The Daniel K. Inouye Solar Telescope is open. I mean science.
The world's largest telescope is dedicated to looking at the Sun, and it uses a 4-meter mirror. It's not a good idea to look at the Sun with your eye, and even using a huge telescope may seem like a bad idea.
But it is not! A bigger telescope can see more detail on the Sun's surface, which is good. The Sun can be monitored in many ways simultaneously and in real-time because the light is split between several different scientific instruments. The real problem is dumping all the heat generated.
In January of 2020, the first official observation a telescope makes, it showed jaw-dropping detail in the Sun's surface. During the testing phase of the telescope, a dramatic image of a sunspot was taken and released, to make sure everything was working. It can take a while to calibrate the instruments, make sure they perform well, and return reliable measurements.
The observatory is now taking scientific observations after all that has been done. An image taken during the shakedown has just been released.
Wow.
I believe this is a picture of Active Region 12822, a small sunspot group that was the only one on the Sun that day. As it crossed the Sun's face, it sent out multiple small solar flares. The sunspot covered over a half a billion square kilometers, the same as the surface area of our planet. That is considered small as far as sunpots go. It was very bad.
Features as small as 20 kilometers wide can be seen in the details of the images. The Sun is 150 million km away.
This is a good time to do it. After the last quiet period, the Sun is starting to ramp up again after an 11-year cycle of activity, which begins at a peak and ends at a minimum.
The magnetic field of the Sun is currently strengthening. Inside the Sun is a huge layer of hot ionized gas called plasma that rises to the surface and cools. Each of the immense convective towers has a magnetic field embedded in it. When the field lines get tangled up, the hot plasma gets to the solar surface and prevents it from sinking again. We call that area a sunspot because it becomes darker and cooler. It is still very hot and bright, but it looks darker next to the brighter material.
A lot of energy can be stored in those field lines. Sometimes one loop tangles with another, and they short circuit. A solar flare is released when the lines snap. These emit a lot of light and have enough energy to create X-rays. A big flare can hit a satellite. This can cause a huge wave of highly accelerated electrons that can short out a satellite's electronics unless it is hardened against such an onslaught. Satellites have been lost due to previous flares.
The coronal mass ejections occur higher off the surface. The size and energy of these are much larger than a solar flare. Their energy goes into a charged particle that flies away from the Sun at tremendous speed. Powerful electric currents can be created in Earth's crust if our own magnetic field hits them. These can cause a current in our power lines, which can overload and destroy them. This can blow out big transformers, which are very expensive and difficult to make, because this cascades across the electrical grid. Sometimes over large areas, and for a long time. To understand why these are so dangerous, read about one such event in Quebec in 1989.
That is the reason I cheer on the observatories. The Sun is the source of light and heat and power for our planet, but it is also a star, a huge and sometimes violent beast that can throw huge blasts of energy our way when it is active. Our modern society depends on electronics and electricity generation, which can be destroyed by a storm. This is the biggest threat we face, far more important than an asteroid or comet impact.
The more we know about our Sun, the better.
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