Looking for signs of life in outer space? Here's one that scientists really weren't expecting: an entire nebula shaped like a DNA double helix.
The 80-light-year-long formation lies near the enormous black hole at the center of our own Milky Way galaxy, say the scientists who report the unusual find in this week's issue of the journal Nature.
"Nobody has ever seen anything like that before in the cosmic realm," said Mark Morris, professor of physics and astronomy at the University of California, Los Angeles, and lead author of the study.
"Most nebulae are either spiral galaxies full of stars or formless, amorphous conglomerations of dust and gas—space weather. What we see indicates a high degree of order."
NASA's Spitzer Space Telescope captured an infrared image of this spiraling stairway to the heavens, shown above in a false-color photo. Astronomers studying the image believe that the irresistible pull of magnetism created the intertwining spiral strands.
Strong magnetic-field lines, perhaps a thousand times more powerful than those around the Earth, run through the nebula. These lines appear to have been twisted at their base. Morris believes that the lines are grounded in the circumnuclear disk—a huge body of gas that orbits around the black hole, like water circling a drain.
He theorizes that the twisting motion travels through the magnetic-field lines, creating the nebula's distinctive spiral shape.
—Brian Handwerk
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