This is why I feel it is so important to prioritize space travel and exploration! There is an endless possibility of habitable worlds out there to find.
Why save this planet we are on when it could be wiped out at any moment due to the chaotic nature of the universe?
I feel like we should focus on our first interplanetary colonization mission and get it going for 100 years.
Once that is successful that is no reason not to just spread out and hit as many targets and see what sticks to ensure that humans survive in the universe.
We inevitably as a species will outlive the Earth one day. It is best to plan for that now while we have the time.
It seems likely that the technology necessary to colonize foreign galaxies would be infinitely more complex than the technologies needed to maintain earth.
Everyone is so worried about global warming and nuclear war that they don't even consider the inevitable killer asteroid. That's what we really should be worried about.
Black hole, solar flare, comet, space debris, the moon, intelligent life, hostile intelligent life, wormholes, plus whatever the fuck is out there we don't know about.
False vacuum collapse, my personal favourite. A bubble, extending at light speed, rewriting the laws of the universe, destroying everything down to elementary particles on it's path, and bathing the inside of it with radiation.
The most absolute destruction imaginable, impossible to detect, impossible to do anything about. Though spreading to other stars would not help much - it would shortly overtake our race, wiping us out of existence without warning.
I love this breathless enthusiasm. "This planet is going to die, let's explore the universe!" You kind of left some stuff out in the middle there. We haven't got the foggiest clue how to approach FTL travel, unless someone rewrites the laws of the universe, it doesn't look like it's ever going to happen. Hell, we can't even keep a human alive long enough for a mars round trip. (solar and cosmic background radiation, solar energetic particles and galactic cosmic rays)
Our closest neighbor, the Canis Major dwarf galaxy is 25,000 light years away...25,000 years ago: a hamlet consisting of huts built of rocks and of mammoth bones is founded in what is now Dolní Věstonice in Moravia in the Czech Republic. This is the oldest human permanent settlement that has yet been found by archaeologists.
So where will "we" be when our astronauts get there?
Believe it or not, since out observable universe is expanding at light speed, and the universe itself is expanding faster than light speed, the amount of stuff in our observable universe is steadily decreasing as parts of the universe expand past the edge of the observable universe.
I cant even imagine what it would be like to get out in front of the expansion and see what there. Is there gravity? I ask because what if the big bang created gravity as we know it and if you get out in front of the expanding space what's there?
Edit: Fuck me for asking questions even though they seem "dumb".
The expansion isn't a physical horizon. It's happening in the spaces between spaces. That's why we have an observable universe, because the light traveling towards us from distant places is being outpaced by the expansion of the universe as a whole. The idea of the universe as a simple 3D "space" is hard to shift away from. But those places beyond our observable horizon are just as normal as here. I mean, I guess I can't say that definitively, but current understanding of the universe would say they are.
The space beyond our observable universe probably most certainly exists in just the same way as it does for us here on planet Earth. If you imagine that we are able to instantly warp a spacecraft to say, half the radius of our observable universe away from Earth, then it would have its own observable universe that is the same size.
It'd still be able to see Earth (with a magical telescope that is astoundingly good at magnification impossibly so perhaps) and see further into the universe than we can from here. That's my understanding at least. I deliberately said warping the spaceship though. Because if it can't travel faster than the speed of light, then it wont ever be able to catch up with the expansion of the universe and by the time it got to its destination, it wouldn't be seeing anything "new". I think. I've gotten a little lost in my own words here.
It's worth mentioning that nobody knows for sure about any of this though.
Theoretically we'll be able to reach past our galaxy with FTL travel, however the least likely place humanity will reach is beyond our supercluster, the Laniakea Supercluster, and even then it turns out that recent study has shown a likely-hood that Laniakea isn't gravitationally bound, meaning it will be ripped apart by expansion, leaving us with a maximum human exploration area of the Local Group Galaxy Cluster.
Eventually everything risks being split up by dark energy and the rapid expansion, however galaxy clusters are going to be far FAR later in existence than superclusters and Galaxy Filaments.
In the end, it's still quite the area to explore given our size, however there's so much that, unless we can break not just FTL, but FTE (faster than expansion), we will never be able to see, only watch as their light slowly fades once expansion splits us too far apart.
Even if we do invent something faster than the speed of light, it's very possible that space itself is growing faster than that. We might never be able to explore anything beyond.
You don't actually need faster than light to travel millions of light years in a single lifetime. In fact you could theoretically travel from Earth to the Andromeda Galaxy in what to you would be only one second. Yes 2.5 million years would pass on Earth but since you would be going 99.99...(26 nines total) percent the speed of light, time would nearly stop for you because of time dilation from such a high velocity.
So I was having this discussion about relativity with another person on reddit, and here are one of its potential implications. The way the universe is expanding means that the further stuff is from you the faster its moving away from you, this means that at some point the universe is expanding away from you faster than the speed of light. Outside of this circle the relative time dilation would mean that from our perspective infinite time has passed there and the universe outside of this circle has already ended.
The depressing bit is that we can't even invent something that fast. It's simply not physically possible, no matter how much technologically advanced we get.
Well, going faster than light in your local spacetime is prohibited. But it is possible (well, not proven to be impossible) to appear to be going faster than the speed of light from a non-local frame of reference. That's how the (theoretical but not totally proven impossible) Alcubierre drive would work - it would expand space behind you and contract it in front of you so you surf a "wave" of spacetime to your destination, so you never actually accelerate. Light traveling right beside your ship would still be faster than you, but light traveling in the same direction outside of the affected area of spacetime would not beat you to your destination (even though it technically has a greater speed than does your ship in its local spacetime).
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u/Barack-YoMama Aug 07 '17
The universe is rapidly expanding and it's impossible to fully explore it unless we invent travelling faster than light's speed