YM COLUMN ARCHIVE

May 6, 2009

Kepler sent out for searching earth-like planets

Banto Yamagata, a merchant scholar of Osaka in the Edo period, presented his unique thought in his book “Yume-no-shiro” (ages of dream); in which is included his cosmic view. In the chapter of astronomy he acknowledged the Copernican system to support the heliocentric system, in which he delivered his thought that the universe is totally dark from the beginning and in its center exists a sun. He defined the range for sunlight reachable as “light world”. This is what we call now “Solar System”. He said there were six major planets in the light world, i.e. Jupiter, Mars, Saturn, Venus, Mercury and Earth. In his time Uranus and Neptune were not known yet. Moon was earth’s attached celestial body and believed that there were also four such objects attached to Jupiter and five to Saturn to have totally called them ten “small planets” including earth’s moon. They are what we call today, “satellites”. Yamagata seemed to have believed that these ten celestial objects and six planets all belonged to the light world and in each body existed humans, animals and plants. He wrote in the book, “Several millions of stars are all suns-----and there are several millions of light worlds in the universe.” What a splendid notion to have thought Solar System, not to mention earth, is not the only existence in the universe!

Does there really exist a planet(s) like earth outside of the Solar System? Controversy on aliens has been long going on in the world in history. Now is the time to think about alien problem and explore the space with help of science. It is evidently clear now that there exists no high intelligent creatures like human beings in the other planets other than earth in the Solar System, but continuous efforts have being energetically carried on for searching microorganism or its traces. Potential bodies for those organisms are increasing as exploration has been reaching out for Mars, Europa, Titan, Enceladus and so forth.

On the other hand, searches for living creatures outside of the Solar System are going on in every possible way apart from that of the Solar System. They are: “Ozma project” that is USA-Russia-centered projects to wait for receiving signals from the outer world started in 1960’s; “Messages to extraterrestrial intelligence” carried onboard Pioneer and Voyager; public participating type project of SETI@HOME to send out signals from Arecibo, among which most remarkable are series of discovering new planets following the first discovery of extrasolar planets in Pegasus in 1996. Astronomers have confirmed over three hundred extrasolar planets so far. However, all of those seem to be gas-giant planets of Jupiter type.

On last April 6, 2009, the satellite weighing one-ton flied over the sky of Florida for the purpose of finding the planets of the solid surface like earth. This is the satellite “Kepler” mounted onboard Delta II rocket. Kepler will not simply stay on the orbit around the earth but will be on Earth-trailing solar orbit constantly staying close to earth to keep transmitting data to earth. Astronomical telescope of field of view with 105 degrees will simultaneously observe a hundred thousand stars to check the brightness of the stars every thirty minutes to enable to monitor slight changes in brightness when planets cut across right in front of mother stars.

Capability of the photometer installed on Kepler is estimated to be able to discover the extrasolar planets of which size are 1/600th of Jupiter class. We can highly expect of its outcome. Already on April 8th, the first light image was transmitted to earth, and on April 23rd the project team completed accurate focusing by moving the primary mirror 40 microns toward the focal plane to finish fine adjustment of tilting the primary mirror 0.0072 degrees. Data will be continuously sent to earth from now on, out of which what kind of “outer space” we can see is really our exciting fun.

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