Stone Age Comet

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Comet C/2022 E3 orbits the Sun every 50,000 years. It last passed Earth during the Stone Age, the time of Neanderthals. And now it’s passing again, close to the tail of the Plough (part of the Great Bear constellation). Finding comets can be difficult, and this Stone Age comet is the hardest I have ever tried to locate.

Scientists believe that most comets originate in the Oort Cloud, the most distant region of our solar system. The nearest part of the Oort Cloud is thought to be around 2,000-5,000 Astronomical Units (AU) away from the Sun (1 AU is the distance between Earth and the Sun). The furthest part of the Oort Cloud is estimated to be up to 100,000 AU from the Sun.

Locating C/2022 E3

The comet comes closest to Earth on 1 and 2 February, when it will be around 27 million miles away. With no guarantee of visibility next week, I took advantage of the clear sky on 25 January to look for C/2022 E3. I find the ‘Night Sky’ mobile app invaluable in navigating the skies. This app is only available on the iPhone Operating System, but there’s a list here of recommended star gazing apps which includes Android and iOS options.

Screen shot from Night Sky iOS app

The comet is nothing like as clear to pick out as it is on the app. But it’s a useful starting point as to where to look for it. The fact that it’s close to the Plough helps, as this is perhaps the easiest constellation to find. As with many celestial objects, the comet is best viewed by looking slightly to one side. I think of comets as having the look of a dandelion clock. Blurred around the edges, and lacking definition.

Images

Comet (smudge towards top left)
Zoomed in image to show position of comet

The photograph lacks clarity of the Comet Neowise images I took in July 2020. The smudged area of the picture (highlighted by the arrow in the second image) is the comet. As it travels closer to the Sun, its surface ice melts into gas, and dislodges dust, creating the cloud around the comet and its tail. I located C/2022 through binoculars, before lining up the camera. The comet was so indistinct that it was impossible to see through the camera lens, and I only knew it was in the picture when I reviewed after taking.

Hoping for clear skies next week, I intend to try to pinpoint C/2022 again. Ideally from somewhere with a lot less light pollution, and a much wider view of the sky. Experts are divided on whether the comet will be visible to the naked eye, but a pair of binoculars or small telescope, and a sky map should be enough to pick it out before it begins its return journey to the Oort Cloud. The Royal Museums Greenwich has further advice on how best to find the comet.

Quick Facts

  • Comet C/2022 E3 (ZTF) was discovered by astronomers at the Zwicky Transient Facility in March 2022
  • It is also known as the Green Comet – the colour is thought to be present because of diatomic carbon
  • The comet is estimated to be around 1 km in diameter
  • In January, strong solar winds caused part of the comet’s tail to break away (known by astronomers as a disconnection event)
  • Watch a livestream of the comet’s closest approach to Earth on 2 February here (film provided by the Virtual Telescope Project)