After a Flawless Launch, Kepler Telescope Gets Ready for Planet Hunting

By Eliza Strickland | March 9, 2009 9:08 am

Kepler launchOn Friday night, a Delta 2 rocket blasted off from the Kennedy Space Center and roared into space carrying a satellite that will search the heavens for Earth-like planets. The craft, Kepler, named after the German astronomer Johannes Kepler, who discovered the planetary laws of motion, is to spend the next three and a half years in an orbit around the Sun, where it will count planets by looking for the tiny blips in starlight caused by planets eclipsing their suns [The New York Times].

The $600 million satellite will stare into a region of the Milky Way that’s thick with stars, in the direction of the constellations Cygnus and Lyra. While Kepler is expected to identify many new planets beyond our solar system, known as exoplanets, the real prize would be to find rocky planets in the “habitable zone” around a star, where conditions might be right for life as we know it. “The habitable zone is where we think water will be,” Bill Borucki, Kepler principal investigator at NASA Ames, says in a video on the space agency’s Kepler site. “If you can find liquid water on the surface we think we may very well find life there. So that zone is not too close to the star, because it’s too hot and water boils, and not too far away where the water is condensed…a planet covered with glaciers. It’s the Goldilocks zone–not too hot, not too cold, just right for life” [CNET].

While more than 300 exoplanets have been found since 1995, so far none of them qualify as prime real estate for life, and few of them reside in systems that resemble our own solar system. Many of the first planets discovered were so-called hot Jupiters, gas giants zipping around their stars in a few days in tight, blisteringly hot orbits [The New York Times]. Most of these giants were found by the so-called wobble method, in which the planet’s gravitational tug makes its star appear to wobble ever so slightly; a planet that is close to its star has a stronger tug and is easier to detect.

However, Kepler will bring new technological sophistication to the task of planet hunting. It uses the transit method, in which it watches for the slight darkening of a star as a planet passes in front of it, and researchers say it will be able to detect smaller planets in more habitable orbits. Every half hour, Kepler will record the brightness of 100,000 stars using a 95 megapixel camera…. The camera is so sensitive, it could spot the imperceptible dimming of a car headlight as a fly wanders across it [The Guardian].

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Image: NASA/Jack Pfaller

  • UncleAl

    SETI! Orbit a string of opaque reflectors about your star. The patterned modulation then broadcasts your message to a suitably enabled universe (orbital belt plus reflection angle – directional and steerable) without further expenditure. 31415 would do it, a mere 14 panels.

  • Nick

    Opaque to which wavelengths of light? They all pass through different materials. You also must not forget about the refractive properties of light, which cause it to bend around the edges of any material like waves – if your reflector is too small relative to the size of our star and where we are broadcasting to, the light will spread out around the reflector and the signal will be lost to interference.

    Honestly, I’d rather have the 95 megapixel camera… My 10 just ain’t cutting it anymore.

  • Steisin

    I have a question about this pls ?
    I suppose that the planet’s orbit around it’s star must be IN-LINE with the Kepler’s camera to be able to detect it ?
    So what if the orbit is perpendicular, or any other angle out-of-line with Keppler ?
    It would miss all those planets eh ?
    Or am I wrong, do all planets orbit in one plane only ?

  • Nelson Thompson

    you are correct! It is very unlikely that all stars have their planets in the same plane. Or even close. But Kepler will tell us if they do. If we assume that orbital planes are “random” around other stars, then those planets have about a one half percent chance of being situated so that they come BETWEEN their star and Kepler’s camera. So, out of 200,000 stars being examined by Kepler, if ALL of them actually do have planets, Kepler should detect planets around ~1,000 stars.

  • Georgia

    The goals of the Kepler mission:
    1.Determine the percentage of terrestrial and larger planets there are in or near the habitable zone of a wide variety of stars;

    2.Determine the distribution of sizes and shapes of the orbits of these planets;

    3.Estimate how many planets there are in multiple-star systems;
    Determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets;

    4.Identify additional members of each discovered planetary system using other techniques; and

    5.Determine the properties of those stars that harbor planetary systems.


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