Earth is being bombarded by particles generated by the largest disturbance on the sun since 2005. NASA says the particles could affect GPS systems and telecommunications satellites. The flare-up also will produce a magnificent aurora borealis in the northern latitudes. There's a tiny -- tiny -- chance that we'll see a faint glow from the aurora in the deserts of San Diego County tonight.
"This will not always be obvious to the untrained eye and is best seen by using long exposure photography," says Mark Lane, director of the Palomar College Planetarium.
We asked Lane for a fuller explanation of the aurora. Here's what he told us:
The Aurora Borealis – or – “Northern Lights” are caused by an interaction between charged particles ejected from the Sun and the Earth’s magnetic field. These charged particles are electrons and ionized atoms that are continuously given off by the Sun as part of the Solar Wind.
When these charged particles interact with the Earth’s magnetic field they spiral down to where the Earth’s magnetic field lines come together at the magnetic north pole of the Earth. Think of a bar magnet with field lines that come out of one pole and arc around to the other pole of the magnet. When these charged particles slam into the Earth’s upper atmosphere they energize the nitrogen and oxygen atoms in the atmosphere causing them to give off light. Different types of atoms will emit different colors of light.
Since the Earth’s magnetic field and its axis of rotation are very closely aligned, the aurora can be seen in latitudes that surround the North and South Poles (usually the arctic/Antarctic regions).
When the Sun experiences an increase in solar activity it will occasionally eject a large mass of charged gas in an event called a Coronal Mass Ejection – or – CME. If this material encounters the Earth on its way out of the solar system we will experience an increase in auroral activity. When this occurs locations near the polar regions of the Earth will have frequent, large, auroral displays and it is common to have this auroral activity reach lower latitudes such as the northern United States and on rare occasions these displays can reach the mid-latitudes of the US.
Unfortunately, San Diego is too far south to experience direct auroral activity in the sky but it is sometimes possible to see the faint glow of the distant aurora along the northern horizon. This will not always be obvious to the untrained eye and is best seen by using long exposure photography.