Filaments are relatively cooler and denser regions in the chromosphere that have been stretched along magnetic field lines. The bright patches could be plages, hot spots in the chromosphere and possibly future sunspots.
A dark, solar filament hovered above the Sun’s surface, extending across more than half the Sun (Feb. 7-10, 2015). If that filament were straightened out, it would be more than 533,000 miles long, longer than 67 Earths. These images were taken in a wavelength of extreme ultraviolet wavelength of light of material heated to about 60,000 degrees C. Filaments are cooler clouds of particles tethered above the Sun by powerful magnetic forces. Though this one has been fairly stable for many days, they are liable to break apart at any time. Credit: Solar Dynamics Observatory/NASA.
Almost hard to imagine, one hundred million images from the Solar Dynamics Laboratory!
Congraduations to the AIA team!
Yesterday, January 19, 2015, at 1749 UTC (12:49 pm ET) the AIA instrument recorded its 100,000,000th image. Here it is, an AIA 193 Å image showing coronal holes in both the northern and southern hemispheres. More information, including some favorite images from team members, is available at the NASA SDO webpage.
The AIA team at LMSAL worked hard to design and build the AIA telescopes, even overcoming a delayed start way back at the beginning of the SDO project. The team continues to operate the instrument, keeping it calibrated and listing the features seen on the Sun. The HMI JSOC team at Stanford University maintains the archive that serves the images to our large and growing number of users.
A beautiful shot of the Sun by the Solar Dynamics Observatory showing the rather impressive first flare of the new year. The flare was produced by the sunspot group AR2257.
I mentioned last week conditions seemed right for an aurora (from this sunspot group). While I didn’t see an aurora on that time out and an aurora is not likely from this particular flare any longer, I would expect to have other viewing opportunities over the next months as the solar cycle progresses. Flares can become more numerous as the solar cycle passes peak activity. We shall see.
This flare/sunspot group did produce a pulse of UV radiation that ionized the upper atmosphere over Australia and the Indian Ocean. The ionization could have impacted HF radio frequencies below about 10 Mhz – being a ham operator these events are important.
Could this be the start of increased activity? Possibly and these things can happen quickly. You can be alerted when an aurora is apt to occur from a few sources. Two of my favorites is Aurora Service Europe based in Scandinavia and as always, Spaceweather.com.
The sun emitted a mid-level solar flare, peaking at 11:24 p.m. EST on Jan. 12, 2015. NASA’s Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth’s atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel.
An image of the sun on 01 Jan taken by the Solar Dynamics Observatory. The image is dominated by a large coronal hole in the southern hemisphere. As the sun rotates we should get an idea of the extent of the size.
NASA’s Dean Pesnell explains:
Coronal holes are regions of the corona where the magnetic field reaches out into space rather than looping back down onto the surface. Particles moving along those magnetic fields can leave the sun rather than being trapped near the surface. Those trapped particles can heat up and glow, giving us the lovely AIA images. In the parts of the corona where the particles leave the sun, the glow is much dimmer and the coronal hole looks dark.
Coronal holes were first seen in images taken by astronauts on board NASA’s Skylab space station in 1973 and 1974. They can be seen for a long time, although the exact shape changes all the time. The polar coronal hole can remain visible for five years or longer. Each time a coronal hole rotates by the Earth we can measure the particles flowing out of the hole as a high-speed stream, another source of space weather.
Charged particles in the Earth’s radiation belts are accelerated when the high-speed stream runs into the Earth’s magnetosphere. The acceleration of particles in the magnetosphere is studied by NASA’s Van Allen Probes mission.
As Solar Cycle 24 fades, the number of flares each day will get smaller, but the coronal holes provide another source of space weather that needs to be understood and predicted.
The largest sunspot of this solar cycle has now rotated around so that it is just about facing Earth. The video clip of filtered light images (Oct. 18-22, 2014) show this substantial active region is 125,000 km wide, almost as big as the planet Jupiter, and many times the size of Earth. The region appears to have the kind of unstable magnetic field that suggests it might well produce more solar storms. It has already blasted out three substantial flares and numerous smaller ones. Sunspots are darker, cooler regions of the sun with intense magnetic fields poking out through the surface. Credit: SDO/NASA.
The Solar Dynamics Observatory gives this beautiful look at a plume of plasma. This plume is huge, going presumably to another active region out of view on the horizon. Seeing a plume traveling this distance is something of a rarity.
The observation was made in the ultraviolet- 171 Angstroms – on 17-19 Sept 2014.
Very nice! Little wonder this was on NASA’s Image of the Day below is the caption from that page if you’re in a hurry:
On July 26, 2014, from 10:57 a.m. to 11:42 a.m. EDT, the moon crossed between NASA’s Solar Dynamics Observatory (SDO) and the sun, a phenomenon called a lunar transit. A lunar transit happens approximately twice a year, causing a partial solar eclipse that can only be seen from SDO’s point of view. Images of the eclipse show a crisp lunar horizon, because the moon has no atmosphere that would distort light. This image shows the blended result of two SDO wavelengths – one in 304 wavelength and another in 171 wavelength.
A coronal hole, almost square in its shape, is one of the most noticeable features on the Sun of late (May 5-7, 2014). A coronal hole is an area where high-speed solar wind streams into space. It appears dark in extreme ultraviolet light as there is less material to emit in these wavelengths. Inside the coronal hole you can see bright loops where the hot plasma outlines little pieces of the solar magnetic field sticking above the surface. Because it is positioned so far south on the Sun, there is less chance that the solar wind stream will impact us here on Earth.