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Comment by _bz1e | Hacker News Reader

Is this 9.8m/s2? So after 1 year at this is 3.156e7*9.8/1000*3600km/h ?

Assuming it's just moving in space away from any massive objects in a straight line...1 billion km/h.

Isn't it too fast?

You have to correct your calculations for relativity. A spaceship accelerating at 1G for 1 year (earth time, not spaceship time) will reach a little less than 0.5c. Accelerating at 1G for 10 years will reach 0.98c and take 4.5 years in the frame of reference of the spaceship. 1G for 100 years reaches 0.9998c and takes almost 9 years for the spaceship. None of these figures account for deceleration.

EDIT:

I echo the comment that it's useful to play around with the relativistic rocket calculators available online. TLDR: If you could actually make an engine that accelerated your spaceship at 1G continuously, that's really all you need. It's good enough for human life scale trips pretty much anywhere. You could travel the diameter of the milky way (approx. 100K light years) in 22.5 years of ship time, including deceleration to stop at the other end. Want to get to the Andromeda galaxy? 28.6 years of ship time. Of course, everything you know back home will be millions of years gone by the time you get to your destination.

Not to mention the power required to continuously accelerate.

Or what happens to anything hitting you when you're traveling at that speed.

Or needing to turn.

Every answer is just a disguise for four more problems.

Sounds like all engineering! On a grander scale than usual though

Even worse, what happens when you get to your destination? Will you find a perfect analog of Earth and with the same kind of star? Assuming the star is very similar to our Sun, then you can ask about the atmosphere of the planet. Pretty much you need 25% oxygen and 75% nitrogen and 14 pound per square inch pressure on the surface. Fine, is the gravity the same? If not, there may be problems getting around. Okay, so what about food? You don't want to die of hunger. Finally, what about viruses and bacteria on the planet? They may attack you instantly and you die a miserable death in two weeks. At that point you may say to your self, Why did I come here.

Viruses and bacteria would not really be my worries. Unlikely they are compatible with our physiology. Maybe bacteria in sense of flesh eating or producing toxins as by-product, but nothing as infection I think.

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