is interstellar or intergalactic travel at all possible

[Lekgolo555]

Is it possible at all to travel to other planets and star system in a convenient time span?

 

I feelings are that civilization has to colonize other planets in order to survive. We are already past the carrying capacity of earth, and it does not look like we a slowing down.

 

Without faster than light travel we are doomed :eek: :eek:

[[Tycho?]]

Other planets, yes. Other stars? Not for quite a while.

[Janus]

Is it possible at all to travel to other planets and star system in a convenient time span?

 

I feelings are that civilization has to colonize other planets in order to survive. We are already past the carrying capacity of earth, and it does not look like we a slowing down.

 

Without faster than light travel we are doomed :eek: :eek:

 

Don't count on FTL to save us from population growth. Even if we had it right now, in order to maintain a fixed population on the Earth, we would have to load people on ships at a rate of 91 million per day.

[Sisyphus]

We are already past the carrying capacity of earth, and it does not look like we a slowing down.

 

Actually, we are slowing down. Growth rate reached its peak in 1963.

[Lekgolo555]

but even still there is not place left to explore or to expand ourselves, and that is what humans need. Except for the ocean. Haha i can just imagine in the near future our society will be like Seaquest.

 

But my main question is interstellar or intergalactic travel even possible?

[Sisyphus]

There is no obstacle except the extreme distance and therefore travel time. It's entirely possible that the best we can hope for is decades or even centuries of travel needed to reach even the nearby stars. As far as intergalactic travel is concerned, the journey could take millions of years, which, I imagine, is far to long a timespan to realistically plan for. If faster than light travel is possible, that makes things considerably better, of course, but it probably isn't.

 

Most likely, outward expansion will take place within our own solar system, and in the form of permanent space habitats. Think about it: if we could design a ship self-sustaining enough to make a centuries-long journey to another star, then why leave the ship at all? We can make our own worlds.

[Lekgolo555]

You mean like a dyson's sphere from ST:TNG

 

So warp drive or quantum slipstream, and hyperspace are all just made up. I always thought there was some sort science behind it. That is very disappointing.

 

Would Mars be good place to live? It is pretty close, but how would we deal with the significantly lesser gravity? I know some of the moons of Jupiter have water on them so maybe those are a possibility. Also we could extract some hydrogen out jupiter's atmosphere right, and that gives us some fusion for heat if we figure a way to use.

[Sisyphus]

A Dyson sphere (which is NOT from Star Trek, which took Dyson's real concept and represented it poorly) would be an extreme example of that, but there's no reason a space habitat need be that enormous. Think hollowed out asteroid, or just very large space ship.

 

The idea behind "warp drive" is presumably to "fold" spacetime around the ship so that it's perpetually travelling a shorter distance. While such a geometry of space is theoretically possible, what's probably NOT possible is actually generating such a thing. (Any even remotely realistic scenario for "superliminal" speed involves not actually going faster than light, but taking shortcuts through folded space or wormholes.) But usually words like "hyperspace" in SF are just shorthand for "magical faster than light engine."

 

And yes, Mars would probably be one of the prime locations for permanent colonies, as would various moons of Jupiter and Saturn. "Mining" Jupiter's atmosphere for hydrogen or anything else is pretty impractical, though, since the escape velocity is so huge.

[Edtharan]

Also we could extract some hydrogen out jupiter's atmosphere right, and that gives us some fusion for heat if we figure a way to use.

Water is made up of 2 parts hydrogen, so why not just use that. Water is actually quite common in the solar system (and presumably others too), it is Liquid Water that is rare, but we can just melt the ice as needed.

[Farsight]

Is it possible at all to travel to other planets and star system in a convenient time span? I feelings are that civilization has to colonize other planets in order to survive. We are already past the carrying capacity of earth, and it does not look like we a slowing down. Without faster than light travel we are doomed :eek: :eek:

 

Yes, it is possible to travel to other planets and star systems in a convenient time span. But it would take a whole pile of resources to do this. You would need very large ships accelerating to huge speeds requiring enormous energy. Then time dilation reduces the elapsed journey time as experienced by the voyagers.

 

The thing is, it would be a whole lot easier to get our own house in order down here on Earth. All people have to do is have fewer children. It's that simple. Oh and cut out all those foreign holidays. And live closer to work. And share a car. And eat local food. All the easy things. Sadly if people don't pay attention to all this, nature will. With increasing population and increased travel, the likelihood of some sweeping pandemic increases every year.

 

But hey, look on the bright side. You won't be saying Eek Eek Eek, because you'll be coughing your lungs up.

[Kojiami]

And, what makes folding spacetime inpossible?

[Realitycheck]

In China, they have already had laws in place for a while limiting families to one child. If this is adhered to worldwide, the population goes down. Kind of wishful thinking, but if it came down to it, we might overcome all of the dogmas and adapt, or Thomas Maltheus will have his way with us.

 

I checked out this website supported by NASA explaining the pitfalls of interstellar travel. Some of the arguments they made regarding the use of traditional types of fuel seemed a bit sketchy. I am not a rocket scientist, but, theoretically, shouldn't it be possible to propel yourself from space using a minimal amount of fuel just to get up to speed and, without any resistance in space, coast as far as you want? I know that there are more optimal fuel sources in mind, but it seemed kind of overboard when they said you would need a billion tankers of fuel to get to the next star system.

 

Also, they say that if you ever get to the point where making your own wormhole is possible, your ship better have some pretty good shields, because it will have to survive temperatures in the millions of degrees.

 

http://www.nasa.gov/centers/glenn/research/warp/scales.html

[Sisyphus]

I am not a rocket scientist, but, theoretically, shouldn't it be possible to propel yourself from space using a minimal amount of fuel just to get up to speed and, without any resistance in space, coast as far as you want? I know that there are more optimal fuel sources in mind, but it seemed kind of overboard when they said you would need a billion tankers of fuel to get to the next star system.

http://www.nasa.gov/centers/glenn/research/warp/scales.html

 

The assumption is that you want to get there in some kind of a reasonable timespan. An Apollo rocket could travel between the stars, it would just take hundreds of thousands of years (for the nearest ones).

[Edtharan]

The assumption is that you want to get there in some kind of a reasonable timespan. An Apollo rocket could travel between the stars, it would just take hundreds of thousands of years (for the nearest ones).

We have already created space ships that will travel to other star systems and launched them. They are called the "Voyager" and "Pioneer" spacecraft. The problem is that they will take thousands upon thousands of years to do so. Not a reasonable amount of time.

 

These small craft are not very big (The Voyager are around 700kg and the Pioneer are around 200kg) and yet they still took the largest rockets available at the time to launch them.

 

A space ship capable of carrying enough people and resource for a self sustaining trip to another star system would most likely weigh in at several million kg. We have nothing that could launch such a vehicle. It would take an enormous amount of resources to build such a craft in orbit (just look at what it is costing to build a space station - that is not even self sufficient - in orbit of the Earth).

 

So, we already have space ships on their way to other star systems, but to build one that could carry people is far beyond us at the moment.

[grifter]

With ever improving engine systems of Rockets, it is now possible to propel large payloads in to space, I've heard a couple of ideas being flung arround about transporting "sections" of space craft in to space and assembling there, making one Huge "space ship" capable of transporting colonies of people in a sustainable state to other habitable areas:

 

this idea in theory is great BUT:

1:/ There are (at present, known to us) no areas worth sending people to.

2:/ Due to the long journeys chances are people will DIE therefore making it nescesarry to reproduce, not the most practicle thing to do in space...

 

feel free to add to this list, it could go on forever, it will take HUGE advances in technology before we can realisticly sucseed in colonising other planets let alone traveling to other solar system etc etc etc

[Klaynos]

I am not a rocket scientist, but, theoretically, shouldn't it be possible to propel yourself from space using a minimal amount of fuel just to get up to speed and, without any resistance in space, coast as far as you want?

 

There is a greatly reduced friction in space, but there is still alot of particles, even in inter-stella space which is what you'd be travelling through.

 

You've also got to remember that you are moving away from the sun, so for about half of your journey (depending on what star you're heading too) that is going to be offering resistance to your motion.

[jackson33]

there are about 25 stars, 4 to 20 light years from our solar system. in theory then, if we achieve .5 C the travel time to the closest would take about 8 to 10 years to reach the closest. as for manned space flight outside our system, for a number of reasons other than time will need addressing. number one, some real form of gravity to keep the body in tack, from both acceleration and long time zero gravity effects.

 

think for obvious reasons actual manned missions will be a very long time coming. probes, especially as equipment for testing and observations are improved these efforts will increase.

 

as for over population, of the planet earth; we are far from this limit IMO.

at 6.5 billion, we have plenty of unsettled space. people in general seem to have little problem living in dense population areas. last i heard all the planets humans could live in Texas, yet not be as dense as NYC, Mexico City or a number of current urban areas...

[Sisyphus]

2:/ Due to the long journeys chances are people will DIE therefore making it nescesarry to reproduce, not the most practicle thing to do in space...

 

You have some experience in that area, do you?

 

number one, some real form of gravity to keep the body in tack, from both acceleration and long time zero gravity effects.

 

I think "artificial gravity" is the least of our problems. Just spin the ship. It's not even limited to large ships - you can attach it by long cable to a counterweight, and have them "orbit" each other.

[jackson33]

think spinning a craft moving .5C and capable of carrying all that would be needed would be a little more than "just spin". NASA, as i understand it has pretty much dropped the idea. if centrifugal force could be useful, space stations in the future will no doubt take advantage.

[Sisyphus]

What does moving at .5C have to do with it? And how can NASA drop an idea for an interstellar craft it's never had plans to make?

[SkepticLance]

The biggest problem with space travel is leaving Earth's gravity well. The best idea in theory for doing this is a space elevator, which is already being worked on. Last I heard, the researchers had built a suitable cable one mile high and lofted it by balloon.

 

We need a ribbon shaped cable 78,000 km long. One end is tethered to the ground and the other is holding the whole thing taut by centrifugal force. 'Trains' travel up and down the ribbon. If magnetic levitation techniques develop sufficiently, travel up and down can be at extreme speeds. It may be that a suitable elevator may be in place within 100 years.

 

Once the first is up, it makes further elevators much easier to construct. There is no theoretical reason we cannot have 100 or more elevators. That could lift into space any number of millions of people.

 

Using the elevator means getting mass into space easily and cheaply. We can then build the habitats that Sisyphus so ably described. Once a habitat is built, there is no reason it must stay near the sun. In that 100+ year period, we should have good nuclear fusion generators of electricity. One per habitat would supply all its energy needs.

 

A Scientific American article some years ago by two NASA scientists suggested that humans will eventually be able to travel at 0.1 to 0.2c. If our habitat shot off to Alpha Centauri at 0.1c, and took 10 years to accelerate plus 10 to decelerate, the entire journey would be 55 years. Once there, it could access debris in space for resources, and perhaps the people could build a second habitat. etc.

 

Using these techniques and these numbers, humans could populate the entire galaxy within a few million years.

[geoguy]

The amount of energy needed to move a spacecraft of any reasonable size to half of c would be multiples the amount of energy mankind has ever used to date. Then it would take an equal amount of energy to slow it down again. It would also be made of ????...hitting a speck of dust at half of the speed of light would release more energy than all the nuclear weapons on Earth.

 

One day we may hope for a 20th or so the speed of light. There is nothing, however, in material engineering to date that would allow stable performance of matter at such a speed without imminent doom.

 

It's no just a matter of saying we could do a tenth of the speed of light one day and that would be 50 years to the nearest star. The acceleration would take multiples times that to get to the top speed and the slowing an equal long process.

 

We're also assuming there is some reason to go to the nearest dozen stars.

[Sisyphus]

Designs like Bussard ramjets or light sails, though perhaps not practical in any form that's been discussed, are at least close enough to tell us it's somewhat premature to say it's impossible. The ramjet in particular simultaneously suggests solutions to two problems: a) you don't have to take fuel with you if you can use what's already there, and b) "what's already there" could include stuff that would otherwise cause tremendous damage.

[SkepticLance]

To geoguy.

 

Because something is not possible today does not mean it will be impossible in 1000 years. The NASA scientists writing the Sciam article were clear in saying that up to 0.2c is theoretically possible. They predicted we would be able to do it in 500 to 1000 years.

[geoguy]

To geoguy.

 

Because something is not possible today does not mean it will be impossible in 1000 years. The NASA scientists writing the Sciam article were clear in saying that up to 0.2c is theoretically possible. They predicted we would be able to do it in 500 to 1000 years.

 

I didn't say it as impossible. Where did I say that? What is reality is the physics. The amount of energy needed is not 'fudge' science and the potential energy of any particle hitting another and releasing huge amonts of energy is not 'fudge'. They are basic requirements of the physical properties you should have learned in high school physics.

 

Comparing your .5c to a possible .2c is the equivalent of comparing a grain of sand to the galaxy...there is an exponential difference in energy requirements to accelerate matter as it increases. Even the energy released in a collision of a subatomic particle of almost zero mass in a partical accelerator is detectable.