Comet Borrelly or Borrelly's Comet (official designation 19P Borrelly) is a periodic comet, which was visited by the spacecraft Deep Space 1 in 2001.

That's how he discovered the comet.

There are exceptions, such as Halley's Comet.

Biela's Comet or Comet Biela (official designation 3D Biela) was a periodic Jupiter family comet first recorded in 1772 by Montaigne and Messier and finally identified as periodic in 1826 by Wilhelm von Biela.

He claimed that he had discovered a new comet.

While I was in Easter Island, comet McNaught was there also, so you get a gratuitous picture of a moai with a comet.

And this is a comet, captured by Dr. Euan Mason.

Caroline Herschel was the first woman to discover a comet.

After the death of Caesar, a comet shone for seven days.

This was the first time that a comet was visited twice.

Emtage remembers her once waking him at 3am to see a comet.

Rosetta's probe, Philae, has successfully landed on the comet 67P Churyumov Gerasimenko.

The name comet comes from the Latin word cometa which means long haired .

When William Herschel discovered Uranus, he at first thought he had discovered a comet.

He noted the comet passed very close to Jupiter during May 1912 and that, prior to this approach, the comet had a perihelion distance of 2.15 AU and an orbital period of 9.43 years.

Compton was initially interested in astronomy, and took a photograph of Halley's Comet in 1910.

32P Comas Solà is a periodic comet with a current orbital period of 8.8 years.

The jazz composer Sun Ra performed the Concert for the Comet Kohoutek in December 1973.

It was on my fourth trip to Everest that a comet passed over the mountain. Hyakutake.

The comet has often suffered the gravitational influence of Jupiter, which has altered its orbit considerably.

It was discovered by Charles Messier in 1764 and included in his list of comet like objects.

Serendipitously, it was well placed to observe the collision of Comet Shoemaker Levy 9 with Jupiter in 1994.

At the time it was only the third comet known to be periodic, after the famous comets Halley and Encke.

After the discovery apparition, the comet has always been over two magnitudes fainter and no fragments have been seen since 1889.

Comet Kohoutek, formally designated C 1973 E1, 1973 XII, and 1973f, was first sighted on 7 March 1973 by Czech astronomer Luboš Kohoutek.

By 6 August, when the Turkish siege was broken the comet had not been visible in either Europe or Turkey for several weeks.

In the year 2005, NASA launched a probe called Deep Impact, which slammed into slammed a piece of itself into the nucleus of a comet.

The three pieces continued in almost identical orbits, and the comet re appeared in the morning sky in late October, showing a very bright tail.

16P Brooks, also known as Brooks 2, is a periodic comet discovered by William Robert Brooks on July 7, 1889, but failed to note any motion.

The 29 June 1456 papal bull of Callixtus III calling for a public prayer for the success of the crusade, makes no mention of the comet.

They were discovered in 1972 and have been observed about every 5 years at each perihelion passage of the comet but often at very low rates per hour.

A few scientists, and many science fiction writers, have also speculated about using nuclear weapons to destroy or damage an asteroid, comet, meteor, or alien spacecraft heading toward the earth.

Some unknown comet or other space object could fly near enough to the asteroid in the next few decades to change its predicted path, perhaps in a way that redirected it toward Earth.

At more than 360 meters in diameter, the asteroid, Apophis, is a dozen times larger than the Tunguska space object (presumably a meteorite or comet) that devastated a large part of eastern Siberia a century ago.

A few scientists, and many science fiction writers, have also speculated about using nuclear weapons to destroy or damage an asteroid, comet, meteor, or alien spacecraft heading toward the earth. The Outer Space Treaty bans placing nuclear weapons in orbit, on celestial bodies, or stationing such weapons in outer space in any other manner, but may be interpreted to permit their one time use.