Can We Travel To That Exciting New Exoplanet?

An anonymous reader writes "The news last week that exoplanet Gliese 581g may be in the 'Goldilocks zone' and could therefore hold liquid water and alien life got everyone all excited, with good reason. A potentially habitable planet — and only 20 light years away! But to put things in perspective, here are a couple of estimates on what it would take to travel to Gliese 581g. One scientist puts the travel time at 180,000 years based on current space flight technology, while another explains that it could be quite quick if we build a matter-antimatter drive, and can figure out how to bring along 530 times as much mass in fuel as is contained in the ship and cargo itself."

Comments

Re:Reality check

[MarcQuadra]

Right? The diameter of our solar system (Pluto's orbit) is about 80 AU. 80 AU is 0.0012 light years. This planet is 20 LY away. That means that it's about 1600 times as far as Pluto.

Remember, you need to bring along just as much fuel to slow down as you did to speed up. This is going to be a long, expensive, boring ride.

Re:I'd like a second opinion...

[Per Wigren]

18 days, 13 hours, 26 minutes and 24 seconds, captin.

Overly pedantic

[dreamchaser]

A man on a good horse can maybe cover 30 miles a day unless he wants to kill the horse. A man on foot maybe 20 if he's in top shape. My comment stands. Maybe I should have said "A dozen or few" but still, you're just being pedantic.

Re:Overly pedantic

[catbertscousin]

I was going to, but I needed Bronze Working first.

Re:Overly pedantic

[GooberToo]

I think its funny how many people don't really understand what they are talking about.

Pragmatically, further back that a couple hundred years ago, people rarely traveled. Period. It was largely the aristocracy and wealthy and/or merchants who did the vast majority of traveling. A minority traveled father than twenty to forty miles; and that was typically a city trip for supplies. Its not like in the movies where everyone is constantly traveling around. Traveling to a new area frequently means months to years to become re-established. Its a big, life changing event.

Some exceptions are the military. On foot, on clear terrain, forty to fifty miles were expected. They could do more but would generally be useless for fighting if they did. On horse, with good terrain, calvary would expected to do roughly eighty miles. On rough terrain, a foot soldier was expected to do twenty miles. In heavy forest and/or mountains, snow, etc., ten miles is a good day. Now keep in mind, these guys had heavy equipment they had to carry too, not to mention supplies. And that's really the magic of it all. Having water and food is key. Sure, you *can* travel a much father distance, but being absolutely useless for the next couple of days, assuming you don't die, assuming supplies can catch up, doesn't do anyone any good whatsoever. And don't forget, most places didn't even have roads outside a city. That's one of the things that made Rome great after all.

There are some noteworthy exceptions, such as some of the African tribes who are legendary at running vast distances (example, Zulu) and going right into combat - and winning. But these guys carried only a shield, spear, and absolutely minimum of food and water, and even then, it was war. It was not an everyday event.

Going back to antiquities, it was exceedingly rare to ever travel outside of your valley - again, unless you were a merchant. Realistically, people did not travel. When they did travel, they rarely traveled father than twenty to thirty miles. Those that did travel farther than that, typically had a vocation which required it (merchant, navy, explorer) or a wallet to simply allow for it (summer, winter home). And even then, when they did travel, it was exceedingly rare to be great distances in a day. And of these, ships are the sole exception - until trains - and then cars and planes.

Re:A further shore....

[dasherjan]

We already have plenty of shores to explore in the solar system. They're just not as sexy as another earth type place. ;-)

Re:Nuclear pulse propulsion

[Mr. Slippery]

A vegan diet reduces the need to support non-human animal mass, but adds a requirement to be able to synthesize some vitamins and proteins.

No, it doesn't. Protein needs are easily met on a vegan diet; the only vitamin that can really be troublesome is B12, which is made by bacteria and so doesn't need to be synthesized.

Re:Our world

[FrangoAssado]

You're forgetting that the volume is proportional to the cube of the radius, while gravity is proportional to the inverse square of the radius. So, while gravity doesn't increase linearly with mass, it's not constant either:

4x mass -> 4x volume -> 4^(1/3)x radius -> 4/4^(2/3)x gravity

So, gravity would be increased about 1.6 times. You should apologize to him if he weighs 380 pounds, not 500. :)