Vacuum Technology Helps Proving Black Holes Exist

- Apr 16, 2019-

Vacuum technology helps proving black holes exist

 微信图片_20190416152426

 

source of the pictureEvent Horizon Telescope Collaboration

At 21:00 on April 10, 2019, the EventHorizon Telescope (EHT) project held a simultaneous press conference in six locations around the world, including Brussels, San Diego, Shanghai, Taipei, Tokyo, and Washington.

 

What is a black hole?

Black hole is a kind of celestial body in the modern general relativity. The gravity of the black hole is so great that the escape velocity within the event horizon is greater than the speed of light. A black hole is an object whose curvature is so great that light cannot escape from its event horizon.

 

In 1916, German astronomer Karl schwarzschild Einstein gravitational field equation is obtained by computing a vacuum in the solution, the solution shows that if a little to concentrate a large amount of material in space, the surrounding will produce strange phenomena, which exists around the particle an interface - the "event horizon" once in the interface, even light can escape. The "incredible object" was named a "black hole" by the American physicist John Archibald wheeler.

 

What are gravitational waves?

 

Gravitational waves are produced when massive objects such as neutron stars or black holes accelerate and orbit each other. When they collide, they travel at close to the speed of light. As they orbit, the gravitational waves they emit compress and stretch space, deforming space-time. The deformation is extremely small and vibratory. Figuratively speaking, it is similar to the ripples on the water caused by a stone thrown into the water.

 

In September 2015, the LIGO (Laser Interferometer Gravitation WaveObservatory) in Louisiana and Washington state in the United States first detected gravitational waves directly on earth, thus confirming Einstein's theory of the limit of strong gravitational field at the source and becoming a breakthrough in astrophysics. Vacuum technology played a key role in LIGO's spectacular measurements. The universal vacuum scheme involves the measurement of LIGO and related basic experiments.

 

E = MC2: this is probably the most famous formula in physics. It is part of the theory of relativity formulated by Albert Einstein in 1905 and describes the equivalence of mass and energy. Years later, the world-famous physicist extended his observations to gravity and mathematically described the existence of gravitational waves as part of his general theory of relativity, published in 1915. For 100 years, the theory has been accepted by physicists. With the help of laser interferometer gravitational-wave observatories in Washington and Louisiana, scientists have been able to detect for the first time the radiation produced when a pair of black holes collide. Subsequently, the existence of a double black hole system was confirmed, and its dynamics were shown to follow Einstein's equations.

 

Remarkable evidence for Einstein's theory

In September 2015, LIGO first detected gravitational waves from the merger of two black holes in a galaxy 1.3 billion light-years away. Not only did this reconfirm Einstein's theory, but these findings are the first to confirm the existence of paired black holes. For researchers, the discovery marks a new era in astronomy, comparable to the astronomical work begun by Galileo in the 17th century.

 

In September 2015, LIGO first detected gravitational waves from the merger of two black holes in a galaxy 1.3 billion light-years away. Not only did this reconfirm Einstein's theory, but these findings are the first to confirm the existence of paired black holes. For researchers, the discovery marks a new era in astronomy, comparable to the astronomical work begun by Galileo in the 17th century.

 

The detector operates on Michelson interferometers. In an interferometer, a laser beam is separated by a beam splitter and passed through an optical mirror system by two optical paths as long as possible. The laser beam is then combined in the detector. In this way, the minimum time difference of flight of the laser beam produced by the gravitational wave can be measured. Even in a mirror 4km apart, gravitational waves cause the laser beams to vary in distance by only a thousandth (10-18m) of the size of a nucleus.

 

'black holes' produce' gravitational waves'
Vacuum technology confirms the existence of gravitational waves!

 

Vacuum technology from Pfeiffer Vacuum, which is used in the LIGO experiment, is needed to confirm the existence of gravitational waves on earth. In order to ensure the normal function, the two light paths of the laser must not be disturbed. As a result, laser beams and optical mirrors are placed in an ultra-high vacuum system. In order to ensure the quality and reliability of the system, so that the experiment can be completed smoothly, it needs up to ten years of preparation. As part of this preparation, fundamental research has been carried out at physics institutes around the world to prepare for gravitational wave experiments.

 

The universal vacuum provides a vacuum for many of these basic experiments. The vacuum in the LIGO probe is also monitored by the PVD analysis system. Universal vacuum HiPace molecular pumps and mass spectrometers are used to safeguard quality and detect leaks for the diagnosis of giant beam tube baking. These devices are used to maintain the necessary vacuum conditions in the piping system and provide the necessary environmental conditions for successful experiments.

 

Overall, what role did vacuum technology play in LIGO's experimental work?

In a 4 km cantilever, a vacuum with a level lower than 10-9 torr is required to avoid the phase noise in the output of the interferometer caused by the forward scattering of residual gas molecules. The most serious phase noise comes from macromolecules, which are highly polarized and move slowly.

 

In the test mass chamber, a vacuum of less than 10-8 torr is required to avoid the momentum fluctuation of the test mass caused by the collision of residual gas atoms. Similarly, heavier atoms make more noise than lighter ones.

 

What specific requirements must the vacuum system meet?
In addition to the above pressure requirements, the vacuum system must operate reliably for several months at a time. Also, the vibration of the vacuum pump should not affect the test quality.

 

The existence of gravitational waves has been confirmed, and with it Einstein's theory of relativity. What does this mean for LIGO's experimental work? How will it work?
Great goals are not yet achieved. Only a small step forward. With improved design precision, LIGO will open up the field of gravitational wave astronomy. This is a new field in astrophysics, exploring the dark universe by observing gravitational waves emitted by accelerating matter throughout the universe. We know that there are double black hole systems and neutron stars. But they remain to be learned. The mass spectra of black holes will provide information about their structure and reveal their importance in astronomy. Neutron stars give us an equation for the state of nuclear matter and may tell us how heavy elements form in the universe. If we could observe a supernova, the gravitational waves would reveal the inner process of star collapse. There may be new sources of gravitational waves that we haven't thought of yet.