Thanks to our blogger pal at The Daley Gator for the Rule Five links!
This fine Monday I find myself in the environs of Knoxville, Tennessee, here to deliver four hours of training before emplaning to Boston, where I will stay until Friday, likewise delivering training. So, posts this pre-holiday week may be a trifle terse.
Meanwhile: Here are the most likely spots for extraterrestrial life in the Milky Way galaxy. Excerpt:
To support life as we know it, planets must have liquid water and orbit in the right place in their solar systems, not too close and not too far from their star. Similarly, life will not emerge or survive for long near the centers of galaxies. Here, the high density of stars means that at any given time several could be exploding, frying off a planet’s ozone layer and exposing any surface life to deadly ultraviolet rays.
So in the new study, researchers led by physicist Duncan Forgan of the University of St. Andrews in Fife, U.K., focused on the regions far from a galaxy’s center. They used computer simulations to model an entire Milky Way–like galaxy and its neighbors, the Andromeda and Triangulum galaxies. They then simulated the distribution of gas, stars, and planetary systems within those whorls of stars. Finally, they allowed these galaxies to evolve over billions of years, while mapping out their evolving habitable zones. “We’re the first to look at how the history of galaxies affects their habitability,” Forgan says.
For every type of star in the simulation, Forgan and his colleagues estimated the probability that terrestrial planets would form, some of which might be Earth–like or might be as inhospitable as Mercury. They also estimated the chance that a giant planet as large as Neptune would form near the star, as it would disrupt potential earths that could have assembled there. Then they analyzed the likelihood of short-lived life-friendly worlds that happened to be in stellar systems too close to dying, exploding stars.
The team’s simulations show, perhaps not surprisingly, that potentially habitable planets are more likely to remain so if they form in areas far from dense conglomerations of stars, where more supernova explosions occur. The results indicate that for the Milky Way and other spiral galaxies, the most dangerous regions are in the galactic centers, whereas the more diffuse spiral arms pose fewer hazards and are therefore more hospitable to life. Earth lies near the inner edge of this habitable zone.
Still, the universal speed limit – that is, the speed of light in a vacuum – makes it highly unlikely we will visit any of these places any time soon, unless we can find some way to sidestep time and space itself – as in the (admittedly wonderful) movie Interstellar.
In the meantime, I’d settle for finding some signs of intelligent life in Congress.