New black hole found

A new black hole more than 500 times the mass of Sun has been discovered using ESA's XMM-Newton space telescope.

The mystery of the missing sunspots explained

An unusually slow-moving solar jet stream buried deep inside the Sun is causing the lack of sunspots and low solar activity, say scientists from the National Solar Observatory (NSO).

The Sun usually follows a fairly regular pattern, cycling through an 11 year period of magnetic intensity – during which, characteristic behaviour such as sunspots, flares and corona mass ejections are typical – followed by 11 years of relative quiescence. At present, the Sun is in a phase of extreme quietness when it should have been displaying more signs of activity, a mystery that has been confounding scientists over the last year.

Noctilucent clouds are back

Noctilucent cloud (NLC) season is here again following a splendid display on Tuesday evening.

NLCs are thin sheets of cloud 82 kilometres high that reflect sunlight when the Sun is between six and sixteen degrees below the horizon. You can tell them apart from other, more normal clouds by their often pearly-blue colour, and ribbed and interwoven appearance. Other clouds at lower altitudes will be in darkness whilst NLCs glimmer high overhead.

The best months for NLCs in the UK are June and July, and they seem to favour lower sunspot activity (which limits the solar heating on the upper atmosphere where they form) so at least the presently dull Sun offers something in exchange for its lack of activity.Even their origin is a mystery, as clouds shouldn’t ordinarily be able to form so high up.

Will the Sun's decline affect climate change?

The lack of current solar activity came under the spotlight today at the European Week of Astronomy and Space Science at the University of Hertfordshire.

The Sun has a (roughly) eleven year cycle of activity, but the onset of the latest cycle, 24, has been a painfully prolonged affair, resulting in very few sunspots and flares. Between cycles, activity drops and the Sun's magnetic field reverses itself, producing new sunspots of opposite polarity to those that came before. The first sunspot of cycle 24 was spotted in January 2008 but the cycle has just never got going. What solar physicists describe as the 'onset' - when the new cycle blossoms eradicating all traces of the old cycle - just hasn't happened yet, with cycle 23's prolonged minimum still clinging on in the Sun's southern hemisphere. Comparing the Sun's magnetic flux ratio over several cycles indicates that deviations from the norm began to occur in the southern hemisphere five or six years ago, suggesting that the Sun's decline has a deep-rooted explanation.