Why does the Universe expand the way it does? Why does it accelerate? Einstein’s equations offer an explanation of gravity that works on the scale we know, but do they work on the grandest scales of space and time? Humanity now has a way to find out. The General Theory of Relativity predicts the behaviour of gravity, and includes a term known as the cosmological constant. Einstein added this term to make the universe static and unchanging, as he believed it was. But when the expansion of the universe was discovered by Edwin Hubble, Einstein regarded it as ‘the greatest blunder...
A direct consequence of Einstein’s theory of general relativity, and an observational way to prove it, is gravitational lensing. It requires a powerful gravitational source to work, such as a galaxy or cluster of galaxies. It works in a similar way to a lens of glass, where rays of light are bent toward a single source, increasing the brightness. In this case, instead of glass, the bending of the rays is due to the curvature of space. Light rays coming from the source would otherwise miss Earth, but instead are bent toward us when there is a massive object in front of it. It’s...
Data is fascinating. And what’s even more fascinating is that the laws of nature produce predictable patterns in data. For example, if you toss a coin 100 times and measure how many times heads comes up, you’ll get a number between zero and 100. If you repeat that experiment again and again and again, you’ll get different values each time, but usually the number will be around 50, and 50 will come up more than any other value if you repeat the experiment enough times. If you plot this data, with the # of heads in 100 coin tosses on...
A long time ago, in a galaxy far far away…. Two black holes, with masses 29 and 35 times the mass of the Sun, merged to form an even bigger black hole. The merger resulted in three entire suns worth of matter converted to pure energy in the form of gravitational waves. The waves travelled a billion light years before a tiny meat-filled species on a pale blue dot in space figured how to see them. Thanks to the smartest one that species had seen in a century, they knew that black holes might merge, and that they would produce these waves if...
Today, the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) is expected to announce a monumental discovery that is 100 years in the making. Theorized by Einstein’s general relativity in 1915, gravitational waves are ripples in space-time, similar to sound waves, but much tinier. The search has been ongoing for decades, with no results. Until now. LIGO has the most sensitive gravitational wave detector ever conceived – in two interferometer facilities in Livingston, Louisiana and Hanford, Washington. They use a laser split along two axes to give an in-phase beam. If gravitational waves along one of the axes affect the beam, it...
You may have heard about the leaked rumour about the discovery of gravitational waves from earlier this week. It was from Lawrence Krauss, who is an amazing science communicator and author, as well as a darn good astrophysicist. My earlier rumor about LIGO has been confirmed by independent sources. Stay tuned! Gravitational waves may have been discovered!! Exciting. — Lawrence M. Krauss (@LKrauss1) January 11, 2016 It’s safe to say that as a guy with an inside scoop on a lot of the latest science news, this is something to get excited about. The ‘LIGO’ he is referring to stands...
When Isaac Newton quantified gravity, his theory explained how everything in the world around us behaved in its presence. It opened a door to an understanding of something fundamental, yet elusive in explanation. Centuries later, Einstein came along and took a step back, finding a larger more comprehensive theory of gravity, one that explained the strange things that happen in the grand universe. His theory could even explain things that Newton’s theory of gravity could not, such as the odd orbit of Mercury around the Sun. But the greatest part of Einstein’s theory is that if you use it to...
Predicting the death of a star is easy. If we know how massive it is, and what stage of life it’s in, we know that it should explode eventually, within a set timeframe of many hundreds of thousands, or even millions of years. But on human timescales, that is just not good enough. What if we could predict a supernova explosion within a few months? For something that lives for so long, this would be a triumph in our understanding of the universe. Over the past couple of years, this is exactly what happened. Here’s how. A supernova is one of the most...
Our planet orbits the Sun. 365.25 days to go full circle (ellipse actually) and bring the seasons to Earth. But the Sun is not really stationary, it’s actually moving through space. It’s orbiting the center of the Milky Way, along with the rest of the galaxy. It actually has a periodic motion as it moves around the Galaxy, slowly moving up above the galactic plane then being pulled back down below by the disk stars. Currently, the Sun is moving toward the constellation Hercules at a speed of around 72,000 Km/h. It is also moving up to the top of the...
Are equations beautiful? Does a mathematician see the machine code of the universe in the complex language they use? Does a Chemist see the flow of matter? Does a Biologist see the evolution of life? Does a physicist see the probabilistic nature of electrons? Many scientists would affirm their view that the equations that dictate their respective fields are artistic, in addition to logical. So if equations can be beautiful, what is the most beautiful equation? Naturally, the most beautiful equation should be simple. It should be somewhat intuitive, yet surprising in it’s result. It should explain something fundamental about the universe,...
