Thursday, March 08, 2012

X-Class Solar Flares Are Here

Earlier this week, two X-class solar flares — the most massive group of flares — erupted on the Sun. The flares sent out a mixture of electrons, protons, and heavy nuclei toward the Earth at speeds exceeding 1,000 miles per second. The leading edge of this Coronal Mass Ejection (CME) reached the Earth earlier this morning.

In the video below, you can see a spectacular video of the erupting solar flares taken by NASA's Solar Dynamics Observatory.

This video of the recent solar flares was taken at x-ray wavelengths. The solar flares appear to have a ripple effect across the surface of the sun. Video Courtesy NASA/SDO.

Although these flares aren't expected to cause significant damage, previous solar flares have had huge impacts. Previously, CMEs have downed satellites, exploded generators and disrupted power grids.

Satellite Setbacks

When CMEs hit satellites, the resulting radiation can cause damaging electrical problems. Because satellites are so expensive to launch, few are outfitted with significant shielding against radiation. Consequently, many satellites remain vulnerable to the sun's radiation during heightened periods of activity.

In addition to the direct influence of radiation, solar flares can cause secondary effects for Low-Earth Orbit satellites. Charged particle emitted during a solar flare can hit the upper edges of the atmosphere and ionize it, causing the atmosphere to expand.

Consequently, the atmosphere will exert more drag force on satellites that are low enough. This drag slows down satellites, requiring adjustments to avoid plunging toward the Earth. In the late 1970s, this phenomenon caused the Skylab space station to eventually re-enter the Earth's atmosphere and crash on the surface.

Power Problems

CMEs can also cause problems on the surface. When these charged particles hurtle toward Earth, they change the magnetic flux on the surface, and Faraday's law stipulates that any change in the magnetic environment will induce a current in a nearby coil.

In the past, induced currents from solar storms allowed telegraph operators to temporarily send messages without external power. The effects on power grids, however, have also been costly and dangerous. For instance, a 1989 geomagnetic storm that hit Quebec induced currents in power lines, tripped circuit breakers, and led to a blackout of the entire city.

But solar flares aren't necessarily all bad. Auroras that usually happen near the Earth's poles can extend down toward the Equator during these flares. Auroras happen when charged particles collide with gases in the atmosphere and energy is emitted in the form of mystifying green or red lights.

To learn more about the recent solar flares, head over to NASA's webpage.

1 comment:

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