September 12, 2012
ESO Shows ‘Witch’s Broom’ Shape In Pencil Nebula
Lee Rannals for redOrbit.com — Your Universe Online
It seems a little early to already start decorating for Halloween, but the European Space Observatory has decided that it's never too early for a nebula shaped like a witch's broom.
A new image of the Pencil Nebula shows a cloud of glowing gas making up part of a huge ring of wreckage left over after a supernova explosion that took place about 11,000 years ago.
ESO has likened the image of the Pencil Nebula to that of a witch´s broom because of the way the gas is shaped in the image.
"Despite the tranquil and apparently unchanging beauty of a starry night, the Universe is far from being a quiet place," ESO said. "Stars are being born and dying in an endless cycle, and sometimes the death of a star can create a vista of unequalled beauty as material is blasted out into space to form strange structures in the sky."
The new image was taken from the Wide Field Imager on the MPG/ESO 7-foot telescope at ESO's La Silla Observatory in Chile.
The glowing filaments seen in the picture were created by the violent death of a star thousands of years ago. The remnant is an expanding shell of gas that originated from the supernova explosion.
Initially the shock wave was moving at millions of miles per hour, but as it expanded through space, it moved through the gas between the stars, which slowed it and created the strangely shaped gas.
The nebula's luminous appearance comes from dense gas regions that have been struck by the supernova shockwave. As this wave travels through space, it rams into the interstellar material.
As the gas is heated to millions of degrees, it is then cooled down and gives off the faint glow that was captured in the new image.
Astronomers are able to look at the different colors in the nebulas to map the temperature of the gas.
Some regions are still so hot that ionized oxygen atoms dominate the emissions. Other cooler regions are seen glowing red due to emissions from hydrogen.
The Pencil Nebula is about 0.75-light years across and is moving through the interstellar medium at about 400,000 miles per hour. Even at its distance of about 800 light-years away from Earth, it will still noticeably change its position relative to the background stars within a human lifetime.