these sunspots are larger than the earth

Scientists have released eight new photos from the state-of-the-art Inouye Solar Telescope in Hawaii. In 2020, this telescope was already taking the most detailed photos of the sun’s surface. Now we see a series with lots of sunspots.

Our sun is not only the nearest star, but also a giant nuclear reactor that burns five million tons of hydrogen every second. Our sun has been doing this for about five billion years and there is enough fuel to keep it going for another 4.5 billion years. However, the sun is not a “boring” ball of gas. Our sun follows a cycle of approximately eleven years, characterized by a solar maximum and a solar minimum. During a solar minimum, the sun is very quiet and generates few sunspots and solar flares. And during a solar maximum, the sun is very active. We are currently approaching a new solar maximum, which means that many sunspots are once again visible on the sun.

What are sunspots?
Sunspots are dark areas of the sun that can be larger than our own planet. The areas are a few thousand degrees Celsius cooler than the rest of the sun’s surface. They are caused by disturbances in the strong magnetic field of the neighboring star. When hot gas bubbles can’t reach the photosphere – the deepest layer of the solar atmosphere – it cools and we see a sunspot. Did you know that sunspots aren’t actually black? They appear black only because the rest of the sun’s surface is extremely bright.

On Earth, sunspots are closely watched. Large sunspots or groups of sunspots can produce solar flares and so-called coronal mass ejections. These coronal mass ejections in particular can sometimes be vicious; during these explosions on the sun, high energy particles and magnetic fields are thrown into space. In addition to generating beautiful Northern Lights, these can also damage satellites orbiting the earth and – in exceptional cases – cause problems for our planet.

New, razor-sharp photos
The photos were taken with the Visible-Broadband Imager (VBI), one of the instruments of the solar telescope. This instrument provides sharp images of our parent star over a wide range of wavelengths and can observe fine detail. This is clearly seen in the last images. For example, a clear difference is visible between the umbra (the darkest part of a sunspot) and the penumbra (the light edge of a sunspot). If you look closely, you can even see lines in the dim light. These are penumbral filaments and are sometimes called “stretch marks”. Click on the images below to see an enlargement.

Astronomers are using the latest photos to learn more about sunspots. In the last photo, umbral fragments are visible on the left. These are old sunspots that have lost their penumbra. These fragments were previously part of the nearby sunspot, suggesting that this may be the last stage in the evolution of sunspots.

More than just sunspots
In addition to photos of sunspots, we also see other phenomena on the sun. Below we will tell you more about it. Click on the images below to see an enlargement.

Are these corn kernels? No, these are granulation cells or “bubbles” in the photosphere. The heated plasma rises in these granulation cells, then cools and falls in the dark intergranular corridors. These cells appear and disappear within minutes. Each kernel of corn is actually the size of France.

In the chromosphere (or atmosphere) of the sun, one can see thin threads of dark plasma emanating from the underlying magnetic network. These so-called “fibrils” can reach a height of thousands of kilometers.

A technological marvel on top of a volcano
The Inouye Solar Telescope, located atop the 3,000-meter Haleakala Volcano in Hawaii, is the largest solar telescope in the world. This telescope has a giant mirror four meters in diameter, complete with a specially designed cooling system. This system uses pipelines over eight miles long that carry coolant throughout the observatory. Cooling is partly done with ice, which is produced every night. The telescope dome is equipped with cooling plates, so that the temperature in the area around the telescope can be regulated. This is further supported by shutters in the dome, which provide both shade and optimal air circulation.

Hopefully we can expect many more beautiful images of the sun in the period ahead, especially now that the sun has woken up and we are heading towards a solar maximum. The peak of the solar maximum is expected to fall in 2024 or 2025.