METI message en route to ETs in star system 70 trillion miles away

A small group of scientists has sent a message to any advanced alien civilization that may be living in a star system 12.4 light years away.

The message, which includes pieces of music, math and technology, was transmitted to the GJ273 star system, over 70 trillion miles (112 trillion km) away, over three days in October and includes instructions about how they should reply to us on a day 25 years from now.

The decision to actively send messages to aliens is controversial. There are two main avenues of thinking. The first, known as SETI (Search for Extraterrestrial Intelligence), is that we should actively look for alien life by listening out for signals.

The second - which has become known Messaging Extraterrestrial Intelligence (METI) - is that we should be sending out messages so any advanced life form out there would be able to find us.

Humans have been beaming signals into space for decades, but now METI has announced it has sent out one deliberately designed to attract the attention of alien life.

This transmission project is called Sónar Calling GJ273b, and is a collaboration between METI, the Institute of Space Studies of Catalonia (IEEC), and Spanish music festival Sónar. They sent the signals to Luyten's Star, a Red Dwarf located 12.4 light years from earth that was chosen due to the presence of a potentially habitable exoplanet dubbed GJ273b.

The transmission was beamed out over three successive days (16-18 October) using the EISCAT 930 MHz transmitter in Tromsø, Norway. Included in the message were 33 10 second music clips, commissioned from a diverse group of musicians, designed to represent Sónar's 'exploratory approach' to music over the past 25 years.

The first message also included a scientific and mathematic tutorial that describes the concept of electromagnetic waves and radio signals as communications tools, starting off with the basics and gradually getting more complex. The idea is that if aliens don't know what radio is they'll be able to work out how to respond. Plus, unlike past attempts which relied on imagery, these tutorials should be able to be interpreted by alien species if they don't have vision as we know it.

It also included a 'cosmic clock' which details how we earthlings perceive time. Each message beamed out was exactly the same, except for the clock element, which changed with each successive transmission.

This first message only sent out signals using two different frequencies, but a second message due to be beamed out next April will use a multitude of frequencies to mimic the musical scale and effectively turn the transmitter into a musical instrument. This message is designed to describe the physics and psychology of music perception, and will end with a countdown to the time when we will start listening out for a reply - 25 years from now.

The METI approach, has some fierce opponents, including renowned physicist Stephen Hawking. He says alerting aliens to our presence could be a fatal error:  "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans," he warned.

Another problem is deciding what we should say in a message to aliens. How can one small group of people be responsible for deciding how the whole of earth is represented in a single message?

In an email interview, Douglas Vakoch, president of METI, told Newsweek, ''Everyone engaged in SETI is already endorsing transmissions to extraterrestrials through their actions. If we detect a signal from aliens through a SETI program, there's no way to prevent a cacophony of responses from earth ... there's no way to enforce the SETI protocols that call for consultation before replying. Once the news gets out that we've detected extraterrestrials, anyone with a transmitter can say whatever they want.

''But once we step back, take a breath, and analyse the situation, we realise there's no added danger of an alien attack if we let them know we're interested in having an interstellar conversation. When people learn more about the project, they'll realise we have nothing to fear.''