Astronomers recently discovered a green comet approaching Earth for the first time in 50,000 years. Comet ZTF, which could be seen hurtling past Earth from the outer reaches of the solar system in late January and early February, is an icy ball of gas, dust and rock that orbits the sun roughly every 50,000 years, as per researchers. Here are a few other great comets of recent times.
Comet PANSTARRS is a non-periodic comet discovered in June 2011 that became visible to the naked eye when it was near perihelion (the point in orbit at which the comet is closest to the sun) in March 2013. It was discovered using the Pan-STARRS telescope located near the summit of Haleakala, on the island of Maui in Hawaii. The comet probably took millions of years to come from the Oort cloud. After leaving the planetary region of the Solar System, the post-perihelion orbital period (epoch 2050) is estimated to be roughly 107000 years.
Comet Lovejoy, formally designated C/2011 W3, is a long-period comet and Kreutz sungrazer. It was discovered in November 2011 by Australian amateur astronomer Terry Lovejoy. The comet’s perihelion took it through the Sun’s corona on December 16, 2011, after which it emerged intact, though greatly impacted by the event. As Comet Lovejoy was announced on the 16th anniversary of the SOHO satellite’s launch it became known as ‘The Great Birthday Comet of 2011’, and because it was visible from Earth during the Christmas holiday it was also nicknamed ‘The Great Christmas Comet of 2011’.
Comet Holmes is a periodic comet in the Solar System, discovered by the British amateur astronomer Edwin Holmes on November 6, 1892. Although normally a very faint object, Holmes became notable during its October 2007 return when it temporarily brightened by a factor of a million, in what was the largest known outburst by a comet, and became visible to the naked eye. It also briefly became the largest object in the Solar System, as its coma (the thin dissipating dust ball around the comet) expanded to a diameter greater than that of the Sun (although its mass remained minuscule).
Comet NEOWISE is a long period comet with a near-parabolic orbit discovered on March 27, 2020, by astronomers during the NEOWISE mission of the Wide-field Infrared Survey Explorer (WISE) space telescope. At that time, it was an 18th-magnitude object, located 2 astronomical units (AU) (300 million km) away from the Sun and 1.7 AU (250 million km) away from Earth. NEOWISE is known for being the brightest comet in the northern hemisphere since Comet Hale-Bopp in 1997. It was widely photographed by professional and amateur observers and was even spotted by people living near city centres and areas with light pollution. Under dark skies, it could be seen with the naked eye and remained visible to the naked eye throughout July 2020.
Comet NEAT is a non-periodic comet that appeared in November 2002. The comet peaked with an apparent magnitude of approximately -0.5, making it the eighth-brightest comet seen since 1935. It was seen by SOHO in February 2003. At perihelion the comet was only 0.099258 astronomical units (14,848,800 km) from the Sun (slight controversy arose when the comet failed to break up when it approached the Sun, as expected by some scientists if it were a small comet).
Comet McNaught, also known as the Great Comet of 2007 and given the designation C/2006 P1, is a non-periodic comet discovered on August 7, 2006 by British-Australian astronomer Robert H McNaught using the Uppsala Southern Schmidt Telescope. It was the brightest comet in over 40 years, and was easily visible to the naked eye for observers in the Southern Hemisphere in January and February 2007. With an estimated peak magnitude of -5.5, the comet was the second-brightest since 1935. Around perihelion on January 12, it was visible worldwide in broad daylight. Its tail measured an estimated 35 degrees in length at its peak.
Comet Hyakutake is a comet, discovered on January 31, 1996, that passed very close to Earth in March that year. It was dubbed the Great Comet of 1996; its passage near the Earth was one of the closest cometary approaches of the previous 200 years. Hyakutake appeared very bright in the night sky and was widely seen around the world. The comet temporarily upstaged the much anticipated Comet Hale-Bopp, which was approaching the inner Solar System at the time.