total solar eclipse

How to Safely View a Total Solar Eclipse

/ Emma / 5 Comments

Did you know that a total solar eclipse is coming up on April 8, 2024?

This one is primarily visible from North America; you can find more information about where to see it (and if it’ll be visible from your location) over here on TimeAndDate.com.

I was planning to travel to “totality” myself, but those plans fell through because I couldn’t get the time off work. Nevertheless, I’ll be helping out at a viewing event up north of Joshua Tree National Park!

In this post, I’ll take you through what you’ll see during a total solar eclipse–and, at each phase, I’ll let you know exactly how to safely view the sun!

(Later this week, we’ll be back to our regularly scheduled programming on active galaxies.)

Important: Always use solar glasses and solar filters that conform to the safety standard ISO 12312-2. Be careful! There are bad actors on the market that print this standard on unsafe equipment. Use this list of trustworthy suppliers from the American Astronomical Society.

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What is a Solar Eclipse?

/ Emma / 18 Comments
solar eclipse.jpg

This post has been updated and republished from Sept 2017.

A solar eclipse is the most amazing astronomical sight you’ll ever see.

Not only is it the only time you’ll ever be able to clearly see the “new moon” phase of the moon, it’s the only time you’ll ever see the sun’s corona. And it’s the only time that, under very specific circumstances, you can actually look directly at the sun for a few moments.

But it’s not just an astronomical event. It’s an experience. You can see the moon’s shadow rushing toward you. Nature falls silent. It’s night during the day.

And there’s one coming up on April 8, 2024.

So, let me tell you a bit about what’s happening in the sky—and give you a few important safety warnings!

(If you’re wondering what happened to our unit on active galaxies, not to worry–I’m still publishing the next post this week!)

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Our Sun: The Corona

/ Emma / 1 Comment
corona1.en.jpg

When we observe our sun’s corona, we discover something odd.

It’s really, really hot.

But…wait a second. How is that odd? Shouldn’t the sun be hot?

Well…yes. It should, and it is. Its surface temperature is almost ten thousand degrees Fahrenheit, and its core is many times hotter. But there’s a basic law of physics that says energy flows from hotter regions to cooler regions.

The core and photosphere (the visible surface) follow this rule. Even the chromosphere, the lower atmosphere, does as it’s told. But the corona is made up of gases that are hotter than the chromosphere.

What’s up with that?

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Our Sun: The Chromosphere

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sun layers

This diagram is a tiny bit misleading.

Here, it looks like the chromosphere is the visible surface of the sun, with the photosphere just below. Really, we never see the chromosphere. If you ever look through a solar telescope at the sun, the photosphere is the surface that you see.

The sun is structured a lot like the Earth, just in that it has a core, a dense region between the core and the surface, a “surface” layer, and a few atmospheric layers. The chromosphere is part of that solar atmosphere. And you never see it.

Well…almost never.

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Einstein: Space-Time Curvature

/ Emma / 2 Comments
3d space time.jpg

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?

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