Hal

Forgetting about colonization, Venus should definitely not be regarded in the same way as Saturn. While Venus' atmosphere is hellish, it has a definite end where it hits something different, the rocky ground. Gas giants are just the same thing all the way down, you'll never "hit" something, you'll just sink to where you can float (or, more likely, be crushed horribly). Colonization is a whole other can of beans. If/When we do get to the point where we're seriously considering expanding onto Venus and the gas giants beyond something like a research outpost, technology will probably be so different that making plans to either settle in the air or on the ground now will be kind of pointless. It's a fun way to pass the time though, and there's no harm, so go ahead, just keep reality in mind.

It's a thought experiment people, try to have some fun. Do you really want to be the guy who goes up to Plato and tell him about how his cave allegory makes no sense because the cave's inhabitants would have to be fed? Deliberately missing the point only works if you're being really funny. As for me, I would be screwed. I guess I would try to hide out somewhere kind of remote and stockpile supplies, but I highly doubt my survival skills are good enough for me to last long. I would try to download as much of, say, Wikipedia as I could onto some safe hard drives. I'd also try to collect important books (sciencey stuff, mostly), and keep them with me. While I might not last long, hopefully I could help to preserve some knowledge for rebuilding after the collapse (although chances are many people or organizations will do something like this and my personal effort may be pointless).

The rover's going to be 660 meters tall? Bravo, ESA, I had no clue we could land something like that on Mars. On a more serious note, on top of the physical changes to the wheels, the rover drivers now know just how dangerous some kinds of terrain can be, and will probably be as careful as they are now of Curiosity from the beginning for Mars 2020, which should help too. Or at least the damage won't be a surprise.

Hmmm. I find it a little odd that he says that 100 billion years from now, there will be no photons our eyes could detect. Maybe that's true if it's all averaged out over the whole volume of the universe, but smallish red dwarf stars are supposed to have lifetimes of up to 10 trillion years, according to Wikipedia. While that is a high bound, even if they only lasted 1 percent of that time, stars that are already formed would still be around, to say nothing of future generations. Also this is probably just a problem of the article itself (not the scientist), like many popular news articles on science, it doesn't convey the doubt very well. While I am speaking entirely out of my posterior here, not being anything like a cosmologist, I get the impression that when it comes to the overall energy balance of the universe, there's a lot that we don't really get (hence dark matter and energy). I wouldn't take it as gospel. It is cool though, thanks for sharing.

I could be very mistaken here, as I feel like I'm forgetting some basic part of orbital mechanics, or maybe just some basic part of logic. But wouldn't the aliens only be able to find where Voyager had come from by backtracking if it hadn't made any extra burns? They wouldn't have any particular reason to assume that the probe didn't, say, perform a 200 dV burn (and then detach the propulsion stage) after reaching a light-year from Earth, or any other one of infinite possibilities that would throw off tracking through simple gravity. I do feel like I'm missing something though, so take that with a big grain of salt.

It would definitely be nice if there was more coverage (and better coverage) of science in the news, although I'm not sure if the LHC turning on is enough for anything but a slow day. However, if you can't talk about the things you like without dumping on other people for liking different things, you need to rethink a little bit. People have different interests, and while some may be more worthy than others ("mine" are best, according to everybody), you're not going to change anyone's mind for the better by insulting them. It's also just bad manners, which aren't good (they're bad!).

The thing is, while there might be some kind of life on Titan, it would have to be fundamentally different than Earth life, and much better adapted to its environment. Titan is so different from any part of Earth that contamination isn't really an issue. Europa or Mars, on the other hand, are problematic for precisely the reason we're so interested in them: they seem like they could possibly host Earth-like life. Because they're so similar (they have some kind of liquid water, or once did), we have to be more careful, as it's more possible that Earth life brought on our probes could actually survive and thrive there, possibly even outcompete whatever life is there. At least this is what I think. I could be way off the mark.

I think the point that's trying to be made is that even if the atmosphere is going to get blown away in a billion years or so, and isn't technically self-sustaining, it's good enough. If humans (or some descendant of us, obviously very different) are still around a billion years from now, terraforming a single planet is going to be laughably easy, if we aren't all artificial and don't even care about the atmosphere at that point. If we're not around then who cares? If it would actually work to substantially improve the Martian atmosphere, I don't see why we shouldn't go for it (once/if we actually get serious about colonization). The lack of magnetosphere might be an issue though, like magnemoe said. I don't know enough to say what kind of an issue, though. But anyway, an atmosphere's probably not going to hurt.

That is really cool. It does have a bit of an unrealistic PR spin, but that's the price for looking awesome I guess. This is a pretty ignorant question, since I really have no idea how fast the central stage is going besides "really fast," but would it be feasible for them to just try to land it on the other side of the Atlantic? I would guess not, because there doesn't seem to be an easy way to ship it back, but someone who actually knows what they're talking about shedding some light on the matter would be nice. Also, what's with the payload? You'd think it would be a Dragon with some kind of transfer stage, but it's not. Is that just a generic commercial satellite?

Hehe. Seriously though, that moon can't be that stable. You'd think even the force from the light of the sun (that they thought was causing the Pioneer Anomaly, I think) would overpower that feeble gravitational attraction soon enough. Maybe even tiny variations in drag from space dust. Cool though.

To answer the OP without resorting to reality, you're forgetting that there may be no way for the universe to end. Then, with your logic, the infinite universe's very existence proves the fact that nothing can happen to end that existence. In reality though, we don't really have any reason to think it's infinite, and we might (I don't know a whole lot on the topic) have good reason not to (big bang model seems to imply that it was limited at some point). I'm pretty sure that it's mathematically possible to have infinities of different sizes, so the universe's size could just be infinity +1 over and over, if that makes any sense. When things get this abstract, we don't really have to assume that it's expanding into anything, it could be expanding into complete nothingness. There's really no way to know what's outside though, so it's all guesswork. Also, if there's a 1 in 5 billion chance for someone to turn into a whale, even if it's over the course of a lifetime, there would be about 1.5 people swapped with whales on the planet right now. Teehee.

I'm not really sure if this belongs in here or the Space Lounge, but it's close enough I guess. Also, this isn't quite news, I just was reminded of it by randomly finding the article that first informed me of its existence, but it's been true for at least a couple of years. There was actually a post on these forums about a month ago on a specific part of it, but it only had 2 responses and didn't really communicate the idea, so here we go. With the boring disclaimers out of the way: MIT course materials are free online! Anyone can have unlimited free access to all sorts of lectures and assignments (and probably videos, I haven't looked around yet much) without so much as even signing up for an account. You can learn things, it's great! And now for the KSP link (meaning the first thing I went to), the Introduction to Propulsion Systems class. While I know a lot of people on these forums don't yet have a full education of tricky physics and mathematics, Wikipedia can be helpful for a lot of things, and you can take your own time. It's also not perfect for sure, learning is (hopefully) a lot more difficult without a teacher and in some of these cases, the book they expect you to be looking at (replaced by Wikipedia?), but it's still a nice thing to have around. There are literally hundreds of courses, it's just... really cool. Also, it's a good several dozen thousand dollars per year cheaper than the real thing, which certainly doesn't hurt. What are you waiting for?

I don't quite want this thread to die yet, it's a nice thing to have around (says the guy who practically only lurks, but's that's neither here nor there). Anyway, I have a couple of questions: 1. What type of radiation is primarily responsible for endangering astronauts (and flight hardware) both inside and outside the Van Allen belts? Is it mostly gamma rays or other high energy photons or different particles? Or, alternatively, am I completely misunderstanding the situation? 2. What's up with the sublight Alcubierre drive? It seems like it could be pretty crazy helpful for traveling around the solar system at least, but always gets kind of brushed over. I've heard that it wouldn't require negative energy densities, but also that it would (in this very thread), so a little clarification would be nice. Is there some reason it would be tricky?

You're right. I was just trying to make a juvenile joke that only made sense to me because I'm American, and hilarious would have been too strong anyway. My bad, I tend to forget how the internet is international. On a different note, I wonder how successful this movie is going to be. While people on this forum obviously are really into it, do you think the general, less science-minded/crazed populace will like it? I hope so, but have no clue.

I don't post here often, but I feel like this is the kind of movie that the people on this forum would love. Here's the trailer that came out today: https://www.youtube.com/watch?v=OXwichuGW28 It's directed and co-written by Neill Blomkamp, who not only has a hilarious name, but directed District 9 and Elysium. Elysium was... alright, but District 9 was one of the best sci-fi movies I've seen (if you haven't seen it, find a way, it's amazing). He seems to be really good at blending a great emotional story with a bit of optimistic but realistic sci-fi. There's not a whole lot to say about the movie yet, but is anyone else excited? I'm excited.