Coronal Holes
Context
- Scientists from the University of Graz (Austria), have developed a new neural network that can reliably detect coronal holes from space-based observations.
About
- Coronal holes are areas in the Sun's atmosphere that appear dark in X-ray and ultraviolet images of the Sun.
- The plasma (electrified gas) in these regions of the Sun's corona (it's upper atmosphere) is cooler and denser than in other parts of the corona.
- They appear dark because plasma particles can escape along the magnetic field from the solar surface into interplanetary space, leaving a ‘hole’ in the corona.
- The escaping particles form high-speed solar wind streams that can eventually hit Earth, causing geomagnetic storms.
- The appearance and location of these holes on the Sun varies in dependence of the solar activity, giving us also important information on the long-term evolution of the Sun.
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