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INSIDE THE SUN

Scientists are using images of the sun to understand the many phenomena that can disastrously impact Earth

By Michael Tabb

It’s easy to look at the stars and get mesmerized by far-off galaxies and exotic phenomena. But sometimes it’s important to refocus our sights a bit closer, where there are still many mysteries to be solved.

Among them: the physics of our own sun. The sun’s visible surface—what we see when we look at it in the sky—is actually relatively cold compared to its outer atmosphere, or corona, which is around a million degrees Fahrenheit (500,000°C) or hotter. And scientists don’t know why.

Using ALMA, the most powerful observatory on Earth, scientists are trying to understand what’s going on. The observatory is taking images of the middle layer of the sun’s atmosphere to probe the connection between the visible part we’re familiar with and the fiery, outer corona captured by recent technology like NASA’s Solar Dynamics Observatory (SDO).

The sun’s corona has tremendous impact here on Earth, and learning more about it could help us understand the occasional bursts of energy and heat that occasionally disrupt our power and communication systems.

ALMA normally looks at distant features of outer space. But turned toward the sun, it’s showing things we’ve never seen before, and that’s because it’s able to measure incredibly high frequency radiation, while instruments like the SDO measure lower frequency, ultraviolet light. Measuring this higher frequency radiation is particularly useful because it correlates directly to the emissions’ temperature.

That means ALMA’s pictures of the sun are basically temperature maps of a little-understood layer of the sun’s atmosphere. Watch the video above to see the incredible images, and get an idea of where the research is headed.