Replies to This Discussion

Permalink Reply by Jared Lardo on July 31, 2010 at 8:12pm

Actually it will be short for the crew due to length contraction. We'd say it seemed short for them due to time dilation, but their perspective, when talking about how things'd be for them, is the relevant one.

Specifically, that is that objects traveling relative to an observer appear to shorten along their line of travel (because the events of the arrivals of their front and back ends at such-and-such a point get distorted). Because of this, as the universe travels relative to the crew in the ship, the astronomical distance between start and end will appear to shrink; although the apparent speed of the ship relative to the universe according to the observers in the ship (the same as the apparent speed of the universe relative to the ship according to the observers in the ship (since they'll still actually know that they're more guilty of travel than the universe)) will still be less than that of light, with the decrease in the distance to travel in their reference frame, they'll thus get there relatively quickly because it's rather close. However, yes, to us they'll get there in little time (to them) because of the time dilation which, in our reference frame, will occur to them.

Permalink Reply by Joseph P on July 28, 2010 at 11:40pm

Actually, there are many problems with approaching the speed of light. The big one is the Doppler Effect. Normal light Dopplers up into the frequency of ... cosmic rays, I think it was. When you hit something like 40% - 60% of the speed of light, it starts becoming deadly to organic life.

I don't remember all of the details. I saw the stuff in a few specials, several years ago. Can anyone help me out?

Permalink Reply by The Secular One on July 29, 2010 at 8:32am

Space radiation is a problem when you leave the Earth's magnetic field...regardless of how fast you are going. Additionally, there's a huge problem with debris putting a hole in your hull. These are just engineering challenges though, and there are already some workable solutions being tossed around as we'll need to deal with them just to get to Mars.

Permalink Reply by Joseph P on July 30, 2010 at 9:55am

Yeah, but there was something about the frequency dopplering up into levels that will allow it to penetrate the hull of just about any material we could make the ship out of, at a certain percentage of the speed of light. Meh, gonna have to go on a research binge. It was too long ago that I saw the special.

Permalink Reply by Joseph P on July 31, 2010 at 12:59am

Well, it essentially comes down to masses of redundancies. That's what it's like, getting to the moon. They had triple, quadruple, and quintuple redundancies of critical systems. We'll do the same thing, with newer technology, for a mission to Mars. It's a huge deal, and it will cost a lot, but it's doable.

Permalink Reply by The Secular One on July 28, 2010 at 8:54am

Eh, life on this planet will survive just about any asteroid. We won't, but life in general will.

There are plans to try and get some spectroscopic readings on these planets to look for water and molecular oxygen and the like.

Permalink Reply by Jared Lardo on July 31, 2010 at 7:20pm

In case this leads--as well it should--to us finding life all over the place in space, we should get to looking in the various holy books that creationist equate to their various gods for whatever lines they'll use to support their beliefs and get to debunking them early. Let's beat them to the punch--as well as to the plate of tiny sandwiches.

Permalink Reply by Фелч Гроган on August 1, 2010 at 2:20am

A bucket of water.

Given that the talk wound up receiving significant coverage in the press, NASA also convinced Sasselov to post a clarification on the Kepler blog. In it, he helpfully points out that he was using a very liberal definition of "habitable" in his talk. There's a big difference between Earth-sized and Earth-like. Even then, by a lot of criteria, Venus is pretty Earth-like, but has a surface temperature that can melt lead.

Permalink Reply by Joseph P on August 1, 2010 at 4:19am

Well yeah, the planets still need to be within the appropriate distance band from their sun, have a workable atmosphere, and such. You're looking at a VERY unlikely set of circumstances on any given planet. It's just that there are so many planets, each of which gets a roll of the dice.

Probability says there's other intelligent life out there somewhere. Probability also says that it's too far away for it to matter.

Permalink Reply by The Secular One on August 1, 2010 at 7:18am

I think we already knew this, or at least knew it was possible. From the data, all I saw was planet size. As far as I know, we don't have environmental data on any of the planets yet to tell the difference between a Venus and a Mars.

Thanks for the link though.

Permalink Reply by Susan Stanko on August 1, 2010 at 10:32am

In order to keep the air it would need an atmosphere.

Permalink Reply by The Secular One on August 1, 2010 at 11:01am

The core of Mars is cold, meaning it has no magnetic field to protect the planet from solar winds. That, plus its low gravity, greatly limits its atmosphere.

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