When speaking of our universe, it's often said that 'matter tells spacetime how to curve, and curved spacetime tells matter how to move'. This is the essence of Albert Einstein's famous general theory of relativity, and describes how planets, stars, and galaxies move and influence the space around them.
While general relativity captures much of the big in our universe, it's at odds with the small in physics as described by quantum mechanics. For his PhD research, Sjors Heefer explored gravity in our universe, with his research having implications for the exciting field of gravitational waves, and perhaps influencing how the big and small of physics can be reconciled in the future.
A little over a hundred years ago, Albert Einstein revolutionized our understanding of gravity with his general theory of relativity. "According to Einstein's theory, gravity is not a force but emerges due to the geometry of the four-dimensional spacetime continuum, or spacetime for short," says Heefer. "And it's central to the emergence of fascinating phenomena in our universe such as gravitational waves." READ MORE...
You wouldn’t know it, but right now, as you read this article, your body is being squeezed and stretched. You don’t feel it because the amplitude of this flexing is only about 1/10,000th the diameter of a proton, but it is happening.
What’s causing it is not anything local, nor anything to do with your body itself. In fact, the entire Earth is being squeezed and stretched in the same manner. Instead, the source origin of these forces acting on you is located millions or even billions of light-years away.
Whilst we can be thankful that we don’t experience these effects on the macro scale, we are reminded that there are extreme forces at play in the Universe – powerful enough to distort the very rigid fabric of space-time itself.
The cause of this effect is gravitational waves, and the sources that are generating them, are massive compact objects in binary systems – like neutron stars or black holes – in inspiral orbits, drawing closer and closer together and emitting gravitational radiation in the form of these waves.
These waves were a predicted outcome of Einstein’s General Theory of Relativity and for the most part of 100 years, they were just that, theory. Then in the ’70s, indirect evidence was published that showcased a binary pulsar-neutron star system whose orbit was decaying with the exact predicted value that Einstein had determined – and the only explanation was that the system was emitting gravitational radiation. This exciting discovery went on to earn a Nobel Prize.
Then in 2015, it finally happened. With technology and instruments advancing to the threshold needed to make a discovery, two kilometre-sized laser interferometers based in the US (designed as a giant version of the Michelson-Morely experiment) confirmed the first-ever chirp from a system of massive compact objects as they merged. TO READ MORE, CLICK HERE...
