A play-off, LISA pathfinder difficult set sail

By Catherine Fox,2015-11-01 11:33
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A play-off, LISA pathfinder difficult set sail

    A play-off, LISA pathfinder difficult set sail!

    Launch day today LISA pathfinder, will pave the way for space gravitational wave detection.Image: ESA

    UPDATE: LISA pathfinder has launched on December 3, is expected to spend 10 weeks is transferred to the final orbit.Expect the test!

    Beijing time at noon Dec. 3 12:15, a vega rocket will be launched into space from French Guiana space center, will LISA Pathfinder (LISA Pathfinder) delivered to a day - 1.5 million kilometers to Lagrangian point 1.The detector worthy of the name, as LISA pathfinder, it will make the first step on the space observation of gravitational waves.

    Gravitational waves

    For physics, exactly a century ago, in 1915, is a year of some divine significance.This year, after 10 years of meditation, Einstein finally determine the describe the gravitational field equations.On November 25, 1915, he formally submitted papers describing the general theory of relativity formula.At the same time,

    he did once a week, in the German academy of sciences report up to four weeks, officially announced to the world that a ground-breaking conclusions: gravity, but is the bending of space and time.

    One hundred years later, at this moment, we will have exciting era.On September 18, 2015, after thoroughly remould oneself, the ground of the gravitational wave detector advanced LIGO formally began to work;Today, LISA pathfinder will officially launch up to heaven.We, our breath, listening to the universe.

    This moment, probably Einstein did not dream of.Is deduced from the general theory of relativity, he soon realized, like waves, gravity is also in the form of wave propagation, and speed is the speed of light.He later wrote in the paper, there is no use, however, gravitational wave is too weak, can not detect.

    Many scientists are desperately trying to prove Einstein wrong, a successful person is not much, detect gravitational waves of people is a part of it.Einstein did wrong this time: gravitational waves are very weak, but not can't detect.By using the method of laser interference, and a series of cow force in technology, we can detect very small disturbance of space and time.How small?Atom is small enough, if the extended our detector, a head in the earth, in the sun, the probe length even if only a atomic scale changes, we all need to detect it out.Such precision, advanced LIGO has now done.

    The detector on the ground, however, have their own suffering.Precisely because it was so sensitive that they sensed it will be affected.Thousands of meters outside the truck drove by highway, dozens of kilometres away someone cut down a tree in the forest, hundreds of kilometres away waves patting beach, will leave traces on the LIGO detector.Due to the existence of noise, on the ground, we can only focus on high-frequency gravitational waves (100-1000 Hz), low frequency gravitational waves can only give up.To detect gravitational waves much lower frequency signal, it must be far away from the earth, into space.


    Space to detect gravitational waves of projects is not like the ground so lucky.Space programme has always been famous for its high risk, in the event of failure, basically, instrument completely scrapped, unless the amount of money spent replacement parts (such as the Hubble telescope) or replace the scientific goal (such as a search for extrasolar planets Kepler telescope).

    Space laser interferometer gravitational-wave detectors LISA, is put forward for the first time in the sixties and seventies of the last century, but to this day, distance from emission is still a distant prospect.Three detectors in the original design, formation, 5 million km away from the interference between two arm, is equal to the distance from the earth to the moon is 13 times, total can constitute three

    interferometer.Distance so far, these satellites in the event of failure, it is impossible to repair.As for those who make detection accuracy to cow force of incredible technology... So to speak, cattle were stable and reliable, basic is a pair of antonyms in technology.