UPDATE (11 a.m. EST): As predicted, the latest coronal mass ejection (CME) hit Earth's magnetosphere Tuesday morning at 10 a.m. EST. The first signs of the CME passage was detected by observatories (SOHO and ACE) located in the L1 point between the Earth and sun, 1.5 million kilometers away - increased particle flux and magnetic disturbances were measured. Now, Earth satellites are registering a hit. The Geostationary Operational Environmental Satellites (GOES) are reporting a rapid change in magnetic field strength - a sign that the magnetic "bubble" of the CME has made contact with our magnetosphere. A geomagnetic storm may (or may not be) in progress shortly. More information will be posted soon.
ORIGINAL: You may not know it, but there's an epic magnetic battle between the sun and Earth raging over our heads.
On Friday, the sun hurled a coronal mass ejection (CME) at our planet that sparked a strong geomagnetic storm and beautiful aurorae at high latitudes on Sunday. Late last night (EST), the sun unleashed yet another CME... and it's heading our way.
One Fast-Moving CME Coming Right Up
A particularly angry-looking sunspot (1402) on the solar surface erupted with a strong, long-duration M9-class flare Sunday night at around 11 p.m. EST. "M" stands for "medium," but the explosive energy was just shy of an X-class solar flare - the strongest kind of flare the sun can produce.
This flare was accompanied by a fast-moving CME that jetted from the lower solar atmosphere and is currently heading our way. Space weather researchers predict the CME will impact our planet's magnetosphere tomorrow (Jan. 24). It will then plough into Mars the following day.
Now that yet another CME is approaching, even more spectacular auroral activity can be expected for the next few nights. We are currently undergoing the largest solar radiation storm since 2005.
"SWPC (Space Weather Prediction Center) has issued a Geomagnetic Storm Watch with G2 level storming likely and G3 level storming possible, with the storm continuing into Wednesday, Jan. 25," the NOAA announced on Monday.
Living With A Star
All these flares, CMEs, space radiation and aurorae may sound scary, but it's all a natural consequence of living with a star.
As our sun approaches "solar maximum" - a time of maximum magnetic activity in its 11-year cycle - we can expect more solar flares and CMEs, some of which will hit the Earth. The next solar maximum is predicted to occur in 2013, so we have a few more months of solar excitement to come.
Our planet is more than capable of protecting us from a solar radiation battering. We live in a dense atmosphere that can absorb ionizing X-ray radiation from the most powerful of flares. Also, our planet has a natural magnetic "force field" (the magnetosphere) that deflects energetic solar particles from CMEs. The particles are funneled toward Polar Regions by the magnetosphere where they collide with our dense atmosphere, generating beautiful auroral displays.
Although solar radiation may not be a direct threat to life on Earth, it can cause problems with sensitive electronics in space. Communications satellites in geosynchronous orbit, for example, are especially vulnerable to solar radiation - there will no doubt be some nervous satellite operators watching the NOAA's SWPC website over the coming hours and days.
Increased solar radiation can also affect unprotected astronauts in orbit, although no problems are expected during this event. "The flight surgeons have reviewed the space weather forecasts for the flare and determined that there are no expected adverse effects or actions required to protect the on-orbit crew," NASA spokesman Kelly Humphries told Discovery News.
The latest geomagnetic storm also generated powerful currents through our atmosphere over the weekend. These currents are generated when charged particles from impacting CMEs rain down through our atmosphere. Occasionally, if powerful enough, these currents can knock out power grids on the ground - a rare scenario that knocked out the Hydro-Québec's power grid during a geomagnetic storm in 1989.
Mars to Take Radiation Hit
We may be generally protected from the sun's radiation on Earth, but spare a thought for Mars.
The poor old Red Planet has an atmosphere 100-times thinner than Earth's and doesn't possess a global magnetic field. When the CME hits Mars, it will experience an increase in radiation on the surface and may even have some of its atmosphere removed completely.
This is another factor that needs to be considered when mankind finally sets foot on Mars - the high radiation environment will pose an interesting challenge to the health of Martian astronauts.
Discovery News' space correspondent Irene Klotz contributed to this article.
Image: The flaring region of the sun in the upper right of the image generated an Earth-bound coronal mass ejection as seen by NASA's Solar Dynamics Observatory (SDO). Credit and hi-resolution versions: NASA/SDO