Welcome to my first “Science Answers” post! About a month ago, I sent out a post requesting science questions from all of you; you can find it here. This post addresses the first of the questions I was asked. If you have a question, you can ask it in the comments here or on that post, or ask it in an email. Or find me on Facebook!
And by the way…I do apologize for getting this post out so late. But here you are.
Q: What is magnetism? And what’s the difference between electromagnetism and the “magnetism” found in minerals? (asked by Simon)
So…let’s start with something most of us are familiar with.
Can I just say, I’ve never seen a fridge with so many magnets?
Usually, the magnets in our lives serve practical purposes. In your typical household, these fridge magnets would be used to hold up notes, photos, recipes, etc. that you’d want to display in your kitchen.
(Of course, magnet collecting is a perfectly reasonable hobby, if the sheer variety on this fridge is any indication.)
Magnets are something we take for granted. But they are even more a part of our lives than we realize.
Have you ever looked at the sun, and seen something like this?
Now, before you decide to look at it right now and see what you see, it’s my responsibility as an amateur astronomer to remind you of the safety risks. Focusing your eyes on the sun is dangerous—there’s a reason our eyes automatically flinch away.
How dangerous, you ask? Dangerous enough to burn and even scar your retinas, permanently damaging or even destroying your vision.
Yes, I’m serious.
Now, all this is not to turn you off solar observing entirely. There are safe—and cheap—ways to look at the sun, and see its spots.
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.