Community Meme | Favorite Season 3 Episode | Remedial Chaos Theory.

How Richard Feynman Convinced The Naysayers 60 Years Ago That Gravitational Waves Are Real

“Just as a pulse of electromagnetic radiation would cause such charges to oscillate, the same would happen in the “gravitational antenna” if a gravitational wave passed through—with the maximum effect occurring if the wave were transverse: at right angles to the stick. Upon the impact of a gravitational wave, one of the masses would accelerate relative to the other, sliding back and forth along the stick. The rubbing movement would generate friction between the free mass and the stick, releasing heat in the process. Therefore the gravitational radiation must convey energy. Otherwise, how else did the energy arise?”

Today, we take the existence of gravitational waves for granted. They were predicted by Einstein almost immediately following the first publication of general relativity, they were indirectly detected decades ago and they’ve been directly detected multiple times by the different LIGO observatories. Yet Einstein and his former student argued, back from the 1930s through the 1950s, that the waves were mere mathematical artifacts, and didn’t physically exist. Oddly enough, it was the non-specialist in general relativity, Richard Feynman, who provided the key way of thinking which resolved the argument. Rather than arguing about the mathematical subtleties of relativity, he approached the problem from a physical perspective, reasoning about how gravitational waves would be able to accelerate “gravitational charges,” a.k.a. masses. The result not only demonstrated that gravitational waves must carry energy, but provided the prototype for the design of LIGO.

Thanks to physicist and historian Paul Halpern, the full story is now available for all to read of how Feynman demonstrated the reality of gravitational waves 60 years ago!

STIR_LING

Radioactivity, beautifully visualized

You’re looking at the tracks of radioactivity – mostly alpha rays, I think – emitted from a chunk of uranium ore placed in a cloud chamber. Alpha particles, and also beta particles, strip away electrons when they collide with atoms in the air inside the cloud chamber, leaving those atoms positively charged, or ionized. Alcohol vapor condenses on the ions, leaving a vapor trail that marks the path of the alpha ray. 

An outfit calling itself Cloudy Labs put the video up on YouTube a while back. 

National Geographic atlases from 1999 through 2014 shows how Arctic ice has melted over time.

Not CGI, actual footage from the International Space Station.

This is my religion.

Source: Knate Myers - View from the ISS at Night | gif by FD

A beautiful 5-cylinder inline Stirling engine.

5-Zylinder Reihe Stirlingmotor (5-cylinder inline stirling engine)

terrarium collection all together :)

Not crying either...

I have nothing to do with this mission, but damn do I feel proud. What peculiar beings we, humans, are. Sending into space a doll in a spacesuit, named “Starman”, seated in an electric car, with a sign “Don’t Panic” on the car’s dashboard, blasting David Bowie’s “Life On Mars?”. I’m not crying, you are.