Gravitational Waves, Now what do we do with them?

We are bounded in a nutshell of Infinite Space: Free Form #3: Gravitational Waves, Now what do we do with them?

“On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of \(1.0 \times 10^{-21}\). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than \(5.1 \sigma\). The source lies at a luminosity distance of \(410^{+160}_{-180}\) Mpc corresponding to a redshift \( z = 0.09^{+0.03}_{-0.04}\) . In the source frame, the initial black hole masses are \(36^{+5}_{-4} M_\odot\) and \(29^{+4}_{-4} M_\odot\), and the final black hole mass is \( 62^{+4}_{-4} M_\odot\), with \(3.0^{+0.5}_{-0.5} M_\odot c^2\) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.”

This is the abstract for the announcement last week for the first direct observation of Gravitational Waves, further confirming Einstein’s Theory of General Relativity, and pushing us to a new frontier of Astrophysics and Observation. We previously discussed the history of Gravitational Waves (see http://ay16-rodrigocordova.blogspot.com/2016/02/gravitational-waves-next-e-m-spectrum.html) and how they could potentially revolutionize astrophysical observation, well now this is a reality! As the abstract describes, the observed gravitational waves had a significance of \(5.1 \sigma\), which means there is great certainty that the observation is correct and real. This significance stems from the amount of falsifiability of the data, meaning the lack of it being anything other than the proposed explanation, two black holes circling and colliding with one another. Furthermore, the authors go on to explain in the later parts of the paper (found here: https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.061102) how the waves were confirmed to move at the speed of light by knowing the distance between the two LIGO detectors (one in Louisiana and one in Washington State) and measuring how the detection lagged one behind the other by a time equivalent to their separation distance divided by the speed of light. This, along with other factors, gives us one of the most important aspects of the discovery: the fabric of space-time is real, and it allows for the propagation of gravitational forces at the speed of light. However, I do not see these as the most relevant consequence of the discovery, rather the prospects it offers are much more enthralling.

The most significant portion of this discovery is the opening of an entire new realm of fields in observational astronomy, and Astrophysics. Now we have the basis to peer deeper into the universe, into its hidden dimensions and a new range of possible objects to be studied and to be gained insight from. From the paper, we know they detected several other sources and objects that were detected, although they were not precise enough to be catalogued as a verifiable event. This hints at how common gravitational wave events could be, sufficiently so that we could see completely new facets of the universe’s construction we haven’t even dreamt of yet.  Within the coming years, Astrophysics will change to accommodate what is the first real shift in observational astronomy since the Ancients, we now have a completely different spectrum to work with, not based on Electromagnetism, but rather the interactions of large masses and the possible reasons for that (we’ll discuss gravitons on another occasion). Regardless of what you may think of physics and astrophysics, how we may just be getting close to explaining mos of the phenomenon we see, events like there are what lead us to other discoveries and new thing to describe and attempt to understand, because for all we know, general relativity might just be a special case of some other, more general, explanation of the universe(s).

References: 

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.061102