Observing Einstein's gravitational waves

[Tormod]

A hundred years ago, Albert Einstein published his theory of relativity. The existence of gravitational waves stems from Einstein's postulates.

 

lefthttp://hypography.com/gallery/files/5/Gravitational_waves_07_L_thumb.jpg[/img]When very massive bodies are disturbed, they radiate waves or ripples that travel through space. Objects they encounter vibrate without moving, but as a consequence of the deformation of the space-time texture in which they are at rest.

 

The Laser Interferometer Space Antenna (LISA) mission, whose launch is envisaged for 2013, will use laser interferometers - very sensitive tools to measure tiny variations in the distance between objects – and proof masses on board three spacecraft flying in formation.

 

The system is designed to detect low-frequency gravitational waves which originate from, for instance, black holes swallowing massive neutron stars or binary star systems revolving around each other. They were also produced at the very origins of time, when the Big Bang occurred.

 

"As far as we know, the Universe began 13.7 billion years ago," explains Karsten Danzmann, Principal Investigator for the LISA mission at the Max-Planck-Institut fur Gravitationsphysik in Hannover in Germany.

 

Listening to the Big Bang

"We have the dream of listening to that Big Bang itself by detecting and studying gravitational waves. It will give us a chance of listening to the dark, invisible side of the Universe."

 

Gravitational waves are so weak they are extremely difficult to hear. Because of our planet's own gravity, laser interferometers on Earth can only detect high frequencies, stemming from sources which are relatively close.

 

"If you want to listen to the high pitch notes of a concert you can do so with small ears, but if you want to listen to the real low pitches, you need big ears, and the only place where you can have big ears is in space," says Danzmann.

 

The LISA mission is one of the most ambitious ever undertaken: positioning and flying three spacecraft in a triangular formation, 5 million kilometres apart. The constellation will orbit the Sun, following the Earth at a distance of 50 million kilometres so as not to be perturbed by its gravity.

 

Infrared lasers will be beamed between the spacecraft, arriving on small 2-kilogram proof masses, 4-centimetre cubes made of gold and platinum.

 

At the University of Trent in Italy, Euronews was able to see the first of these proof masses destined for the LISA Pathfinder precursor mission. Due to be launched in 2008, its single satellite will test the general concepts and technologies of the LISA mission.

 

"We will be flying totally new technologies in space," says Professor Stefano Vitale, the Principal Investigator for the LISA Pathfinder mission. "The structure of the satellites will protect the proof masses. They will float much like astronauts hover in the void of space. But their precise position will be constantly monitored to detect when they are influenced by a passing gravity wave."

 

Precise is a euphemism when one details the accuracy of such measurements: LISA will need to detect infinitely minute movements of the proof masses, of the order of a tenth of an atom, that is a billionth of a millimetre! It will also identify the polarisation of waves, and thus the direction they come from.

 

Einstein's missing links

lefthttp://hypography.com/gallery/files/5/Gravitational_waves_01_L_thumb.jpg[/img]The detection of these gravitational waves will complete the missing links in Einstein's theory of relativity and throw wide-open a new avenue of exploration in fundamental physics and astronomy.

 

"Einstein had foreseen the eventual detection of gravitational waves," concludes Stefano Vitale. "But a hundred years ago, no suitable instruments were available and Einstein's work was entirely theoretical. Now we have the technologies, we are picking up the challenge, and he would no doubt be greatly pleased to see that we are pursuing his work."

 

Source: European Space Agency

[HIENVN]

Gravitational waves are a subject that scientists around the world currently pay attention to these waves, which also is my consideration for a long time.

Einstein really deal with gravitational waves in his general relativity theory in 1915 (or 1916?) that recent scientists are trying to discover these waves in a prediction that they call “the prediction of gravitational waves in 1916’s Einstein general relativity theory,” with a lot of gravitation group such as LISA [Home Page] http://lisa.jpl.nasa.gov/ , which stands for The Light Interferometer Space Antenna, the Light Interferometer Gravitational Wave Observatory LIGO [Home Page] http://www.ligo.caltech.edu/, etc…

In my study to Einstein’s life and work, the prediction of Einstein in 1916 maybe wrong, because the general relativity theory has some defeats that Einstein confirmed in 1923, when he come to Sweden to receive the Nobel Prize for Physics in 1921. This award was not recognized his famous relativity theory.

In my opinion, the discovery of gravitational waves should be progressed if scientists around the world study these waves in a direction of unified field theory that Einstein introduced in 1920.