EXOPLANET NUMBERS INCREASE DRAMATICALLY
Illustration Credit: NASA of Kepler 22b. CLICK illustration for larger photo and see below for links and information.
When in 1584 Italian Catholic monk, philosopher & astronomer Giordano Bruno “II Nolano” claimed that there were “countless suns and countless earths all rotating around their suns,” he was imprisoned for 8 years and ultimately found guilty of heresy then burned at the stake. Upon hearing his judgment of death, he was quoted as saying, “Perchance you who pronounce my sentence are in greater fear than I who receive it.”
Let’s fast forward to 1992 when Polish radio astronomer Alexander Wolszczan working at Arecibo changed the world when he discovered two planets in orbit around pulsar PSR B1257+12. We, from that point on knew that, although there was unlikely any life around a pulsar, we as planets were no longer alone in the universe.
On October 6, 1995 a Swiss team (Didier Queloz and Michael Mayor) in Geneva used a difficult method called radial velocity (wobble method) to detect the first exoplanets in orbit around a sun-like star cataloged as 51 Pegasi. With technological advancements in astronomy and the community now realizing that exoplanets are out there without question, the flood gates of new world discoveries were just beginning to unlock.
Well just this week on Wednesday, February 26, 2014; using data collected by Kepler before its untimely reaction wheel failure has now added 715 new planets orbiting 305 stars to the planet zoo out there in our vey local region of the Milky Way. 95 percent of these newly verified planets appear to be smaller than the planet Neptune. The verification process was led by planetary scientist, Jack Lissauer at the NASA AMES Research Center at Moffett Field, CA. They used a method known as “Verification by Multiplicity,” which is reliant on the logic of probability. After careful study of mountains of Kepler data, 715 new exoplanets have been verified. Four of these new planets are only 2.5 times the size of Earth AND they’re located in the habitable “Goldilocks” zone around their respective star and who knows what possibilities that could lead to. Look for this discovery in detail in the March Astrophysical Journal.
Kepler’s work in confirming exoplanets brings our current total to 5535: 1690 confirmed with 3845 candidates. Remember of course these are all within roughly 3000 light years away and in a spot encompassing only 0.25 percent of the night sky. That’s one quarter of one percent of the night sky!
Something to keep in mind here is that Kepler uses the “Wink” method of detection by transit. As a planet crosses in front of its host star, the light from that star diminishes a fraction of a percent. So these planets discovered are the lucky ones who just happen to be crossing their host star in a plane that allows us to detect them. This usually means detection of planets that are fairly close to their host star as more distant planets usually less well behaved. If aliens were using Kepler there is only about a 10 percent chance they would see Earth; possibly 12 percent chance to spot Venus. In addition, Kepler needed to witness multiple transits of the same object to verify planet status. For planets with orbits longer than the years Kepler was working properly they haven’t been verified and shall remain in the “candidate” class for now. The data used to find these new 715 planets came from the first two of four years of data that Kepler collected. Scientists infer that one in five sun-like stars has an Earth-like planet in its habitable zone. From that one could also infer that there are tens of billions of Earth-like habitable zone planets in our galaxy alone and in total, combined with rogue planets; planets themselves may match or even surpass the number of stars in the galaxy.
It’s truly incredible how far we’ve come in such a relatively short time. We can only speculate on what Kepler “would have” done had it remained 100% operational. For now, telescopes such as Keck, Gemini, Hubble, HARPS etc. are still on the hunt and making discoveries as well. The Transiting Exoplanet Survey Satellite (TESS) is NASA’s newest planet hunter and it’s tentatively scheduled for launch in 2017 and ESA’s PLAneary Transit and Oscillations (PLATO) planet hunter scheduled to launch in 2024.
NASA/Kepler press kit on this latest discovery: http://www.nasa.gov/ames/kepler/digital-press-kit-kepler-planet-bonanza/
NASA JPL Planet Quest: http://planetquest.jpl.nasa.gov/
NASA Kepler Mission: http://kepler.nasa.gov/
Exoplanet Database: http://exoplanets.org/
Exoplanet Catalog: http://exoplanet.eu/
Planetary Habitability Laboratory (PHL): http://phl.upr.edu/
Planetary Society page on exoplanets: http://www.planetary.org/explore/space-topics/exoplanets/
KECK exoplanet page: http://www.keckobservatory.org/exoplanets/exoplanets_explained
Gemini planet imager: http://planetimager.org/
ESO’s HARPS planet hunter: http://www.eso.org/public/usa/news/eso1134/
Hubblesite exoplanets page: http://hubblesite.org/newscenter/archive/releases/star/extrasolar-planets/