The sun is the star responsible for life on Earth. Without it, we wouldn’t be here and it’s a constant fixture in our everyday lives. With all that in mind, it’s a real shame you’re not supposed to look directly at it. The sun is an incredible thing and astronomers have come up with ways to observe it without scorching their retinas. One of those tools is the Solar Dynamics Observatory, an “unblinking eye” that observes the sun constantly.
Images from the SDO are produced by capturing only a specific ultraviolet wavelength that lets scientists see the star’s corona, which is its outermost layer. For a decade, the SDO has been staring at the sun and recording every blip of activity it can spot. Now, we can enjoy it all for ourselves.
The timelapse video NASA just released is absolutely incredible. It shrinks ten years of sun observations into just over one hour. Yep, it’s an hour-long video, so grab a cup of coffee and enjoy it.
The video, which is available in up to 4k resolution, is stunning. It shows a wealth of activity on the star’s surface early on, ramping up until there are magnetic loops of plasma covering a huge percentage of its surface. Then, just as quickly as they appear, the hot spots of activity seem to fade away, leaving the star looking much calmer.
This is the regular sun cycle, where it moves from a period of high activity called the Solar Maximum to a period of low activity called the Solar Minimum. The intensity of the maximum and calmness of the minimum can vary, but the cycles themselves are very apparent.
As for why you occasionally see the sun’s orb shake in the frame, or see momentary frames of darkness throughout the video, NASA has a very good explanation:
While SDO has kept an unblinking eye pointed toward the sun, there have been a few moments it missed. The dark frames in the video are caused by Earth or the Moon eclipsing SDO as they pass between the spacecraft and the sun. A longer blackout in 2016 was caused by a temporary issue with the AIA instrument that was successfully resolved after a week. The images where the sun is off-center were observed when SDO was calibrating its instruments.
Observing the sun and keeping track of how active or inactive it is can be vital for predicting things like solar storms and other space weather that can affect Earth. When the sun spews plasma into space, charged particles that reach Earth can damage communications satellites and even put space missions in peril.