Coolest comets

Photographer Chris Cook and his son watch Comet PanSTARRS from First Encounter Beach in Eastham, Mass., on March 13. The photograph was taken via remote shutter release. Even though PanSTARRS has passed its peak brightness, the comet can still be seen by Northern Hemisphere observers after sunset in the western sky.

Comet PanSTARRS twinkles amid the glow of the northern lights over Lempaala in central Finland on March 17.

Comet PanSTARRS takes its place next to the waxing crescent moon in the skies over Los Angeles on March 12, 2013. The pairing of the comet and the moon made for one of the year's best opportunities for astrophotography.

Comet PanSTARRS and the crescent moon loom over a mountaintop row of wind turbines near Mojave, Calif., on the night of March 12, 2013.

The comet PanSTARRS, above and to the left, passes over the Stratosphere Casino Hotel along with a waxing crescent moon at twilight over the Spring Mountains range on March 12, 2013 in Las Vegas.

Comet PanSTARRS is just one of many comets that have made a big impression over the past couple of decades. John Sarkissian, operations scientist at the Parkes Radio Observatory in Australia, captured this view of PanSTARRS hanging in the sky over the Parkes Radio Telescope on March 5, 2013. The telescope was made famous in a movie from 2000 titled "The Dish."

Minoru Yoneto captured this picture of Comet PanSTARRS shining over Queenstown, New Zealand, on March 2, 2013. The comet's tail has two components, consisting of glowing gas and shining dust. Yoneto told SpaceWeather.com that "it's a splendid appearance."

Rufus Canty shared this picture of Comet PANSTARRS on March 5, 2013. "From Puerto Rico, looks awesome," Canty said in a Facebook message.

Australian amateur astronomer Terry Lovejoy captured this view of Comet PanSTARRS on Feb. 9, 2013. Lovejoy has discovered several comets, including the 2011 "Christmas Comet" better-known as Comet Lovejoy.

Comet PanSTARRS shines in the sunset skies over the European Southern Observatory's Paranal Observatory in Chile. Photographer Mike Theiss shared the photo on March 7. For more from Theiss, visit the Extreme Nature website.

Comet PanSTARRS shines above a mountain range in Tierra del Fuego, Argentina. The picture was taken on Feb. 26, 2013, by Ushuaia photographer Victor Gabriel Bibe.

Comet PanSTARRS glows with a fanlike tail in this Feb. 15, 2013, picture from Argentine astrophotographer Ignacio Diaz Bobillo.

Dieter Willasch snapped this picture of Comet PanSTARRS on March 2, 2013, from Somerset West in South Africa.

Comet Lovejoy glows in a picture taken by NASA astronaut Dan Burbank from the International Space Station in December 2011.

Australian photographer Colin Legg captured this photograph of Comet Lovejoy's tail flaring up from the horizon just before sunrise on Dec. 21, 2011.

Comet Lovejoy streaks through the pre-dawn skies above the European Southern Observatory's Paranal Observatory in Chile on Dec. 22, 2011. The stars of the Milky Way can be seen scattered in the heavens.

Skywatcher Michael Jäger of Stixendorf, Austria, took this photo of Comet McNaught C/2009 R1 on June 6, 2010, while the comet was visible in the northeastern morning sky.

Comet Siding Spring C/2007 Q3 appears to streak across the sky like a superhero in this infrared image from NASA's Wide-field Infrared Survey Explorer, or WISE. The comet was discovered in 2007 by observers in Australia. This image was released on Feb. 17, 2010.

Comet Lulin is seen in the early-morning sky during this half-hour time exposure, photographed with a 300mm telephoto lens on Feb. 23, 2009, in Stedman, N.C. The camera tracked the comet during the exposure. This rendered background stars as short streaks.

Comet Hartley 2, also known as 103P/Hartley, exhibits a green coma as well as a reddish tail in this Oct. 21, 2010, picture from British astrophotographer Nick Howes. The coma is the haze of dust and gas that surrounds a comet's nucleus.

Comet McNaught C/2006 P1 was one of the most photogenic comets of recent times. After making quite a show in the Northern Hemisphere in early January 2007, the comet moved south and developed a long and unusual dust tail that dazzled Southern Hemisphere observers. This view shows Comet McNaught above Santiago de Chile.

Comet McNaught C/2006 P1 flares in the skies above Dunedin in New Zealand on Jan. 18, 2007. The comet was named after its discoverer, Australian astronomer Robert McNaught.

Comet McNaught's long tail spreads across the early-morning sky above Pucon, about 500 miles south of Santiago, Chile, on Jan. 19, 2007.

A wide, hazy coma surrounds the nucleus of Comet Holmes in this picture from Nov. 12, 2007.

Comet 17/P Holmes glows in a picture taken Nov. 1, 2007, by astrophotographer Alan Dyer in southern Alberta, Canada. The observations were recorded through a 105mm apochromatic refracting telescope at f/5 with a Canon 20Da camera at ISO 400.

A long-period comet called 2001 RX14 (LINEAR) streaks streaks across the sky in an image captured in 2002 by the Sloan Digital Sky Survey's telescope in New Mexico.

Photographer Jamie Cooper captured this view of Comet Hale-Bopp from Northamptonshire in England in March 1997, using a Canon SLR camera with a timed exposure of approximately 40 seconds.

Comet Hale-Bopp streaks over 12,388-foot (3,776-meter) Mount Fuji, Japan's highest mountain, on March 31, 1997.