Just when we thought we were through the worst of it, a
second gigantic solar flare has erupted, sending another coronal mass
ejection directly towards Earth. The X10-class flare was detected by an
orbiting GOES satellite at 3:37 p.m. EST on Wednesday, Oct. 29th and peaked
at 3:49 p.m., according to the National Oceanic and Atmospheric
Administration.

“It’s like the Earth is looking right down the barrel of a giant gun pointed
at us by the Sun…and it’s taken two big shots at us,” says John Kohl, a
solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics
(CfA) and principal investigator for the Ultraviolet Coronagraph
Spectrometer on board NASA’s Solar and Heliospheric Observatory (SOHO)
spacecraft.

“The Sun is really churned up. The timing of two very large X-class flares
aimed directly at the Earth, occurring one right after another, is
unprecedented,” says Kohl. ” I have not seen anything like it in my entire
career as a solar physicist. The probability of this happening is so low
that it is a statistical anomaly.”

As the faster moving particles from the second eruption catch up to the
slower moving particles from the first eruption – the combined effects
cannot be predicted. Kohl states, “This second blast is moving like a fast
freight train that very soon will plow into the back of the slower moving
freight train in front of it just as it pulls into the station. The station,
in this case, happens to be the planet Earth.”

The two eruptions may create a combined geomagnetic storm that could
influence the Earth in a number of ways, including disrupting satellite
communications and power grids. However, precautions have already been taken
to minimize the potential impact. For example, power companies have reduced
the line loads to allow leeway for possible surges.

People on the ground are well protected from the ongoing geomagnetic storm
due to the Earth’s natural shielding. Pacemakers and similar devices are not
affected. Airline travel also is safe, since the Earth’s magnetosphere and
atmosphere block the solar radiation. The web site space.com reports that
the astronauts aboard the International Space Station are taking the
precaution of staying in the most shielded areas of the station during these
periods of high solar activity.

A solar flare is a magnetic storm on the sun. It appears as a very bright
spot, and blurps gas from the Sun’s surface into space. Solar flares are
classified based upon their x-ray energy output at peak burst intensity.
Solar flares generally don’t have much of an effect on our world.

A coronal mass ejection (CME), by contrast, can affect the Earth
dramatically. A CME is a huge eruption from the Sun that blasts a billion
tons of highly charged particles into space at speeds greater than a million
miles per hour. When those charged particles reach the Earth, they can
damage orbiting satellites. The particles also interact with the Earth’s
magnetosphere to create spectacular auroras known as the Northern and
Southern Lights.

Solar flares and coronal mass ejections often occur together like touchdowns
and field goals in football games. Astronomers see the X-rays from the solar
flare first because they travel at the speed of light. Then, the
slower-moving (although still blazingly fast) high-energy protons from the
CME reach the Earth, and that’s when the fireworks begin!

“We thought we were getting through this first major solar event relatively
untouched,” muses Kohl, “but now it’s turned into a cliffhanger. Part two is
yet to come!”

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for
Astrophysics is a joint collaboration between the Smithsonian Astrophysical
Observatory and the Harvard College Observatory. CfA scientists, organized
into six research divisions, study the origin, evolution and ultimate fate
of the universe.