This article is part of a special report on the total solar eclipse that will be visible from parts of the U.S., Mexico and Canada on April 8, 2024.
Amir Caspi: On April 8th this year, 2024, we are having a total solar eclipse that crosses the United States starting from Eagle Pass, Texas, all the way up to Houlton, Maine and everything in between.
I'm Amir Caspi, I am a principal scientist here at Southwest Research Institute, and I'm also the principal investigator or project lead for two eclipse experiments.
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One is going to fly two of NASA's WB-57 jets to chase the eclipse with telescopes mounted in the nose cone and under the wings to make observations of the solar corona in infrared and other wavelengths. And the other is going to deploy 35 teams of amateurs across the eclipse path, people from Texas to Maine, giving them telescopes that can measure the polarization of light from the ground.
There are a lot of open questions about the sun even though it is our star. The corona is millions of degrees, and the surface of the star is only about 10,000°F. The corona is millions of degrees, but it's the atmosphere of the star. Why is the atmosphere hotter than the surface?
This is something that's counterintuitive. It's like when you walk away from a campfire, somehow it gets warmer. So the standard laws of thermodynamics don't really explain that.
We know that energy has to be getting up into the corona somehow. What we want to find out is exactly how. It's got to be the magnetic field that's in the corona. The sun's magnetic field is really complex, and it permeates the corona. And that magnetic field is the only way that energy can get from the interior of the star out into the corona and deposit that energy and heat it up to millions of degrees. But we don't really understand the physics of how that's happening. So observing this corona during an eclipse gives us a window into that to understand what are the physical mechanisms that could be depositing that heat.
NASA flies the only remaining airframes of the WB-57F aircraft. This is a Cold War era jet. It used to be used for surveillance and weather reconnaissance, and NASA has the only three currently operating and operational in the world. These have been retrofitted with modern avionics, and with scientific instruments that are outfitted in the nose cone of the aircraft and under the wings of the aircraft. The wings are some of the longest things you can imagine just, you know, when you're standing next to this tiny little plane. It has a canopy like a fighter jet does.
It's been retrofitted with a new nose cone that has a ball turret in it, and this ball turret can point in any direction, and it has cameras mounted inside. And those cameras can see anything in the forward hemisphere of the airplane. So the airplane can be flying this way, and the cameras can be looking up and to the right or to the left or down. The airplane can be flying along the eclipse track, and we can be tracking the sun in the sky at the same time with scientific instruments aboard.
The airplanes are going to take off and they're going to head from Ellington Field near Houston, their home base, down southwest to Mexico, to the coast of Mexico, over Mazatlan. When the time is right, they launch down the eclipse path and hit their marks at exactly the right time. And that's when the cameras will acquire the sun and start to observe that solar corona that we really want to see, and that we can only see clearly during totality.
We have another project which is involving community participants. It's called Citizen CATE 2024. Instead of trying to actually physically chase the eclipse, we're having the eclipse chase us. Each of our observing stations passes the shadow to the next observing station. So we have 35 teams of community participants, people who are not professional astronomers or professional scientists. We're giving them telescopes. We're teaching them how to make observations during the total solar eclipse. And we're using special cameras that can measure
the polarization of light. When we put all of these observations together, because they overlap, we're going to get one hour of totality between all of these stations. That lets us make measurements that are different than what we could make on a plane chasing the eclipse. We get a lot more time.
If you do not catch this eclipse, you'll have to wait 20 years before the next solar eclipse in the United States in 2044, and the next big one in the United States in 2045. If you are in the eclipse path, make plans to go out. Look up. Please make sure you follow all safety guidelines and always use appropriate viewing glasses whenever totality is not happening.
People don't think of the sun as a star. They think of it as our sun, but it's a star. It's an astrophysical object and we happen to live right next to it. So I think that is really mind boggling to me, as we have this astrophysical object that tells us about processes that happen throughout the universe, and it's right here for us to measure.