Well with that said, non-nerd will understand what kind of time I am asking here.. :v

Qmechanic
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user23139
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  • Since the distance is 1400 lightyears, then it would take at least 1400 years because you can't travel faster than light... – Minethlos Jul 25 '15 at 14:07
  • I really hope I did not make silly question.. since this is online, I assume none of you would care :v – user23139 Jul 25 '15 at 14:09
  • Also might be related: http://physics.stackexchange.com/q/109776/(you can travel for more than 1400 years as measured on Earth but still survive because of time dilation :) – Minethlos Jul 25 '15 at 14:11
  • @Minethlos You are incorrect. The time measured by the travelling person can be much shorter. Length contraction is one of the most elementary points in special relativity. – ProfRob Jul 26 '15 at 01:03
  • @RobJeffries Yes, the measured time on spaceship can be shorter. That is why I said the person can possibly survive. The details are all in John Rennie's post. – Minethlos Jul 26 '15 at 07:45
  • @Minethlos If you agree that your first comment on this post is incorrect (it is), then delete it. – ProfRob Jul 26 '15 at 08:52

1 Answers1

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It's true that the natural speed limit is the speed of light. So the minimum time required is 1400 yrs. However, it is imposible to reach that speed. We can't even accelerate subatomic particles to that speed.

You asked for the fastest rocket in Earth. The actual record of speed is the Helios II spacecraft (obtained from here) which traveled at 70.22 km/s. Light speed is more or less 300000 km/s. So the speed record is 4272.3 times slower than light, and we would need 5981202 yrs to reach the planet. That are more or less 6 million of years.

Well, of course, we could try to create a very-very fast rocket. Even with 1000 km/s, we need 420000 years. I guess you're not going to become an astronaut.

Time dilation effects are important if you're able to travel at very high speeds. Time dilation means, the faster you travel, the slower the time goes for you. First, even at 1000 km/s time dilation effects are not going to be very important. And also, you're not going to notice it inside the spaceship. If you go to that planet at 90% of the speed of light and you return, your iOS time app would mark 2800 years, as usual. But my iOS time app on Earth would mark 6042.6 yrs since you left. On the other hand, if you used the 70.92 km/s speed, both time apps would mark 2800 years. About time dilation you may want to read about the Twin Paradox. It's easy to understand and directly related with our planetary travel =)

EDIT. As @ChrisCundy mentioned in the comments, above calculus has an error -I didn't take in account space contraction. So in fact the time in your clock is less, 1360 yrs.

Victor Buendía
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  • yay! I wouldnt need to go through 5 years of PhD!! :v and "Also might be related: physics.stackexchange.com/q/109776/(you can travel for more than 1400 years as measured on Earth but still survive because of time dilation :)" – Minethlos BTW, NASA requires at least 3 year of study in relating subject o.O – user23139 Jul 25 '15 at 16:27
  • Also, for the first time, someone is actually speaking English in Physics StackExchange XD even though this physics.stackexchange.com/q/109776/ has non-nerd section, my brain still need to process some bit of information.. – user23139 Jul 25 '15 at 16:34
  • 'If you go to that planet at 90% of the speed of light and you return, your iOS time app would mark 2800 years, as usual.' This isn't correct. From your perspective your clock would run as usual but the distance to Cygnus would be contracted by a factor of $\gamma$, meaning in this case it would take (2800c*year/(0.9c))/$\gamma$ = 1360 years. – Chris Cundy Jul 25 '15 at 19:39
  • @ChrisCundy Oooops! Forgot space contraction. Thank you very much! – Victor Buendía Jul 25 '15 at 20:08