The US space agency, NASA, is preparing for a new research project to discover Earth-like planets in other solar systems
"Operation Kepler" to discover the twin-earth Kepler spacecraft
In the last nine years, many planets (outside our solar system) orbiting and orbiting others have been discovered. The number of discoveries so far: 63, and it increases every year. Only recently have 11 extraterrestrial planets of this type been discovered.
The method by which most of these planets were discovered is based on measuring the "oscillation" of the sun (the star) and tracking the planet that orbits it. Now another method has been invented, perhaps more effective - and a NASA space mission will be based on it at the end of the decade. A spacecraft named after the German astronomer Johannes Kepler (1630-1571) would discover extraterrestrial planets by measuring the eclipse of the star ("solar eclipse") through its planet. Kepler is supposed to discover at least 50 Earth-like planets this way.
This research was done as part of the search for life - also intelligent - in outer space. The requirements, for a planet to be "considered" Earth-like, limit its mass and its distance from the Sun around which it is orbiting. So far, in the discoveries of the planets, they have been particularly sensitive to planets with a large mass, at least as large as Jupiter, that orbited their sun very close to it, in cycles measured in days.
But life like ours cannot exist on these planets: they are too hot and their atmosphere is dense. A fact that facilitated disclosures. The large mass pulls on the star (the sun) which the planets orbit sufficiently to be detected when studying the changes in the speed of the star's movement, relative to us. In each cycle, the star moves towards us half a circle, and away from us - another half.
In the last decade, methods were developed to measure the speed of the movement of the stars, which are sensitive to movements of tens of meters per second, (ckcs) the size of the oscillation that the planet induces in the star it orbits.
The newer method will be based on very partial eclipses that the planet makes to the orbiting star. In our solar eclipse, the moon passes between us and the sun. The sunlight is then reduced, relatively, to a normal state. The reduction in the mean magnitude is easy to detect and measure due to the apparent size of the Sun and the Moon: from Earth they both look almost identical.
Sometimes, an inner planet—such as Venus or Mercury—passes across the Sun, as seen from Earth. Then you see a black dot passing by the sun. But the reduction of light in this situation is minimal: about a hundredth of a percent and there is no way to measure it from the ground because of atmospheric disturbances.
"Kepler" will thus measure other suns, with the help of an observation point very far from our atmosphere. It will be equipped with a light-collecting scope with a primary mirror with a diameter of 1 meter and a field of view of 105 square degrees - a quarter of a percent of the angular size of the entire sky and will be placed in space in orbit around the sun, which is getting further and further away from the earth. The observation will be made from the constellation "Swan" - in the direction to which an arm of the "Milky Way" extends - where a hundred thousand stars that are candidates for being suns for Gemini-Earth will be photographed at the same time.
It is already known that no less than 220 stars will appear in this section of the sky - but about half of them will not be "interesting" for research on "Gemini Earth" because they are too hot/cold, and too big to be "good" suns for Gemini Earth.
Repeated photographs - once every 6 hours in the 4 years of the operation - will make it possible to discover the transit of planets across their suns (due to the temporary, tiny decrease in light intensities). The method was made possible thanks to the development of detectors resistant to prolonged stay in space and high sensitivity to light intensity. The special position of the telescope eliminated the problem of atmospheric interference.
The decision on the budgeting of "Kepler" will be made at the end of the summer. If the program is approved, the spacecraft will be launched in 2005 and the data collection will continue until 2010. Perhaps then we will receive the "awaited gift": clear signs of the existence of life like ours in other solar systems in the universe.
