14 DAY TRIAL // Intriguing sounds coming from the Sun's atmosphere resemble those of an organ in the church, as astronomers recently discovered.
During a discussion at the Royal Astronomical Society National Astronomy Meeting in Preston, Dr Youra Taroyan and Professor Robert von Fay-Siebenburgen of the Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield explained the origin of these magnetic sound waves.
The magnetic field in the outer regions (the corona) of our nearest star forms loops that carry waves and behave rather like a musical instrument.
"These loops can be up to 100 million kilometers long [62 million miles] and guide waves and oscillations in a similar way to a pipe organ." - says Dr Taroyan.
But don't make front row reservations just yet.
The frequency of the sound waves is below the human hearing threshold. While humans can make out sounds between 20 and 20 000 hertz, the solar sound waves are on the order of milli-hertz - a thousandth of a hertz.
They are only heard when their frequency is artificially increased.
Some explosive events at the sun's surface appear to trigger acoustic waves that bounce back and forth between both ends of the loops, a phenomenon known as a standing wave.
"These magnetic loops are analogous to a simple guitar string," von Fay-Siebenburgen explained. "If you pluck a guitar string, you will hear the music. These energies are plucking these magnetic strings or standing pipes, which set up standing waves, exactly the same waves you see on a guitar string."
In the cosmic equivalent of a guitar pick, the so-called microflares at the base of loops could be plucking the magnetic loops and setting the sound waves in motion, as researchers speculate. While solar flares are the largest explosions in the solar system, microflares are a million times smaller but much more frequent; both phenomena are now thought to funnel heat into the sun's outer atmosphere.
Extremely energetic, these acoustic waves can reach heights of tens of miles and can travel at speeds of 45 000 to 90 000 miles per hour. "These [explosions] release energy equivalent to millions of hydrogen bombs," von Fay-Siebenburgen said.
However, the space music is not long lasting, since the "sound booms" decay to silence in less than an hour, dissipating in the hot solar corona.