NASA's sun-watching telescope, the Solar Dynamics Observatory, this week spotted and watched a giant sunspot -- over six Earth diameters across-- form in under 48 hours.
According to NASA the spot quickly evolved into what's called a delta region, in which the lighter areas around the sunspot, called penumbra, exhibit magnetic fields that point in the opposite direction of those fields in the center, dark area. This is a fairly unstable activity that scientists know can lead to eruptions of radiation or solar flares.
NASA defines a solar flare as "an intense burst of radiation coming from the release of magnetic energy associated with sunspots. Flares are our solar system's largest explosive events. They are seen as bright areas on the sun and they can last from minutes to hours." Solar flares can spawn coronal mass ejections (CME) where billions of solar particles are blasted into space and can affect electronic systems in satellites and on Earth.
NASA also notes that we are entering a period of increased solar activity known as a solar maximum.
From NASA: "The sun goes through cycles of high and low activity that repeat approximately every 11 years. Solar minimum refers to the several Earth years when the number of sunspots is lowest; solar maximum occurs in the years when sunspots are most numerous. During solar maximum, activity on the sun and the possibility of space weather effects on our terrestrial environment is higher. The next solar maximum is expected in the 2013-2014 time frame."
NASA's SDO recently celebrated its third birthday in orbit. Launched on Feb. 11, 2010, SDO has sent back some pretty amazing, almost surreal images of the Sun and has helped scientists better understand solar flares and all manner of new evidence to comprehend its impact on space weather.
The SDO has had some novel experiences as NASA calls them. For example:
- Over the last year scientists spent much time poring over data from comet observations. Comets that travel close to the sun - known as sun-grazers -- have long been observed as they move toward the sun, but the view was always obscured by the sun's bright light when the comets got too close. But SDO has now captured images of two comets as they passed close to the sun. In December 2011, Comet Lovejoy swept right through the sun's corona, with its long tail streaming behind it. SDO sent back pictures of the comet's long tail being buffeted by systems around the sun. Such comet tails move in response to the sun's otherwise invisible magnetic field, so they can also act as tracers of the complex magnetic field higher up in the corona, offering scientists a unique way of observing movement there. Observations of the comet's long trail of water vapor and the material its lost, as well as how it vaporizes in the intense radiation of the sun could also be used to study atomic material and their ratios in the corona.
- On June 5, 2012 SDO captures Venus as it crossed in front of the sun, an occurrence that will not happen again for more than 100 years. SDO cameras trained on the transit to help calibrate its instruments and to learn more about Venus's atmosphere. Since the points at which Venus first touched and later left the sun are known down to minute detail, SDO could use this information to make sure its images are oriented to true solar north - calibrating its orientation to within a tenth of a pixel. Scientists also recorded how the sun's extreme ultraviolet light traveled through Venus's atmosphere in order to learn more about what elements exist around the planet, NASA stated.
- The SDO's helioseismic and magnetic imager (HMI) instrument offers real time maps of magnetic fields of the surface of the sun, showing how strong they are and - for the first time ever -- in which direction they are pointing. NASA says since HMI is providing a type of data never before collected, and so it has opened up a whole new area of inquiry. Changing and realigning magnetic fields are at the heart of the sun's eruptions, so this too is a crucial set of data. Scientists have spent time over the last year to figure out how to best create visual maps from the data - as well as how to interpret them. The HMI images have been affectionately referred to as "hedgehog pictures" since they show spiky quill like lines pointing out of - or in toward - the sun, NASA stated.
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