Can you spot a dirty snowball?

  • Comet Hale-Bopp in 1997 - Credit: BARRY BATCHELOR/PA Archive/Press Association Images

    Comet Hartley 2 seen by the EPOXI probe in 2010 - Credit: NASA

    Forecast cloud cover on at 9p.m. on Saturday 17th and Sunday 18th January 2015 - Credit: MeteoGroup

  • Can you spot a dirty snowball?
    17.01.2015 15:26

    Snow has affected the UK this week, and in some places there's been more than enough snow to build a decent sized snowman. If you're prepared to brave the cold then you might be able to see a different kind of snowball altogether. Comet Lovejoy is currently visible in the evening sky, and although it isn't as bright as some comets we've seen in recent years, you may be able to spot it if you're lucky enough to get clear skies this week.

    Comets have been in the news recently, mainly due to the Rosetta mission which landed a probe on the surface of Comet Churyumov–Gerasimenko at the end of last year. Rosetta is the latest space probe to visit a comet, following in the footsteps of Giotto which flew past Halley's Comet in 1986 and the EPOXI probe which visited Comet Hartley 2 in 2010 (pictured), to name but two. These missions have confirmed that comets are, essentially, dark, dirty snowballs and made of a combination of rock, dust, water ice and other frozen gases. The ice and gases evaporate as the comet nears the sun and the resulting stream of gas and dust form a coma and tail, these giving a comet its recognisable shape.

    Comet Lovejoy was discovered in August 2014 by Terry Lovejoy and is the fifth comet he has found. Having spent the end of last year in the southern skies, it has now moved north and is well placed for observers in the northern hemisphere. It is currently lying close to the Pleiades or Seven Sisters in the constellation of Taurus and will continue to move northwards over the next couple of week. A more detailed map can be found here (credit: Sky and Telescope magazine). You’ll probably need a pair of binoculars to see Comet Lovejoy, although if you’re lucky enough to live somewhere with dark skies, you may be able to glimpse it without any optical equipment.

    So, the big question is which parts of the country are going to have clear skies over the next few nights. The attached cloud cover maps show that many central and eastern parts of the country should be clear this evening, whilst tomorrow evening (Sunday) most parts of the country ought to be reasonably clear. If you are going to try to spot the comet then wrap up warm! It’ll get very cold during this evening and tomorrow evening with an early frost in places.

    The following night may not be as promising, as cloud is expected to build ahead of a weather system approaching from the west. However, the comet is likely to be visible until at least the end of the month and there should be more opportunities to see it before it fades. If you miss it, don't worry. It should be back in around 8,000 years.

    By: George Goodfellow