The elongated double helix nebula stretches 80 light years in length.
Thursday, March 16, 2006 Posted: 1818 GMT (0218 HKT)
WASHINGTON (Reuters) -- Cosmic nebulae usually look like blobs in space, but astronomers using the Spitzer Space Telescope reported on Wednesday they have found a nebula twisted like the double helix of DNA.
"Nobody has ever seen anything like that before in the cosmic realm," said Mark Morris of the University of California, Los Angeles.
Most nebulae are "formless, amorphous conglomerations of dust and gas," Morris said in a statement, adding that this one "indicates a high degree of order."
The discovery of the twisted nebula, which stretches across 80 light-years at the center of the Milky Way, the galaxy that includes Earth, was reported in the current edition of the journal Nature.
A light-year is about 6 trillion miles (10 trillion kilometers), the distance light travels in a year.
"We see two intertwining strands wrapped around each other as in a DNA molecule," said Morris, lead author of the Nature article.
DNA, which forms the basic material in chromosomes, has a molecule that looks like a twisted ladder, known as a double helix.
The strands of the nebula may be torqued by twisted magnetic fields at the Milky Way's center, Morris said by telephone.
These magnetic fields are indirectly spawned by the gaping black hole at the galactic heart, he said. Black holes are massive matter-sucking drains in space, pulling in everything around them so powerfully that not even light can escape.
But before the matter falls into the black hole, it swirls around its edges. This rotation twists the magnetic fields, which in turn twist the nebula's strands, Morris said.
The nebula is relatively close to the black hole, just 300 light-years away. Earth is more than 25,000 light-years away.
NASA's Spitzer Space Telescope detects the infrared energy emitted by objects in space with high sensitivity and resolution, enabling it to clearly see the nebula's distinctive shape.