Instapundit links to an interesting article discussing how many potential planets there are in our galaxy, suggesting that as many as “40% of red dwarf stars may have Earth-sized planets orbiting them that have the right conditions for life.” This strikes me as awful premature, given that I don’t think our species are experts on what constitutes “the right conditions for life.” Most of what we believe about how exactly life came about, why, and under what conditions, is speculation, backed by some experiments that show you can synthesize complex organic molecules in laboratory conditions that mimic the early earth.
In fact, if I had to wager, I’d say that Earth-sized planets that orbit in the habitable zone of stars are remarkably common, but that life is comparatively rare, and intelligent life is extremely rare. Professor Reynolds concludes with one of his trademark “We need interstellar travel. Faster, please!” and I tend to agree we need to figure it out fast, but I’ve always been skeptical of the possibility of this, despite the fact that it’s necessary for man’s long term survival.
For one, there’s an intergalactic speed limit, which is the speed of light. Sure, you can speculate about being able to warp space and time, but even if it’s theoretically possible, we have no idea how to even go about it. That leaves us with traveling at sub-light speeds absent discovery of some new physics we don’t understand currently. The nearest star to ours is about 4 light years. There are about 50 stars within about 16 light years of us. Most of them different types of stars from the sun. The fastest you could reasonably move a craft with foreseeable technology would be about 5 to 10% of the speed of light, making a trip to the nearest star take 40-80 years. You don’t get serious time dilation until you get up to 70% or 80% light speed, and at those speeds, we have no idea how we’d make a ship survive even a micro meteorite collision, let alone how to make the crew survive the radiation they’d be plowing through on their way across the galaxy. The amount of energy involved is also unimaginable. We’re talking exajoules to get to the nearest star, even at a pretty modest speed of 5 to 6% c.
So I’m afraid unless we have a lot of breakthroughs in the next 50 years, we’re hundreds of years away from visiting a nearby star system. I think the only way we’ll even accomplish it is either to figure out how to move our consciousnesses to machines, or alter our genetic makeup to live longer, and be adapted for the high radiation environment of space. If we do make the trip, it’s likely going to be one way, which means we’ll need to improve our ability to observe and analyze exoplanets from here in our solar system, so that if we aim for a target, we know we’ll hit something that supports human life.
And that’s not even mentioning what the life there would do to us once we get there. It’s a tough, tough problem, and I’m just not sure humans are smart enough to pull it off at this point in our evolution.