The sun, with all those planets revolving around it and dependent on it, can still ripen a bunch of grapes as if it had nothing else in the universe to do.
Galileo Galilei
You may have heard that there was a solar event a little bit ago. At 6:41 GMT on June 7th a solar flare erupted causing a very large coronal mass ejection (CME). Below is the fascinating video from the NASA LittleSDOHMI YouTube channel showing a video montage from the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the The Solar Terrestrial Relations Observatory (STEREO) satellites.
The spectacular videos showing the solar flare and the subsequent coronal mass ejection triggered my curiosity about how we are able to view the Sun in such wonderful detail. All four of the solar observatories are incredible instruments that slake our human thirst for knowledge. Tonight we will take a look at one satellite in particular.
A solar flare is a sudden energetic release of energy resulting in an intense brightening of the surface of the Sun. Solar flares release massive amounts of electromagnetic radiation across the entire spectrum from radio waves to gamma rays as well as highly energetic protons, electrons, and even heavy ions. The total energy released can be as much as 10²⁷ joules, as much as 10% of the total energy output of the Sun per second.
The June 7th event was a medium sized solar flare, rated as M2.5 by solar astronomers which pretty much means that it’s a great show but not particularly dangerous.
Solar flares are classified as A, B, C, M or X according to the peak flux (in watts per square meter, W/m2) of 100 to 800 picometer X-rays near Earth, as measured on the GOES spacecraft. Each class has a peak flux ten times greater than the preceding one, with X class flares having a peak flux of order 10⁻⁴ W/m². Within a class there is a linear scale from 1 to 9, so an X2 flare is twice as powerful as an X1 flare, and is four times more powerful than an M5 flare. The more powerful M and X class flares are often associated with a variety of effects on the near-Earth space environment. This extended logarithmic classification is necessary because the total energies of flares range over many orders of magnitude, following a uniform distribution with flare frequency roughly proportional to the inverse of the total energy. Stellar flares and earthquakes show similar power-law distributions.Wiki
Image of the solar corona, taken by the SECCHI outer cor- onagraph (COR2) by STEREO B on June 7, 2011
(create your own slideshow of the event)
SWPC Space Weather Advisory
Summary For June 6-12 A category S1 (Minor) solar radiation storm was observed on 07-08 June from active sunspot Region 1226. A Category R1 (Minor) radio blackout was observed on 07 June due to flare activity from active sunspot Region 1226.
Outlook For June 15-21 No space weather storms are expected.
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It did, however, produce a sizeable coronal mass ejection (CME).
The CME was expected to cause a minor (S1) solar radiation storm and a minor (G1) geomagnetic storm.NOAA / Space Weather Prediction Center
NOAA’s space storm ratings tables for solar radiation, geomagnetic, and radio blackouts which rate the severity of possible storms and their effects can be found here.
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As the Chinese like to say, may you live in interesting times, but I, for one, don’t find that a particularly onerous curse, though it certainly is interesting that there are 4 solar observatory satellites keeping an eye on the Sun just in case.
NASA, and NASA/ESA, in the case of SOHO, maintain mission websites which follow the satellites mentioned above.
The STEREO and SOHO satellites are quite fascinating instruments that I'm sure we'll cover in more detail at some time in the future, but it is the Solar Dynamics Observatory that we will unearth tonight. The SDO is the device used to image some the videos we see tonight, including the angry Kossack orange sun (see below), taken by the SDO's Atmospheric Imaging Assembly (AIA).
304 Å video of the June 7th solar flare.
The Solar Dynamics Observatory, the newest solar satellite, was launched in February of 2010 and has been active now for a little more than a year. I’m ashamed to say I wasn’t paying attention at the time or I’d have noticed this humorous little introduction...
Ok, too cute :) Here’s a better introduction to the SDO following it’s mission statement from the SDO Guide (pdf)—A very slick and informative NASA publication.
SDO will study how solar activity is created and how space weather results from that activity. Measurements of the Sun’s interior, magnetic field, the hot plasma of the solar corona, and the irradiance will help meet the objectives of the SDO mission.
The satellite carries three observational instruments: the Helioseismic and Magnetic Imager (HMI), the Extreme Ultraviolet Variability Experiment (EVE), and the previously mentioned Atmospheric Imaging Assembly. You just have to see 'em put it all together...
The fully assembled Solar Dynamics Observatory weighed in at about 8,800 pounds (mass= 3,100 kg). From the press kit, "The overall length of the spacecraft along the sun-pointing axis is 4.5 m (14.8 ft), and each side is 2.22 m (7.3 ft). The span of the spacecraft with extended solar panels is 6.5 m (21.3 ft)." Here we see the SDO team packing up the satellite for its trip to Cape Canaveral...
The SDO was launched February 9th, 2010 from Cape Cananveral aboard an Atlas V rocket and inserted into a geosychronous orbit. The satellite is a 3 axis stabilized fully redundant spacecraft with a five year mission although it has enough fuel to function for up to 10 years. 10, 9, 8, 7,...
From the SDO's launch press kit (PDF)...
SDO will improve our understanding of the physics behind the activity displayed by the sun’s atmosphere, which drives space weather in the heliosphere, the region of the sun’s influence, and in planetary environments. The sun's 11-year cycle of activity is driven by the change in polarity of sun's magnetic dipole. The magnetic field lines run from pole to pole of the sun, and over an 11-year time period they "turn inside out" to switch the polarity. The field lines get scrambled during the inversion, resulting in the loops of magnetic reconnection observed in NASA's Transition Region and Coronal Explorer (TRACE) science images. The extent of solar activity is associated with the amount of scrambling. Inside the field lines, at the center of the sun, is the sun's dynamo.
First light was observed in late March of 2010. The first video from the AIA was a spectacular flare.
Soon after the instruments opened their doors, the Sun began performing for SDO with this beautiful prominence eruption. This AIA data is from March 30, 2010, showing a wavelength band that is centered around 304 Å. This extreme ultraviolet emission line is from singly ionized Helium, or He II, and corresponds to a temperature of approx. 50,000 degrees Celsius.SDOmission2009 Channel
Likewise for EVE, interesting data was returned almost immediately...
EVE opened its doors, and less than 1 hour later the Sun celebrated with a flare. The image shows the Sun observed in X-rays, with EVE's (extremely) high-resolution spectra jumping drastically. And this was a minor flare! EVE measures the many wavelengths, or spectra, that affect different layers of the Earth's atmosphere.SDOmission2009
Well, this diary is gettig a bit long. I’m going to break here and pick it up next time with the Solar Dynamics Observatory’s observational instruments and experiments—the Helioseismic and Magnetic Imager (HMI), the Extreme Ultraviolet Variability Experiment (EVE), and the Atmospheric Imaging Assembly (AIA). I hope you'll join me then.
palantir
Links
Goddard Space Flight Center -- SDO | Solar Dynamics Observatory
SDO Is A Go -- SDO Blog
NASA -- SDO Mission Site
Solar Dynamics Observatory
STEREO
Solar and Heliospheric Observatory
Solar flare