NASA captures footage of 'rain' on the sun

By Paul Harper

The bottom two black spots on the sun, known as sunspots, appeared quickly over the course of February 19-20, 2013. Image / NASA/SDO/Goddard Scientific Visualization Studio
The bottom two black spots on the sun, known as sunspots, appeared quickly over the course of February 19-20, 2013. Image / NASA/SDO/Goddard Scientific Visualization Studio

NASA has captured footage of "rain" on the sun.

The footage, of an eruption on the sun on July 19 last year, was taken by the Solar Dynamics Observatory's Atmospheric Imaging Assembly instrument.

"Eruptive events on the sun can be wildly different," Karen Fox, from Nasa's Goddard Space Flight Center, wrote on NASA's website.

"Some come just with a solar flare, some with an additional ejection of solar material called a coronal mass ejection (CME), and some with complex moving structures in association with changes in magnetic field lines that loop up into the sun's atmosphere, the corona."

This one came with all three.

"A moderately powerful solar flare exploded on the sun's lower right limb, sending out light and radiation. Next came a CME, which shot off to the right out into space. And then, the sun treated viewers to one of its dazzling magnetic displays - a phenomenon known as coronal rain," Ms Fox said.

"Over the course of the next day, hot plasma in the corona cooled and condensed along strong magnetic fields in the region. Magnetic fields, themselves, are invisible, but the charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, which highlights material at a temperature of about 50,000 Kelvin. This plasma acts as a tracer, helping scientists watch the dance of magnetic fields on the sun, outlining the fields as it slowly falls back to the solar surface."

Every second in the video corresponds to about six minutes of real time.

The SDO has more recently captured an image of a massive black spot on the sun, known as a sunspot. The spot, larger than six Earths across, formed in less than 48 hours on February 19 and 20, Ms Fox said.

"The spot quickly evolved into what's called a delta region, in which the lighter areas around the sunspot, the penumbra, exhibit magnetic fields that point in the opposite direction of those fields in the center, dark area. This is a fairly unstable configuration that scientists know can lead to eruptions of radiation on the sun called solar flares," she wrote on the NASA website.

- nzherald.co.nz

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