(Lyrical content can always be a challenge for songwriters. Some of us have no problem at all, yet many cringe at the idea of telling a real story in their song. Well, Tad Doyle looks to the furthest reaches of the known universe for much of his lyrical muse. Brothers of the Sonic Cloth delve into subjects as wide open and ethereal as our planets basic elements; you know, earth, wind, fire, water and all that jazz. On the podcast this week, Tad also told us about his love for shit outside our solar system, like exoplanets. I am no astrophysicist, but am a verified science fiction nerd and love all things outer space. So, here’s a bit of info we found from the interweb on exoplanets. Pretty awesome stuff, and holy crap it makes for good doom metal lyrics. – FATS)
An exoplanet or extrasolar planet is a planet that orbits a star other than the Sun, a stellar remnant, or a brown dwarf. Nearly 2000 exoplanets have been discovered (1924 planets in 1216 planetary systems including 483 multiple planetary systems as of 20 May 2015). There are also rogue planets, which do not orbit any star and which tend to be considered separately, especially if they are gas giants, in which case they are often counted, like WISE 0855−0714, as sub-brown dwarfs.
The Kepler space telescope has also detected a few thousand candidate planets, of which about 11% may be false positives. There is at least one planet on average per star. Around 1 in 5 Sun-like stars have an “Earth-sized” planet in the habitable zone, with the nearest expected to be within 12 light-years distance from Earth. Assuming 200 billion stars in the Milky Way, that would be 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if red dwarfs are included. The rogue planets in the Milky Way possibly number in the trillions.
Size comparison of Jupiter and the exoplanet TrES-3b. TrES-3b has an orbital period of only 31 days and is classified as a Hot Jupiter for being large and close to its star, making it one of the easiest planets to detect by the transit method.
The nearest known exoplanet, if confirmed, would be Alpha Centauri Bb, but there is some doubt about its existence. Almost all of the planets detected so far are within the Milky Way, but there have also been a few possible detections of extragalactic planets. As of March 2014, the least massive planet known is PSR B1257+12 A, which is about twice the mass of the Moon. The most massive planet listed on the NASA Exoplanet Archive is DENIS-P J082303.1-491201 b, about 29 times the mass of Jupiter, although according to most definitions of a planet, it is too massive to be a planet and may be a brown dwarf instead. There are planets that are so near to their star that they take only a few hours to orbit and there are others so far away that they take thousands of years to orbit. Some are so far out that it is difficult to tell if they are gravitationally bound to the star.
The discovery of exoplanets has intensified interest in the search for extraterrestrial life, particularly for those that orbit in the host star’s habitable zone where it is possible for liquid water (and therefore life) to exist on the surface. The study of planetary habitability also considers a wide range of other factors in determining the suitability of a planet for hosting life.
For more fun searching for stuff really, really far away from here, check out http://www.exoplanets.org. Really fucking far away. Really.