And to think that Giordano Bruno was burned alive only for hypothesizing the existence of infinite worlds, other planets around the other stars. But only in the last thirty years did we have the evidence of the existence of planets who orbit around other themselves, the so -called “exoplanets”. We have discovered different: super-terre (larger rocky planets of the earth), mini-nectuo (smaller gaseous planets than Neptune), giant giants (like Jupiter, or larger), ocean worlds (planets covered with vast oceans and atmospheres rich in hydrogen).
The last one is called K2-18B, it is 124 light years from us, and it could be one of the aforementioned ocean worlds. This was noted by the James Webb spatial telescope (who is reserving great satisfaction), but the interesting thing is that in its atmosphere there are traces of compounds that are considered biosignures, that is, signatures of life. In particular, traces of DMA (dimelet sulphide) and DMDS (disolfur of dimelet) have been seen, compounds that on earth are produced only by living organisms. Of course, it is not said that on other planets these same compounds cannot be produced even in the absence of life (it cannot be excluded), however they are relevant clues, which are making the whole scientific community debate, which as usual is prudent and awaits further confirmations to be sure beyond any doubt.
In short, we put that at 124 light years there is a planet that hosts life: we would know it precisely from these biological markers. Among other things, other possible lands, in recent years, have identified different ones, but someone might think “why don’t we go to see?”. Eh, a word. The distances are insurmountable. One hundred and twenty -four light years seem even few in cosmic terms (they are: the galaxies that we can see of the visible universe are thirteen billion light years away), but I would like to give you the measure of things: only in our galaxy there are almost two hundred billion of stars, each, apparently, with its planets. The diameter of the Milky Way is one hundred thousand light years, i.e. the light puts one hundred thousand years to follow it aside, and the light travels to three hundred thousand kilometers per second (the maximum speed that can be reached, because photons have no mass). To get to us, the K-2-18B light, being 124 light years, takes 124 years. Now, let’s think of the Voyager probes: they were launched by NASA in 1977 and have just left our sun system.
They travel at 61 thousand km per hour, and to get to the nearest star, Proxima Centauri, who just 4 years light years away, would take about eighty thousand years. In any case, if on K2-18b there should be life, do not imagine green greens: most likely bacteria and algae, extraterrestrials of course.