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...
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...
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...
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...
The biggest problem in theoretical physics today is the marriage between Quantum Mechanics and Gravity. Throw in the fact that whatever theory comes out of it has to additionally be able to explain Dark Matter and Dark Energy, and we have ourselves a massive problem to solve. How do we reconcile the seemingly random probabilistic nature of quantum mechanics with the smooth, pliable space-time of General Relativity. We have two incredible theories that explain the Universe, make predictions accurately, and have led to amazing advances in technology and understanding, yet they completely disagree with each other at common scales. So...
A set of questions I get from kids and adults alike while doing my Astronomy in Action planetarium shows consists of the following: Does the Universe have an end? How big is the Universe? Where is the center of the Universe? What is the ‘Observable Universe?’ How is it different from just saying ‘the Universe?’ First of all, let me say that it is really hard to imagine the Universe as it is, even with a solid understanding of large-scale Physics. This is because there is no analogy in our lives, no reference point in our everyday experience. It’s very...
