Nov 162017

From the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo:

HEC: Periodic Table of Exoplanets

You know how many exoplanets were known when I was in college? None. Zero. Zip. Nada. Now? 3,700+.


 Posted by at 7:47 pm
  • Derek

    Its only a matter of time before we detect signs of some sort of extraterrestrial life. More planets that we find, the better our chances. I bet we’ll find signs of ET before the end of the century.

    I’m thinking we’ll discover a Dyson Sphere type of construct first.

  • Herp McDerp

    The thing to remember about those numbers is that there are enormous selection biases imposed by the detection methods. The radial velocity method can only detect Earth-mass and smaller planets that orbit stars less massive than the Sun. The transit method requires that our line of sight nearly match the plane of the exoplanets’ orbits, and the exactness of the alignment required for detection increases for planets farther away from the star — so we detect relatively few planets in wide orbits. Even worse, planets in wide orbits take more time to orbit their stars; the main Kepler mission lasted less than four years, so if Kepler had been observing the Sun it likely would have missed even one transit of Jupiter (in a twelve-year orbit) and never would have seen two transits (to determine the size of the orbit).

    Bottom line: we still can’t detect many of the planets that are out there; we miss most of the Earth-sized worlds that would be the best candidates for “habitable” planets. (NASA uses “habitable” to mean “potentially life-bearing.” By that standard, a super-Europa with the mass and temperature of Earth would be “habitable” … but I wouldn’t want to colonize it.)