Nine years ago today, at 10:23 am ET, SDO rose into the sky atop an Atlas V 401 launch vehicle. Since that day SDO has returned over 350 million images of the Sun, produced over 3000 scientific articles, and allowed millions to enjoy the Sun. Solar Cycle 24 was just starting in 2010. SDO watched it grow to maximum in 2014 and now the Sun is often spotless.
Here is a summary slide of what SDO saw. The AIA 193 Å shows the lower corona and the HMI magnetogram shows the surface magnetic field. We try to understand the Sun by watching what happens at the poles. The dark areas near the North and South poles in the October 2010 and February 2019 193 Å images are the polar coronal holes. They have disappeared by solar maximum (the February 2014 images). The magnetograms show how the Sun's magnetic field gets more complicated at maximum and quite simple at minimum. What happens in the poles at solar minimum seems to be one of our best predictors of future solar activity.
SDO data is the basis of accurate models of the solar corona. Machine Learning algorithms are being used to squeeze even more information out of our 12 PB of data. We are looking forward to another lengthy lunar transit next month and the Mercury transit in November.
You can make your own SDO Anniversary movie at our website sdo.gsfc.nasa.gov or the Helioviewer website.
Happy Anniversary SDO!
