To follow up on my recent tale of Alpha Centauri I have what may be considered bad news if you were looking to move to the recently discovered Proxima b. Apparently it may lose too much of the atmosphere/oxygen to support liquid water, hence life.
I have 2 problems with the above statement – the first because it needs the word theoretically added to it and second because if true it isn’t life that is won’t survive, just us. (unless we wear suits etc.)
While traditionally scientists have determined habitable zones basing it on the amount of eat & light the host star gives off, there is new research that adds a dimension. Stellar eruptions and the loss rate of atmospheric oxygen shows a more detailed picture. When arriving at these amounts the team further investigated the varying high-energy X rays and Ultraviolet emissions given off by Red Dwarfs which could take a planet that by the original standards was in the habitable zone but now allows the atmospheric escape. It comes down to the more X-ray and extreme ultraviolet energy there is, the more electrons are generated and the stronger the ion escape effect becomes.
Because of Proxima b’s tight orbit around its star, Proxima Centauri, it is estimated that the planet goes through atmosphere-stripping stellar storms every 2 hours. Given the data collected on Proxima b’s size and composition, its oxygen is estimated to be fully eliminated within 10 million years. Basically, the assumption is things are not looking good for life on Proxima B—or planets that orbit red dwarf stars in general which unfortunately is 20 to 30 of the stars closest to our solar system.
I have one comment to make. There is much to do about the requirements for life. I had in fact thought scientists were getting away from making the connection between O2 & H2O for us and extending it to anyone else. In my opinion if there are around 400 billion stars in the Milky Way and on average each star has at least one planet. AND there are about 100 billion to 200 billion Galaxies – if 40 billion (Out of ~400 billion) in each of those galaxies are Earth-like that means the majority are not. So, are you telling me that life finds a way in 1/10thof the situations but not in 9/10ths or 90% of the time? Seems unlikely to me. Perhaps much like we are carbon based – maybe there’s silicate based life.