Space...

Hm, one could write a whole book about this. I´ll try to be a little more brief  

1. If I would be offered a job on a space mission?
Where do I have to sign?

2. What´s out there? 
Well, to quote Jody Fosters father in Contact: "If we are alone in the universe, it is an awfull waste of space".

Seriously, I do belive that there is/was life out there.
This being said, the chances that two sentient races develop in the same neighbourood (say, some couple thousand ly)at the same time are rather remote. The time part is the important one IMO. The universe (as far as we know) is roughly 15 billion years old. Because there were no elements beside Hydrogen and Helim in the beginning, lets say the first sentient race appeared 10 billion years ago.
Lets assume 1 in 1000 stars is of a type to support life(1), then 1 in 1000 of those has planets where they can develop life(2) and on 1 of 1000 of those life becomes sentient(3). This gives us a 1 in 1 billion chance for a star to be home of a sentient race. As there are some 100 to 200 billion stars alone in our galaxy, this would leave us with 100 to 200 alien races in the milkyway.
However, those 200 races would be spread over 10 billion years. If each race would stay communicative (starts with radios, ends with, who knows) those races would cover only 200 million years. So the chance for 2 of those to be communicative simultaneously(sp) is 1/50 or 2%.

Yes, I know, a lot of assumption.

Ralph Hoenig, Germany

(1)
This number is actually somewhat backed up by data we have.
Most of the stars in the milkyway are brown dwarfs, who simply don´t have the radiation-spectrum to support life.

A lot of stars are part of a binary/trinary system, which either blows orbits of planets to hell (if they are orbiting only one of the stars) or forces the plaets too far away, if they orbit the common center of gravity of the two/three stars.

All stars above, say, double sunmass are simply too short lived to develop life.

(2)
The actual number is just a guess, but it took a lot of coincidents to make earth habitable to human life (A Jupiter big enough to sweep most asteroids away, so we have only a big impact every 30 million years or so, instead of every 300.000 years, the giant moon to stabilise the earth-axis and so on)

(3) Simply a wild guess and using the 1000 for three times just looks too good  

Live and the Universe is always evolving, already our space probes and statelite-telliscopes have picked up about 300 planets that have started going through phases of development our planet did in its begging. Though it said that those planets still have millions of years to go before becoming habbitable, that doesnt mean that we still wont be here to view other life come into existance. Though there might not be much in our galaxy(being one of the lesser dense ones), there might be something out there in others.

Who knows?

For the space mission program, i would rather wait. I mean it will take them at least 2 decades more to really perfect space station construction and colonization of the moon. Yes, i think the moon will be colonized before the '20s. After that there will be major development and movement to the other planets. Once the ISS is completed other stations will follow, each one will then be able to refuel and re-supply ships after they are in orbit. Thereby increasing the distance we will be able to go. Now space travel will still take years or months, because even if we do discover light speed(and not create an accidental wormwhole, or mini-dwarf star) it would be dangerous to travel at that speed in a solid object. Every single atom or ion that would hit the hull will be like a mini-nuke explosion.

Dont quote me on anything though, most of this is based what i know(very little), and pure speculation. Still thinking about the future in a promising way is a nice change right?  

your exactly right about the particle-nukes at such high speeds. but it isnt true that so called "light speed" would be nescessary to colonize the universe. relativity basically states that if you go fast enough, everything will flatten to the point that you can basically move to the other side of the galaxy simply by flattening it to the size of a nickle.

fun eh?

and
Y=
where

L0 is the proper length (the length of the object in its rest frame),
L is the length observed by an observer,
Y is the Lorentz factor,
v is the relative velocity between the observer and the object, and
c is the speed of light.




basically what this means is that as v->c (which it cannot overtake) L->0
just thought you would find this tidbit interesting. means I can flatten the universe to a pancake and move just a few inches to get to alpha centuari

Wow... i read that somewhere in a book, i think it was by Asimov, he explained it almost like that. Except light still travels too slow for us to move across too much space. Our best bet is to prove that wormwholes exist and then find out how they occur and harness that power. We would be able to open then at will then and travel to the other ones around the galaxy. Sure it wouldnt be too accurate, but untill we discover fussion then its our best bet. To make that equation possible you would need SO much energy, probably equaling that of the sun maybe even more.

2 words gentleman... Space Elevators

Except light still travels too slow for us to move across too much space.

thats hardly a problem. light isnt tied to a single inertial reference frame (I.E no matter how fast your going, light STILL is going 3.00x10^8 m/s in relation to you)

the only real problem with it is that it requires an INCREDIBLE amount of energy, like way WAY more than is really feasible. this would require a 100% efficient matter->energy engine to even be worth considering for short distances. (i.e. a few hundred thousand light years)

To make that equation possible you would need SO much energy, probably equaling that of the sun maybe even more.

well, not for getting to alpha centuari... but if you want to cross the known universe, yeah, probably even more than that.




one quick question, in my earlier post one of the pictures appeared to have changed to a "physics forum" banner... is that only me? because I'll fix it if I have to.

2 words gentleman... Space Elevators

???
whats this got to do with space travel? thats just getting into space, thats more than easy enough.

wait a second... we had an arguement on the old forum about the space elevator didnt we...

Space Elevators would help us. We would be able to diliver matterials into orbit, and then from orbit we would be able to construct ships much larger than those we could under the restriction of our gravity. We could also deliver more fuel and necessary equipment for outgoing or ingoing voyages.

What i meant by too slow is that at this moment the light leaving our sun will still take a decent amount of time to get to alpha centauri. But, its better than nothings.

Space, a fun place to visit, but I wouldn't want to live there. Imagine a rainy day, a really really rainy day where it was really cold too. Whether so bad that you can't go outside (or really really don't want to). So you have to stay inside all the time. Don't you hate days like that? Well, that is what living on a space station or moon colony would be like - every day! I think that the novelty would wear off pretty quickly. I like being where I can go outside and go hiking, or for a run. Where I can lay out at night and look at the stars and see shooting stars (no shooting stars in space). And I think a lot of people would feel similarly cramped not being able to feel the wind or rain, never getting a breath of fresh air, and never seeing wild plants and animals.

For that reason I think that habitation on the moon and elsewhere will be confined to utilitarian purposes. Just like at present the only people on the ISS are people who are working there, on the moon it will be the same. Only workers for a refueling station or whatever else they build will live there. Kind of like a deep-sea oil rig. The crew lives there while they are working but comes back to shore when they aren't. People aren't going to live there just because they can.

means I can flatten the universe to a pancake and move just a few inches to get to alpha centuari

Sounds like a bummer for everyone else though. How would you like it if someone squashed your universe into a pancake? Would kinda tick me off

People aren't going to live there just because they can.

I would go for the novelty of it! true enough you cant go hiking and stuff, but that is completely outweighed just by the concept.

What i meant by too slow is that at this moment the light leaving our sun will still take a decent amount of time to get to alpha centauri.

your thinking in terms of a fixed reference frame. that doesnt apply here.

c relative to your own motion is not modified by your speed. i.e. the velocity of the light from the sun c is not going to change because your velocity is v. even if your "rocketing thru space" at "several hundred thousand m/s" your STILL going to register the speed of light as c, even if it is emitted by a third party who is "standing still"

note the location of the ""s

think along these lines: your in a boat flying along over a river. you dip your finger in and it creates a SPHERICAL ripple, unnaffected by the speed you are moving. in this case the lake is the preserved reference frame, the ripple moves relative to the water, not the boat.

now, light works like that except that no matter how fast things are moving relative to the observer, the "prefered" reference frame is always with the observer (or rather, the observer observes his reference frame to be preserved, although other people would see his reference frame as severely incorrect)

Well then why is there a measurement of light years and such. Doesnt light still take time to travel from place to place. The light leaving our sun takes 8 seconds to travel to the Earth, however light is always traveling from the sun so there is a constant stream of it.

What about a supernova, we might still think that sun is there because the light has to travel for so long the last death throw of the star followed by the super nova hasnt reached us yet.

Well then why is there a measurement of light years and such

its relative movement. I can be moving 20 mph compared to you, but 0 mph compared to the road beneath my feet.
actualy this proves my point, this absolute speed X a specific time measurement=the distance of time. and that is lightyears. but a lightyear to me may be half a lightyear to you, depending on if we are moving at comparative relativistic speeds.

leaving our sun takes 8 seconds to travel to the Ear

for us it does, but not for someone moving at relativistic speeds in comparison

What about a supernova, we might still think that sun is there because the light has to travel for so long

now, if I move fast enough to flatten the universe to the size of a pancake, then it wont have to move so far!



really think about what your trying to argue. your saying that we live in EXACTLY a PERFECT reference frame in which the universe's information moves in perfect synchronization with us. this is the same exact thing like saying the sun revolves around us, except much much broader.

if light had an absolute limit our universe would act VERY wacky. first of all adding enough energy to something would allow it to exceed the speed of light, which would be really REALLY wierd. second of all unless we lived in perfect (or very near perfect) synchro with light's prefered reference frame then shooting a beam left would go slower or faster than shooting a beam right. which isnt true.

and besides. what medium would light travel through? pressure travels through air. ripples through water and solids, but light doesnt have a corrosponding medium. it was proposed that "ether" existed in which light traveled through, that planets would sweep through this medium and twist it with their motion. but that doesnt exist, if that was true absolutely none of our technology would work, just the movement of earth would cause electromagnetic interference that would disturb interaction of matter significantly.

I need to make a clarification for the sake of explanation:
all my statements are made from the position of the object thats inertial reference frame is changing.
agh god... this is getting way too hard to explain in type   

Light tavels in wave lengths through something, we dont know that something, but most are certain its matter.

As for me trying to argue, i am not im just asking question to see if your theory holds so far it does.

Wave Particle Duality

granted its a theory, but its not my theory. question Einstein if you want to see if its true.
under all tests so far relativity holds up under it's current setup. its only known problem is that it doesnt integrate so well with Quantum Mechanics.

All theories are proven wrong with time, we thought the atom was the smallest particle 20 years ago, we know that now we are wrong. We dont know the universe that well yet to say anything. Our progress is stifled by human error and the fear of progress. Einstein was a great man, but though he was the brightest mind of his age, it was an age that has faded. We dont know if hes right or wrong, so far his theories hold and well thats because no one has proven it wrong.

no fundamental theory is ever proven wrong. see, this is what stifles progress.

if you ask a scientist why he works, even if his work will be overshadowed some day, he'll tell you that its not being right that matters, its being the next step in an eternal progression.
besides, its quantum mechanics thats so far incomplete, they need a better way to describe gravity.

Not true, ofcourse it matters what time period you start from. The only "theories" that havent been proven false are the natural laws of science, like gravity, or living things being made out of cells.

But, i dont know much about this subject anyways so ill refrain from stating a true opinion. And what other way would there be to describe gravity.

well, true enough that in the medieval ages and prior there were some wacky theorys, but for the most part anything after is built upon, not proven wrong.
you dont build a skyscraper by tearing down all floors when you want to build 1 more.

The real problem isn't that we don't have the technology to expand into space, its just that the governments have so many more "important" things to do.

Yes, i think that the world needs one more war to truly unite, hopefuly union can happen without war. But, it seems that people only learn well with negative reinforcement.

frankly the real spacerace is already in motion. we have the clear headstart, but thanks to a bunch of knownothing politicians (cough, UN, cough) we aren't allowed to use nuclear warheads in space.
that UN resolution needs to be repealed before any real space travel is possible.

What do you mean, what use will nuclear warhead be to us in space. Maybe nuclear reactors but that wont be practical.

nuclear reactors aren't really usefull, what would they do for us? absolutely nothing.

the concept of the nuclearbomb-plate idea was that you would have a spaceship with a large, flat plate at the back. you would blow up nuclear warheads behind the ship and propel it forward, far more efficient than our current system.
stupid UN, stupid ultra-liberalism
sorry, but you do have to see this