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Human interstellar travel

Started by GSOgymrat, March 05, 2015, 10:15:26 AM

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GSOgymrat

Growing up reading science fiction I always believed that eventually humans would travel to other solar systems but now I seriously doubt human interstellar space travel will ever be possible. There are two major obstacles I see in human interstellar travel: physics and people. Some of the physical challenges of human interstellar travel are known. I won’t go into the details but traveling to the closet star is 4.24 light years away and in the best case scenario would take hundreds of years to reach that destination. The energy requirements for sending humans to another star would be huge. For example, there is not only acceleration to consider but also the time and energy to decelerate when reaching the destination. Brice N. Cassenti, an associate professor with the Department of Engineering and Science at Rensselaer Polytechnic Institute, stated at least the total energy output of the entire world [in a given year] would be required to send an unmanned probe to the nearest star. Then there are the problems of time dilation, communication, interstellar medium (hit a pebble while moving half the speed of light would be bad) and all the problems associated with humans living in space. Additionally, there are the unknown challenges of interstellar travelâ€"we won’t know these problems until someone attempts the journey. According to Wikipedia, at a 2008 Joint Propulsion Conference, multiple experts opined that it was improbable that humans would ever explore beyond the Solar System. I know there are theories about wormholes, Alcubierre drive and other notions but these ideas seem fanciful.

The people part of the challenge has to do whether humans will be able to continue to exist on Earth and advance technologically without dying off. Humans could face challenges that slow or halt technological progress: severe climate change, plague, asteroid impact, etc. There have been at least five extinction events and 99% of all species that have lived on Earth have already died out. We could also end up just killing each other. There are large numbers of people right now who are actively trying to kill each other and a sizeable number of people who believe in, and welcome, an apocalyptic future. In order for interstellar travel to be possible we need the ability to create huge amounts of energy. If we develop technologies that can create that kind of energy we create a situation where that power could be used to endanger life on Earth, either by accident or design. I always thought the idea of humans being endangered by a malevolent artificial intelligence was fanciful but there are scientists smarter than I who consider this an actual possible threat. I don’t consider myself to be a pessimistic but there is the real possibility that human life on this planet is limited and we won’t figure out a way to keep life going long enough to discover ways to successfully travel to other habitable worlds.

I’m posting this hoping someone will convince me I’m wrong.

kilodelta

I wish I could prove you wrong. There are challenges. I see the biggest one really being human beings. Can our society make similar leaps in advancement, not just technological but social, that we did in the past 2,000 years? Maybe, maybe not.
Faith: pretending to know things you don't know

Solitary

GSOgymrat, thanks! Unless the physics is correct with regard to Worm Holes, it will never be, for the reasons you give. Solitary
There is nothing more frightful than ignorance in action.

Hydra009

Without the advent of practical FTL (which seems a smidge unlikely), humans will never live outside of the solar system.  And yes, simply maintaining our high-tech lifestyle while at the same time not irrevocably damaging the Earth is a dicey challenge.

However, it is possible that human-produced machines could carry on space exploration.  Machines require little life support, do not suffer any psychological problems associated with prolonged isolation, and loses would be far more tolerable than loss of human life.  And unlike humans, machines can be continually upgraded, transhumanism notwithstanding.  There's a reason why robotic probes explored the moon and nearby planets well in advance of humans.

It's entirely possible that self-replicating machine explorers could continually planet-hop the galaxy without regular contact with humans.  Should human civilization collapse, that might even be humanity's main legacy.

stromboli

I hear you, GSO. I grew up reading SF during the golden age of SF, with Asimov, Simak, Brunner, Heinlein, Van Vogt, Bradbury and so on. The idiocy is that if we were all on the same page minus religion, a whole bunch more would have and could have happened. Quantum teleportation is now a thing, if only experimentally.

http://phys.org/news/2014-09-quantum-teleportation.html

I believe what humans can conceive they can achieve. We have been doing so for centuries, and even if FTL drive or Star Trek Warp Drive isn't achievable, many other things are; life extension, a clean pollution free world, the end of diseases and so on. How sad that we can visualize these things only to be held back by bronze age stupidity and greedy politicians.

GSOgymrat

#5
Quote from: Hydra009 on March 05, 2015, 12:11:14 PM
Without the advent of practical FTL (which seems a smidge unlikely), humans will never live outside of the solar system.  And yes, simply maintaining our high-tech lifestyle while at the same time not irrevocably damaging the Earth is a dicey challenge.

However, it is possible that human-produced machines could carry on space exploration.  Machines require little life support, do not suffer any psychological problems associated with prolonged isolation, and loses would be far more tolerable than loss of human life.  And unlike humans, machines can be continually upgraded, transhumanism notwithstanding.  There's a reason why robotic probes explored the moon and nearby planets well in advance of humans.

It's entirely possible that self-replicating machine explorers could continually planet-hop the galaxy without regular contact with humans.  Should human civilization collapse, that might even be humanity's main legacy.

I agree that using machines for interstellar travel is a much more viable option and I believe unmanned probes are better for space exploration. I'm actually not too keen on the recent focus on sending humans to Mars. Our recent technological advances have been in computer software, hardware, miniaturization and robotics and this lends itself to unmanned exploration more than manned. I feel sending humans to Mars at this point in our technological development is more political than practical and diverts resources that would be better spent on projects that are currently feasible. The Mars One project is a perfect example of what I consider to be a publicity stunt-- a reality television, corporate funded mission with completely unrealistic goals. I also confess that I find the idea of sending people to Mars to die inherently a failure-- why not just fire corpses to the planet and claim you put people on Mars. I'm confident that eventually we can successfully have manned missions to Mars but at this point I feel our resources are better spent exploring the solar system with unmanned probes.

Fun Fact: at its closest distance Mars is 0.5 AU from Earth, while the nearest star system, Alpha Centauri, is 13,000 AU from Earth.

stromboli

Been reading the "Long Earth" series by Terry Pratchett and Steven Baxter. The concept is based on a suddenly discovered means to travel to parallel dimensional earths- each fractionally different than ours. Fascinating idea. We as yet don't know so much about our universe, multiverses or other conceptual ideas. You never know; stepping across dimensions might one day be a possibility. But I'm no physicist, Hijiri or josephpalazzo might poo poo the idea. 

GSOgymrat

Quote from: stromboli on March 05, 2015, 06:49:14 PM
Been reading the "Long Earth" series by Terry Pratchett and Steven Baxter. The concept is based on a suddenly discovered means to travel to parallel dimensional earths- each fractionally different than ours.

Reminds me of the TV show Sliders.

stromboli

Similar in concept to Sliders, except in this case just about everyone is given the means to "step" as they call it. It poses several interesting conflicts when you consider the ability of mass movement of people to a new earth with every resource available and no government to control them. I won't try to describe the scenario because it is complicated, but it is a fairly good series- 3 so far- based on an interesting concept.

The big difference is that the earths are all without humans. Other life forms and sentient beings are encountered, and the earths change incrementally as they step, so earths thousands of steps away are quite different and not like ours. It also talks about what constitutes intelligent life and how tiny the odds of an earth teeming with life is.

GSOgymrat

Sounds interesting. I downloaded the first book in the series to my Kindle, only $3.99!

stromboli


Johan

Quote from: GSOgymrat on March 05, 2015, 10:15:26 AM
I’m posting this hoping someone will convince me I’m wrong.

You're not wrong. When you get right down to it, we are animals. Savages really. We are genetically wired to want to band ourselves together into groups and then kill or otherwise control every other group we can find. These genetics can of course change over time. But these changes happen at the speed of evolution which is orders of magnitude slower than the speed at which we develop and use new technologies.

Which means we are almost certain to invent and produce a weapon that will easily and effectively drive our species and most others into extinction long before evolution bestows us with the genetic wiring required to keep us from ever building such a weapon much less using it.

In short, we're fucked. Truth be told, we were probably fucked the moment that first primate realized hitting your enemy in the head with a rock was more effective than using your fists.

The good news is in the mean time, we've got beer and sex. If you can't get off the train, you may as well enjoy the ride.
Religion is regarded by the common people as true, by the wise as false and by the rulers as useful

Light Craftsman

The big problem with interstellar travel is it makes no economic sense. The distances are so vast that it takes tremendous amounts of energy to send anything larger than a small, slow-moving probe between the stars. the original Voyager space probe left our planet 38 years ago and is still within our Sun's protective bubble. There are several glaring engineering problems to overcome when trying to build an interstellar space ship. No.1 is reliability. You'll need spare parts. No. 2 is fuel. How are you going to power something for the decades or centuries it will take to reach another solar system?

That doesn't even get into the problem of identifying a candidate system. You'll need to send probes to many systems to find one suitable for exploration, wait decades or longer for it to arrive then several years for it to send a signal home. Then you'll need to start planning an expedition, including how to finance it. Which gets us back to the original problem: return on investment. There is no way to make the expedition pay for itself. that is assuming we still have a civilization capable of planning such an expedition once we identify a suitable solar system to explore. The way things are going I have my doubts about that.

Powering our civilization takes energy from the Earth; energy which took millions of years to develop. We have burned though more than half that energy in 200 years. Without oil we cannot feed the billions of people on our planet, and our oil will run out before the end of this century. Believing we will send a privileged few off-planet while billions of people starve and fight over increasingly rare energy resources is naive.
You cannot have a rational discussion with someone who holds irrational beliefs.

GSOgymrat

Quote from: Light Craftsman on March 10, 2015, 03:19:50 PM
The big problem with interstellar travel is it makes no economic sense.

You seen to know about economics and I am curious if you think a manned mission to Mars make economic sense.

Light Craftsman

#14
Economics is not my area of expertise, but my wife got her undergrad degree in finance. Does that count?

As for Mars, no, a manned mission does not make sense, financially or otherwise. Not right now, anyway. Keeping the crew safe from stellar radiation on the trip will be a major problem. The Earth's magnetic field protects us, but a spacecraft obviously does not have a magnetic field absent a huge generator, so how do we shield astronauts from radiation on a six-month trip? No one has answered that. Then when the astronauts get to Mars they'll have the same problem. Mars has a very weak magnetic field; too weak to protect it from solar radiation. The atmosphere is too thin to retain heat, so terraforming is out of the question. That means any permanent base will rely on some form of shielding, magnetic or otherwise, from solar radiation and inhabitants will have to recycle all materials between supply runs from Earth. Growing food on Mars will be problematic even indoors. And where is the economic payoff to a manned mission? Selling commercials on a reality TV show is not sustainable and there are little to no resources on Mars.
You cannot have a rational discussion with someone who holds irrational beliefs.