If Earth falls, will interstellar space travel be our salvation?

January 22, 2015 by Fredrick Jenet And Teviet Creighton, The Conversation
Is this how space travel will look some day? ‘Sulu, punch it!’ Credit: Shutterstock

Some climatologists argue it may be too late to reverse climate change, and it's just a matter of time before the Earth becomes uninhabitable – if hundreds of years from now. The recent movie Interstellar raised the notion that we may one day have to escape a dying planet. As astrophysicists and avid science fiction fans, we naturally find the prospect of interstellar colonization intriguing and exciting. But is it practical, or even possible? Or is there a better solution?

Science fiction has painted a certain picture of space travel in popular culture. Drawing on stories of exploration from an age of tall ships, with a good helping of anachronisms and fantastical science, space exploration is often depicted in a romantic style: a crew of human travelers in high-tech ships wandering the Galaxy, making discoveries and reporting back home. Perhaps they even find habitable words, some teeming with life (typically humans with different-colored skin), and they trade, colonize, conquer or are conquered. Pretty much, they do as humans have always done since the dawn of their time on Earth.

How close do these ideas resemble what we may be able to achieve in the next few hundred years? The laws of physics and the principles of engineering will go a long way to helping us answer this question.

Nature's speed limit

Nature has given us a speed limit. We call it the speed of light – about 186,000 miles per second – because we first noticed this phenomenon by studying the properties of light, but it is a hard upper limit on all relative speeds. So, if it takes light one year to get somewhere, we can't possibly get there sooner than one year.

There is also the fact that the universe is big, really big. It takes light about eight minutes to get to our Sun, three years to get to the next-nearest star, 27,000 years to get to the center of our own Galaxy and more than 2,000,000 years to get to the next galaxy. The amazing thing about these distances is that, as far as the universe is concerned, this is all in the neighborhood.

The vast distances between solar systems combined with the speed-of-light limit puts severe constraints on the realities of space travel. Every space-based writer has to decide early on how to deal with this white elephant standing proudly in the room. Much of the more recent science fiction employs some form of "worm hole" or "warping space": bending the four-dimensional structure of space and time to create shortcuts between two spatial locations in the universe.

Such possibilities have been analyzed with some mathematical rigor, and although the studies are tantalizing, they show that these methods cannot work unless we discover a form of matter that behaves very differently than anything we have ever seen.

Limits of propulsion

Practical space propulsion systems available today and for the foreseeable future are based on Newton's laws. In order to move forward, we have to throw something backwards or get hit by something moving forward. It turns out that even using the best propulsion systems available, there is not enough mass in the entire Universe to propel even a single human being up to half the speed of light. Even relative speeds of 0.01% of the speed of light start to get prohibitively expensive.

Nature’s speed limit – light – means it’s unlikely we’ll be able to hop in a space ship and roam the galaxy. Until we develop ‘warp’ technology, that is. Credit: Shutterstock

Things look slightly better with advanced propulsion concepts such as thermonuclear propulsion, but optimistic near-future designs still top out at a few percent of the speed of light.

Finding a habitat for humanity

Large distances combined with low speeds means that exploration is going to take time. Astrobiologists tell us that our galaxy has no shortage of habitable worlds: estimates range from at least 1 every 10,000 stars to as many as 1 every 10 stars. Even so, given the vast distances between stars and the low speeds achievable by realistic spacecraft, you should plan on voyages between worlds taking centuries to millennia.

Consider also what is meant by a "habitable world." To an astrobiologist, this means a planet with water oceans orbiting a sun-like star. But habitability by humans requires more than just water, and the chances that ordinary humans could simply step out and populate such a world is slim. The atmosphere and living ecosystem of Earth is the result of its own unique evolutionary history, one that is unlikely to occur coincidentally on any other planet.

Despite its current problems, the Earth is still far closer to the ideal that our species grew up in than any world we are likely to discover out in the Galaxy. Climatologists warn us of the devastation that could result from increasing the carbon dioxide in our atmosphere by less than a tenth of a percent. Compared to that, another living world, with its own unique ecology, would most likely have an environment that is unbreathable and infertile at best, lethally toxic at worst.

Terraforming, or modifying such a world to be habitable to humans, would require reconstructing its atmosphere and biosphere practically from scratch, eradicating any native ecosystem. This would be a task orders of magnitude more challenging than the relatively minor tweaks needed to restore the Earth's environment to a pristine state.

Artificial worlds

Perhaps a more fundamental question, then, is why humans would wish to colonize other worlds. Given the centuries-long treks between stars, interstellar voyagers would necessarily have moved beyond the need for a planet to support their lifestyle: their vessels would be their habitat, autonomous and self-sufficient. They would not have to seek out new homes, they would build them.

From an economic standpoint, this would be vastly more resource-efficient than converting entire planets. NASA-sponsored researchers have developed detailed plans for spinning habitats that could accommodate tens or hundreds of thousands of inhabitants, from material that could be mined on site from an asteroid a few hundred meters across. This type of construction would avoid one of the major expenses of space colonization: the cost of lifting millions of tons of building materials into space.

Are there habitable worlds in this cloud of stars? Or at least ones we could make livable via terraforming? Credit: Shutterstock

Since our Solar system contains millions of such asteroids, they could support a population many times that of Earth, in air-conditioned comfort, with a fraction of the effort and none of the exotic technologies envisioned to terraform Mars, for example.

So why travel the stars?

Ultimately, travel to other stars and colonization of other planets will be driven not by need, but by desire: the intellectual impulse to explore strange new worlds, and perhaps an aesthetic preference for "natural" (albeit engineered) environments.

Where do we go now? The commercialization of space flight promises to bring the cost of down considerably, from tens of thousands of dollars per kilogram to just hundreds of dollars per kilogram, through economies of scale and reusable rockets. This means that space will be more accessible to more and more people.

Clean and green: an interior rendering of the Torus, an artificial world imagined by scientists at NASA and Stanford. Credit: NASA

Already the lure of asteroid resources has fueled commercial competition. A single kilometer-sized metallic asteroid could supply hundreds of times the total known worldwide reserves of nickel, gold and other valuable metals. Space-based solar power could provide limitless renewable energy – once the cost of construction in space becomes manageable.

The hyper-exponential growth that we have seen in other areas like automobiles and computers can now take place for space technology. The physical realities described above paint a very clear picture of the near future: orbital habitats perfectly designed for our lifestyle using resources obtained from our Sun, Earth, and the asteroids.

So if Earth ever become uninhabitable, we won't need to traverse the stars to find a new home. Orbital habitats will require a significant expansion of space industry, but this will happen soon enough, especially if we are forced to leave the planet for a little while so it can recover from our mistreatment.

Of course, if we discover warp drive, the picture will be entirely different.

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axemaster
2.6 / 5 (5) Jan 22, 2015
It turns out that even using the best propulsion systems available, there is not enough mass in the entire Universe to propel even a single human being up to half the speed of light.

Yeah, that's complete garbage. A simple check with nonrelativistic momentum:

mH*vH = mP*vP

where mH=70kg, vH=150,000km/s, and vP=4.5km/s. mH is mass of the human, mP is mass of the propellant, and so on. Calculating this out, you get mP=2.3*10^6 kg of propellant. Granted, it'll be more if you use the relativistic equations, but you'd have to be utterly daft to think this approaches the mass of the entire universe.

EDIT: I'd also like to point out that if we ever send people to other stars, they won't be making the journey in their meatbag bodies. We'll send streamlined probes with their minds stored in computer hardware, with a complement of manufactoring technology to build them bodies at the destination. Assuming that they want bodies, and that they actually want to travel.
Whydening Gyre
4.3 / 5 (6) Jan 22, 2015
Axe,
Per yer EDIT-
how do you know that's not what we are doing NOW....?
altizar
2.4 / 5 (7) Jan 22, 2015
I hope we don't have a salvation. After looking at our species as a whole, there aren't any redeeming qualities . . .
thefurlong
5 / 5 (3) Jan 22, 2015
@axemaster
You aren't taking fuel into account (and relativistic effects, but you already acknowledged that). In order to accelerate a human to 1/2 the speed of light, you also have to accelerate much of the fuel for most of the way too. I thought I could do a quick back to envelope calculation to show you, but it's too complicated for that, so if you don't believe me, you'll have to wait. Or you could just look it up.
jediknight190501
5 / 5 (1) Jan 22, 2015
What I fear is that if we are able to go to other worlds orbiting other stars, all the habitable planets will be inhabited by life forms who are, how shall we say? . . . not exactly anxious to share their worlds with others.
grondilu
5 / 5 (1) Jan 22, 2015
> Some climatologists argue it may be too late to reverse climate change, and it's just a matter of time before the Earth becomes uninhabitable

Oh come on. Is climate change *that* bad?
Uncle Ira
4 / 5 (12) Jan 22, 2015
Whatever way they fix something to go into space on, you can be pretty sure the only peoples with enough money to afford a ticket are the peoples that poisoned the planet to start with to make their billions of dollars.
axemaster
3 / 5 (2) Jan 22, 2015
@axemaster
You aren't taking fuel into account (and relativistic effects, but you already acknowledged that). In order to accelerate a human to 1/2 the speed of light, you also have to accelerate much of the fuel for most of the way too. I thought I could do a quick back to envelope calculation to show you, but it's too complicated for that, so if you don't believe me, you'll have to wait. Or you could just look it up.

Yes I am aware of the exponential nature of the rocket equation. You don't have to use a rocket to accelerate a human sized mass to 1/2c though. For example, you could shoot the probe out of a gun - that neatly sidesteps the rocket equation. I would also point out that I was being quite generous to the author by using a chemical fuel - we all know that any interstellar craft would use nuclear, at the very least, and would have far higher exhaust velocity.
thefurlong
4.6 / 5 (9) Jan 22, 2015
Oh come on. Is climate change *that* bad?

Yes. Nature adapts to change slowly, which means that abrupt change is very disruptive to the eco-system. What we are doing to the climate is extremely abrupt, and will have devastating effects on flora and fauna. For example, climate change leads to the acidification of the ocean, which kills of plankton, which happen to drive the ocean's food chain.
It won't be much better on land either. Please do not delude yourself. Climate change, if left unchecked, will be bad, and not just for us, but for most animals.
thefurlong
3.7 / 5 (3) Jan 22, 2015
You don't have to use a rocket to accelerate a human sized mass to 1/2c though. For example, you could shoot the probe out of a gun - that neatly sidesteps the rocket equation.

That's true, but you are neglecting the first part of the claim in question:
"It turns out that even using the best propulsion systems available, there is not enough mass in the entire Universe to propel even a single human being up to half the speed of light."
Systems involving, say nuclear pulse cannons, are not current technology. Also, taking relativity into account, you would still need, at a minimum, 2.08557*10^18 joules of energy to accelerate a 150kg human to 0.5 the speed of light, and that's assuming 100% efficiency. That's the equivalent of about 9 tsar bombas, the largest nuclear device ever detonated. And you would have to take this explosion, contain it, and refocus its energy so that almost all of it goes towards accelerating the human.
Skepticus
5 / 5 (1) Jan 22, 2015
I don't really get it, this problem of acceleration at relativistic speeds. In the reference frame of the ship, with the increase toward the speed of light, all atoms of the ship and fuel will increase in mass in the same proportion, So, the exhaust of the rocket engine will get heavier and will give more "kick" to propel the more massive ship+fuel. The thrust to mass ratio will remain the same, irrespectively of speed. An explosion, ie fuel burn, happens just as fast and powerful in the reference frame of the ship as when it is standing still. Otherwise, the equivalence principle aka throwing a ball in the accelerating elevator example will be invalid. So what is the problem? Everything I've read to date only mention the increase in mass of the ship, and nothing about the proportional increase of the exhaust mass? Anyone cares to explain? Thank you all!
axemaster
5 / 5 (2) Jan 22, 2015
The difference is that from the starting inertial frame - i.e. the "rest frame" with respect to earth, the ship is moving faster than the exhaust (since the exhaust is thrown behind it). Thus the effective mass increase of the ship is greater than the fuel, causing the fuel to become less efficient at higher velocities.

I would also point out that from the perspective of the ship, there is no mass change at all - the ship can't "see itself" moving after all.
indio007
1.4 / 5 (5) Jan 22, 2015
Let's stop kidding ourselves shall we? If the visible stars are the distances we believe, human kind is effectively imprisoned here. We need a break through in travel. Namely, teleportation by macroscopic quantum tunneling between stars.

thefurlong
5 / 5 (5) Jan 22, 2015
, So, the exhaust of the rocket engine will get heavier and will give more "kick" to propel the more massive ship+fuel

Actually, no, it will give less of a kick. In the moving frame, whatever force we see applied to the rocket will be multiplied by the cube of the lorentz factor in the rest frame.
The thrust to mass ratio will remain the same

No, this isn't true. Here is what I have calculated: Assuming that in the rest frame of the rocket, the exhaust leaves at a rate of k kg/s at a relative constant velocity of v_t, then, in the moving frame, dP/dt = (-k*v_t/(1-(v_t^2/c^2)))*G^3, where P is the momentum of the rocket, and G is the lorentz factor. This yields a solvable equation,
-kv+kv^3/c^2 + (m_0 - kt)dv/dt = -k*v_t/(1-v_t^2/c^2), where m_0 is the initial mass, and t is time.

So, dv/dt is on the order of (R-v^3)/(m_0 - kt), where R is a constant. So, the time rate of change in velocity is going to diminish really quickly--faster than exponential.
Caliban
5 / 5 (6) Jan 22, 2015
"If Earth falls, will interstellar space travel be our salvation?"

I'm with Ira on this one.

Sure, space travel may well make it possible to H. sapiens to survive as a species,

just not you, or your family, or descendants, with the same going for pretty much anyone else you know.

thefurlong
5 / 5 (3) Jan 22, 2015
Let's stop kidding ourselves shall we? If the visible stars are the distances we believe, human kind is effectively imprisoned here. We need a break through in travel. Namely, teleportation by macroscopic quantum tunneling between stars.

Yes, typical propulsion won't cut it. I think, though, we suffer from a bit of myopia. We never know what discoveries lie ahead. In the 16th century, it was inconceivable that a bomb could level an entire city, or that we could see inside a human body without damaging it. You could say that such things would have been considered physically impossible.

I maintain that we should start thinking about why the postulates of relativity are true in the first place. We all sort of just accept it without really trying to understand why it should be. Maybe if we can come up with a viable model from which this postulate emerges, we can understand how to possibly break it.
thefurlong
5 / 5 (2) Jan 22, 2015
I said
Actually, no, it will give less of a kick. In the moving frame, whatever force we see applied to the rocket will be multiplied by the cube of the lorentz factor in the rest frame.

I meant that it will be divided by a cube of the lorentz factor in the rest frame. Sorry about that.
WillieWard
4.3 / 5 (6) Jan 22, 2015
"We won't survive another 1,000 years without escaping our fragile planet" - Stephen Hawking
The future of mankind is in space seeking for new worlds and new civilizations. http://www.youtub...9abFF3ZE
Whydening Gyre
3.7 / 5 (3) Jan 22, 2015
> Some climatologists argue it may be too late to reverse climate change, and it's just a matter of time before the Earth becomes uninhabitable

Oh come on. Is climate change *that* bad?

Wrong thread, sir...
Whydening Gyre
3.7 / 5 (3) Jan 22, 2015
We are currently ON an "optimized" speed (energy output vs mass consumption) spaceship...
Benni
1.4 / 5 (5) Jan 22, 2015
There's an equation heretofore unmentioned of the effects of micron sized particle collisions with hulled craft at the minimum speeds needed for interstellar travel: KE=1/2mv2.

Within each cubic meter of interstellar space are usually a couple of micron sized particles of dust, Just a single micron sized particle in a headon impact will tear through a hulled craft with such an impact of kinetic energy that the craft will quickly become space junk if speeds are not kept well below 100,000 mph, otherwise it's a suicide mission.

Make the hull thicker you say? This adds to the mass that must be accelerated. Now you need a higher output propulsion engine, that's yet additional mass. How thick a hull do you imagine may be needed to withstand the imparted KE impacts of micron sized dust particles? Many feet even at a low 100,000 mph.

Now at 100,000 mph, calculate the length of time required to safely reach the nearest star.
indio007
2 / 5 (4) Jan 22, 2015

You could say that such things would have been considered physically impossible.

I maintain that we should start thinking about why the postulates of relativity are true in the first place. We all sort of just accept it without really trying to understand why it should be. Maybe if we can come up with a viable model from which this postulate emerges, we can understand how to possibly break it.

Relativity is a dead end.

So let's ask, What is the voltage differential between 2 stars? How much energy is required to "quantum tunnel" a human body to a star? Maybe there is already a voltage bias?

It's possible to tunnel through vacuum.
Here's one example
Phonon transport across a vacuum gap
http://ntpl.me.cm...cuum.pdf
Robert_D
not rated yet Jan 22, 2015
So... should I sell my grave plot?
Osiris1
1 / 5 (4) Jan 23, 2015
Nobody has said a thing about Sr Alcubierre and his warp drive theory, nor about NASA's modifications to make it a LOT more achievable....no more jupiter masses needed. After all, our alien visitors got here and I am quite sure that they did not travel in generational ships. No limit on travel speeds of a warp bubble surfing the expansion and contraction of space itself. Hints of its methodology are appearing every other day in THIS web site if one just.........looks.
Whydening Gyre
4.2 / 5 (5) Jan 23, 2015

Now at 100,000 mph, calculate the length of time required to safely reach the nearest star.

Dang.. I gotta lay off the Crown. That one took me almost 5 minutes (what with the metric conversion n all...)
The answer is - Assuming Alpha Centauri is 25.827 trillion miles away(4.4 LY)...
29,463 years(roughly).
Did I win? A trip to Benni's neighborhood?
Here's one for you - Spaceship SOL is traveling around the galaxy at roughly 220 KPS. How many miles would a person travel in 29,463 years?

Whydening Gyre
3.7 / 5 (3) Jan 23, 2015
Hints of its methodology are appearing every other day in THIS web site if one just.........looks.

Hey, O... Point us all in a general direction, then...
fadingfool
not rated yet Jan 23, 2015
I hope we don't have a salvation. After looking at our species as a whole, there aren't any redeeming qualities . . .

Stop looking in the mirror and meet some other people then ;)
alfie_null
5 / 5 (3) Jan 23, 2015
What problem is the article trying to solve? Satisfying the hubris of preserving the human race, albeit in the form of a small representative group? Or saving the lives of the entire population of Earth? If the former, why? If the latter, figuring out how to make fast rockets is only one of many insurmountable obstacles.
JJMason
not rated yet Jan 23, 2015
If and when it comes time for us to venture outside of "our" solar system it is extremely unlikely there will be a one-method solution for propulsion. It will only be through a combination of technologies that we will actually be able to get anywhere. Chemical propulsion to get into orbit, solar power for all non-essential systems (as well as a battery reserve for essential systems). Nuclear power (either through successive detonations or sustained energy) and likely fusion energy also. There is also the likely addition of a solar sail.
thefurlong
5 / 5 (7) Jan 23, 2015
I hope we don't have a salvation. After looking at our species as a whole, there aren't any redeeming qualities . . .

I'm really tired of this meme. Most evil comes from two places: ignorance, and psychopaths/sociopaths. People, in general, are highly empathetic and altruistic. As long as we don't see another living being as "the other" we are actually quite generous and protective.

The problem largely comes from psychopaths inducing sociopaths and ignorant people to do bad things.

Really, though, would you rather be a komodo dragon that eats everything, including its own offspring? How about a rhododendron plant that poisons the ground around itself so that nothing else can grow or a red algal bloom that poisons surrounding marine life?

The reason we discourage the distribution of invasive species is because most species would ruin the environment in a heartbeat, if left unchecked. At least we can tell when we're doing it and can do something about it.
bluehigh
1 / 5 (6) Jan 23, 2015
Let's stop kidding ourselves shall we? If the visible stars are the distances we believe,

- indio007

They are not the distance believed by the brainwashed. Interstellar travel has been shown to exist in many of your reports. You reckon I would choose to sit in a propelled tin can for many years to get here?. Thats silly. 6 weeks was at my limit! Depressing assignment. You creatures have some crazy notions.
Whydening Gyre
4 / 5 (4) Jan 23, 2015

The reason we discourage the distribution of invasive species is because most species would ruin the environment in a heartbeat, if left unchecked. At least we can tell when we're doing it and can do something about it.

Hence, the Prime Directive...
indio007
4.9 / 5 (7) Jan 23, 2015
Let's stop kidding ourselves shall we? If the visible stars are the distances we believe,

- indio007

They are not the distance believed by the brainwashed. Interstellar travel has been shown to exist in many of your reports. You reckon I would choose to sit in a propelled tin can for many years to get here?. Thats silly. 6 weeks was at my limit! Depressing assignment. You creatures have some crazy notions.

uhmmmmm.... waiter .... check please.
cantdrive85
1 / 5 (4) Jan 24, 2015
As astrophysicists and avid science fiction fans


That's quite funny that they're trying to separate astrophysics and scifi when in fact they are one in the same.
Skepticus
not rated yet Jan 25, 2015
The difference is that from the starting inertial frame - i.e. the "rest frame" with respect to earth, the ship is moving faster than the exhaust (since the exhaust is thrown behind it). Thus the effective mass increase of the ship is greater than the fuel, causing the fuel to become less efficient at higher velocities.

I would also point out that from the perspective of the ship, there is no mass change at all - the ship can't "see itself" moving after all.

So, what you are saying in plain English was: Near the speed of light, the captain of the ship sees his thrusters are running like hell, but there is no more appreciable acceleration felt or measured, is it?
Skepticus
not rated yet Jan 25, 2015
, So, the exhaust of the rocket engine will get heavier and will give more "kick" to propel the more massive ship+fuel

Actually, no, ...

In the same vein as my new question to axemaster, so, near the speed of light, If you hold a hypothetical cannon on your shoulder (!) and fires, there would be negligible recoil (acceleration to yourself), and if the engines at the rear blow up, you won't be hurt at all upstream next to it, because the explosion can't impart any acceleration forward at that speed?
Skepticus
not rated yet Jan 25, 2015
The difference is that from the starting inertial frame - i.e. the "rest frame" with respect to earth, the ship is moving faster than the exhaust (since the exhaust is thrown behind it). Thus the effective mass increase of the ship is greater than the fuel, causing the fuel to become less efficient at higher velocities.

I would also point out that from the perspective of the ship, there is no mass change at all - the ship can't "see itself" moving after all.

Another thing that comes into mind, regarding rocket propulsion. As far as I know, a rocket exhaust velocity is on the order of 10km/s at best, while it still can push the ship to some hundreds of km/s, if fuel allows. It is the difference in speed between the ship and the exhaust that continue to give the ship the push. At the speed of light, the exhaust mass still went one way, and give a reaction the other. Newton's Third Law still applies in the reference frame of the ship, so why there is no jolt to the ship?
PhotonX
5 / 5 (5) Jan 25, 2015
Nobody has said a thing about Sr Alcubierre and his warp drive theory, nor about NASA's modifications to make it a LOT more achievable....no more jupiter masses needed. After all, our alien visitors got here and I am quite sure that they did not travel in generational ships. No limit on travel speeds of a warp bubble surfing the expansion and contraction of space itself. Hints of its methodology are appearing every other day in THIS web site if one just.........looks.
That's because it's speculative four martini back-of-a-cocktail-napkin bullshit, viewed with a bemused smile by NASA. To quote directly from their website: "Q: Is there any work being done to search for these breakthroughs (Alcubierre 'drive' and Worm Hole transportation)? A: Yes, but not much."
http://www.nasa.g..._prt.htm
.
Maybe you should direct them to your alien friends for some advice. I'm sure we'd all be grateful.
.
.
Whydening Gyre
1 / 5 (1) Jan 25, 2015
If an abusive parent kills their child, would you support their adopting another?

Human expansion may quickly answer the question about intelligent life in the vicinity of the solar neighborhood. Surely if they exist they will move to preempt any such expansion. Hopefully, even as we write, some advanced alien civilization has noted the CO2 change in the atmosphere, knows the syndrome well, has looked into the state of our ecosystems and is planning a cull for the good of the planet and the local galactic neighborhood.

Pretty dire, there, j man...
Bongstar420
not rated yet Jan 25, 2015
If we were space faring status, the environment would be pretty irrelevant now wouldn't it? After all, if you can live in space or at the bottom of the ocean, why does some weather matter?
Moebius
5 / 5 (1) Jan 25, 2015
ROFL. And export the exact same problems to other planets (us)? If we can't survive our stewardship of this (once) paradise planet, does it make any sense?

We need to face the facts. If we were intelligently designed god wouldn't have chosen as our bloodline the murderous chimps that we are.
Urgelt
not rated yet Jan 26, 2015
This article doesn't do much to nail down its dismissal of interstellar travel - and makes incorrect assumptions along the way.

You don't need half of the speed of light to colonize other worlds. You just have to deliver a live human population.

If you can build huge well-populated habitats in Sol's system, you can build huge habitats that move. Yep, you'll need a lot of mass to move them. There's plenty of mass in the Oort cloud. If you assume cheap fusion power is available, getting up to 10% of light speed or even higher isn't out of the realm of possibility.

Once you get there, terraforming will probably take thousands of years, but... that really isn't that much of a problem if you've brought a big huge habitat right from the get-go and have plenty of cheap fusion power.

The biggest obstacle might not be technology at all, but rather human nature. It's not clear that we can construct civilizations that will not collapse.
Whydening Gyre
3 / 5 (2) Jan 26, 2015
You don't need half of the speed of light to colonize other worlds. You just have to deliver a live human population.

If you can build huge well-populated habitats in Sol's system, you can build huge habitats that move. Yep, you'll need a lot of mass to move them. There's plenty of mass in the Oort cloud. If you assume cheap fusion power is available, getting up to 10% of light speed or even higher isn't out of the realm of possibility.

Once you get there, terraforming will probably take thousands of years, but... that really isn't that much of a problem if you've brought a big huge habitat right from the get-go and have plenty of cheap fusion power.

The biggest obstacle might not be technology at all, but rather human nature. It's not clear that we can construct civilizations that will not collapse.

You just pretty much described planet Earth and our solar system...
Whydening Gyre
1 / 5 (1) Jan 26, 2015
You just pretty much described planet Earth and our solar system...

(Not to mention - the galaxy we're riding in...)
petepal55
3 / 5 (2) Jan 26, 2015
Until the human race learns how to control itself the civilizations we create are doomed. A democratic system can't work, people are too selfish. We will breed until something stops us. If a worldwide tyrant ever comes to power and literally decimates the population, several times over, we might have a chance to become greater than our present selves. All I see in the future is a near-complete world-civilization meltdown followed by generations of petty tyrants governing their own little slice of hell.
We are primates governed by a primates directives; eat, sleep & make little primates. We'll never be anything more unless we "evolve" new directives, which won't happen because there's no ecological impetus to direct the necessary changes.
So be happy with what you've got. If you want the same for your children plan ahead so that it's possible for them and future generations. If you don't, it won't be. Period.
Whydening Gyre
3.7 / 5 (3) Jan 26, 2015
Until the human race learns how to control itself the civilizations we create are doomed. A democratic system can't work, people are too selfish. We will breed until something stops us. If a worldwide tyrant ever comes to power and literally decimates the population, several times over, we might have a chance to become greater than our present selves. All I see in the future is a near-complete world-civilization meltdown followed by generations of petty tyrants governing their own little slice of hell.
We are primates governed by a primates directives; eat, sleep & make little primates. We'll never be anything more unless we "evolve" new directives, which won't happen because there's no ecological impetus to direct the necessary changes.
So be happy with what you've got. If you want the same for your children plan ahead so that it's possible for them and future generations. If you don't, it won't be. Period.

Big downer with no vision...
petepal55
not rated yet Jan 26, 2015
You want vision? Then come up with a scheme that guides humanity to act in such a way that it preserves the world in a state suitable for future generations that they can also utilize. Leaders, and priests, have been trying to come up with such a scheme(I think most are called religions) for quite a while but they all seem to have fatal flaws.
But then, I don't think they had the proper vision. Who has?
Whydening Gyre
3.7 / 5 (3) Jan 27, 2015
You want vision? Then come up with a scheme that guides humanity to act in such a way that it preserves the world in a state suitable for future generations that they can also utilize. Leaders, and priests, have been trying to come up with such a scheme(I think most are called religions) for quite a while but they all seem to have fatal flaws.
But then, I don't think they had the proper vision. Who has?

all of us - as a collective...
petepal55
not rated yet Jan 27, 2015
I doubt that any other species can be so easily mislead concerning reality. As a collective the human race is just another group of animals who will breed themselves to self-destruction. Only true visionaries can save us now and atheists like that are rather rare. I wrote a paper on pessimism once, I'm afraid my research unduly influences my opinions. It has led me to question all that offer less than concrete answers(i.e., propaganda) to life's little conundrums. If it's not a real answer it's not an answer at all, it's burying your head in the sand like humanity is wont to do. Thus does humanity seal it's own fate and ensure it's doom. I'm afraid your answer only bolsters my own conclusions. I shall keep my lamp lit and continue searching for a visionary that has real answers. But I'll also continue my training on how to navigate in the dark, for I find it the pragmatic course.
Whydening Gyre
3 / 5 (2) Jan 27, 2015
I doubt that any other species can be so easily mislead concerning reality. As a collective the human race is just another group of animals who will breed themselves to self-destruction. Only true visionaries can save us now and atheists like that are rather rare. I wrote a paper on pessimism once, I'm afraid my research unduly influences my opinions. It has led me to question all that offer less than concrete answers(i.e., propaganda) to life's little conundrums. If it's not a real answer it's not an answer at all, it's burying your head in the sand like humanity is wont to do. Thus does humanity seal it's own fate and ensure it's doom. I'm afraid your answer only bolsters my own conclusions. I shall keep my lamp lit and continue searching for a visionary that has real answers. But I'll also continue my training on how to navigate in the dark, for I find it the pragmatic course.

Once again, another dark vision of the future...
Why can't some of you lighten up?

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