One of the most legendary PR disasters in the history of astronomy happened in 1973 when the world awaited the arrival of comet Kohoutek, discovered by Czech amateur astronomer Luboš Kohoutek early that year. Once the orbit was plotted, astronomers knew that the comet was a first time visitor from the hypothesized Oort Cloud, a gigantic 2 light-year wide …

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The true identity of centaurs, the small celestial bodies orbiting the sun between Jupiter and Neptune, is one of the enduring mysteries of astrophysics. Are they asteroids or comets? A new study of observations from NASA’s Wide-field Infrared Survey Explorer (WISE) finds most centaurs are comets.

Until now, astronomers were not certain whether centaurs are asteroids flung out from the …

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Astronomers using NASA’s Spitzer Space Telescope have observed what most likely are strong carbon dioxide emissions from Comet ISON ahead of its anticipated pass through the inner solar system later this year.

Images captured June 13 with Spitzer’s Infrared Array Camera indicate carbon dioxide is slowly and steadily “fizzing” away from the so-called “soda-pop comet,” along with dust, in a …

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Across the world, children fall asleep under the faint light from glow-in-the-dark astronomy stickers. Though undeniably adorable, these ceiling planetariums are too jam-packed to be realistic. You’d never see stars, dozens of spiral galaxies, and comets all at the same time, all shining together from the same patch of sky. Unless, of course, you had Hubble.

On April 30, NASA’s …

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Later this year, Comet ISON is expected to become a naked-eye object when it skims through the atmosphere of the sun. The Hubble Space Telescope has just obtained a sneak preview.

Hubble photographed ISON on April 10th. At the time, the comet was 386 million miles from the sun (394 million miles from Earth), just inside the orbit of Jupiter. …

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Anticipation is building as Comet ISON plunges into the inner solar system for a close encounter with the sun in November 2013. Blasted at point-blank range by solar radiation, the sungrazer will likely become one of the finest comets in many years.

When NASA’s Swift spacecraft observed the comet in January 2013, it was still near the orbit of Jupiter, …

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Over the years, the spacefaring nations of Earth have sent dozens of probes and rovers to explore Mars. Today there are three active satellites circling the red planet while two rovers, Opportunity and Curiosity, wheel across the red sands below. Mars is dry, barren, and apparently lifeless.

Soon, those assets could find themselves exploring a very different kind of world.…

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Comets visible to the naked eye are a rare delicacy in the celestial smorgasbord of objects in the nighttime sky. Scientists estimate that the opportunity to see one of these icy dirtballs advertising their cosmic presence so brilliantly they can be seen without the aid of a telescope or binoculars happens only once every five to 10 years. That said, …

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Comet Pan-STARRS (C/2011 L4) is now inside the orbit of Mercury and it is brightening as it approaches the sun. Observers in the southern hemisphere say the comet can be seen with the naked eye even through city lights. Currently, it is about as bright as the stars of the Big Dipper (Ursa Major) (magnitude +2 to +3). The comet …

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Far beyond the orbits of Neptune and Pluto, where the sun is a pinprick of light not much brighter than other stars, a vast swarm of icy bodies circles the solar system. Astronomers call it the “Oort Cloud,” and it is the source of some of history’s finest comets.

One of them could be heading our way now.


A comet …

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