Looking for other worlds

2000/05/01 Arregi Bengoa, Jesus Iturria: Elhuyar aldizkaria

• Astronomia

Until a few years ago, talking about life off Earth opened the way for speculation. An example of this is Drake's well-known formula that calculates the probability that life outside the Solar System will be intelligent. It certainly does not lack scientific bases, but also speculation due to data scarcity.

Continuing with the example, we cannot say that this calculation is currently more reliable than in its day, but, at least in one of the variables that requires it, it can be said that solid projects have been implemented to overcome the aforementioned data shortage. I am referring precisely to the problem of extrasolar planets. The consequences of these solid programs are evident, as since 1992 32 planets have been found outside the Solar System. The last two were obtained in March: Two planets smaller than Saturn around so many other stars. The discoveries have been much greater than them, most greater than the giant Jupiter, and therefore the importance of these last discoveries. This latest discovery reveals that there may be planets in size and shape of Earth.

However, the orbits of both the new planets found and those previously known present a remarkable peculiarity: they are very close to the central star, more or less close to the Mercury Sun. This leaves little room for planets like Earth that should be closer.

However, the mere discovery of large planets is due to the limited resolution offered by current detection techniques and observation instruments. The proximity to stars may be because studies have begun a few years ago. The closer the planet of the star is, the less time it takes to turn around it, and we can know it before Earth. Given this limitation, the next interesting step would be to find a planet like Jupiter and, in addition, the distance from Jupiter to the Sun to the verse. Considering that the Jupiter period is almost 12 years, it is estimated that measurements should be extended for another five years to reach the target. If this is achieved, the chances of securing the existence of other small planets would increase, but scientists do not want to stay there. For the next decade, two space missions are taking place in search of small planets to increase the resolution of observations. The first, the Space Interferometry Mission, is scheduled for 2006. Regardless of the discomfort caused by the atmosphere, you will be able to detect a planet with five times the mass of the Earth at a distance of 33 light years and, logically, if the smaller planets were closer. The Terrestrial Planet Finder mission, which would orbit in 2011, will be able to find Earth-sized planets up to a distance of 50 light years.

It is clear, then, that within about ten years things will be much clearer in relation to this problem, because among many other things, we can say that those similar to our Solar System are normal or rare, with all the consequences that this entails, such as the construction of planetary theories and systems, or the search for life outside the Earth.