Filament 50 Earths wide snakes across the sun

NASA's Solar Dynamics Observatory catches sight of an extremely long filament of solar material in the form of a long, dark tendril across the sun's surface.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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Two white arrows point out the filament.


The sun is huge. It has a diameter of around 865,000 miles (1,392,000 kilometers) compared with the Earth's dainty 7,900 miles (12,740 kilometers). That's how the face of our solar friend can sport a dark filament as long as 50 Earths lined up.

NASA's Solar Dynamics Observatory (SDO), a joint project of NASA and the European Space Agency, took note of the massive filament on October 21, and NASA released information on the fascinating phenomenon Monday. The dark snaking line can be seen on the upper half of the sun.

"Filaments are elongated clouds of solar material that are tethered above the sun by magnetic forces," NASA explains. The SDO captured this view in extreme ultraviolet light, which makes the filament appear as a dark jagged line amid the swirling material of the sun's surface.

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Filaments of this size aren't an everyday occurrence. In late 2014, NASA noted a million-mile-long filament on the sun. Filaments tend to have short lifespans, sometimes fading into obscurity and sometimes spewing material out into space in the form of impressive eruptions.

We've had quite a bonanza year so far for spectacular sun images. In February, a daring comet came within 2.2 million miles of the sun and managed to survive the relatively close encounter. NASA's Solar Heliospheric Observatory spacecraft saw it as it emerged intact on the other side.

This fall, we saw the International Space Station transit the sun, and the SDO treated space fans to a rare "="" of="" the="" earth="" and="" moon"="" shortcode="link" asset-type="article" uuid="0d625fea-4090-47a0-9c06-6df27159de1c" slug="nasa-shares-earth-moon-double-photobomb-of-the-sun" link-text="" section="news" title="Earth and moon 'double photobomb' of the sun is a NASA rarity" edition="us" data-key="link_bulk_key" api="{"id":"0d625fea-4090-47a0-9c06-6df27159de1c","slug":"nasa-shares-earth-moon-double-photobomb-of-the-sun","contentType":null,"edition":"us","topic":{"slug":"science"},"metaData":{"typeTitle":null,"hubTopicPathString":"Science","reviewType":null},"section":"news"}"> taking dark bites out of the sun during a partial solar eclipse. The very long filament seen by the SDO is another in an illustrious line of sun images that are both beautiful and fascinating.