Quasars: 'final test' for relativity?

Until now astronomers have received very convincing evidence that objects of high mass bend space-time significantly, according to the predictions of general relativity.

Although from 1919, for the first time, the geometric properties of gravity could be proved as soon as Arthur Eddington discovered that the Sun had little effect on the path of light coming from other stars, again. once again that result provides a real test of Einstein's theory of strong gravitational fields

From the Tuorla Observatory in Finland, Mauri Valtonen explains that these achievements provided the first authentic evidence of the existence of black holes, objects with such mass density that relativity had anticipated that space-time bends itself completely: 'Some people relentlessly rely on the concept of black holes, but with a serious perspective, they must prove that general relativity still true for gravitationally intense gravitational fields before making sure that black holes are real, " the scientist said.

The recent test of general relativity involves the center of a distant galaxy, a quasar called OJ827, known for producing intense light in a period of nearly 12 years. In 1988, Valtonen and several others hypothesized that the phenomenon could be generated by a black hole 17 billion times more massive than the Sun and around it a second black hole about 200 times lighter. In such a binary system, in orbit, the movement of the smaller black hole causes the disk of material around the black hole to emit the strongest energy at two intervals separated by about 12 years.

Quasar OJ287 artwork.(Photo: VISPA)

With the sketching of this binary system, scientists had to test general relativity through which to predict the period of energy generation. During this period, later fragments (present in the 1990s) can only be accurately predicted at a few weeks' level, which is not enough to test the effectiveness of relativity. But in recent years, based on many innovative models and many years of observing OJ287, Valtonen and his colleagues have been able to predict the next occurrence date of the pulse: September 13, 2007, to be exact. 12 days.

To be able to find the impulse, more than 25 astronomers from 10 countries had to work together. Because in September, east of OJ287 appeared earlier than the Sun, it was only seen within 30 minutes before the sky became too bright. They can observe in order from Japan, to China, to Europe and finally from Canarie Island. In sum, about 100 measurements were taken from September 4 to October 20 by astronomers.

Quasar's most brilliant moments have been recorded, proving that OJ287 is indeed a double-black system. Moreover, when measuring the massive mass of the main black hole, the results proved that the orbit of the second black hole was progressed 39 degrees in each of its cycles. By comparison, the Sun's impact on the nearby space-time caused an increase of more than 0.1 degrees into Mercury's orbit for a century.

In addition, the works also show that the black hole system consumes energy when emitting gravitational waves, which is a basic prediction of relativity that needs to be tested directly. As soon as this glow is no longer in the model, the quasar glow is predicted to replicate by at least 20 days, which provides an indirect proof of the occurrence of gravitational waves. According to Valtonen, the emission from OJ287 is the high frequency emission source of gravitational waves of the universe and obviously the best target for laser interferometer like LISA, especially in the period 2016-2019, time The time that OJ287 will be "dazzling" again.