Kepler is an interstellar hunter with a very specific prey: alien worlds.
He’s by no means alone, either. Planet hunting is an old pursuit, but recent technological innovations have sent forth a surge of exciting new discoveries — especially in the last year. In September 2010, headlines hit of a potentially earth-like planet in a habitable zone, Gleise581g, followed by the discovery of the first planet outside our galaxy in November. In December, astronomers even reported the analysis of a distant planet’s apparently steamy atmosphere— a possible water-world! And with Kepler still prowling the skies, new data is pouring in.
But how are these planets found, despite modern technology’s glaring lack of a warp drive? How do we, the non-astrophysicists, make sense of the slew of exciting new planet-hunting news amidst the jargon? Why do planets have such horrendously bland names, like HD8799? (And why is Johannes Kepler floating around in the vacuum of space? Isn’t he dead?)
In the following series of articles, we’ll explore the exploration itself, in order to help you better keep track of the myriad means and results of planet hunting, beginning with history and hunting techniques. Future articles will lay out the tools of the trade, and explore the planetary prey itself, from the hot-Jupiters to the super-Earths.
And by the way- Kepler isn't dead. He's just been reincarnated as a space camera.
Planet Hunting: A Brief History
Disappointingly enough, neither you nor the Earth are the center of the universe.
Niccolo Copernicus proposed this against the grumblings of the Church in the 16th century, but like many good theories, it raised as many questions as it answered. A Copernican supporter and contemporary, Italian philosopher Giordano Bruno, took the assertion a step further and proposed that the fixed stars in the night sky might be similar to our sun, and thus also orbited by planets (at this point, the Church moved beyond grumbling, and burned him at the stake in 1600).
Fortunately, with the later backing of Newton’s brains and Galileo’s telescope, this speculation lived on, and gradually gained ground to form the “Many Worlds” view of the universe, and the spark that began our hunt for
exoplanets—planets outside our solar system
(Newton, Principia).
Throughout the 19th and 20th centuries, several exoplanet discoveries were claimed, mostly limited to vague mumblings by the British about the “probable presence of planetary bodies” in binary star system 70 Ophiuci. However, all claims were later retracted when evolving detection techniques called their accuracy into question
(WS Jacob, Anomalies).
Despite a wealth of science fiction that would lead us to believe otherwise, it wasn’t until the end of the 20th century that planet hunting really took off (or got anywhere at all). The first confirmed exoplanet discovery was made in 1988 by the Canadian astronomers Bruce Campbell, G. A. H. Walker, and S. Yang using a then-new technique called radial velocity (see “Hunter’s Techniques”).
In October of 1995, French astronomers used this technique to discover the first exoplanet around an earthlike sun—51 Pegasi-b, nicknamed Belerophon
(Campbell, A Search for Substellar Companions).
In the interceding years between that discovery and the Kepler Space Camera’s recent data dump on February 2nd, approximately 500 exoplanets had been discovered. But how do we even find planets in the gaping maw of space, and what tools do we now have at our disposal?
The first thing you might reach for might be a camera, to trap the alien world on film, but this isn't as easy as it sounds. To learn more about the problem with snapshots, tune in for the next article in the series, as we kick off our look at the Planet Hunter's toolkit with "Planet Hunting Techniques: Direct Imaging."
