Editor’s Note - Yep, this was the project I was working on! Now that I’ve a new, better website to compensate for the old one. Functionalities should (hopefully) work!
There’s been news recently claiming startling evidence pointing us towards the gravitational wave background (sometimes known as a stochastic background) has been found. As an astrophysics nerd, this is big, BIG news, and shockwaves have already been felt across the astronomical world.
Before we mull over the significance of this news, ask yourself: have you ever considered gravity as a “wave”? The waves emitted by our sun don’t seem to jog any synapses regarding gravity, so what could they be? They’re actually ripples in spacetime, which seems to be the trend with anything einstein-esque, or anything that came out of General Relativity for the matter. Two big, incomprehensibly dense objects which orbit each other slowly lose energy as their influence on the space-time manifold around them conforms space to their will, leading to outgoing ripples in the manifold similar to wind-waves on our planet Earth. In fact, any sort of gravitational perturbation in an orbital system results in these waves - they’re just too weak for us to detect most of the time. We rely on two transcontinental detectors in North America known as LIGO that can only detect the strongest of gravitational waves (although there is another detector being built in Japan), hence the reliance on black hole or pulsar collisions.
Onto the news. It’s been discovered that there is strong evidence for a background of low-energy gravitational waves that permeate through the universe (or at least our local group). This is essentially another piece of evidence pointing to a cataclysmic, highly energetic event which would’ve occurred during the Universe’s infancy, or the Big Bang, even. Most of the gravitational waves we’ve detected are of short periods - they oscillate at least once a day, sometimes even once a minute! However, what we’ve found oscillates with periods of days or even months - meaning that they’re very, VERY low energy.
However, there are other possibilities to this low “hum” of gravitational waves - perhaps it could be the cumulative sum of hundreds or even thousands of high-energy collision events between black holes or pulsars, or even the result of starquakes - small irregularities on the surface of neutron stars collapsing thanks to magnetic fields, creating low-energy gravitational waves in the process.
Whatever’s the case, this news has sent shockwaves around the astrophysics community, paving the way for a proof of the Hellings-Downs Curve as well as cosmic inflation. I’m looking tremendously forward to the day when LISA comes online, but until then we can only hope to dream about the mystical, stochastic background of gravity that litters our cosmic background.
For more information on this groundbreaking discovery, feel free to take a look at the paper making this announcement:
https://arxiv.org/pdf/2306.16213.pdf
Like what you see? Feel free to subscribe to our blog to receive updates whenever we post.