London, Aug 22 : Dropped mobile phone calls, mysterious signals in undersea communication cables, and tiny tremors on the Earth are all caused by vibrations on the Sun, according to a team of scientists from Queen's University in Kingston, Ontario, Canada.

Churning motions inside the Sun produce various kinds of waves, including sound waves called p-modes and another type of wave called g-modes.

G-modes arise when a pocket of material rising up from deep within the Sun get pulled downwards again by gravity, leading to a wave motion similar to the rise and fall of waves on the surface of the ocean.

Both types of waves vibrate very slowly. The p-modes vibrate with periods of a few minutes, while the periods of g-modes are even longer, lasting tens of minutes or even several hours.

Way back in 1990, a team led by engineer and statistician David J Thomson reported seeing fluctuations in the solar wind - a stream of charged particles from the Sun - with periods in the same range as p-modes and g-modes.

Now, they have said they have evidence that these modes not only travel through space in the solar wind, but also influence natural phenomena and human technologies on Earth.

Thompson said voltages on undersea communications cables experienced unexplained fluctuations with periods characteristic of p-modes.

Seismic measurements of the Earth also showed very long periods in the range of g-modes, he said, adding that the number of dropped mobile phone calls seemed to fluctuate regularly with periods that tied them to solar vibrations.

"We can't think of anything else that generates that kind of frequency and is this stable," said Thomson, adding that Ulysses spacecraft data has also suggested oscillations persisting at the same frequencies for years.

He said as geomagnetic storms caused by solar activity is widely acknowledged to have effects on power lines, so it is likely that they also affect undersea cables.

"As for shaking the Earth, magnetic materials within the planet, such as nickel, could respond to the solar wind fluctuations. It's a really odd kind of phenomenon. It's not a very violent shaking, but it is measurable," said Thompson.

However, many scientists are sceptical that the fluctuations could affect things on Earth.

"It seems extremely unlikely to me," said David Hathaway, a solar physicist at NASA's Marshall Space Flight Center in Huntsville, Alabama, US.

He said previous studies have shown that vibrations may not be able to escape from the Sun at all.

G-modes in particular should be extremely weak by the time they rise to the Sun's surface and that they will not have any effect on the solar wind, he said.

However, Thomson believes that magnetic field lines that penetrate the visible surface of the Sun could help channel the g-modes into space.

"You could, in fact, radiate a fair amount of energy," New Scientist quoted him as saying.