WHAT'S UP: Earth may have dodged a bullet

Jun 10, 2011


Links to movies created from SDO images of the eruption are available at the SDO website: http://sdo.gsfc.nasa.gov/. The clips are nothing short of spectacular.
The movies are also available, along with detailed commentary, at http://www.thesuntoday.org/ — a blog maintained by solar scientists at the NASA Goddard Spaceflight Center, where SDO is managed.

As the song by the pop band They Might be Giants goes: “The sun is a mass of incandescent gas, a gigantic nuclear furnace.” The source of nearly all energy here on Earth, we depend on the sun for our very existence.

Most of the time, the sun is a benevolent provider, heating and warming our world magnificently yet steadily. But from time to time, the tenuous outer layers of the sun — the surface of the sun we see with our eyes — seems to get twisted up on itself; and when it untangles, it erupts with a fury.

The sun isn’t as steady as we like to think. Over the past four billion years, the sun has gotten steadily brighter, which has helped Earth stay warm as the carbon dioxide concentration in Earth’s atmosphere decreased to the present-day level.

Carbon dioxide, a major greenhouse gas which traps heat near Earth’s surface, has been becoming more concentrated in Earth’s atmosphere since the beginning of the industrial revolution — leading many to speculate that Earth will grow increasingly warmer in the coming decades and centuries.

On a much shorter time scale, the sun’s level of activity waxes and wanes with an 11-year period.

The sun’s activity is most obviously tracked by counting sunspots. Sunspots are Earth-sized and larger regions of the sun that appear dark in contrast to the sun’s 6,000-degree Celsius surface.

The number of sunspots visible on the sun has been regularly recorded by sun watchers for about 300 years.

The sun’s 10- to 11-year activity cycle is clearly evident in long-running graphs of the sunspot number.

Presently, the sun is climbing out of a deep and prolonged activity minimum that bottomed out in 2009. Predictions are that the sun will reach maximum activity levels in 2013.

As the sun becomes more and more active in the coming months and years, we can expect more solar eruptions like the one that occurred on Tuesday.

When large solar eruptions — solar flares and coronal mass ejections — are directed towards Earth, we can expect communications outages, wide-spread power outages and increased auroral (northern lights) activity.

Tuesday’s solar flare and coronal mass ejection, which wasn’t as powerful as it was spectacular, is expected to deliver only a glancing blow to Earth’s magnetic field today — but it is a reminder of what happens when you live near a star.

— By Doug Furton, a member of the physics faculty at GVSU. Send questions and suggestions to dgf@inbox.com. An archive of some of his “What’s up” columns is available online at http://gegenshein.wordpress.com/.


Post a Comment

Log in to your account to post comments here and on other stories, galleries and polls. Share your thoughts and reply to comments posted by others. Don't have an account on GrandHavenTribune.com? Create a new account today to get started.