We’ve all seen the pictures: a pitch-black circle enclosed by airy celestial tendrils. This is the iconic image of a solar eclipse. Every so often the moon passes between the Earth and the sun, creating a shadow that passes over the surface of the earth for a brief few minutes. Onlookers of solar eclipses unanimously say that a total eclipse of the sun is, “The most beautiful and awe-inspiring event that they have ever witnessed.”
As someone that is dying to see a solar eclipse, these people annoy the crap out of me. We get it, you saw something insanely rare and beautiful, yadda yadda yadda, rub it in some more, why don’t ya? Luckily, on my birthday this year there will be a partial solar eclipse that should be visible from Chicago! Look out, I will soon be one of these eclipse snobs myself. But I digress…
Back to the eclipse image. Have you ever wondered what the wispy cloud encircling the moon is in these images? Eclipses offer the rare chance to view a distinct region of the sun that is otherwise flooded out by direct sunlight. This region is known as the corona. No, it is not a cheap Mexican beer, but rather a part of the sun that is still very strange to astronomers. The corona is basically part of the sun’s atmosphere. It is composed of superheated gas known as plasma and extends up to millions of kilometers away from the surface of the sun.
What is so strange about the corona is that it is hundreds of times hotter than the surface of the sun, despite being 10 billion times less dense than the atmosphere of the earth. The surface temperature of the sun is about 5800 kelvin while even the calmer regions of the corona that are far away from the sun tend to be around 2 million kelvin. Needless to say, it’s a little toasty.
This idea of something being hotter the farther away you are goes against all common sense. Imagine that someone lights a match on the other side of a room and you are immediately incinerated. It’s actually quite mind-boggling. The corona of the sun is unlike anything hot that exists on earth, yet it has been proven beyond a doubt that it is actually this scalding temperature.
It’s still unclear why the temperatures vary in this extreme and odd fashion. Scientists are fairly certain that it at least has something to do with the wild magnetic fields that the sun creates. The white, hot gas of the sun’s body moves in such a way that twisting strong magnetic fields are created. When these magnetic fields meet other magnetic fields, sometimes they connect to each other in a new way. Though this may sound simple, when this happens near the surface of the sun, extreme amounts of energy and matter are released, creating geomagnetic storms that smack into the earth and create aurorae like the Northern Lights. This extreme heat release could be an explanation for the heating of the corona, but there is no substantial evidence of this happening.
Scientists are close to a solid explanation for what’s going on in the corona, but in the mean time, see if there will be an eclipse happening in your area anytime in the near future. I’m already counting down the days!