Sources of Earth’s “hum” pinpointed

Washington, August 9 (ANI): A new research has found that the Pacific coasts of North America and Central America are important sources of the Earth’s low-frequency vibration, or “hum”.

Previous studies had found that this hum is excited by infragravity waves, a type of ocean wave that originates in shallow water along coasts, but it was uncertain whether hum is generated primarily by infragravity waves in the deep ocean or along coastlines.

To pinpoint the sources of Earth’s hum, Peter D. Bromirski and Peter Gerstoft from the Scripps Institution of Oceanography, University of California, US, correlated hum intensity data from the EarthScope US Array transportable array with ocean wave height measurements and model simulations.

Their results show that the hum is generated primarily along coasts, with no significant hum generation in the deep ocean.

In particular, they found that the Pacific coasts of North America and Central America are important sources of the hum, and the west coast of Europe is a strong secondary source region, while no significant hum was detected from the Southern Hemisphere during the study period, which is November 2006 to June 2007.

The study is the first to identify these specific source regions for Earth’s hum. (ANI)

Methane-producing mineral discovered on Mars

London, March 28 (ANI): Scientists have reported the discovery of a methane-producing mineral on Mars.

According to a report in Nature News, the evidence for the existence of the mineral, known as serpentine, was found by Bethany Ehlmann, a PhD student at Brown University in Providence, Rhode Island.

Ehlmann used a spectrometer on the Mars Reconnaissance Orbiter to identify two small outcrops of the mineral.

Serpentine arises from another mineral, olivine, in a hydrothermal process in which hydrogen gas is produced – a potential energy source for microbes that could in turn produce methane.

The process of serpentinization also produces methane itself, without the need for life. “It was a past source of methane, for sure,” said Ehlmann.

Serpentine can also be altered, in lower temperature water, into carbonate.

However, the finding does not rule out life on Mars today. That depends on whether the presence of serpentine has anything to do with the apparent production of present-day methane.

“It’s certainly an intriguing coincidence that one of the major regions in which we find these minerals has been highlighted as a possible source region of methane. But, there’s this timing problem,” said Ehlmann.

The problem of timing arises because serpentine on Mars is ancient, about 3.8 billion years old, whereas the reports of methane gas are contemporary.

Yet it is possible, according to Ehlmann, that fractures deep underground could be providing the necessary water and heat for serpentine to be formed today, and for methane to percolate up. (ANI)