What is a comet?

• Frozen chunks of ices, gravel-sized rocks and dust, comets are material left over from the formation of the Sun and planets 4.6 billion years ago.
• Most reside well beyond the orbit of Pluto but occasionally swing into the inner solar system where they brighten to become easily visible.

Why is this comet special?

• About October 23, 2007, this comet brightened by nearly a million times -- from an object only visible in large telescopes to an object that we can now see with the naked eye.
• At its current distance, it is very unusual that the comet has brightened so much and so quickly.

About periodic comet 17P/Holmes

• “17P" indicates Holmes was the 17th comet discovered to periodically orbit around the Sun.
• 17P/Holmes is now more than 1.6 times farther than the Sun.
• The comet can be observed on a 6.9-year cycle.

Discovery of 17P/Holmes

• Periodic comet 17P/Holmes was discovered by the British amateur astronomer Edwin Holmes on November 6, 1892.
• Edwin Holmes was making his regular observations of the Andromeda Galaxy (M31) when he noticed changes similar to the current outburst though with a less spectacular increase in brightness.
• Over a period of several weeks he and other astronomers watched it fade. Astronomers expect the same will occur this time.

Finding the comet:

• Face East. 17P/Holmes is now easily visible from dusk to dawn in the constellation Perseus. To find it, locate the constellation Cassiopeia, the one that looks like a W or M (depending on the time of night).
• From the two brightest stars at the western side, draw a line towards the horizon. Just east of that line you will find a moderately bright star called Algol.
• Holmes is near it. With binoculars, you can easily see how different it is from a star.

Media contact: Kelly Ray
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