In a rare cosmic event, a “two-way highway” was opened up between Earth and the Sun through which they exchanged charged particles. This caused the skies to light up with auroras in the US states of Arizona and Arkansas along with parts of Australia and New Zealand.
Generally, auroras are created on Earth when the planet is engulfed by a solar storm. However, that was not the case last April when a rare cosmic event occurred between the Earth and the Sun.
The wind of the Sun generally punches into the magnetic field of Earth and the planet creates a bow shock towards the Sun.
But on April 24, 2023, charged particles were released from the Sun and lit the skies of Arizona and Arkansas and parts of Australia and New Zealand.
For a moment, these particles were able to switch off the bow shock of the Earth which opened up a “two-way highway” between the planet and its star through which charged particles were also exchanged between the two and created a solar light show.
In comparison to the brightness of the Sun, those auroras were comparatively far too dim.
“Particles trapped by Earth’s magnetism suddenly had an escape — a direct path to the sun!” wrote NASA last week on social media.
How was Earth’s bow shock switched off?
The “two-way highway” was formed because of solar wind’s plasma-rich component known as a coronal mass ejection (CME) which generally travels faster in comparison to the speed at which magnetic waves called Alfvén waves pass through plasma. The speed is called the Alfvén speed.
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During the solar eruption in April, NASA’s Magnetospheric Multiscale spacecraft observed that the CMEs were faster than usual which led to the temporary disappearance of the bow shock.
NASA explained that the Alfvén “wings” magnetically connected the Earth to the portion of the Sun which had erupted recently.
The instruments of the spacecraft recorded plasma getting released from Earth and entering the Sun for nearly two hours, said the American space agency, in its social media post. “The data revealed unprecedented insights about the sun-Earth connection,” NASA stated.
(With inputs from agencies)