Space Weather - and a light show of a special kind.
The image shows a coronal mass ejection (CME) of our home star, a medium-sized yellow dwarf or G-star we call the Sun. A CME is a gigantic energy explosion in which a huge, highly magnetized plasma cloud erupts into space from the solar corona, the Sun's atmosphere. These eruptions occur when the motion of the plasma inside the Sun twists its magnetic fields. When the magnetic fields explosively realign, an immense cloud of magnetized particles, called plasma, is hurled into space.
In the form of massless (m=0) photons, light from the Sun travels at the speed of light (≈300,000 km/sec). It takes just eight minutes to cover the 150 million km to Earth. The plasma cloud travels slower; it can reach our planet in as little as 15-18 hours. Slower CMEs can take several days to arrive. The arrival of the CME at Earth can trigger a geomagnetic storm. Such a geomagnetic storm could damage satellites, power grids and radio communications on a massive scale and cause electrical blackouts that might not be repaired for weeks, months, or even years. [ESA]
Image: NASA/GSFC/SDO
