Einstein: Space-Time Curvature

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When you hear about “space-time,” it’s just a way to say that space is related to time. And the curvature of space-time, as Albert Einstein predicted, is the way space and time alike literally bend around a mass such as the Earth or the sun.

That’s what’s diagramed above. This is a three-dimensional concept diagram of the way space sort of “clings” to an object. Notice the way it sort of tightens up when you get close to Earth? And because time is part of this whole equation…time sort of tightens up, too.

I assume that explains the “twin paradox,” as it’s called. That’s where the space-traveling twin returns home to Earth younger than their Earth bound twin.

Why? Seems to me it’s because time was tighter and passed faster on Earth, while it spread out and passed a bit slower for the traveler. (Don’t quote me on that, I just guessed that from this diagram.)

Einstein figured all this out. But scientists need evidence. Trusting Einstein’s genius wasn’t enough for them. How did they accept relativity as fact? Continue reading

Einstein: General Relativity

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Albert Einstein may have been the genius among physicists, but like all others before his time, he stood on the shoulders of giants.

Einstein did not propose that the sun was the center of the solar system; that idea was already widely accepted when he came around. He didn’t discover elliptical orbits; that distinction belongs with Johannes Kepler.

But Kepler never could figure out why planets orbit the sun in ellipses instead of circles. Even Isaac Newton, who at last identified gravity as the reason we stick to Earth’s surface, couldn’t explain what gravity was—only how it worked.

Einstein provided that explanation with his general theory of relativity. Continue reading

Einstein: Special Relativity

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Albert Einstein’s name literally sends shivers down my spine.

This is the man who discovered physics as we know it. This is the man who filled in the gaps where even Newton’s laws of motion went wrong and expanded our understanding of the universe.

This man was a genius in every right—even if his social skills were somewhat lacking.

By the way…I can’t help but notice this is my first post with actual photographs of the scientist in question, instead of portraits. We’re moving along, people…

So. To the point. Einstein is famous for taking revolutionary and widely accepted laws of physics—those that Newton figured out—and showing where there were some holes in the math. But Einstein wasn’t just an annoying critic.

He took it all a step further…and showed us how physics really works.

He came up with the idea of relativity. Continue reading

How Orbits Work

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Since Aristotle’s time over 2000 years ago, we have accepted that the moon orbits the Earth. We didn’t always know why, and we didn’t always accept this for the right reasons.

We used to assume that it happened just because we saw the moon move across the sky, and we believed the Earth to be the center of all motion in the solar system. But even when we realized—in the 1540s CE—that the sun was in fact the center of the solar system, the moon kept its place around the Earth.

And rightfully so. Astronomers now know that the moon orbits the Earth based on scientific observation, rather than the “logical” guesses of Aristotle’s time. And we even know why it orbits—gravity, the one force in all the universe we can’t escape.

But I can tell you, the moon’s orbit isn’t a perfect circle, and if gravity were the only reason it orbited, it would crash straight into the Earth. After all, people stay grounded on Earth’s surface because of gravity, and we don’t orbit our planet, do we?

So how does the moon orbit the Earth? For that matter, how does any satellite? Continue reading

Newton and Gravity

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So, the moon stays in orbit around the Earth, right?

Yeah, I thought so. But why? The moon’s orbit is not a straight line, which means it’s accelerated motion (using the physics definition, which is absolutely any change in speed or direction).

And in order for acceleration to happen, according to Newton’s first law of motion, a force has to happen—meaning, something has to reach out, touch the moon, and drag it into orbit around Earth.

Well, that doesn’t happen, last I checked. I mean, it’s not like we have some kind of giant cord connecting us to the moon. How crazy would that be?

So why does the moon orbit the Earth? Continue reading

Newton’s Laws of Motion

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It’s said that Sir Isaac Newton was sitting under an apple tree when an apple fell on his head, and that’s when all his discoveries began.

Personally, I doubt that story—just as I doubt that Galileo Galilei ever dropped iron and wooden balls off the Leaning Tower of Pisa. His goal would have been to show that both objects hit the ground at the same time. Unfortunately, wind resistance would have gotten in the way.

Regardless of how Newton discovered gravity, his scientific achievements are monumental. In fact, we recognize him today as one of the greatest scientists to ever live, second only to the famous Albert Einstein.

Newton’s revelation that gravity draws objects toward Earth changed the course of modern science. But what exactly did he find out? Continue reading

Galileo and Motion

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Before Galileo’s time, Aristotle was the god of gravity.

Seriously. Before Galileo came along, the question of how gravity worked was answered with another question: “What would Aristotle say?” Obviously, this method was faulty, since Aristotle was actually wrong about most scientific things he wrote about.

But Galileo began a tradition that would persist into the modern day. He’s credited for having performed the first true science experiments when he observed falling objects.

You could, of course, call Tycho Brahe’s night sky observations and Kepler’s correct application of mathematics to the heavens true science, but neither of them really performed experimental science. That distinction lies with Galileo.

Wait a second…so I thought Isaac Newton was the guy who discovered gravity? Continue reading