some kind of fuel for there spacecrafts. we have plenty of it, its not like well notice it. so maybe they just consider earth as a pitstop, with the exception of picking up a souvenir or two and a crash of course.

yeah that could be possible. But highly unlikely. If time slows down more as you go toward the speed of light and stops when you reach 100% the speed of light then it would be stupid to think this. If they can travel billions of light years to another planet I highly doubt they do it just go get some oxygen. I mean if the rules apply the same in all the universe then they could make oxygen from some stuff in their space ship if they had to. Also time means nothing if you can travel at the speed of light....which yeah i guess you would have to have an engine that some how gets you at the speed of light but still. I hightly doubt it would use oxygen. if that's so why don't we think of that and try it?

sounds possible and cool

well hombreconunpollo, i understand time slows down as you reach the speed of light, like you wrote. it still doesn't mean that they still might need it for something. and as for making it, i guess thats where we differ from then.

If aliens needed oxygen how would they get to earth in the first place? It may be possible, but I do not think it is very probible.

im with hombre. if they need oxygen, make it. its not exactly that hardest thing to do. besides, wouldn't it be smarter to just take part of it with some trees and produce their own or something?

Oxygen is an element though, I didnt think you could create the elements. Well I know that we cant :S

A very interesting Idea, I'd like to see scientists tell us that oxygen is light enough and powerful enough to fule a jet plane, let alone a space ship...lol they use Liquid Oxygen for the space shuttles, but because oxygen freezes at very low temperatures, in space it would be like liquid-solid oxygen...lol then that would be heavy...haha...

They could always find a lot of Hydrogen peroxide solution (H2O2 (aq)) and wait for it to decompose to create the pure form of Oxygen (remember Oxygen in our atmosphere also contains nitrogen and carbon dioxide and other gases so it would make it even more heavier). But the problem with this, is that Hydrogen Peroxide takes agesss to decompose for so little...but using catalysts...i.e. Manganese (IV) Oxide could speed up the reaction dramatically...that also depends ont eh concentration of Hydrogen Peroxide.

It's a good Idea to have a level, like in the middle, top or bottom of the ship to have a whole forest in there, but they would have to provide sun-light like lighting,to trick the plants into thinking it's day so they take in carbon dioxide and produce Oxigen...but then, they would have to balence it to half of the time...like every 12 hrs switch off the lights to let the trees and plants to breath in their belovid carbon dioxide. Not only would this be a good idea, it is a great place to relax and enjoy yourself...

Phoenix

[edit on 18/7/04 by PhoenixSGC]

Originally posted by racos
Oxygen is an element though, I didnt think you could create the elements. Well I know that we cant :S

it can be converted though.

i kinda agree with most of what you guys are saying, but theres just alot of holes in them, phoenix i think is right you'd need alot of caring for the plants to make them be useful. and whos to say that having trees is enough. maybe they somehow can better pressurize the oxygen that we have when there flying so fast, almost like how a jet works but it doesnt release it just stores it away.

Well, since most of our atmosphere is made of Nitrogen (I think about 60-70%) I highly doubt it, but you never know there either!

aye, if time stops when light speed is reached, then why do radio transmissions to and from Mars craft take 20 minutes each way?

lol SGC, designing your own spaceships?
Also, oxygen would not be used on fusion, fission, antimatter or ion propulsion engines, so why do you believe it necessary?
Do aliens still use combustion rockets like the old Russian rockets and US space shuttles?

- Tass

Originally posted by Tassadar
aye, if time stops when light speed is reached, then why do radio transmissions to and from Mars craft take 20 minutes each way?

If you were traveling the speed of light then time would indeed stop for YOU but to everyone else (not traveling at the speed of light) time would continue at the same speed. So according to the people on earth it takes you 20 minutes traveling at the speed of light to reach mars but according to you it was an instant travel from earth to mars. Time is relative to the viewer.

Anyhow, aliens coming here for our oxygen doesn't really make much sense. Why would aliens build their ships to operate on a fuel that they have a shortage of? Surely there must be some other fuel source on their home planet they could use that doesn't require them to travel possibly hundreds of light years to get.

And I'm no expert but I don't see how a rocket engine that would take advantage of oxygen as its fuel would even be able to reach the speed of light. The amount of oxygen needed to reach that speed if possible would be very high and if the aliens already had a shortage then surely using oxygen to power their space vehicles should be their last choice.

I would disagree with the statement time is always relative, however, I believe this merits another a thread.
- Tass

Whats there to disagree with? It's been proven many times. It's basically the basis for Einstein's theory of general relativity.

Well time relativity has been proven but general relativity/special relativity covered more than just that and I assume some of those parts are still unproven or/and new data has come to light that shows a more accurate view then what Einstein had first envisioned. So I referred to it as the "theory of general relativity" because I assumed some parts were still unproven but that doesn't mean the whole thing remains unproven.

On another note that link you provided doesn't work.

It's apparent gas/chemical fuels are not the way to go in the future.

Any craft would more than benefit from a nuclear type propulsion system. This would include either fission or fusion.

Fusion would be the ultimate long term solution as it merely runs off of readily available substances (deuterium, found in oceans) or Helium-3(abundant on our moon, which could be mined...hrmm...?!!! maybe someon else is already doing this)

But, not enough research has gone into fusion, it is a technology far from perfection.

well in my question that i posted, i never said the ships soley depended on oxygen, but maybe it makes up for a part of what they need, maybe sometimes they need a fillup on what inside of oxygen, i dont know the scientific things that inside oxygen or what it can be used for. but maybe they have something that can convert what they need from it like i wrote before, but we def. dont have the ability to as of yet