If you think you’ve missed another solar eclipse when you look at this picture: don’t worry! The total darkness in this image from the US Naval Research Laboratory’s Compact Coronagraph (CCOR) is artificially created. The small space telescope is the first operational coronagraph in the USA and is intended to make the sun’s outer atmosphere, the solar corona, visible. To do this, CCOR shields the bright surface of the sun with a cylindrical device.
In June 2024, the telescope began its journey into space on board the weather satellite GOES-19 and opened its aperture for the first time in mid-September. Just in time to image the October 3 coronal mass ejections. Coronal mass ejections are giant “clouds” of solar plasma ejected from the Sun. The process looks as if the sun is breathing out a cloud of gas. If the plasma ejections are circular and concentric – as in the photo above – they are called halos.
Halos are usually directed towards Earth – including the one on October 3rd. A few days after its appearance, it had noticeable effects on our planet: in the northern United States, for example, there was a rare opportunity to see the northern lights. The natural phenomenon occurs when charged particles from the solar wind interact with the Earth’s magnetosphere.
But coronal mass ejections aimed at Earth not only produce pretty green lights in the sky, they can also damage satellites, disrupt radio communications and cause power outages. This makes it all the more important to keep an eye on the solar corona using special telescopes such as CCOR. Another US coronagraph, CCOR-2, is scheduled to be launched as early as mid-2025.