Solar Blob Attacks the Earth!
On January 13, the National Weather Service’s Space Weather Prediction Center issued a
scary-sounding news flash. “ALERT,” it said. “Type IV Radio Emission.” If that
was too arcane-sounding to get you spooked, there was this detail that followed:
type IV emissions usually result from a major eruption on the Sun.
That is exactly what had happened. The Sun is currently entering the peak of
its 11-year cycle of magnetic activity. When that happens — the actual peak
comes in 2013 — its surface becomes blotchy with sunspots, its luminosity grows
fractionally brighter, and it sends giant flares up in sweeping arcs above the
solar atmosphere. Every so often, it also ejects a blob of hot, charged
particles speeding into space.
(More: Stellar
Dust Ring Could Promise Big Things)
Typically, we don’t have much to fear from these kinds of events, but the
January 13 blob, known more formally as a coronal
mass ejection, or CME, was blasted more or less directly toward Earth, at
about a million m.p.h. (1.6 million k/h)
.
In principle, that could have led to a
disaster. When a mass of charged particles slams into our planet’s magnetic
field, it can send jolts of electromagnetic energy shooting in all directions,
causing what’s known as a geomagnetic storm that can threaten
communications satellites and radio transmissions, and even trigger
blackouts like the one that struck Quebec in 1989 when a CME zapped a
regional power grid.
On the plus side, geomagnetic storms also tend to trigger
amazing displays of the Aurora
Borealis — the Northern Lights, to you and me. A CME that passed by last
spring, for example, seems
to have had that effect.
But like breathless warnings of wintertime blizzards that turn out to be mere
flurries, this CME was something of a dud. “We’re not going to be in for a big
disturbance,” the Space Weather Prediction Center’s Norm Cohen told MSNBC
shortly after the eruption was detected.
(More: Weather
Patterns On a Cosmic Oddball)
Sure enough, when the blob finally arrived on Thursday after covering the 93
million miles (150 million km) between Sun and Earth, the disruption was
minimal. “Weak power grid fluctuations may occur,” read that day’s alert. “Minor
impact on satellite operations possible.”
(Photos: Window on Infinity:
Pictures from Space)
We hadn’t exactly dodged the bullet; instead, the bullet turned out to be
made of rubber. The Sun will be crackling with magnetic storms for many months
to come, however and may spawn more CMEs or even the fantastic fiery tempests
known as solar
tornados. The pyrotechnics, in other words, are hardly over — and neither is
the danger.
(More: An
All Wet Meteorite Arrives From Mars)
Read more: http://science.time.com/2013/01/22/solar-blob-attacks-the-earth/#ixzz2IkLynVVU
Original post link:
http://science.time.com/2013/01/22/solar-blob-attacks-the-earth/?hpt=hp_c3
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