It’s a reference to Larry Niven’s Known Space universe - in which humans are actually the larval stage of a race called The Pak, whose normal life-cycle involves eating a specific tuberous plant which is host to a virus that transforms young adult humans into immortal, armoured ‘protectors’, but the plant (called ‘tree-of-life’) can’t grow unless there is sufficient Thallium in the soil - on planets (such as Earth) where this is not the case, humans never progress past the larval stage.
Throwing the bodies away would be considered a monstrous waste. Even a huge generation ship would need every scrap of material, especially organic material. The bodies would probably be composted and then used in the growing of more food. After, of course, removing any transplantable organs.
I added that bit in as a wink and nudge to my fellow science fiction fans. It’s a reference to Larry Niven’s Protector subseries, set in his Known Space universe. Unless you read hard science fiction, you are unlikely to get the reference, or to use it.
All it takes is ONE dinosaur killer meteorite to exterminate a species…if that species is confined to just one planet. By the time we see that thing coming, it’s going to be too late to start building space ships and colonizing another planet. Now, I’ll grant you, the odds of another dino killer hitting us any time soon is very, very low, but it’s happened before.
And even if we don’t need to, maybe some of us would like to.
I think you misunderstood me. I’m saying that solving the problems of visitng another solar system is the same as being able to live indefinitely in space without planets - so if we can do that, we’d maybe just stay in space.
Ah, yes, I DID misunderstand you. And yes, you’re right…if we can achieve interstellar travel, we’ll probably be able to just park those big honking starships in L5, or in a Trojan point. This way would also prevent the human race from being wiped out by a dinosaur killer.
Lynn Bodoni: “This way would also prevent the human race from being wiped out by a dinosaur killer.” “Dinosaur” being defined here, of course, as “that which is exterminated by a dinosaur-killing asteroid (or volcano)” 
Mangetout: “It’s a reference to Larry Niven’s Known Space universe - in which humans are actually the larval stage of a race called The Pak . . .” Ah, that certainly explains things I’ve never known about my own perpetually larval existence . . .
Lynn Bodoni: “Throwing the bodies away would be considered a monstrous waste.” Yes, I’d have thought so.
Thanks for the fighting of ignorance here.
To put in perspective how “general” your assertion is, you must understand just how far away the “stars” are and just how lacking our current technology to get there is.
Using napkin math and rounding 
The absolute nearest star to us is 4.3 light years away which, relative to other stars is practically brushing elbows with us.
Speed of Light - 186,000 miles per second which is approximately 670 million MPH
Our technology - The Helios probe is traveling at approximately 157,000 MPH which seems pretty fast. However that speed is (again approximately) 0.000211 % the speed of light.
This means even if we could travel with human lives on a ship that could attain a speed of 157,000 MPH, the years it would take us to get to our next door neighbor is counted in the millions. As for your worry about the Sun burning out, most scientists agree the Sun is approximately 4.6 billion years old and has at least another billion years left before it begins the process of turning in a red giant and engulfing our little home. Chances are we as a species will do the Suns job of destroying Earth, long before that so Mars is at least something within reach.
A Mars colony would be just about the craziest waste of money imaginable. In the first place, it isn’t clear that humans could grow food crops on Mars-and shipping food to Mars would be prohibitively expensive. Second-return flights would be iffy-high probability that returns would fail.
I’d say wait till we have nuclear propulsion systems.
And many more. For every dollar we spend on space exploration, we get at least seven dollars in return. It’s crazy to NOT invest in it.
I’m a huge fan of space travel, but it is way premature to set up a Mars colony as a defense against a world-ending asteroid strike or other calamity, for the simple reason that an outpost, which is all Mars would be for a long, long time, is orders of magnitude in size away from being a self-sustaining colony.
As a guess, for humans to survive on Mars after earth’s destruction you would need *tens of thousands * of colonists, either a terraformed biosphere or a very cheap way to build habitats in large scale, and large-scale self-sustaining agriculture.
And that estimate may be way low. Unless people can ‘live off the land’, on Mars without high technology, sooner or later everything will start breaking down. Before that happens, you need an entire technological manufacturing base. You need mining, transportation, energy, etc. It might take millions of people to have enough specialized labor to pull that off.
We aren’t going to see even the beginnings of such a colony in our lifetimes, or in our children’s lifetimes.
People assume humanity is going to have to find another planet to live on. I don’t see why. It seems easier to build large, really large orbiting colonies complete with earth-normal “gravity.”
Planets are more trouble than they’re worth. You have to get on and off them, the gravity is never right and the weather brings entirely new meaning to the term “sucks.”
I see asteroids, moons, and planets as resources best used for making bigger and better orbiting colonies.
It’s way easier to dodge asteroids too. We can’t move a planet out of the way.