Indian solar mission’s new findings throw light on enduring Sun mysteries
India’s Aditya-L1 solar mission has provided new evidence that may help explain why the Sun’s outer atmosphere, the corona, is far hotter than its visible surface and remains heated despite frequent energy-losing eruptions. The findings matter because coronal mass ejections can produce auroras but also trigger geomagnetic storms that disrupt power grids and satellites.
Researchers say energy reaches the corona through waves generated by boiling motions on the Sun’s surface and through magnetic field lines that break and reconnect. The corona is typically about 2 million°C, compared with roughly 5,500°C at the photosphere, and can occasionally reach 40 million°C; the Sun produces two to three coronal mass ejections daily at low activity, rising to 10 or more during peak periods in its 11-year cycle.
- Aditya-L1 findings may explain how the corona stays exceptionally hot.
- Solar waves and magnetic reconnection appear to replenish lost energy.
- Solar eruptions can affect satellites, communications and power grids.
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The Sun has a visible surface, called the photosphere, and a much hotter outer atmosphere known as the corona. The corona can reach about 2 million°C, far hotter than the photosphere at roughly 5,500°C, and scientists are still investigating how it gets and keeps so hot.
India’s Aditya-L1 spacecraft observes the Sun from space. Researchers study how energy from motions on the Sun’s surface and changes in its magnetic field may heat the corona.
The corona can send out huge bursts of charged particles called coronal mass ejections. These can create auroras on Earth, but may also cause geomagnetic storms that disrupt power networks and satellites.