10 BEST-KNOWN COMETS

1. HALLEY’S COMET

Halley’s Comet is the most famous celestial visitor. It’s named after British astronomer Edmund Halley, who predicted its return in 1757 after observing it in 1682 and tallying it to previous appearances. The comet, 8km wide and 16km long, travels around the Sun every 75 to 76 years in an elongated orbit. It last passed close to Earth in February 1986 and is expected to return in 2061.

2. SHOEMAKER LEVY-9

Shoemaker Levy-9 broke into 21 pieces under the stress of Jupiter’s gravity in 1992 and then slammed into the giant planet in 1994.

3. HYAKUTAKE

Comet Hyakutake is an icy-blue blob that passed 15 million km from Earth in March 1996 — the closest it had come to the Sun in 9,000 years. Its tail is at least 570 million km — double that of any known comet. Its next passage will be 14,000 years from now.

4. HALE BOPP

Comet Hale Bopp is much larger than Halley’s Comet, with a nucleus up to 40 km in diameter. It is so bright that it can be viewed from Earth with the naked eye. Hale Bopp made its closest approach to Earth for 4,000 years in January 1997.

The comet is believed to have come from the Oort Cloud, a theorised sphere surrounding the solar system that is home to mysterious icy objects.

5. COMET BORRELLY

Borrelly is the second comet after Halley’s to be viewed closely as Nasa’s Deep Space 1 paid a visit in 2001, giving researchers a glimpse of the pitch-black core. Its next closest approach to the Sun will be on December 11, 2028.

6. COMET ENCKE

Comet Encke first recorded sighting was in 1786. It is the parent body of the annual Taurid meteor shower in October and November. It was last seen in 1997 and will be back in 2030.

7. TEMPEL-TUTTLE

Temple Tuttle is the progenitor of the annual Leonid meteor shower. Thousands of shooting stars streak across the night sky every November as the Earth passes through the dust and rocky meteoroids shed by the comet. It orbits the Sun once in 33 years, the last closest approach being in 1998. It will return in 2031.

8. COMET WILD 2

Comet Wild 2, discovered in 1978, was visited by Nasa’s Stardust mission in January 2004. In samples collected by the probe, scientists discovered glycine: a fundamental building block of life. Wild 2 last made its closest approach to the Sun in 2016. It has an orbital period of 6.17 years.

9. COMET TEMPEL 1

Tempel 1 is a small comet (6km in size) discovered in 1867. It orbits the Sun every 5 to 6 years, and the last passage was in March 2022.

10. CHURYUMOV-GERASIMENKO

Comet 67P/Churyumov-Gerasimenko was discovered in 1969 and orbits the Sun every 6.6 years. Its last approach was in 2021. It will return on April 9, 2028.

Source: New Scientist