I’m still trying to figure out why we need to be worried about being annihilated…before it’s too late. What happens if the moment of “too late” comes, and we haven’t been annihilated?
You will probably get better answers from more knowledgeable 'dopers, but my Science Channel view, FWIW:
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Does this mean other galaxies (and their planets) are being pushed further away (though extremely slowly) from us? Or to us?
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Actually, they are (in most cases) moving away from us very rapidly, not slowly. I believe some are moving towards us, and I seem to recall that one galaxy is destined to smash into our own sometime in the far distant future. The sun and earth will be long gone by then, so it’s not a particular worry.
In 5 million years the Earth will still be here and pretty much the same as it is today (discounting how the continents will drift or what the weather will be like then…or whether or not humans are still about to see what it’s like). I don’t think galaxies are ‘stretching’, per se. They tend to dissipate over time (the parts that don’t get sucked into the supermassive black holes comprising the centers of most large galaxies) very slowly, and in hundreds of billions of years they will eventually lose cohesion, from what I understand…but that’s in an unimaginably distant time, much more than double the time the universe has already existed for.
I’ve always found the image of the galaxies painted on an ever expanding balloon to be one of the better ones, though it’s not entirely accurate. I don’t think that the universe really has a ‘shape’, as such, but it’s a good image to try and visualize what’s happening.
-XT
To answer the OP, I’ll paraphrase from Douglas Adams: Space is big. Really REALLY big! You just won’t believe how vastly, hugely, mind- bogglingly humongous it is. We’re talking really big here…so big it’s hard to imagine the bigness.
Even if it’s possible to travel to another star (I think it is), you are going to have to have a REALLY good reason to do so. You aren’t going to do it just for the fun of it. And the odds of another advanced civilization being in the next star system over are going to be, well, astronomical. So…even if there happens to be another advanced civilization in our galaxy (or many such civilizations), the galaxy alone is over 100,000 LIGHT YEARS in diameter, and there are over a hundred billion stars in it (probably many times that number). Think about that for a while.
-XT
the bullet points above are spot on, i just have one to add
we search for ET life under certain impressions and assumptions… mainly reflecting light that is part of our visible spectrum, and the presence of air and water.
this avoids the entire range of frequencies that we are not tuned to see and hear.
this is just speculation as an example: what if “ghosts” are just some other lifeform sharing our planet, and every so often there is a human who is tunes slightly differently who can see them.
Look, you can argue various ways that the SETI is framed and executed in a narrow and parochial way. You can assert that advanced civilizations would no more use broadband EM transmissions to communicate than we would bongo drums.
You can’t, however, try and tie that into ghosts, ESP or other garbage.
This isn’t even remotely true. Most searches for extraterrestrial life have looked outside the visible spectrum.
good call. i dont know why i blanked on that… i have seen different spectrum aural and visual imagery. i was thinking more along the lines of the way we give meaning to the data we receive, and the preconceived notions that go along with that. by nature we associate what we find with what we know, blind to many things that we dont know how to interpret
not tying anything to anything. that was just to illustrate thinking differently. if you go in looking for something, you are apt to only see or not see what it is you are looking for, while other things may slip by.i have no evidence to prove or disprove anything about ghosts or esp, and the specific mention of ghosts is completely irrelevant to my comments.
Thanks for your responses. sigh I was really hoping something would collide and we’d find new neighbors in my lifetime. 
(Okay. I didn’t really think that.)
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[li]Is it possible that space travel can happen and we’re just people from the future? <insert joke about Mormons or other religious revelations> Or if I sent something outwards into the air, where does it go? If it keeps traveling and goes outside of earth’s gravitational pull, could it hit a force (I don’t have the words for it) and come back?[/li][/ul]
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[li]If something <insert madness> happened, could Earth split into pieces? Then what happens? Do we still have oxygen? Can we live somehow? What if the Earth didn’t have a core? Technology aside, what happens to people without an electromagnetic sphere? We just get burned up by the Sun? [/li]
[li]Is it possible to build a spacecraft that could withstand the pressure of a black hole? Could you actually go through one or is it impossible to get through the center? I mean, if they exist. Does that mean white holes can exist? Why don’t we just shoot all of our pollution into space? [/li]
[li]And is it possible that life on Venus existed billions of years ago - life like ours?[/li]
[li]Easter Island? Atlantis? Why can’t this stuff be in the Bible? :([/li][/ul]
Sorry. All the space and Armageddon movies have been taken already. 
And I would still like for Pluto to be a planet.
Well, if spacetime were like a 4d balloon, how many ways can you slice it? where’s our timeline? If i throw something up in the air, it just crossed space and time.
No Easter Island because the Iron Age Hebrews didn’t know about the Pacific Ocean. No Atlantis is actually a good question. Assuming that the eruption of Thera was the “Atlantis Event” that inspired Plato, it wasn’t that far out of the sphere of experience of ancient Palestine, and was possibly the impetus for the invasions of the Sea People (who eventually became the Philistines). Then again, except for the Philistine connection (which the aggregation of Biblical sources may not have known about), there really isn’t anything in the destruction of Minoan civilization that touches on the Hebrews themselves, so it’s not THAT notable an omission.
If you send something into the air, it’ll decelerate, stop rising, and fall back to Earth. If it has enough velocity to break free of the earth’s gravity, you’d need some other force to make it come back. There’s no reason it would do so on its own. The earth’s gravity would have less effect on it and other objects would have more.
I imagine the physical force of the impact or breakup would kill everyone. I think the answer to the oxygen question would depend on whether the remaining Earth-bits were large enough to maintain an atmosphere. If not, no.
I don’t think I can explain this well, but it’s not like air pressure and water pressure. We’re talking about gravity on a whole different scale and even if a ship survived a black hole, I’m not sure what it would experience in terms of time.
They exist.
They’re not known to.
Because it would be difficult and very resource intensive and we already have a lot of stuff floating around the Earth. The more stuff that’s floating around, the more stuff bumps into our satellites and spacecraft.
Doesn’t sound too likely from what I know. There was water at one time.
I’m not sure what space travel has to do with time travel. I do think you’re watching too many movies.
Sure. Maybe it eventually slingshots around another gravity well (like a planet) and rebounds. Or it could keep going forever. If you mean, “Is there some mystical ‘wall’ that will send things back?”, the best current answer is no. We’ve already sent the V’ger probe out past Pluto’s orbit, and it hasn’t rebounded, yet.
I will note that getting something to leave Earth’s gravity well is very, very difficult. Even the Apollo moon missions were still basically in Earth’s pull.
Could some catastrophic event happen such that the Earth splits into several pieces?
Yes. Getting hit by some sufficiently large rock would do it. In fact, the currently accepted theory for the formation of the Moon involves the Earth getting hit by some massive space rock and the Moon splitting off.
What the heck is an electromagnetic sphere? Do you mean the Earth’s magnetosphere? Without it, we’d see increased incidences of cancer and radiation related sickness. The Earth wouldn’t just “burn” up, though, and we wouldn’t die immediately.
With our current tech? No friggin’ way. We’re not even close. Kind of like asking if it’s possible for a man survive a 2000 degree oven for an hour.
I won’t venture a guess as to the possible future limits of technology, though.
It would be a horribly inefficient use of energy. Are you under the impression that it’s simple to leave Earth’s orbit? It’s not. It requires huge resources just to get to low earth orbit.
Even if we launched it beyond the moon, unless we did so with sufficient ‘oomph’, it would simply come back eventually.
Toss it into the sun? Even more energy. It’s be easier to launch it into deep space.
Launching pollution into space is like spending an extra $5000 to buy a hybrid vehicle to save $500 in gas. If your interest is only in saving money, you’ve failed.
Also, what happens on the 1 in a 1000 launch where something goes wrong? We’d have our waste falling on the earth.
Seriously? I hope this isn’t a whoosh. The Americas, Antarctica, and Australia aren’t even mentioned in the Bible, much less Easter Island.
Google “Fermi paradox”. Basically it raises the question that given the age and size of the universe, there should statistically be civilizations that are advanced enough to travel to other starts. So why have we never seen any evidence of them?
WHAAAAAAAAAT!!!:eek:
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Google “Fermi paradox”. Basically it raises the question that given the age and size of the universe, there should statistically be civilizations that are advanced enough to travel to other starts. So why have we never seen any evidence of them?
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Perhaps it’s because advanced civilizations tend to travel to other ends?
-XT
Even worse, it’s probably on a collision course! It’s coming right for us!
Yeah, I’d look out in a few billion years or so, our galaxy will be toast!
Perhaps, despite our optimistic science-fiction heritage, there really is no practical way to travel interstellar distances. Perhaps, even if they’ve sent out things similar to our Voyager messages, those probes just never got here, bypassing this solar system completely. Perhaps no civilization achieved a level of technology that allowed for the radiation of electromagnetic energy in ordered form within the time that that energy would have reached us yet. After all, even the earliest of our radio broadcasts would have only reached 105 light-years out at this point, which is a ridiculously small area.
The idea that other possible civilizations on other planets are necessarily more advanced than us is speculation, at best. It could be that we are the first intelligent life in the galaxy to achieve civilization and technology to the point of escaping the bounds of our planet, even temporarily.
I figured he meant “Initiated” as in “The Galactic Council of Spacemen have chose to initiate Earth into the League of Space-Planets” or something.
Maybe he meant isimilated? Like the Bjorg.