Visiting Other Worlds (or Why Relativity is Your Friend).
It seems more and more we’re discovering planets outside our solar system and now we’ve even managed to find one that has some very interesting properties:
Exoplanet researchers have discovered the lightest exoplanet found so far. The planet, “e”, in the famous system Gliese 581, is only about twice the mass of our Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist.
“Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. “‘d’ could even be covered by a large and deep ocean — it is the first serious ‘water world’ candidate,” continued Udry.
A bit more information on the system here.
It would seem like this planet system would be a great place to investigate. It’s close, about 20 light years or so away, has several known planets with one being a veritable haven for extraterestial lifeforms and of course would be a great boon to science as a whole. Problem is, 20 years at light speed is still 20 years needed to be self sufficient and enclosed in what could be a very small space ship.
Or would it?
Enter our good old friend Albert Einstein and his Special Theory of Relativity. Among his various predictions using this theory the important one (for this discussion) is that of time dilation. In essence Einstein postulated that as you approached the speed of light the passage of time would slow down for you, but not for an observer. So whilst us sitting back here on earth would perceive a light speed ship taking 20 years to reach the Gliese system for them it would be a mere 6 years (assuming a light acceleration of 1g, with 2g it drops to 3.5!), something which would seem a lot more palatable to those people who dared to brave the final frontier.
The great thing about this is that it’s not a linear scale, larger trips of up to 400 light years or so only take the time up to about 11 years or so and even cross galaxy trips of millions of light years don’t add much extra time. Sure, for the people aboard the ships it might not be the greatest thing to arrive at their destination and find that we invented faster the light travel and got there before them (and that whole “everyone you ever knew is dead” thing) it still brings a small sense of joy to me that, no matter what, humans would be able to explore the universe in its entirity with just a normal lifetime. Sure our space technology isn’t up to light speed travel yet but we’re getting very close.
No matter how small a step this might be, it does bring my dream of visiting other worlds one step closer.