Requirements for Light Speed Travel (as we understand now)

[wcdrotar]

Hey y'all,

I've been lurking for a little bit and just reading since I'm not as knowledgeable as many of y'all. I'm a university student preparing for web design/database administration but consider studying physics/cosmology my (only) hobby.

My question is about the requirements for light speed.

Some say it is and will always be impossible- could you explain your reasoning?

Some say it may be possible but there are seemingly paradoxical obstacles to overcome, or obstacles that we may never discover how to work around them. What do you think about what we'll have to do?

As it stands there's almost no question in my mind that I don't think we'd ever be able to actually just propel ourselves in the traditional sense of traveling to speeds anywhere even close to light. Even with new fuels that we've developed we can't construct metals strong enough to not burn up in the engines that contain them.

Assuming we can make it around our small solar system using traditional fuel propeling methods of travel- what changes in space travel would have to be developed to allow us to travel to say the closest planet in a Goldilocks zone?

I'm not talking about objects or rockets I mean actual shuttles.

 

[Ken G]

Assuming we can make it around our small solar system using traditional fuel propeling methods of travel- what changes in space travel would have to be developed to allow us to travel to say the closest planet in a Goldilocks zone?

The problems are energy, and survivability. With enough of an energy source, a shuttle could be made to go arbitrarily close to the speed of light, but you'd be spending an awful lot of energy just to make the trip shorter onboard-- it would still be a long trip for those waiting back on Earth (remember, time dilation can make the trip arbitrarily short for the people on the rocket, but only very very close to the speed of light). But if you're only goal is to make the trip short onboard, and not back at Earth, it makes a lot more sense to just invent a kind of stasis, like they used in Planet of the Apes. Then it really doens't make much difference if it takes 100 years or 1000 years, if it's longer than an Earth lifetime (I could imagine some scientists volunteering to go into stasis on Earth to wait for the outcome of the mission).

But survivability is a huge problem too. The acceleration would need to be gradual to be survivable, and that really limits how much you can shorten a long trip even with unlimited energy. And, at super-high speeds, space dust is deadly, and systems still have to operate for hundreds or thousands of years with only robotic maintenance (or technicians could be brought out of stasis temporarily). You could even imagine a robotic effort to transport human fetuses to a potentially survivable planet, and that might overcome some of the ethical problems associated with what is probably going to be a suicide mission. There's no easy way to test a mission that takes thousands of years, it would make more sense to send out 100 such missions just in the hope that one gets through. One could even go sci fi and imagine scenarios, like if an overpopulated Earth made a law that couples could only have two children, and any babies after that get put into stasis and sent into space. I frankly can't see how you're ever going to have a conscious, aging, human crew on a mission to a distant star, unless you can make life onboard rewarding, and go the many-generations approach.

Of course, if you find a way to do it, and can find many suitable planets, the sky would be the limit. It can't be too easy, or else in 4.5 billion years, somebody would already have done it to Earth-- many times.

Crossing again into sci fi, one might speculate that a mission like that need not send humans at all-- just the genetic seeds that might be expected to one day evolve into humans. Planned panspermia, the ultimate sociobiology.

 

[wcdrotar]

Thank you Ken, and very good points. It's obvious you've thought about this quite a bit.

By the sounds of it we're a long ways off from colonizing other planets. Frankly I'd look forward to that as our crowning achievement.

My biggest concern is that overpopulation or us destroying our atmosphere and planet (perhaps the earthquakes have something to do with us) will make the Earth uninhabitable before we figure out how to do so. If we could all work together (instead of each country trying to spend billions of dollars to put their own flag on the moon) and realize that our continued existence depends on reaching this goal I think we'd be able to get it in perhaps a couple hundred years or less. As it is right now we're quite confused and almost no one realizes how important that is.

I DO think there will be plenty of educated individuals willing to embark on a space mission with no promise of success or return. Especially single doctorate students and scientists. The sense of adventure is part of being human, and I think plenty of people would be willing to trade a seemingly grim and hopeless life here for the adventure of exploring space.

I imagine we'd need to establish something on Mars as a testing platform first.

 

[Ken G]

By the sounds of it we're a long ways off from colonizing other planets. Frankly I'd look forward to that as our crowning achievement.

I agree on both counts-- it is such a spectacularly difficult undertaking, it's almost like the universe is set up to award that as its highest prize for its most difficult accomplishment. I suspect it is only accomplishable by the most worthy of species, and that jury may be out on us for many more centuries. If we do it at all, I doubt it will be done in a thousand years, but I'm just guessing.

My biggest concern is that overpopulation or us destroying our atmosphere and planet (perhaps the earthquakes have something to do with us) will make the Earth uninhabitable before we figure out how to do so.

Yes, even though the timeframe is probably quite long, it is likely not so long that natural disasters, or other such things that are outside our control, play a key role-- if we fail to accomplish it, it will probably be ultimately our own fault. Come to think of it, whether or not we've reached it, this is an important moment for any species: the moment when their technology is advanced enough such that, if they never succeed at colonizing distant stars, it will be their own fault. Whether or not we are there yet may depend on what nature has laid out in terms of the next energy source, because at the moment she does not appear to have made things too easy on that score.

If we could all work together (instead of each country trying to spend billions of dollars to put their own flag on the moon) and realize that our continued existence depends on reaching this goal I think we'd be able to get it in perhaps a couple hundred years or less. As it is right now we're quite confused and almost no one realizes how important that is.

It's possible that we're not developmentally ready. I'm not sure if the right metaphor is "the clock is ticking and we need to figure this out before we go extinct", or "we are still sociologically children who haven't got the maturity to address that undertaking yet, and should instead concentrate on more immediate concerns like greed, war, and overpopulation." Personally, I think interstellar technology is too far away to make that a goal at the moment, we need the next energy source to be our main goal, along with ways to guarantee that everyone is more willing to tolerate the status quo than to go to war to change it.

I DO think there will be plenty of educated individuals willing to embark on a space mission with no promise of success or return. Especially single doctorate students and scientists. The sense of adventure is part of being human, and I think plenty of people would be willing to trade a seemingly grim and hopeless life here for the adventure of exploring space.

Yes, future pilgrims will probably be more or less like past ones!

I imagine we'd need to establish something on Mars as a testing platform first.

That's debatable-- the Moon is probably better. It may have just as many basic resources as Mars, with less gravity to fight when launching rockets. There's very little on Mars that would make it a significantly easier place to live, so I doubt we'd ever want to colonize it. I would say colonies only work if you have a place worth going to.

 

[Drakkith]

Strictly speaking, we currently have NO evidence that it will ever be possible for something with mass (like us or a spaceship) to travel at light speed. We can get very close, but that requires a huge amount of fuel. And even then, light speed is a fairly slow speed to get around at compared with a human timescale. The nearest star is minimum of 4 years away at light speed.

 

[ibysaiyan]

Strictly speaking, we currently have NO evidence that it will ever be possible for something with mass (like us or a spaceship) to travel at light speed. We can get very close, but that requires a huge amount of fuel. And even then, light speed is a fairly slow speed to get around at compared with a human timescale. The nearest star is minimum of 4 years away at light speed.

Fuel,definitely.We are better off knowing more about the un-observed universe and solving various paradoxes than trying to have a 'space-shuttle' reach 299792458 m/s.The fuel consumption alone is a huge factor without mentioning other hazards.
GR states that going close to 'c' causes time dilation and space contraction too.

For now a sci-fi movie is the only way to give us a feel of near light speed experience or getting sucked into the EH of a BH

ibysaiyan,
Regards

 

[Drakkith]

For now a sci-fi movie is the only way to give us a feel of near light speed experience or getting sucked into the EH of a BH

ibysaiyan,
Regards

Well, for the person traveling that fast, there is no change in experience. What changes is their view of the outside world.