New Worlds and Irrational Thought

"...given what we now know about the number and orbital positions of the galaxy’s planets, the degree of pessimism required to doubt the existence, at some point in time, of an advanced extraterrestrial civilization borders on the irrational."

-- Statement by astrophysics professor Adam Frank in a New York Times article titled "Yes, There Have Been Aliens." He discussed the findings of a paper titled "A New Empirical Constraint on the Prevalence of Technological Species in the Universe," which uses the Drake equation to re-estimate the likelihood of intelligent alien life given what we have learned to date about exoplanets, concluding "...even if you grant that level of pessimism, a trillion civilizations still would have appeared over the course of cosmic history."

Exoplanets: The Count Increases

NASA announced this week that scientists analyzing 2015 data from the refurbished Kepler space telescope, now called K2, has discovered another 1,284 exoplanets. This doubles the number of planets discover by the telescope since it was put into operation.

Among these newly discovered exoplanets, 550 are rocky like Earth and 9 are within their sun's habitable zone. As a result, the Kepler mission has discovered a total of 21 exoplanets that appear to be similar to Earth.

This is goods news as K2 continues its mission while other space telescope missions are being planned to help with the search in the near future.

Help Name the Exoplanets

If you are looking to name something outside the solar system, a few exoplanets await you. The International Astronomical Union has a list of 20 exoplanets in need of a name.  All you need to do is visit this site to vote. 

For instance, four planets orbit mu Arae above and the voting allows you to vote in clusters, naming both the sun and orbiting planets.  One of the naming clusters is shown below and has a Portuguese theme.   

Voting is open until October 31 and the winners will be announced in November (the timeline and rules are here).  Here is your chance to impact a whole new world. 

More Earth-Like Planets Located

If you are looking for a little bit of bedtime reading, you could do worse than this 138 page paper from NASA titled "Validation of Kepler’s Multiple Planet Candidates. III: Light Curve Analysis & Announcement of Hundreds of New Multi-planet Systems."  Released on February 25th, the paper highlights the expoplanets found to date as well as a few new ones:

The Kepler mission has discovered over 2500 exoplanet candidates in the first two years of spacecraft data, with approximately 40% of them in candidate multi-planet systems. The high rate of multiplicity combined with the low rate of identified false-positives indicates that the multiplanet systems contain very few false-positive signals due to other systems not gravitationally bound to the target star (Lissauer, J. J., et al., 2012, ApJ 750, 131). False positives in the multi-planet systems are identified and removed, leaving behind a residual population of candidate multi-planet transiting systems expected to have a false-positive rate less than 1%. We present a sample of 340 planetary systems that contain 851 planets that are validated to substantially better than the 99% confidence level; the vast majority of these have not been previously verified as planets.

Among these 851 planets, the ones of particular interest are the "...768 planets across 306 systems being newly validated."  That is a nice collection of new new planets. 

For some reason, in its press release, NASA's Jet Propulsion Laboratory announced 715 new planets around 305 star systems. But why quibble?  But here is the important part:

Four of these new planets are less than 2.5 times the size of Earth and orbit in their sun's habitable zone, defined as the range of distance from a star where the surface temperature of an orbiting planet may be suitable for life-giving liquid water.  One of these new habitable zone planets, called Kepler-296f, orbits a star half the size and 5 percent as bright as our sun. Kepler-296f is twice the size of Earth, but scientists do not know whether the planet is a gaseous world, with a thick hydrogen-helium envelope, or it is a water world surrounded by a deep ocean.

I expect that more research on all the data acquired in the earlier Kepler mission will continue to bring forward new findings.  And, as noted earlier, Kepler may still have some life left for new missions.  

Image Credit:  NASA/JPL-Caltech/R. Hurt (SSC-Caltech)