According to the National Center for Space Weather (NCSW) of the China Meteorological Administration, a moderate or greater geomagnetic storm, possibly even a severe geomagnetic storm, may occur on March 25, and geomagnetic activity is expected to persist until March 26.

What is a geomagnetic storm?

A geomagnetic storm is a typical solar eruptive activity. When the Sun erupts, a coronal mass ejection (CME) occurs; a single ejection can hurl hundreds of millions of tons of solar material away from the Sun's surface at speeds of hundreds to several thousand kilometers per second. This material carries not only the kinetic energy formed by its enormous mass and velocity, but also the Sun's powerful magnetic field energy. Once it strikes Earth, it triggers changes in the direction and magnitude of the geomagnetic field—that is, a geomagnetic storm.

The CME in this event occurred at a position almost directly facing Earth, so viewed from Earth the ejected material forms a circular disk—what we have previously referred to as a "full halo." The solar material ejected by such eruptive activity is relatively fast and has high coverage relative to Earth, and may trigger fairly strong geomagnetic activity.

Who is affected by geomagnetic storms?

According to a statement from the National Center for Space Weather of the China Meteorological Administration, from the perspective of aurora viewing, such a "textbook, solid" eruptive event can be considered template-grade, and combined with the excellent timing shortly after the spring equinox, aurora chasers can indeed add a few more "+" signs to their expectations.

However, for the vast number of racing pigeon fanciers, they should be extra vigilant in the coming days and minimize release activities under adverse weather conditions and over long distances.

Zong Weiguo, director of the Space Weather Technology Research and Development Office at the National Center for Space Weather, said that geomagnetic storms will not affect human health. Earth's magnetic field is a protective layer; with it, solar activity does not act directly on Earth's surface, and much of the energy and material is blocked by the magnetic field, so it will not have much impact on human life. It can be understood that Earth's magnetic field is like an "immune system," and a geomagnetic storm is an "immune response" to solar material.

Will auroras still occur?

On the evening of December 1 last year, due to a geomagnetic storm, netizens in Mohe and Daqing in Heilongjiang, and Tengger and Genhe in Inner Mongolia, all photographed auroras in northern China; auroras were even recorded in Huairou and Mentougou in Beijing—the second aurora image record in Beijing's history.

As to whether auroras can still be observed in Beijing in the coming days, Zong Weiguo explained that aurora observation depends on many factors, including weather and the timing of the aurora's appearance. "We are not yet certain of the exact time the geomagnetic storm will occur; we can only estimate that it may occur on the evening of the 25th or by noon the next day. If the aurora appears during the day, it cannot be observed because the background light is too bright."