IF cellphones get the thumbs-up for use on aircraft, detecting intelligent life on other planets will get a lot harder. Radiation from mobile phones in the sky would swamp any faint radio signals from outer space, seriously hampering radio astronomy and the search for extraterrestrial intelligence (SETI), astronomers warned last week.
The warning came because both the US Federal Aviation Administration and the US Federal Communications Commission are reviewing the ban on cellphone use on aircraft.
Besides transmitting signals at their operating frequencies, cellphones also leak radiation that happens to fall in a frequency band that reveals the molecular signature of newborn and dying stars. It is also among the 2 per cent of frequencies in this part of the spectrum reserved for radio astronomy.
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鈥淚t could be a disaster for us,鈥� says Michael Davis, of the SETI Institute in Mountain View, California. 鈥淲e have incredibly sensitive radio telescopes 鈥� even a single cellphone on a plane 100 miles away could cause pretty serious damage.鈥� That is partly because cellphone signals from the sky could be in a telescope鈥檚 direct line of sight, unlike signals from phones on the ground. 鈥淧utting cellphones in a plane is like building a cellphone tower 40,000 feet high,鈥� says Davis. Fitting planes with devices that can transmit on a frequency that doesn鈥檛 interfere with radio signals could solve the problem.
