Northern Arizona Astronomy: A Neanderthal Comet | Williams Grand Canyon News

Comets have been observed and recorded since ancient times by many cultures and in many regions. It orbits the sun and is the frozen remnant from the formation of the solar system, consisting of dust, small rocky particles, and various ices that can range from hundreds of feet to tens of miles in diameter.

However, unlike planets, which have relatively circular orbits, comets have very long (cigar-shaped) elliptical orbits that can take several years to several thousand years to orbit just once.

Comets are mostly found in the solar system. Some, known as short-period comets, reside in a wide disk called the Kuiper Belt, which lies beyond the orbit of Neptune and takes less than 200 years to orbit the sun. Long-period comets come from the Oort Cloud, the spherical outer edge of the solar system about 50 times farther from the Sun than the Kuiper Belt, and can take up to 250,000 years to make just one trip. the sun.

As they approach the inner solar system, solar radiation and the solar wind heat them up enough that the icicles begin to blow out of the nucleus along with the dust, forming the coma (the glowing head of the comet) with its ion tail and dust. . Comas may be up to 15 times the diameter of the Earth, while their tails may extend beyond 1 Sun-Earth distance. If it is bright enough, a comet can be seen from Earth without the naked eye; Very bright comets are observed approximately every decade.

The most famous comet is Halley’s comet, which was observed by the British astronomer Edmund Halley in 1682, who correctly predicted that it would return again in 1757. This comet, with a period of about 75 years, has been historically identified since 2000 years and is believed to be the comet On display at 1066 Bayeux Tapestry.

Another famous comet is Shoemaker-Levy 9, which, under the enormous gravity of Jupiter, split into a total of 21 comet fragments before each colliding with the gas giant in 1994. Sometimes, comets can also get very close to the Sun due to their elliptical orbits. Very torn apart. There are currently more than 6,000 known comets.

There is a comet visible in the evening sky with the symbol C/2022 E3 (ZTF). It has a very long orbital period of about 50,000 years, making it the last time it appeared near Earth, Neanderthals were still running around Europe. Although it was at its closest point to the Sun on January 12, it will be well-positioned for observation in February. This comet is expected to be of moderate luminosity.

The brightness of comets cannot be predicted, as this depends on the scattering of sunlight from dust and ice particles in the comet’s nucleus and tail. As matter flows away from the core, the density at any time is determined by the rate of sublimation of the ice in the core as it is heated by the sun. It also depends on the amount of dust mixed with the ice. Therefore, while the future locations in the sky of comets are known with a high degree of confidence, their future brightness is not.

As shown in the sky chart, Comet C/2022 E3 (ZTF) will be visible north of the bright star Capella in the constellation Auriga on February 5. By February 10, it will have moved north of Mars. On February 15, it will be located in the “wedge” of the constellation Taurus. And on February 20, it will have traveled near Orion’s left arm.

As long as you have an unpolluted sky, you should be able to observe the comet visually. However, a standard pair of binoculars will enhance viewing and should make the tail more visible, as well as show the slight green hue of this once-in-a-lifetime visitor to the solar system.

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