Recently, the NASA shared an image of the sun seemingly ‘smiling’. Captured by the NASA Solar Dynamics Observatory, the image has dark patches on the sun’s surface resembling eyes and a smile.
- The patches are called coronal holes, which can be seen in ultraviolet light but are typically invisible to our eyes.
What are coronal holes?
- Coronal holes are regions on the Sun where the magnetic field is open to interplanetary space, sending solar material speeding out in a high-speed stream of solar wind.
- Because they contain little solar material, they have lower temperatures and thus appear much darker than their surroundings.
- Coronal holes can last between a few weeks to months.
- The holes are not a unique phenomenon, appearing throughout the sun’s approximately 11-year solar cycle. They can last much longer during solar minimum – a period of time when activity on the Sun is substantially diminished.
- These coronal holes are important to understanding the space environment around the earth through which our technology and astronauts travel.
- While it is unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, without looping back down to the surface as they do elsewhere.
- Scientists study these fast solar wind streams because they sometimes interact with earth’s magnetic field, creating what’s called a geomagnetic storm.
- Geomagnetic storm can expose satellites to radiation and interfere with communications signals.
(Sources: NASA and Indian Express)
