Monday, December 12, 2011

Exoplanets and space colonization

Astronomy is a fast developing science with an increased number of scientists who believe that humans could already be able to colonize other, earth-like planets. Many scientists also agree that humanity simply needs to find ways to live on other planets if it wants to avoid extinction in years to come.

The astronomers have recently discovered hundreds of planets that could potentially in future be used for human colonization. In order to explore these planets science will have to evolve to the point where long term space exploration could be done without harmful effects to health of astronomers. The science will have to overcome challenges of radiation exposure and musculoskeletal deterioration in order for humans to colonize and settle on other planets.

The planets that have potential to support life are called exoplanets. Most of the hundreds of exoplanets that have been detected to date have been found by the so called transit method, which detects a dimming in light as a planet moves in front of a star, or by looking for a wobble as a star is tugged by the gravity of an orbiting planet.

In September 2011, The astronomers at HARPS (The HARPS spectrograph on the 3.6-metre telescope at ESO's La Silla Observatory in Chile is the world's most successful planet finder) led by Michel Mayor (University of Geneva, Switzerland), have announced the discovery of more than 50 new exoplanets orbiting nearby stars, including sixteen super-Earths (planets with a mass between one and ten times that of Earth are called super-Earths, so far there hasn't been discovered any of these planets in our Solar system but apparently they seem to be very common around stars in other galaxies.). The pace of discovering new exoplanets is accelerating.

The astronomers have already coined the term the "habitable zone" which refers to the region around a star where a planet of Earth-like size, composition and atmospheric pressure can maintain liquid water on its surface. Under the currently available scientific knowledge liquid water is considered to be the prerequisite for life on other planets, though this doesn’t have to be necessarily true. Exoplanets orbit their sun at a distance where the temperatures on the planet's surface allow for the presence of liquid water.

Some scientists believe that the chances for finding life at habitable zone around low-mass stars are pretty bleak and that astronomers should focus more on finding new Sun if they are to find new Earth. One of these scientists is René Heller of the Astrophysical Institute Potsdam (AIP) who says that current astronomic science didn't include tidal effects into equation which significantly modifies the traditional concept of the habitable zone.

It is expected that in the next couple of years the number of exoplanets will reach thousands so science will have to limit their focus only on few of them, namely the ones that apparently exhibit the most Earth-like of conditions. The current number of exoplanets stands around 600.