Physics / Relativity / Science And Math

General Relativity is the Dynamics of Distance

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kogler crazy art installation

This is part two in a many-part series on general relativity. Last time, I described how Galileo almost discovered general relativity. In particular, I told you that gravity isn’t a force. In fact, gravity is the same as acceleration. Now, this is a completely crazy idea. After all, we’re all sitting in the gravitational field of the Earth right now, but we don’t feel like we’re moving, let alone accelerating. But let’s take this crazy idea at face value and see where it leads us. (Of course, the Earth is spinning, which is an acceleration. And it’s orbiting the sun,

Physics / Relativity / Science And Math

Galileo Almost Discovered General Relativity

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Hipster Galileo

We all know the (probably apocryphal) story. Galileo Galilei, all around physics bad-ass, went up to the top of Leaning Tower of Pisa and dropped stuff off the top. He found that objects of vastly different weights, like bowling balls and feathers for example, would fall at exactly the same rate and hit the ground at exactly the same time. Air resistance gets in the way, of course. But if you perform the experiment in vacuum, as these guys did, then you do find the bowling ball and the feather land at exactly the same time: This leads to

Astrophysics / Physics / Science And Math

Type 1a: The Other Type of Supernova

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Supernova 1994D

When people hear “supernova” they usually think of a star that runs out of fuel. Without the engine of nuclear fusion to heat it, the star collapses under its own weight, which triggers a huge explosion. This is a “core-collapse supernova,” one of the most energetic events in the universe. The result is usually a neutron star or a black hole. However, there’s another type of supernova, one in which a star whose nuclear fires long ago petered out is reignited, causing a catastrophic explosion. This is the type Ia supernova. We start our story with the type of

Astrophysics / Geometry / Mathematics / etc.

Speculative Sunday: Can a Black Hole Explode?

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Cassiopeia A Spitzer Image

Nothing can escape the gravitational pull of a black hole, not even light. That’s why they’re, well, black. (Of course, as I’ve described before, black holes can glow very brightly, thanks to all the in-falling matter. Sometimes they even produce gamma rays. I’m also ignoring the negligible amount of Hawking radiation that black holes theoretically produce.) Once you pass the event horizon of a black hole, you cannot ever escape. Escape is simply forbidden by the laws of physics. That is, of course…if there actually is an event horizon, not just something that looks like one. Carlo Rovelli ,

Astrophysics / Physics / Relativity

The Curvature of Spacetime

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Abell 2218

Spacetime is curved. We’ve all heard the line. But what does it mean? Well on the largest scales, the curvature of spacetime is abundantly clear as the warped fabric of the universe distorts images of distant objects. The image below is of the Abell 2218 galaxy cluster, taken by the Hubble Space Telescope. The cluster is very massive so it warps the spacetime around it. This warped spacetime acts as a lens so that light light coming from galaxies behind Abell 2218 is spread out much more than it should be. The result is that images of galaxies behind

History / Physics / Relativity

The Men Who Weighed Mountains

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 In 1687, Sir Isaac Newton published the Philosophiæ Naturalis Principia Mathematica, his magnum opus describing the laws of motion and the secrets of the universe. One such secret is Newton’s law of universal gravitation, which states that the same gravitational force that pulls us down to the Earth holds the planets in their orbits around the sun. Indeed, every mass attracts every other mass through gravity. This means that not only are we pulled downwards towards the Earth, but we are pulled towards pieces of the Earth. We are all gravitationally attracted to mountains. In fact, this is an excellent test of Newton’s

Astrophysics / Physics / Relativity / etc.

Simulating Gamma Ray Bursts

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It was the mid 1960s. The United States and the Soviet Union had recently signed the Partial Nuclear Test Ban Treaty, which forbid the detonation of nuclear weapons except underground. Since neither nation trusted the other, each was carefully monitoring the other for non-compliance. In particular, the United States feared that the soviets might be, I kid you not, testing bombs behind the moon. Vela The United States solved this problem with the Vela satellites. When a nuclear bomb goes off, it emits a short burst of gamma rays, which are rays of extremely high energy light. The Vela

Electronics / Geometry / Mathematics / etc.

Lightning Detection

Michael T. Schmidt

Since I’ve been very busy lately my good friend Michael Schmidt agreed to do another guest post! Mike has a masters degree in physics from the University of Colorado at Boulder. You can check out Mike’s own blog at duality.io or his personal website Mike’s Personal Website. Without further ado, here’s Mike: Lightning Detection   Currently, in the mid-west of the United States the first thunderstorms of the year have begun. Because I am a giant geek, I love lightning and I think tracking lightning is quite interesting. My personal favorite site is LightningMaps. On LightningMaps website you’ll see

Astrophysics / Physics / Science And Math

The Long Arms of the Black Hole

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Black holes are incredibly messy eaters. As matter falls into a spinning black hole, that matter can be accelerated to incredible velocities and launched out the poles. In the case of the supermassive black holes at the centers of galaxies, these are the most energetic events in the universe since the Big Bang. The exact mechanism for the creation of these jets is unknown. There are two competing theories, one called the Blandford-Payne mechanism, and one called the Blandford-Znajek mechanism. The details are too fiddly to get into here, but the former has more to do with the in-falling

Physics / Quantum Mechanics / Science And Math

Aharonov-Bohm Effect

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Since I was busy last week and I’m feeling ill this week, my good friend Michael Schmidt has agreed to write a guest post for me this week. Mike has a masters degree in physics from the University of Colorado, an interest in teaching, and a passion for math and physics.  You can find out more about him on his personal website or read more on his blog, duality.io. So, without further ado, here’s Mike’s article. Force Vs. Energy When we teach physics, usually force is one of the first concepts. Force is easy to understand. I can have