Wednesday, 16 October 2013

Terraforming: It’s a nice planet, but we can make it better.

Last week we looked at some of the doom and gloom associated with planets and how they change over time. Things heat up and habitable zones drift away leaving planets both balmy and dead. This week we will try to come up with an escape plan for the human race.

While it is pretty uncertain whether or not humans will exists when the issue becomes relevant, scientists agree that if we plan on surviving indefinitely as a species we will eventually have to leave Earth. So where do we go? We’ve been to the moon so we could set up shop there for a while, but since the moon is tied to the Earth it doesn’t solve much in the way of the sun roasting us to death. We could go to Venus, but moving towards the growing Sun would be equally unproductive. No, if we want a new home the most accessible options will be nearer to the edge of the solar system.

Astrobiologists have proposed three options within our own solar system. Two of them are moons. Titan is the largest of Saturn’s 53 known moons and has an atmosphere similar to what the Earth’s may have been like early in its development. Unfortunately, with a surface temperature of -178 degrees Celcius (-289 Fahrenheit), oceans of liquid methane, and a sky that rains gasoline, the comparisons end there. Europa is our other potential moon-base. It orbits Jupiter once every 3.5 days and is smaller than Titan but, like Earth, it has an Iron core and oceans made of water. The problem is that the oceans are deep enough to cover all the land and they are frozen. While Titan and Europa both have potential, there is only one object in our solar system that is even close to Earth in its current condition, and luckily it’s right next door.

Mars has long been of interest to astronomers both because of its proximity and its characteristics. It is a rocky planet (like Earth) with an atmosphere and evidence suggests that it may have once had liquid water. The problem is, that water is now frozen and as far as we can tell the planet is lifeless. It has an atmosphere that is 95% carbon dioxide and only 0.2% oxygen, but it takes more than poisonous air to squash an astrobiologist’s optimism. Enter terraforming.

Terraforming (literally “Earth Shaping”) is the process of changing a planet so that it can support human life. It sounds like science fiction, and right now is more or less is, but one day it might be just another thing that people do in space. We are already shaping our own planet through the burning of fossil fuels and the release of chemicals into the atmosphere, so why not try it someplace else?

Theorists have proposed three methods we might use to turn Mars into Earth 2.0 and they all focus on turning up the Martian thermostat. They are:
  1. Orbital Mirrors
  2. Pollution Factories
  3. Smashing Asteroids Into It
None of those options is a joke.

Orbital Mirrors (up to 250 kilometers in diameter) would be positioned around Mars to deflect more sunlight at the surface and begin to heat things up. Pollution factories would do what they do here on Earth and pump greenhouse gases into the atmosphere, trapping more of the heat that reaches the surface. Finally, for the impatient terraformer, there is the option of strapping rockets to asteroids that have a high ammonia content, pointing them Mars, lighting the fuse, and running like hell. The impacts would heat the surface by a few degrees each, but leave the planet off limits for a few centuries due to the generally unfavourable state of chaos they produce.

The idea is to warm things up enough for liquid water to begin flowing. From there, bacteria could be introduced to do what they did in the early days of the Earth and convert the atmosphere from almost entirely carbon dioxide to a more congenial mix of oxygen, nitrogen, and greenhouse gases.

The technology and the motivation to change Mars into humanity’s next home are likely many many years away, but as the Sun heats up and Earth gets crowded the red planet may gradually become the apple of our collective eye.