There have been many tests of General Theory of Relativity at low speeds, that is, in the order of 0.001 times the speed of light. The specialty of GW150914 was that it was emitted due to a high-speed event, the black hole merger described above. Here are a few of the ways in which it was shown that the equations of General Theory of Relativity stood the test at the high speeds: first, the spin and mass of the merged entity, as predicted by the part of the signal representing the inspiral phase, matched
with what was calculated using the part of the signal representing the merger and ringdown phases.
Second, during the inspiral phase, when the black holes are far apart, they are moving at about 0.1-0.4 times the speed of light. This is, relatively speaking, a low speed, and
the system may be treated as a perturbation, or correction, to the Newtonian description. In Newton’s theory, the black holes are just orbiting each other in a circular or elliptical orbit and there is no energy lost by way of gravitational waves which causes them to spiral towards each other (fall inwards).
In other words, the black hole pair can be described by an equation of motion based on Newtonian dynamics with appropriate correction terms which come in at higher orders. Using this approach, when one calculates the so-called post-Newtonian coefficients, They are found to match with what has been inferred from the experimentally detected signal.
Lastly, according to the General Theory of Relativity, gravitational waves must be “dispersionless” that is, the field particle associated with gravity, the graviton, must have a zero mass. This means different wavelength components of the wave would travel at the same speed. This was also verified by the form of the wave. ‘The famous “chirp” that was heard attests the dispersionless character of the component waves. Dispersion will introduce a characteristic change in the shape of the observed signal. If they had had a strong dispersion, what would have been heard is an “inverted chirp”’, says Dr. P. Ajith of the International Centre for Theoretical Sciences, Bengaluru.
Q.1. As per the passage, the LIGO Scientific Collaboration is submitting another paper on which of the following?
(1) the much-discussed, many-author paper in Physical Review Letters revealed the
detection of a gravitational wave.
(2) the merger of two black holes of mass 36 and 29 times the mass of our Sun.
(3) many tests of General Theory of Relativity at low speeds.
(4) how the characteristics of the signal detected vouch for Einstein’s general theory of
relativity.
(5) both option 1and 2
Q.2. According to the General Theory of Relativity, gravitational waves must be-
(1) intense.
(2) directionless.
(3) dispersionless.
(4) in continuation.
(5) full of particles.
Q.3. “Different wavelength components of the wave would travel at the same speed” which sentence confirms this statement?
(1) there is no energy lost by way of gravitational waves
(2) that they are found to match with what has been inferred from the experimentally
detected signal.
(3) the field particle associated with gravity, the graviton, must have a zero mass.
(4) both option1st and 2nd.
(5) None of these.
Q.4. What should be the best suitable title of the passage?
(1) black holes.
(2) Einstein’s theory of relativity.
(3) gravitational waves.
(4) So Einstein was right after all, and here’s why.
(5) The gravitational wave and black holes.
Q.5. In Newton’s theory, the black holes are just orbiting each other in what type of
orbits?
(1) circular orbit.
(2) elliptical orbit.
(3) both option 1st and 2nd.
(4) concentric orbit.
(5) oval orbit.
Q.6. In Newton’s theory, what causes the black holes to spiral towards each other (fall inwards).
(1) because of energy lost by way of gravitational waves.
(2) because of orbit shift.
(3) because of
(4) because of no energy lost by way of gravitational waves.
(5) different wavelength components of the wave.
Q.7-8. SYNONYMS
Q.7. lock
(1) rigid.
(2) stop.
(3) Hold fast.
(4) steady.
(5) support.
Q.8. stood
(1) Occupy.
(2) location.
(3) Withstand.
(4) standing.
(5) specified state.
Q.9.-10. ANTONYMS
Q.9. emitted
(1) emanated
(2) exuded
(3) allowed
(4) refrained
(5) suppress
Q.10. perturbation
(1) faulty
(2) composure
(3) clatter
(4) active
(5) dormant
ANSWERS –
Q.1. (4) how the characteristics of the signal detected vouch for Einstein’s general theory of relativity.
Q.2. (3) dispersion less.
Q.3. (3) the field particle associated with gravity, the graviton, must have a zero mass.
Q.4. (4) So Einstein was right after all, and here’s why.
Q.5. (3) both option 1st and 2nd.
Q.6. (4) because of no energy lost by way of gravitational waves.
Q.7. (3) Hold fast.
Q.8. (3) Withstand.
Q.9. (4) Refrained
Q.10. (2) composure
