A satellite duo called STEREO has produced the first ever three-dimensional images of the Sun, NASA announced on Monday.
快猫短视频s hope the images of the Sun鈥檚 outer atmosphere, or corona, will help improve their computer models of solar activity. Better predictions could help engineers protect the sensitive electronics on satellites from the ravages of solar storms.
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The two STEREO (Solar Terrestrial Relations Observatory) spacecraft, which launched into space in October 2006, are able to make the 3D images by taking simultaneous pictures as one flies front of Earth and the other flies behind it in the planet鈥檚 orbit around the Sun.
Among the new observations are ultraviolet images showing holes in the scorchingly hot corona; the holes appear dark in part because they contain fewer particles that emit light. A (learn how to to get the full effect). The solar wind 鈥� a stream of charged particles from the Sun that flows throughout the solar system 鈥� emanates from these holes.
STEREO also captured an active region on the Sun. Magnetic loops in this stormy region are visible in this . It is when these loops get twisted that the Sun can unleash a torrent of radiation that can be hazardous to spacecraft or astronauts.
New vantage point
Before the STEREO mission, images of the Sun were taken from only one vantage point 鈥� an imaginary line drawn from Earth to the Sun. For instance, the prolific Solar and Heliospheric Observatory (SOHO) spacecraft orbits the Sun at a point on this line where the gravity of the Sun and Earth are balanced.
鈥淲e have to move away from the traditional Sun-Earth line . . . to really get a deeper understanding of what鈥檚 inside the Sun [and] how is it affecting the entire solar system we live in,鈥� says NASA鈥檚 STEREO programme scientist Madhulika Guhathakurta.
That is not the only way in which STEREO is an improvement over its predecessors. SOHO can study solar eruptions stretching just a short distance from the Sun 鈥� only 15% of the distance from the Sun to Earth.
STEREO can observe these eruptions as they travel all the way from the Sun to the Earth (see Advancing solar blasts filmed for the first time). 鈥淭o cover the vast distance from the 15% that we viewed to the 85% that we didn鈥檛, scientists were modelling in the dark,鈥� Guhathakurta says.
Quiet period
The new images were taken during a quiet period in the Sun鈥檚 11-year cycle of activity, when there is an eruption of particles and radiation from the Sun about once every other day. By contrast, there can be five or more storms per day at solar maximum.
鈥淚t鈥檚 much better if we can have clean events, where we see there鈥檚 only one active region in the Sun鈥檚 centre,鈥� says team member Spiro Antiochos of the US Naval Research Laboratory in Washington, DC, US.
鈥淭his one active region puts out one nice, well-shaped solar storm, which comes right at us where STEREO takes pictures. Then we can see how well (the) models do, to the point where we can handle the more complicated regions,鈥� he says.
