In September of 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected, for the first time ever, gravitational waves in the fabric of spacetime -- the ultimate validation of Einstein. Since then, LIGO has detected gravitational waves twice more, with the latest detection occurring on January 4, 2017. Caltech recently announced this third detection, and like the previous two, it comes from two black holes colliding and forming into one — a cosmic calamity 3 billion light-years away and resulting in a new black hole with a mass 49 times that of the Sun.
It was doubtlessly an epic cosmic event, and the accompanying visualizations provided by Caltech and MIT add a nice dose of whoaaaa cool to the profound findings.
The detection of gravitational waves, which are ripples in the fabric of spacetime that propagate at the speed of light and are caused by the sudden acceleration of massive objects, was, and continues to be a big deal in the cosmological community -- it helps to further verify the predictions produced by Einstein's general theory of relativity. Gravitational waves also give cosmologists and astronomers a new sense, an ability to detect cosmological events that would otherwise go unobserved. Black holes are a little camera shy with being so massive that even light can't escape their gravity and whatnot.
With this third detection, dubbed GW170104 and published in the journal Physical Review Letters, LIGO researchers were able to determine that another prediction of gravitational waves generated by Einstein's theory, a lack of dispersion, is also valid. Caltech provides an analogy to light waves in order to understand dispersion in this context, noting in its press release that light waves of different wavelengths bend differently when passing from one medium into another, hence the Pink Floyd prism rainbow. Einstein's theory predicts no dispersion with gravitational waves (no change in wavelength), and LIGO found no evidence to suggest the contrary.
The researchers at LIGO also believe that this detection is notable because they've found clues that suggest the two black holes were spinning with orientations opposite each other, and unaligned with their orbital plane. This suggests that the two black holes were formed separately, and then were attracted to each other, rather than forming simultaneously.
Visualization from the second gravitational wave detection. Image: YouTube/ LIGO Lab Caltech : MIT
Moving forward, the team at LIGO is aiming to detect other large-scale cosmological phenomena that would cause detectable gravitational waves here on Earth, like the possible collision of two neutron stars. In a video YouTuber Veritasium made for this occasion, Caltech Professor David Reitze says that "If we improve our detector sensitivity, by say a factor of two or three, the rates [of detection] will go up from seeing one every month or every two months to seeing one every day or every week."
What do you think about this third gravitational wave detection and these visualizations? Propagate your thoughts in the comments below!
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