A Glittered Backdrop of Promise

When searching for exoplanets, our primary interest is in life. "Is this planet habitable?" we often ask. "Is there other life in the Universe?" "Can we make this our own home if we need to?" These questions lead us to the search for a very specific type of exoplanet - Earth-like ones. These questions, and the search for Earth-like planets, have led us to the creation of the Kepler Space Telescope.

Kepler Space Telescope

The Kepler space telescope, or "Kepler," is a modern-day NASA space craft tailored to a certain type of observation - transits. Transits were covered in my post entitled "A Tale of Two Atmospheres." This celestial phenomenon occurs when an object (in this case, a planet) comes between the Earth and the target star. When this happens, we are able to observe a slight dip in the brightness of the light that reaches our eyes, camera, or any other light detector. With this dip in brightness, we are able to determine a lot about the transiting object, including its size and atmosphere.

Kepler is equipped only with a photometer. Wisegeek says "In astronomy, a photometer is used to measure the amount of light contained within stars or other celestial points." Kepler's photometer is very sharp, and can accurately measure the brightnesses of stars with extreme precision. This enables it to survey a field of stars simultaneously, instead of focusing on one target object at a time.

Using Kepler, NASA has been able to locate and confirm the existence of 156 exoplanets, and discover 3,602 planetary candidates. With this data, it is estimated that there are 60 billion habitable exoplanets in the Milky Way Galaxy alone.

A size comparison between a Kepler exoplanet and planets in our solar system.

These numbers alone speak very highly of modern-day astronomical techniques. With the tools currently at our disposal, we are able to discover so much more than we could possibly imagine. As technology advances, we will be able to process more and more data, and learn so much about the Universe we live in.