Reasonable people agree that Earth dwellers will not achieve the technology to visit other solar systems anytime in the forseeable
future. But our sun is pretty far out on one of the Milky Way’s spiral arms. Toward the
center of the galaxy, aren’t the stars much closer together? How close together are they? If a civilization with technology equal to ours were located closer to the center of the Milky Way, couldn’t they travel to other solar systems?
Actually, Sputnik, we do have the technology to reach the nearest solar system. Alpha Centauri is only 4.3 light years away, so we could get there in under a decade with our current cutting edge technology.
So, yes, if alien solar system A was even closer to alien solar system B, they could make the trip.
To travel 4.3 light years in a decade, you’d have to travel at .43 the speed of light which roughly translates to 80,000 miles per second. Well beyond human technology, cutting edge or no.
Nickrz:
It might be possible in a decade (I prefer 50 years.)
It depends on how many and how powerful the atom bombs are that you spit out the back of your Orion spacecraft. You better have a damn good shockabsorber, or else you’d just be smashed into grape jelly by the time you got to A.C.
.43C is well below the cosmic speed limit, and theoretically achievable with today’s (or 1945’s) technology.
One scientist (on a program on space travel on “Discovery,” I think) mentioned this cosmic roadblock:
To go to any star, you would need to travel at some “significant percentage” (my paraphrase) of the speed of light.
Even once you’ve been decelerating for a while, as you’re approaching the new star’s Oort Cloud, you’re still traveling so fast that the dust particle would tear your ship apart.
one major problem would be slowing down once you got there. if you hit their ort cloud at .43c you would be impailed by tiny dust particles. you would need to use the same amount of fuel to stop as you used to get there. (i got this concept from a TLC–or maybe PBS-- show about interstellar travel.)
eggo
Deflector shields baby, deflector shields.
Didn’t you see Star Wars?
Seriously:
If you kick atom bombs out of the back of a ship where they push aainst the back of a giant ablatable “Plate,” (Orion Spacecraft)
Once you turn the ship around, the plate protects you against minor particles.
If you hit a comet head on… well… that’s another story.
Often wrong… NEVER in doubt
In classic, “impulse” power science fiction stories, the interstellar spacecraft would accelerate constantly, and when half way there, would flip over 180 degrees and spend the rest of the trip decelerating. I think it would be tough to average .43c for the entire time.
Is that ten years in ship time, or for the losers left back on earth? How long a trip is it for the astronauts?
Back to the original question. Does anyone know how close together the stars are toward the center of our Galaxy? Are they less than one light year? Is that an achievable interstellar travel distance with current, off-the-shelf Earth technology?
Well … the stars are closer. There’s the rub. Some people have theorized that the center of the galaxy is a large black hole. Even if not, the levels of radiation from closely packed stars might make life infeasible.
It’s difficult to say what we could reach with a manned mission with current technology. Mars (despite current evidence to the contrary), probably. The edges of our solar system – probably not.
So you could probably rephrase the OP as
“If there were a sun-sized object with its own planets at the distance of Pluto, would the orbits of the planets be stable? Would the amount of thermal and solar radiation be too much to support life?”
Has anybody else heard of the Orion Spacecraft. The design is really simple, and it was first proposed in the 1950s.
It could be built today.
Here’s a link to this badboy:
http://imagine5.com/FAQS/spacecraft/faq0002.html
Often wrong… NEVER in doubt
I think Finagle has found the major objection to the idea suggested in the OP. If the stars are close enough together to be within commuting distance, so to speak, they will be close enough to disturb planetary orbits significantly. On earth, anyway, our biology requires a stable, circular orbit at just about the distance we’re at. Any significant changes would drastically alter earth life.
Assuming there is some extra-terrestrial biology that is not similarly constrained, then I suppose communication and/or travel between planetary civilizations is more likely toward the galactic center.
Near Trantor, perhaps.
“To do her justice, I can’t see that she could have found anything nastier to say if she’d thought it out with both hands for a fortnight.”
Dorothy L. Sayers
Busman’s Honeymoon
Another Project Orion link. They were working on (non-nuclear) prototypes 50 years ago.
http://www.friends-partners.org/~mwade/articles/probirth.htm
Perhaps aliens are catching a glimpse of our planet through their most powerful telescopes, and asking themselves the following:
“Could there be life on that third object from the star? It would seem that the bath of cosmic and UV rays is too intense for anything to survive. And with so many planetary bodies, moons, asteroid belts, and roaming meteoroids in the system, there’s no way life could have evolved.”
I think the development of life under conditions that we consider adverse is perfectly feasible. Thermophilic microorganisms such as archaea survive in extremely hot and acidic environments. Some of them survive on materials that we can’t metabolize, such as sulphur, and they don’t require organic carbon. Was it Clarke that said, “Life will find a way”?
On the topic of accelerating an object to a significant percentage of the speed of light in order to reach other stars, the problem is that even at high acceleration it would take an extremely long time to hit, say, 20% of the speed of light (which would get you to the nearest star in 21.7 years or more of Earth time IF you started and ended the trip at that speed). In the process of attaining this high velocity, the acceleration force of the ship might squash the human passengers like so many bugs, or place too much stress on the structure of the vessel. We need someone to invent those inertial dampers before we can step on the gas, otherwise it will be the slow way all the way.
Once you go very fast there is the problem of slowing down. As has been mentioned, the maximum rate of deceleration cannot exceed the maximum rate of acceleration, so there you go again squashed like a bug. In addition to that, you might want to add several years to the trip, to allow for acceleration and deceleration.
Then there is the problem of fuel for the starship. Unless they find a way to tap so-called vacuum energy, I don’t see how one can carry enough fuel material to A) accelerate to such monstrous velocity, and B) decelerate.
Finally, even space dust would wreck a starship travelling at 20% of the speed of light. Assuming that you could deploy “force fields” to protect the ship from the deadly particles (and bigger sized objects, like meteoroids the size of a pea), your force fields would literally be getting sandblasted and could not last very long.
I have no doubt that in the future we will attempt to reach other planetary systems, but it will probably be a long time from now and by the use of generation ships, or giant spacecraft carrying entire communities within them–because the ones who set out on the journey will be long dead at destination. Unless someone develops suspended animation.
If, if, if.
Abe
IDIOT, n. A member of a large and powerful tribe whose influence in human affairs has always been dominant and controlling.
–Ambrose Bierce
APB–at .43 lightspeed, relativistic effects would be noticable but small. I don’t have the formula in front of me, but my WAG is that maybe 8-9 would pass for the astronauts while 10 passed on Earth.
Please explain where you will get enough fuel to accelerate an Orion type spacecraft to .43c and deccelerate at the destination.
A quick look at the rocket equation shows that you need significantly more uranium/plutonium as fuel than the mass of the solar system. This does not seem achievable in 10 years, whether one prefers to think of it that way or not.
This idea (that we could pull off a 10-year mission to Alpha Centauri with today’s technology) seems to be quite common in the ‘space advocacy’ community, but simply ignores physical reality.
Not merely with present technology, but with any drive system we know is physically possible*, achieving a significant fraction of c is simply impossible if you carry your fuel on the spaceship. We can’t really come up with a way for ramscoop engines to work, light sails powered by lasers from home accelerate very slowly and require the people at home to keep on going, and mass drivers firing fuel at starships have similar problems plus are much harder to aim and have a difficult time at high speeds.
The straight dope is that anyone who tells you that we can achieve a significant fraction of c with present technology either doesn’t know what they’re talking about, is making it up, or should give me some of whatever they’re smoking.
- Things like the Alcuberrie (sp) warp drive require exotic materials like matter with negative mass, which are not known to be possible.
Kevin Allegood
Riboflavin:
I think you only looked at the 1st page of the link I provided which describes a ship suitable for scooting around the solar system.
I think 50 years could be done, and so apparently did Carl Sagan in his book Science A Candle In The Darkness.
10 years MAY be possible.
The idea behind Orion is that you build a habitat, attach it to a REALLY good schock absorber which in turn is attached to an ablation plate.
You set off a nuclear bomb right next to the plate. If you are smart the explosion is channeled so that most of the force is directed against the plate.
A nuclear explosion converts mass to energy according to the formula E=MC (squared.)
This comes out to Very Big numbers.
The lighter your ship, and the faster you chuck bombs out the back, the quicker you go.
The problem here is not the ability to accelerate or carry enough mass, but rather stopping the plate from ablating to quickly, and developing the Shock Absorber so that passengers arrive intact.
10 years is a WAG of mine, but 50 is pretty close to Sagan’s #.
Argue with Sagan, not me. I understand he’s available at your local Deity.
Often wrong… NEVER in doubt
I personally like the method that they used in the movie DUNE. Folding space, travelling without moving. If you could create a gravitational force large enough for you to distort space, in esscence curve (fold) space than you may be able to cut your traveling time significantly. 
There are only two things that are infinite…the Universe and Man’s stupidity…I’m not sure about the Universe though.
Fuel is a problem, but at a steady acceleration of 1G, it is only a matter of months to get to a respectable fraction of the speed of light.
John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams