The Other I

October 3, 2010

Will it ever end?

Filed under: Uncategorized — theotheri @ 8:16 pm

I watched a tv programme last night featuring Stephen Hawking, the renowned astro-physicist.  The first half of the programme covered the time from the big bang to now.  The second half asked:  what next?

Here’s the options for the future as Hawking sees them:

Eventually planet Earth will no longer be habitable.

  • This might happen as a direct result of human activity.  We might make the world inhabitable for ourselves, or even for all living things.
  • Or it might become inhabitable because something big enough lands on earth from outer space and incinerates the planet.  Major catastrophic collisions with objects from space have happened more than once before, destroying more than 90% of all the life forms existing on the entire planet.
  • Or the gamma rays from an exploding novo-star in our neighbourhood could reach us.  Gamma rays are so destructive that they would rip off our protective ozone layer exposing us to the unfiltered deadly rays of the sun.
  • Or the galaxy in which we live, the Milky Way, is on a collision course with another entire galaxy called Andromeda.  The two galaxies will begin to collide in about 3 billions years and will take at least another 2 billion years to be resolved.

But assuming that we as a species survive long enough, Hawking thinks our best bet is to colonize another planet.

  • For starters, he recommends Mars.  Even at today’s speeds of space travel, humans could get there and back in several years.  Mars itself, however, would require some major adjustments if it were to be made habitable for the likes of us.  The gravity on Mars is about 35% as strong as it is on earth.  That would eventually lead to mass bone loss so crippling that we could not get ourselves around.  There is so oxygen on Mars or vegetation.  And the temperatures range from -200 degrees to 100.  Worse yet, they can change from the two extremes in a matter of minutes.  Yet Mars could conceivably be made habitable.

But eventually – in about 5 billion years, the sun will burn out.  In the process of dying, the sun will initially expand in intense heat, gobbling up the planets in its nearest orbit and incinerating Earth.

So then we will have to go much further than Mars to survive.  We will have to leave our solar system altogether.

  • Getting to the nearest planet we’ve actually identified which has reasonable temperatures and liquid water is far more daunting.  At current speeds of space travel, it would take 730 years to get there.  Generations would have to be born, live, and die in a space capsule with the hope that some day their heirs would reach some place they could call home.  Apart from the practical questions of feasibility, there are ethical questions about imprisoning unconsulted generations on this kind of trip.

But not only will our solar system eventually burn out;  so will the Milky Way.  To survive, we will have to travel through space not just to another planet but to another galaxy.

And if we manage to do that, we will still have to face the question of the survival of the entire universe itself.  The universe is even now in process and will not remain the same.  The universe seems to face two opposing futures, neither of which is reassuring.  Right now, a mysterious force called “dark energy” is pulling the universe apart.  The force of gravity is pulling it together.  Which one wins will determine the outcome:

  • The Big Crunch will happen and the universe will eventually return to the incredibly dense black hole called a singularity out of which it first emerged with the big bang.  Right now, however, dark energy is pulling the universe apart faster than gravity is crunching it together.
  • The Big Chill is what will happen if the balance between dark energy and gravity remains as it is today.  Scientists estimate that at its current rate, in about 30 billion years – that’s just a little more than twice as long as the universe has already been in existence –  the universe will consist of nothing more than isolated particles so far from each other than absolutely nothing ever happens.  The universe will by an infinity of cold emptiness.

By then life may have figured out how to get into another universe.

But we probably won’t live to see that:  the trip from Earth to Mars, beyond our solar system, into another galaxy and eventually to another universe is a little further than the local supermarket.

And it’s probably not even round trip.

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