Category: einstein

This Is How, 100 Years Ago, A Solar Eclipse Pr…

This Is How, 100 Years Ago, A Solar Eclipse Proved Einstein Right And Newton Wrong

“Today, May 29, 2019, marks the 100th anniversary of the day, the event, and the expedition that validated Einstein’s General Relativity as humanity’s leading theory of how gravitation works. Newton’s laws are still incredibly useful, but only as an approximation to Einstein’s theory with a limited range of validity.

General Relativity, meanwhile, has gone on to successfully predict everything from frame-dragging to gravitational waves, and still has yet to encounter an observation that conflicts with its predictions. Today marks a full century of General Relativity’s demonstrated validity, with not even a hint of how it might someday break down. Although we certainly don’t know everything about the Universe, including what a quantum theory of gravity might actually be like, today is a day for celebrating what we do know. 100 years after our first critical test, our best theory of gravity still shows no signs of slowing down.”

Happy 100th anniversary to the critical observations that demonstrated Einstein was right and Newton was wrong when it came to gravitation. There’s an incredible story to how this all occurred, and you won’t want to miss a drop of what it all means.

It took one of the longest solar eclipses in modern history for us to get there, but oh, was it worth it. Come find out why and how for yourself.

Messing around with people once more :p (can’t…

Messing around with people once more :p (can’t swear it will be the last omegle chat log)

How Far Could A Human Travel In A Constantly-A…

How Far Could A Human Travel In A Constantly-Accelerating Rocket Ship?

“Imagine that we could constantly accelerate at the same rate as Earth’s gravitational pull, 9.8 m/s2, indefinitely. While you’d initially speed up, you’ll rapidly approach the speed of light.

Owing to Einstein’s Special Relativity, time will dilate and lengths will contract. As you continue to accelerate, the distances and travel times to faraway destinations will plummet.

At the halfway mark, simply reverse your thrust to accelerate in the opposite direction for the remaining journey.

If you wanted to travel to a star that was 100 light-years away, you might think it would take you at least 100 years to get there. That might be true from the perspective of someone who remains on Earth, but for an astronaut who journeyed there at close to the speed of light, Einstein’s Special Relativity tells you that it would take far less than a century of travel. In fact, if you could accelerate at a constant rate, you could pretty much reach anywhere you wanted within 15 billion light-years of us within a human lifetime.

I even went and did the math for you here. Don’t be afraid to see how far a human could travel if we had the dream technology to get us there!

How Far Could A Human Travel In A Constantly-A…

How Far Could A Human Travel In A Constantly-Accelerating Rocket Ship?

“Imagine that we could constantly accelerate at the same rate as Earth’s gravitational pull, 9.8 m/s2, indefinitely. While you’d initially speed up, you’ll rapidly approach the speed of light.

Owing to Einstein’s Special Relativity, time will dilate and lengths will contract. As you continue to accelerate, the distances and travel times to faraway destinations will plummet.

At the halfway mark, simply reverse your thrust to accelerate in the opposite direction for the remaining journey.

If you wanted to travel to a star that was 100 light-years away, you might think it would take you at least 100 years to get there. That might be true from the perspective of someone who remains on Earth, but for an astronaut who journeyed there at close to the speed of light, Einstein’s Special Relativity tells you that it would take far less than a century of travel. In fact, if you could accelerate at a constant rate, you could pretty much reach anywhere you wanted within 15 billion light-years of us within a human lifetime.

I even went and did the math for you here. Don’t be afraid to see how far a human could travel if we had the dream technology to get us there!

Relativity Wasn’t Einstein’s Mirac…

Relativity Wasn’t Einstein’s Miracle; It Was Waiting In Plain Sight For 71 Years

“If the Universe had a frame of reference that was distinct from all the others, then there should be some measurement you could make that revealed to you how the laws of nature were different when you moved at one particular speed in one particular direction. But that is inconsistent with the Universe we have. No matter how fast you move or what direction you move in, the laws of physics are the same, and any physical experiment you can perform will give the same measurable results and result in the same physical phenomena.”

When we think about Einstein and the principle of relativity, we normally talk about the Michelson-Morley experiment, which showed that the speed of light remained constant whether it was aligned with or at an angle to Earth’s motion. We might think about the Lorentz transformations like time dilation or length contraction. Certainly, those results played a role, but Einstein himself was thinking about a puzzle that came to light much earlier: about what’s physically occurring to cause Faraday’s law of induction. If you move a bar magnet into a stationary coil of wire, you generate an electric current. If you move a coil of wire onto or off of a stationary bar magnet, you also generate an equal intensity electric current. But the physics of how is entirely different!

Why are they equivalent? How can we reason our way into this? It was thinking about this that led Einstein to relativity. Come see how he got there, from a result 71 years in the making.

Ask Ethan: How Can We Measure The Curvature Of…

Ask Ethan: How Can We Measure The Curvature Of Spacetime?

“The Universe is not simply made of point masses, but of complex, intricate objects. If we ever hope to tease out the most sensitive signals of all and learn the details that elude us today, we need to become more precise than ever. Thanks to three-atom interferometry, we can, for the first time, directly measure the curvature of space.

Understanding the Earth’s interior better than ever is the first thing we’re going to gain, but that’s just the beginning. Scientific discovery isn’t the end of the game; it’s the starting point for new applications and novel technologies. Come back in a few years; you might be surprised at what becomes possible based on what we’re learning for the first time today.”

Go out and measure how an object falls: that gives you gravitational acceleration. Go out and measure how that falling is different between two locations identical in every way except at different elevations, and you’ll measure a gravitational gradient, sufficient for telling Einstein’s theory apart from Newton’s. But if you can measure the differences in gravitational acceleration between three locations at once, you can measure changes in that gradient, and come away with an understanding of spacetime curvature.

This technique took a full 100 years from when Einstein first published General Relativity until it was performed successfully, but we’ve now done it. Here’s what it means for us, our present, and our future.

Ask Ethan: How Do Massless Particles Experienc…

Ask Ethan: How Do Massless Particles Experience Gravity?

“Given the equation for gravity between two masses, and the fact that photons are massless, how is it possible for a mass (like a star or a black hole) to exert influence on said photon?”

You know the law of universal gravitation: you put in what any two masses are, how far apart they are from each other, and the gravitational constant of the Universe, and you can immediately know what the force is between any two objects. Set one of the masses to zero, and the force goes to zero. So why is it, then, that if you take the ultimate particle with no mass, a photon, and pass it close by a mass, its path does bend? Why do massless particles experience gravity?

To understand why, you should think about what happens if you and I start at the same place near a mass, but I’m stationary and you’re moving. How far away is that mass? What’s the “r” that goes into Newton’s equation? And who’s right: me or you?

The answer is that we both need to be right, and Newton won’t get us there. Come get the real story on gravity, and learn why, in the end, massless particles feel it, too!

Physicists Used Einstein’s Relativity To…

Physicists Used Einstein’s Relativity To Successfully Predict A Supernova Explosion

“When the lens and a background source align in a particular fashion, quadruple images will result. With slightly different light-travel paths, the brightness and arrival time of each image is unique. In November 2014, a quadruply-lensed supernova was observed, showcasing exactly this type of alignment. Although a single galaxy caused the quadruple image, that galaxy was part of a huge galaxy cluster, exhibiting its own strong lensing effects. Elsewhere in the cluster, two additional images of the same galaxy also appear.”

We normally think of light traveling in a straight line, but that’s only true if your space is flat. In the real Universe, mass and matter not only exist, but clump together into massive structures like galaxies, quasars, and galaxy clusters. When a background source of light passes through these foreground masses, the light can get bent and distorted into multiple images that are magnified and arrive at slightly different times. If an event occurs in one such image, we can predict, based on General Relativity, cluster dynamics, and dark matter, when that event will appear in the other images.

In November 2014, we discovered a multiply-lensed supernova, and predicted where and when it would appear in the other images. Einstein and dark matter both win again!

Regular

Regular

If infinite parallel universes exist…