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Earth reaches its closest point to the sun all year in an event called perihelion on Jan. 4, 2023. Photo/NASA
The earth does not orbit the sun in a perfect circle but rather in a wobbly ellipse. This elliptical orbit naturally means that the Earth approaches the sun at certain times of the year.
For many years, Earth’s perihelion occurred within weeks of the winter solstice. It’s the official start of winter in the Northern Hemisphere, when the North Pole is tilted farthest from the sun and the South Pole is tilted closest to the sun.
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However, this marriage of solstice and perihelion is just a coincidence. This is because the solstice is about the Earth’s tilt towards or away from the sun, while perihelion is about the Earth’s physical distance from the sun.
The actual time of perihelion fluctuates all the time, changing about two days every century due to a small quirk in Earth’s orbit. In 1246, perihelion and winter solstice actually occurred on the same day.
“Thousands of years from now, in the year 6430, perihelion will align perfectly with the vernal equinox on March 20,” said the Space page statement, Thursday (5/1/2023).
This year, when the Earth is closest to the sun, a small G1-class geomagnetic storm is known to hit Earth. On January 4 and 5, 2023, a group of slow-moving solar particles called a coronal mass ejection (CME) will strike Earth’s magnetic field.
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According to NOAA, the collision is expected to trigger a minor G1-class geomagnetic storm that could temporarily cripple power grids. It also causes radio blackouts and pushes the colored aurora further south than usual.
Geomagnetic storms are triggered by CMEs, giant explosions of charged particles that are ejected from the sun when magnetic field lines on the sun’s surface fluctuate. These events are often associated with sunspots, dark areas of intense magnetic activity that periodically open and close on the sun’s surface.
If sunspots were pointed at Earth when one of these magnetic outbursts occurred, the resulting CME would have headed toward Earth within days. CME is expected to hit Earth on January 4 and 5 due to the explosion of an Earth-facing sunspot on December 30, 2022.
“However, storms in this weak category are unlikely to have a lasting impact on our planet (Earth) or its inhabitants, so enjoy the cosmic light show (Aurora) if you can,” NOAA said in a statement quoted by the Live Science page.
(wib)