The Sun has unleashed its strongest flare in four years, observers say.

The eruption is a so-called X-flare, the strongest type; such flares can affect communications on Earth. The monster flare was recorded at 0156 GMT on 15 February and directed at the Earth. According to the US space agency, the source of this activity – sunspot 1158 – is growing rapidly.

Solar flares are caused by the sudden release of magnetic energy stored in the Sun’s atmosphere.