Summary of Sounds Created On Merging Black Holes
In 1916 Einstein wrote a paper introducing gravitational waves. Although the concept and
understanding of gravitational waves have been known for a while we haven’t been able to
prove its existence until recent years in September 2015 at the Laser Interferometer
Gravitational-wave Observatory (LIGO) [2] nearly 100 years after Einstein first proposed the
theory. It is because Gravitational-wave is an “oscillating distortion of space and time” and its
wavelength is really difficult to measure since its “produced by moving of massive masses
travelling at the speed of light and distorting spacetime”, but even the biggest and strongest
events in our universe the wavelength is only produced up to magnitude of 10−21 .
The “LIGO measured the gravitational waves through a collision and merging of two massive
black holes, twenty-five times the size of our sun” using a massive and very sensitive detector.
And when first detected the distortion was very clear and matched the theory but could only
detect it approximately up to 0.2 seconds.
Fig 1: Similar measurements were observed in (LIGO) when discovering the black hole. Taken
from (B. P. Abbott et al. [2])
Previously believed to be an impossible task to detect the gravitational waves many physicists
tried to introduce their own concept of gravitational waves and methods of detecting them. One
instance is when “physicist Joseph Weber claimed the detection of gravitational waves in 1969
in his paper [3]”, but the experiment had controversial results and nor could it be repeated and it
was believed that his findings were wrong. Not until physicist Pirini one the greatest contributor
to the detection of gravitational wave suggested using “phase measurements instead of timing
the short light pulses [4]”, outset us to what we now know as LIGO. There were various genius
minds and scientist that contributed us towards the detection of gravitational waves, but it is just
a small step towards what the future of Physics holds. Such breakthrough detection is what
keeps us humbling towards the unknown Physics and every step LIGO takes towards
understanding the gravity, we might eventually answer the big questions of Dark Matter, or the
Dark Energy and its effects with the theory of gravity introduced by Einstein [5].
REFERENCES
[1] Berti, E. (2016), Viewpoint: The First Sounds of Merging Black Holes, Physics, 9, 17.
[2] B. P. Abbott et al. (LIGO Scientific Collaboration and the Virgo Collaboration), ‘‘Observation
of Gravitational Waves from a Binary Black Hole Merger,’’ Phys. Rev. Lett. 116, 061102 (2016)
[3] https://physics.aps.org/story/v16/st19
[4] R. Weiss, ‘‘Electromagnetically Coupled Broadband Gravitational Antenna,’’ Quarterly
Progress Report of the MIT Research Laboratory of Electronics, No. 105, 54 (1972), available
online at http://dspace.mit.edu/bitstream/handle/1721.1/56271 /RLE_QPR_105_V.pdf
[5] N. Yunes and X. Siemens, ‘‘Gravitational-Wave Tests of General Relativity with
Ground-Based Detectors and Pulsar-Timing Arrays,’’ Living Rev. Relativity 16, 9 (2013).