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Extraterrestrial Life
- Thread starter FattyButt
- Start date
The edge of the observable universe is 46.5 billion light years away. That means that, even by going at the speed of light, it would take 46.5 billion years to reach the "edge". And, that "edge" is simply the observable part... there could be much more beyond that.
Either way, travel at the speed of light would require infinite energy. And, traveling faster than light will, according to the Theory of Relativity, cause "time travel", i.e. time and velocity are no longer related by constant shifts.....
Basically, it's highly unlikely that we will be able to move faster than light. Not to say that it isn't impossible, though.
Owing to special relativity, that 46.5 billion years only applies to the journey time as measured from Earth. Measured on the spaceship, it can be as short as you like, reaching zero if you could travel AT the speed of light (which you can't).
However, the energy requirements are prohibitive. Even matter-antimatter annihilation can only take you so fast. We can probably explore our stellar neighbourhood, perhaps even the entire Milky Way, but we can't go jetting across the other side of the Universe. You also have to consider humans can only take a certain amount of acceleration. And then there's the risk of crashing...
However, the energy requirements are prohibitive. Even matter-antimatter annihilation can only take you so fast. We can probably explore our stellar neighbourhood, perhaps even the entire Milky Way, but we can't go jetting across the other side of the Universe. You also have to consider humans can only take a certain amount of acceleration. And then there's the risk of crashing...
A hundred thousand across. I haven't actually done the energy calculations. (They can't be THAT hard. Set either your desired journey time or your constant acceleration, and calculate what the kinetic energy would be at the halfway point, using special relativity. There's always numerical methods if the analytical solution is a pain. Of course that neglects change in spacecraft mass as fuel is consumed, and you also ought to consider power as well as energy, but it will do for a first estimate of plausibility.)
My bad, was just guestimating :\
And either way, the huge problem with all these hypothetical calculations is that we have no ideaabout furture forms of space transportation. The U.S. only just decided to trash our shuttles, and we don't have anything revolutionary yet. We can guess and make speculations, but in the end, they are just that: speculations.
Either way, I digress. Back to extraterrestrial life!
You really should stay out of this thread because you haven't the first clue of what you're talking about. There is also no need to guesstimate something that can be easily found by quickly googling, either. The universal speed limit is that of light, and even though time dilation can be exploited so that you can have the crew live throughout the journey, time on Earth will pass as normal. There is nothing speculative about the ultimate speed limit of any spaceship we build, unless you want to include lol the Alcubierre drive, which is pretty much what warp drive is. The mathematics behind it is rather sound and it's not completely out of the realms of possibility to use it to travel faster than the speed of light (which it only does so by bending space, which requires stupid amounts of energy), but it's riddled with problems, such as the speculation that an Alcubierre drive is required to build one, and that even conservative calculations put the energy required to send a spaceship across the Milky Way to be way beyond our entire civilisation's energy output.
We *could* build a spaceship that takes thousands of years to reach its destination given signifcant enough advances in ecology, genetics and many other branches in science but even if technical hurdles are overcome there still remains the problem that no government is going to devote a serious amount of resources for a project that will only bear fruition in the far future, after everyone who ever was involved in it has long gone (most humans are selfish like that).
Hah, I dunno, it's certainly theoretically feasible Cookie. I think the issues with Mars is that it's not a one way trip and it's not meant to be sustainable, just temporary. A one way trip wouldn't be that bad, since inertia carries pretty nicely in space, a directional change other than slight corrections wouldn't be necessary.
At any rate, if we did arrive at a planet, we might well end up like the aliens in District 9. No, not living a ghetto under the heel of aliens, but certainly like they were when the ship was opened- starving, weak and covered in our own shit. I'm not to worried about it, we have billions of years to figure stuff out before the sun flips out on us.
At any rate, if we did arrive at a planet, we might well end up like the aliens in District 9. No, not living a ghetto under the heel of aliens, but certainly like they were when the ship was opened- starving, weak and covered in our own shit. I'm not to worried about it, we have billions of years to figure stuff out before the sun flips out on us.
I'm fairly certain that travelling faster than the speed of light is actually physically impossible. When one approaches the speed of light, instead of accelerating, time slows down to compensate for the "lost" speed. There was a program on the History Channel the other night discussing various possible methods of time travel, and this was the most reasonable one, despite the energy constraints. If one were to travel at near the speed of light for a week (riding a train circling the Earth at roughly 7 times per second was the example used in the program), about 100 years would pass on Earth. But yes, you are certainly correct. It is inconceivable to attempt to travel to other galaxies, let alone the edge of the universe (which is impossible, considering the universe is constantly expanding).
OT: I think that there is most certainly life on other planets, but the degree of intelligence of the lifeforms is questionable. I doubt that there is any alien fleet travelling the universe that will arrive on Earth any time soon, and I also doubt that humans will be able to achieve intergalactic travel very easily, if at all.
Wanting something to be true won't make it true... There could be life elsewhere, but it's not "interesting" enough for most common people to really care anyway.
The article is saying the mathematical probability of intelligent life outside the galaxy is pretty high, and since humans are such dicks maybe other life would be similar. It's not a serious thing to worry about as the article tries to pan. That "other galaxies" thing is part of it...
The article is saying the mathematical probability of intelligent life outside the galaxy is pretty high, and since humans are such dicks maybe other life would be similar. It's not a serious thing to worry about as the article tries to pan. That "other galaxies" thing is part of it...
Well, according to Einsteins predictions, there can be a way. Einstein wrote something along the lines of a worm hole could exist. A thing where the fabric of space was torn, and if you went through it, you would come out in an entirely different part of the universe. Yet even this, which according to Einstein is possible, it still seems far-fetched. A worm hole needs to first, be real. Then we have to know where it is. Then we have to know if/how we can send something into it.
I watched a video about this on National Geographic or NOVA, I forget which, but that's what they said there. I have never actually read any of Einsteins theories.
I dunno guys, Einsteins "theories" (more like untested or untestable hypothesis if you ask me) have been taking a few nasty hits of late. He was always just assumed to be correct...
Looks like he was wrong about black holes, potentially.
I'd be looking at some of his other work, or work that assumed he was correct (see: all theoretical physics) and take it with a grain of salt. By this I do, of course, mean FTL travel.
Looks like he was wrong about black holes, potentially.
I'd be looking at some of his other work, or work that assumed he was correct (see: all theoretical physics) and take it with a grain of salt. By this I do, of course, mean FTL travel.
FYI, that's not a new theory (it's been bandied around since the 50s), and it's not even a theory in the scientific sense; it's entirely related to a mathematical device. It's a representation of a series of coordinate changes that allows you to map the entire universe down to a small tile pattern, and then making the assumption that the tiles fit together with identical tiles because the tile can tessalate. I would take that article with a grain of salt, and trust in Einstein's relativity and the photoelectric effect. You know, the things with experimental evidence and lots of rigorous testing.
Actually, as a general rule, anyone claiming anything about General Relativity being wrong or having some bizarre interpretation is usually someone who doesn't actually research in the field. The 'singularity' at the center of a black hole is a mathematical one, and not necessarily a physical one. There is no reason to assume white holes even exist (In fact, Hawking Radiation suggests it won't, there are other mechanisms for the Black Hole to lose energy/information). We won't be able to accurately describe the center of a black hole until we actually have one to experiment with.
EDIT: Also, there is a theoretical mechanism for FTL travel. It is called the Alcubierre Warp. It is a gravitational metric that creates a strange bubble of normal space time that can move around the rest of spacetime faster than light can (because it's not actually matter or energy that is moving). The only problem is you need a region of 'negative energy' or something like that, and we have no idea of how to create it.
EDIT 2: Oh, cookie beat me to it. Although I'll add; tachyons are mathematically sound, and they travel faster than light (and backwards in time) but they are constrained to never travel slower than light by the same mathematics, which probably makes them physically impossible to detect. Also, we're yet to find a CPT violation in nature (although CT and CP, as well as T, and P are all individually violated as I recall, maybe C too).
Who says it has to be a government? More likely it would be an eccentric quadrillionaire. And their going off thousands of light years away would be preceded by numerous unmanned probes to nearby stars, and maybe even manned mission. Big science is quite happy to wait decades for results at present.
About relativity: special relativity prohibits FTL travel. General relativity allows it in certain exotic situations. (And any time you allow FTL travel, you also allow time travel). These situations are mathematically valid, but that doesn't mean they're necessarily physically possible.
There's nothing wrong in Einstein's theories - though we do know their are situations they break down, notably black holes. There's nothing wrong in the mathematical work that devises scenarios for FTL travel. What is wrong is assuming those scenarios are physically possible. General Relativity describes our own Universe, but it can also describe Universes that are nothing like our own.
Analogously, videos can depict fantasy situations that are impossible in the real world. But that doesn't mean ALL videos depict fantasy.
Thank you for reminding me why I think theoretical physics is among the worst branches of science today, right up there with astrobiology (funny enough I should bring that up in this thread).
Why does FTL = time travel 100% of the time? I don't understand this.
I'm saying that because some of his work has been questioned, it's reasonable to question the rest of the work considering it was basically given a free pass as being correct without much question for the duration of its existence.
How the fuck is it reasonable to make assertions about the universe that aren't physically possible?
Why does FTL = time travel 100% of the time? I don't understand this.
I'm saying that because some of his work has been questioned, it's reasonable to question the rest of the work considering it was basically given a free pass as being correct without much question for the duration of its existence.
How the fuck is it reasonable to make assertions about the universe that aren't physically possible?
If you take a velocity greater than c, and stick it into the relativistic equations of motion or Lagrange equations, you can create reference frames in which the order of causality is reversed (i.e. when A occurs 10 seconds before B in one reference frame, you can make B occur before A in another reference frame). This means that by travelling faster than light, you can travel backwards in time.
It wasn't given a free pass by any means. General Relativity has been heavily tested by experiment from the moment it was possible to do so, and they're STILL testing it by looking for extremely-low-frequency gravity waves and other such things using elaborate and complicated oscillator probes.
Most of the stuff people suggest to counter Einstein's relativity is either mathematically incorrect (i.e. the authors don't understand how to construct or use their equations), done by non-physicist mathematicians (i.e. they don't know how to physically interpret their mathematical results, like with r=0 singularities in black holes) or done by non-physicist non-mathematicians (i.e. both of the above).
What assertions are you referring to?
It's not. And indeed, I believe many scientists will simply publish the mathematics, without claiming it could be a physical possibility. The mathematics is correct, and is reasonable - but it's maths, not really physics. (The maths of General Relativity is hard, so such work is of publishable value). It then tends to be others who say "hey look this paper says we can do time travel" while ignoring the fact that you need an infinitely long cylinder made of impossibly strong and dense material, or that it only works in a spinning Universe that contradicts what we observer
