Free Astronomy Magazine January-February 2015

5 ASTROBIOLOGY A nyone who frequently reads about space and astronomy news, soon re- alizes that in this branch of science there are very few absolute truths, such that even the more renown- ed theories are continually be- ing called into question by new discoveries. It can hap- pen that a research team reaches a certain, seemingly incontrovertible, conclu- sion and after a short time another team arrives to a significantly different, if not diametrically opposed, conclusion. And this is the essence of science; namely the ability to call into que- stion everything for the pur- pose of learning, demonstrating and reproducing the reality of things. An example of this was had in 2014, with regard to the habitability of Earth’s size plan- ets orbiting red dwarfs. Within a few months, we saw the publication of scientific works that repeatedly overturned our perception of those scenarios, at times describing them as ex- tremely hospitable, sometimes as completely hostile. Let us briefly look at the main points of the story and the con- clusions reached by researchers, without exempting ourselves from a quick introduction that will be useful to better understand the is- sue. When astronomers began towon- der around which stars would be less difficult to discover planets potentially suitable for life, red dwarfs met the high- est approval, even if the only known bio- sphere is hosted by a yellow dwarf, i.e. the Sun. Given the Sun’s mass equal to 1, that of red dwarfs is by convention comprised I n the background, a hypothetical planet (with satellites) of a red dwarf. This type of scenario may not be as favourable to life as believed so far. [NASA/Harvard-Smithsonian Center for Astrophysics/D. Aguilar] JANUARY-FEBRUARY 2015