America’s Previous Coast-To-Coast Eclipse Almost Proved Einstein Right
“While the Moon slowly moved across the Sun’s disk, a mostly cloudless sky heralded great excitement for the team, as many stars near the Sun would have been visible under those conditions. But the duration of eclipse darkness was to last just barely two minutes, and with totality approaching, thin clouds began to cover the Sun just prior to the critical moments where the sky grew dark. For about 15 minutes, including all of totality, the Sun was eclipsed not only by the Moon, but by clouds as well. Not five minutes after it ended, the area surrounding the Sun was completely clear again.”
On August 21st, a total solar eclipse will travel coast-to-coast across the United States, bringing darkness during the day to portions of 14 separate states. The last time such an event occurred was 99 years ago, back in 1918. Back then, Einstein’s General Relativity still had not been proven, and this eclipse not only provided that opportunity, but held an opportunity for America to rise to scientific prominence in the world. The U.S. Naval Observatory sent a team of physicists to Baker City, Oregon, to attempt to make the critical observations. If Einstein was right, starlight would deflect during the day the closer a star’s position was to the Sun. If nature was kind to those fastidious observers, the data could indicate which theory, Newton’s or Einstein’s, was correct. But at the critical moment, the Americans were defeated by nature itself, in the form of clouds.
Still, the last Great American Eclipse almost proved Einstein right. As the 2017 eclipse approaches, take a look back at a little-known slice of American history!
Inertia and Iris
In this spectacular gif one can witness the inertia of the fluid in the eye that is still motion even after the eye has stopped moving. Can’t get better than that!
The Failed Experiment That Changed The World
This null result — the fact that there was no luminiferous aether — was actually a huge advance for modern science, as it meant that light must have been inherently different from all other waves that we knew of. The resolution came 18 years later, when Einstein’s theory of special relativity came along. And with it, we gained the recognition that the speed of light was a universal constant in all reference frames, that there was no absolute space or absolute time, and — finally — that light needed nothing more than space and time to travel through.
In the 1880s, it was clear that something was wrong with Newton’s formulation of the Universe. Gravitation didn’t explain everything, objects behaved bizarrely close to the speed of light, and light was exhibiting wave-like properties. But surely, even if it were a wave, it required a medium to travel through, just like all other waves? That was the standard thinking, and the genius of Albert A. Michelson was put to work to test it. Because, he reasoned, the Earth was moving around the Sun, the speed of light should get a boost in that forward direction, and then have to fight that boost on the return trip. The perpendicular direction, on the other hand, would be unaffected. This motion of light should be detectable in the form of interferometry, where light was split into two perpendicular components, sent on a journey, reflected, and then recombined.
The null results of this experiment changed the Universe, and the technology is still used today in experiments like LIGO. Come learn about the greatest failed experiment of all-time!