Astronomy Picture of the Day
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October 4, 1995
The Sun Spews X-rays
Soft X-ray Telescope,
Sun is really very hot. The Sun's outer
atmosphere is so hot that it emits much light in the
X-ray band, which was unexpected.
X-rays are usually emitted from objects having a temperature in the
millions of degrees, not the mere thousands of degrees of the Sun's
surface. The above X-ray picture shows the
Sun one particularly active day
in August of 1992. Evident are hot spots on the solar surface, showing that
areas above the
surface really do reach millions of degrees. But
possibly more puzzling is the broader X-ray glow visible surrounding the
This glow is now attributed to the Sun's X-ray
the origin of which is currently a subject of much discussion and debate. The
is one of the most photographed objects, with frequently updated pictures
over the WWW. In fact, an X-ray picture from Yohkoh taken earlier today
over the WWW. Compare it to the above picture!
Tomorrow's picture: CG4: A Ruptured Cometary Globule
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