(Image: Mike Hankey/mikesastrophotos.com)

If we’re lucky, this is just the start of a really spectacular show. Comet ISON dramatically brightened on Wednesday night as it drew ever closer to the sun. It is now visible to the naked eye.

ISON is expected to keep brightening over the next few weeks – and could become a once-in-a-century comet so bright that it can be seen during the daytime. It all depends on whether it survives its close approach to the sun, when the searing heat and intense gravity could tear it to pieces.

Comet ISON, also known as C/2012 S1, was discovered in September last year. It has been journeying towards the inner solar system for at least a million years, having been pulled in from the distant Oort cloud, at the edge of our solar system. On 28 November, it will make its closest approach to the sun, just 1.2 million kilometres above the solar surface.

An army of spacecraft, balloons and ground-based telescopes is poised to pay homage to ISON as its big day approaches.