I just wanted to take a quick moment to thank you all… Continue reading
I just wanted to take a quick moment to thank you all… Continue reading
Right next to light, the telescope is an astronomer’s most valuable tool. There are so many different varieties of telescopes, it can be hard to keep them all straight. But they can all be sorted into a few basic types, and that makes choosing one a lot simpler.
Two very common types are reflectors and refractors, and each one in the image above is one of these. You can tell a reflector by its cylindrical design. They all look like cylinders, you say? Well…refractors are a little bit different.
Take the two telescopes on either end of this lineup, for instance. These two—the far left and the far right—are refractors. And you may notice that, unlike most of the rest, they’re not perfect cylinders.
Look closely. You’ll see that, not only is the end pointing up a bit wider than the rest of the telescope, but there’s a little tiny piece tacked onto the end. That same little tiny piece is tacked onto the side for the reflectors.
Does this look familiar?
People think of rainbows as a symbol of happiness and fortune. There are even myths that leprechauns hide gold at the end of a rainbow. That’s more of a tease than good fortune, if you ask me, because it’s impossible to reach the end of a rainbow.
That’s right. Impossible.
Some people wonder if rainbows look the same from the back. The answer’s no. They don’t. You wouldn’t see a rainbow if you were standing behind it.
Whoa…why would that be? Continue reading
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
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
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
Have you ever been to the beach?
If you’re from California like me, then I’m betting you have. If you’re from a place that’s not near an ocean and you’ve never been near the water all your life, then I’ll tell you a little bit about the tides.
They happen every day, twice a day. If you find yourself a nice comfortable spot overlooking the beach, you can see the waves come into the shore and then gently roll out again. If you stay for hours on end, you’ll see the water level eventually rise a bit.
And if you stay even longer, you’ll see the water level lower back down. When it’s high, it’s called high tide, and when it’s low, it’s called low tide.
The tides are partially responsible for the myth that the moon’s gravity affects you in some kind of metaphysical way. But this isn’t true at all.
So why do the tides happen? Continue reading
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
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
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