Brian Marsden of the Central Bureau for Astronomical Telegrams noted that the comet lay only about 4 degrees from Jupiter as seen from Earth, and that while this could of course be a line of sight effect, its apparent motion in the sky suggested that it was physically close to the giant planet.

Astronomers estimated that the visible fragments of SL9 ranged in size from a few hundred metres to two kilometres across, suggesting that the original comet may have had a nucleus up to acrosssomewhat larger than Comet Hyakutake, which became very bright when it passed close to the Earth in 1996.

* 1770 – Lexell's Comet passed closer to the Earth than any other comet in recorded history, approaching to a distance of 0. 0146 a. u.

Earth moves through the meteoroid stream of particles left from the passages of a comet.

This showed that the meteoroids are mostly behind and outside the path of the comet, but paths of the Earth through the cloud of particles resulting in powerful storms were very near paths of nearly no activity.

Its total mass is not known with certainty, but, assuming that Halley's comet is a suitable prototype for all comets within the outer Oort cloud, the estimated combined mass is ( or roughly five times the mass of the Earth ).

McVeigh argued that " imminent " does not mean " immediate ": " If a comet is hurtling toward the earth, and it's out past the orbit of Pluto, it's not an immediate threat to Earth, but it is an imminent threat.

* April 9 – Comet Austin, the brightest comet visible from Earth since 1975, makes its closest approach to the sun.

* July 1 – Lexell's Comet ( D / 1770 L1 ) passes the Earth at a distance of 2184129 km, the closest approach by a comet in recorded history.

* 2. 19 Gm — Closest approach of Comet Lexell to Earth, happened on 1 July 1770 ; closest comet approach on record

Moreover, if a fragment of an icy comet were to strike the Earth, the most likely outcome, due to the low tensile strength of such bodies, would be for it to disintegrate in the upper atmosphere, leading to an air burst explosion analogous to that of the Tunguska event.

At the time of the observation, the comet was 99. 5 million miles from Earth and 115. 3 million miles from the Sun.

Sagan suggests that in antiquity a comet could have approached so close to Earth that the jets of gas streaming from it, bent by the comet's rotation, became visible, leading to the adoption of the swastika as a symbol across the world.

Halley is the only short-period comet that is clearly visible to the naked eye from Earth, and thus the only naked-eye comet that might appear twice in a human lifetime.

Indeed, on 19 May, the Earth actually passed through the tail of the comet.

A planet ( or asteroid or comet ) is simply said to be in conjunction, when it is in conjunction with the Sun, as seen from the Earth.

Impact breccias are thought to be diagnostic of an impact event such as an asteroid or comet striking the Earth, and are usually found at impact craters.

* The Aurigid shower parent comet C / 1911 N1 ( Kiess ) returns to the inner solar system and sheds the dust particles that one revolution later cause the 1935, 1986, 1994, and 2007 Aurigid meteor outbursts on Earth.

* 1866 – Giovanni Schiaparelli realizes that meteor streams occur when the Earth passes through the orbit of a comet that has left debris along its path

An impact event is the collision of a large meteorite, asteroid, comet, or other celestial object with the Earth or another planet.

The first observation of a major impact event occurred in 1994: the collision of the comet Shoemaker-Levy 9 with Jupiter ; to date, no such events have been observed on Earth.

This has led to the suggestion that the Chicxulub impact was one of several that occurred almost simultaneously, perhaps due to a disrupted comet impacting the Earth in a similar manner to the collision of Comet Shoemaker-Levy 9 with Jupiter in 1994.

These terms have historically been applied to any astronomical object orbiting the Sun that did not show the disk of a planet and was not observed to have the characteristics of an active comet, but as small objects in the outer Solar System were discovered, their volatile-based surfaces were found to more closely resemble comets, and so were often distinguished from traditional asteroids.

Intense studies of the comet were undertaken, and as its orbit became more accurately established, the possibility of a collision became a certainty.

Messier was a comet hunter, and was frustrated by objects which resembled but were not comets, so he compiled a list of them, in collaboration with his assistant Pierre Méchain, to avoid wasting time on them.

There were multiple ideas of how to spread Max's immunity to humanity, including: an air burst that would spread the antibody and dispersed through the human race and save everyone from the comet or, the immunity would be attached to the viruses associated with the common cold and thus spread through the common cold ( he detailed how a scene would show original Cindy sneezing as part of the beginning of the immunity spread ).

Although he had suspected that two comets that had appeared in succession in 1680 and 1681 were the same comet before and after passing behind the Sun ( he was later found to be correct ; see Newton's Comet ), he was unable to completely reconcile comets into his model.

This calculation enabled him, after examining historical records, to determine that the orbital elements of a second comet which had appeared in 1682, were nearly the same as those of two comets which had appeared in 1531 ( observed by Petrus Apianus ) and 1607 ( observed by Johannes Kepler ).

On 8 November 1985, Stephen Edberg ( then serving as the Coordinator for Amateur Observations at NASA's Jet Propulsion Laboratory ) and Charles Morris were the first to observe Halley's comet with the naked eye in its 1986 apparition.

The development of space travel gave scientists the opportunity to study the comet at close quarters, and several probes were launched to do so.

Similar comments were made even in Constantinople, where John Kyriotes Geometres penned a poem offering a punning comparison between the Bulgarian Emperor and a comet which appeared in 989.

In 1998, two films were released in the United States on the subject of attempting to stop impact events: Touchstone Pictures ' Armageddon, about an asteroid ; and Paramount / DreamWorks ' Deep Impact, about a comet.

Two more Earth flybys were scheduled in February 2007 and 2008, and a flyby of comet d ' Arrest might have occurred on 16 August 2008 at a relative velocity of 11. 8 km / s, 1. 35 AU from the Sun and 0. 36 AU from Earth.

The shattered moon and the ruins of the former human civilization were caused by the passage of a runaway planet ( more resembling a comet ) between the Earth and the Moon in 1994, which, from scenes shown in the opening sequence, caused radical changes in the Earth's climate, geography and tidal effects.

* a meteor or comet, seen in the full light of day when in comparatively recent times, the Ngati Hau tribe were besieging the fortress named Rangiuru at Otaki, occupied by the Ngati Awa.

Observations of comet C / 1999 S4 ( LINEAR ) with the Chandra satellite in 2000 determined that X-rays observed from that comet were produced predominantly by charge exchange collisions between highly charged carbon oxygen and nitrogen minor ions in the solar wind, and neutral water, oxygen and hydrogen in the comet's coma.

However, although Schwarzschild's best known work lies in the area of general relativity, his research interests were extremely broad, including work in celestial mechanics, observational stellar photometry, quantum mechanics, instrumental astronomy, stellar structure, stellar statistics, Halley's comet, and spectroscopy.

The spacecraft were equipped with a dual bumper shield for dust protection from Halley's comet.

Images started to be returned on March 4, 1986, and were used to help pinpoint Giotto's close flyby of the comet.

The early images from Vega that showed two bright areas on the comet, which were initially interpreted as a double nucleus.

The spacecraft were equipped with a dual bumper shield for dust protection from Halley's comet.