Explanation: On Valentine's Day (ET) the Sun unleased one of its most powerful explosions, an X-class flare. The blast was the largest so far in the new solar cycle. Erupting from active region AR1158 in the Sun's southern hemisphere, the flare is captured here in this extreme ultraviolet image from the Solar Dynamics Observatory (SDO). The intense burst of electromagnetic radiation momentarily overwhelmed pixels in SDO's detectors causing the bright vertical blemish. This X-class flare was also accompanied by a coronal mass ejection (CME), a massive cloud of charged particles traveling outward at nearly 900 kilometers per second. Skywatchers at high latitudes should be alert for aurorae tonight.
A powerful solar eruption that has already disturbed radio communications in China
could disrupt electrical power grids and satellites used on Earth in the next days ...
(c) 2011 AFP
Re: APOD: X Class Flare (2011 Feb 17)
Posted: Thu Feb 17, 2011 1:41 pm
by sicnarf
As I missing something. 900 meters per second is 613.63 mph and the sun is approximately 93 million miles from earth. How could the effects get here that soon.
Re: APOD: X Class Flare (2011 Feb 17)
Posted: Thu Feb 17, 2011 1:43 pm
by sicnarf
I made an error. That should be kilometers per second which is a lot more than meters per second.
Re: APOD: X Class Flare (2011 Feb 17)
Posted: Thu Feb 17, 2011 3:14 pm
by NoelC
Wow, a flare bright enough to overwhelm the detectors in a solar watching imaging system...
Was that bright enough in the visible spectrum to have made a noticeable difference in the visible light illumination reaching Earth?
-Noel
Re: APOD: X Class Flare (2011 Feb 17)
Posted: Thu Feb 17, 2011 3:15 pm
by Sophron
On Valentine's Day (ET) the Sun unleased one of its most powerful explosions, an X-class flare.
unleased? or unleashed? May be a slip of the pen.
Re: APOD: X Class Flare (2011 Feb 17)
Posted: Thu Feb 17, 2011 9:14 pm
by keir
I have heard that in the early 1900 solar flares interfered with telegraph operation, in one case where the telegraph would operate when the power was disconnected. This seems to me to be an apocalyptic omen. To what extent could these coronal mass ejections blow out electronics and power on earth? Are satelites shielded well enough?
Re: APOD: X Class Flare (2011 Feb 17)
Posted: Thu Feb 17, 2011 10:01 pm
by rstevenson
keir wrote:... This seems to me to be an apocalyptic omen.
Oops, wrong forum for that sort of comment.
keir wrote:To what extent could these coronal mass ejections blow out electronics and power on earth? Are satelites shielded well enough?
Wikipedia wrote:When the ejection is directed towards the Earth and reaches it as an interplanetary CME (ICME), the shock wave of the traveling mass of Solar Energetic Particles causes a geomagnetic storm that may disrupt the Earth's magnetosphere, compressing it on the day side and extending the night-side magnetic tail. When the magnetosphere reconnects on the nightside, it releases power on the order of terawatt scale, which is directed back toward the Earth's upper atmosphere.
This process can cause particularly strong auroras in large regions around Earth's magnetic poles. These are also known as the Northern Lights (aurora borealis) in the northern hemisphere, and the Southern Lights (aurora australis) in the southern hemisphere. Coronal mass ejections, along with solar flares of other origin, can disrupt radio transmissions and cause damage to satellites and electrical transmission line facilities, resulting in potentially massive and long-lasting power outages.[3]
Humans in space or at high altitudes, for example, in airplanes, risk exposure to intense radiation. Short-term damage might include skin irritation. Long-term consequences might include an increased risk of developing skin cancer.[4]
Rob
Re: APOD: X Class Flare (2011 Feb 17)
Posted: Thu Feb 17, 2011 10:10 pm
by Chris Peterson
keir wrote:I have heard that in the early 1900 solar flares interfered with telegraph operation, in one case where the telegraph would operate when the power was disconnected. This seems to me to be an apocalyptic omen. To what extent could these coronal mass ejections blow out electronics and power on earth? Are satelites shielded well enough?
A really large flare can disrupt power grids, and can certainly damage satellites. They are protected to a degree, but it's always a tradeoff in terms of cost. So designers shield based on the value of the asset, and on the probability of an event of a given energy level. It is well understood in the satellite community that an extremely large flare could cause significant damage. Fortunately, events of that size are rare.
X Class Flare
Darn clouds. Darn moon. Darnit 