Other rumors -- that the Earth's magnetic field will suddenly reverse or that the planet will travel almost 30,000 light-years and fall into the black hole at the center of the Milky Way galaxy -- were also dismissed. (A light-year is the distance light travels in one year, or about 6 trillion miles, or 10 trillion km.)
One popular rumor that the planet will undergo a complete blackout from Dec. 23 to 25 earned a "What?" and blank looks from the panel of scientists.
Ultimately, concerns about Earth's fate would be better focused on slow-acting problems such as climate change rather than some sort of cosmic catastrophe, said Andrew Fraknoi, an astronomer at Foothill College in California.
Mitzi Adams, a heliophysicist at NASA's Marshall Space Flight Center, agreed.
"The greatest threat to Earth in 2012, at the end of this year and in the future, is just from the human race itself," Adams said.
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