Comet – Astronomy Now

The largest comet ever seen has been measured – and it’s a whopper

14 April 2022 Keith Cooper

The nucleus of the largest known comet in the Solar System, C/2014 UN271 (Bernardinelli–Bernstein), has been measured by the Hubble Space Telescope to be 129 kilometres across.

Interstellar comet 2I/Borisov may be most pristine ever seen

31 March 2021 Astronomy Now

The interstellar comet 2I/Borisov may be the most pristine ever observed, astronomers say, an untarnished remnant of another star’s nursery.

A naked-eye comet graces our skies

7 July 2020 Mark Armstrong

Comet 2020 F3 (NEOWISE) is putting on a fine showing in the pre-dawn northern sky after emerging intact from perihelion (closest point to the Sun).

’Oumuamua was a unique object. Now astronomers think there could be trillions just like it

14 April 2020 Keith Cooper

The mysterious interstellar object 1I/‘Oumuamua, and trillions of others like it, could have formed when its parent body was pulled apart by gravitational tides from a star, resulting in elongated shards being ejected into interstellar space.

Get ready for Comet ATLAS (C/2019 Y4) in the northern spring sky!

2 April 2020 Ade Ashford

Comet C/2019 Y4 was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on 28 December last year and brightened 6000-fold in just two months to attain magnitude +7.5 on 1 April. Alas, the comet’s nucleus has now fragmented, dashing hopes for a conspicuous naked-eye spectacle in the constellation of Perseus. Here’s our telescopic observing guide.

See Comet Iwamoto’s dash through Leo, Cancer and Gemini before full Moon

10 February 2019 Ade Ashford

Grab your binoculars to catch a glimpse of speedy Comet C/2018 Y1 Iwamoto over the coming week before the glare from a full Moon on 19 February drowns it out. Potentially attaining magnitude +6, the comet passes closest to Earth on 12 February when it can be found traversing Leo at a rate of 7.2 degrees/day. Don’t miss C/2018 Y1’s close enounter with galaxy NGC 2903 on 13 February – by eye, camera, or live online.

Catch close Comet 46P/Wirtanen near the Pleiades on 16 December

12 December 2018 Ade Ashford

Bright Comet 46P/Wirtanen skims past Earth just 30 lunar distances away on 16 December when it could become a diffuse magnitude +3 object almost a degree wide located between the Pleiades and Aldebaran in the constellation of Taurus. Grab your binoculars and find a dark sky location well away from streetlights to enjoy this Christmas comet before the glow from a waxing Moon gets too bright from 17 December.

Jets seen by Rosetta caused by comet’s strange shape

25 May 2018 Astronomy Now

ESA’s Rosetta spacecraft observed unusual jets of gas and dust spewing from comet 67P/Churyumov-Gerasimenko every morning as the sun came up. A new study shows those jets formed as a result of the comet’s strange topography.

See a trio of comets in the April sky

2 April 2017 Ade Ashford

Despite the glow of a waxing Moon, early April is a good time to catch a glimpse of comets 41P/Tuttle–Giacobini–Kresák and C/2015 V2 (Johnson) that are currently circumpolar and visible throughout the UK hours of darkness. And if you’re an early riser, there’s seventh-magnitude C/2017 E4 (Lovejoy) low in the pre-dawn eastern sky too!

See Comet 45P’s close brush with Earth in the pre-dawn sky

9 February 2017 Ade Ashford

Comet 45P/Honda–Mrkos–Pajdušáková passes just 0.08318 astronomical units (7.73 million miles, or ~32 lunar distances) from Earth on the morning of 11 February. Early risers can catch the magnitude +7 comet speeding through the constellations of Hercules, Corona Borealis (CrB) and Boötes at up to 9 degrees/day.