|Proxima Centauri image credit: ESA / Hubble / NASA|
A planet has been spotted in that habitable zone of our nearest neighbor, Proxima Centauri. As a kid, I saw television shows and movies with space aliens claiming to be from Alpha Centauri, and thought that it was our nearest neighbor. Well, yes and no. Alpha Centauri is the nearest star system, with three stars. The faint red dwarf Proxima Centauri is the actual closest star to our own planet, Dirt.
"You mean Earth, not dirt, Cowboy Bob".
A red dwarf has a planet in the habitable zone? The habitable zone is only the first consideration, as there are many others involved to make a planet suitable for life. One problem is that red dwarf stars are bad medicine for life forms. Then there are many areas of concern. Our Creator made Dirt — I mean, Earth — a unique place orbiting the right kind of star with special conditions, all keeping us safe. Nothing approximate happening here like up yonder, no siree!
A little more than two decades ago, astronomers discovered the first known exoplanets, planets orbiting other stars. The current exoplanet tally is about 3,500, but that number is sure to grow. The impetus for the search for exoplanets is to find planets on which life is possible. The vast majority of extrasolar planet discoveries clearly are hostile to life. However, from time to time there are reports of the discovery of a possible earth-like planet. This is the situation of Proxima Centauri b, announced on August 24, 2016.
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What qualifies an extrasolar planet as being earth-like and hence a possible haven for life? First, a planet must orbit in a star’s habitable zone. The habitable zone is the narrow region around a star in which the possibility of liquid water, thought essential for life, can exist. If a planet orbits its star closer than the habitable zone, the planet’s surface likely is too hot for liquid water to exist. If the planet orbits farther away, the planet’s surface probably will be too cold for liquid water. The distance of the habitable zone from a particular star depends upon the star’s temperature and brightness.To read the rest, click on the star feature, "Proxima Centauri b: An Earth-Like Planet?" Then, I highly recommend, "Hope, Not Evidence, Drives Astrobiology".