Aliens face Earth TV switch-off

ET is about to miss out on all his favourite TV shows from Earth, according to the world’s top alien-hunter. The global switchover to digital TV will destroy the signal for “zillions of viewers” on other planets, says Seth Shostak, chief astronomer at the SETI Institute – the Search for Extra-Terrestrial Intelligence.

Jodrell BankDr Shostak paints a humorous picture to make an interesting scientific point – that humans have been making their presence known thanks to more than half a century of broadcasting.

Standard analog TV signals have been leaking away into space for more than 60 years. It means that, travelling at the speed of light, they have reached planets orbiting stars up to 60 light-years away.

If other civilisations have giant radio telescopes, they could be tuning in to some TV classics, according to Skymania’s own calculations.

Aliens in the Tau Eridani star system could currently be enjoying early episodes of top British soap Coronation Street from 1960. Around Capella, they will be catching up with the first episodes of Doctor Who, from 1963, while at 55 Cancri they are getting early Star Trek Original episodes of the BBC’s EastEnders are now puzzling any residents of planets orbiting Chi Bootis.

Dr Shostak tells Space.com: “Digital TV sounds like a winner. But there may be losers, zillions of viewers who might not have a converter box or a digital-ready TV – namely, the aliens.

“Ever since the Second World War, television signals (as well as FM radio and radar) have served as Homo sapiens’ emissaries into deep space. High-frequency, high-power broadcasts have filled an Earth-centered bubble more than 60 light-years in radius with signals.

“Unfortunately, the switch to digital might leave the aliens with nothing but snow on their wall-size plasmas.”

Dr Shostak says old-fashioned analog TV broadcasts produce energetic spikes in the signals that would tell aliens we are here. But DTV just gives out a “low, smooth hiss” which would be harder to detect at cosmic distances.

He says: “It’s not impossible to pick up our DTV broadcasts from your favourite planet, but I reckon it would require antennas at least five times larger than demanded for good, old analog TV. ET may balk at the additional cost.”

Dr Shostak says aliens will still be able to discover that we are here thanks to other signals broadcast from Earth, such as radar signals aimed at the upper atmosphere and asteroids. That is apart from stunts like sending adverts for snacks into space or broadcasting the Beatles’ hit Across The Universe to the Pole Star.

He says: “Earthlings will continue to pump the kilowatts into the ether. And eventually, when those signals have washed over a few hundred thousand star systems, someone may notice.”

There has also been some debate as to whether we should actively beam messages out into space in a deliberate bid to contact any aliens. You can read Seth Shostak’s original article here on Space.com.

Picture: A giant radio telescope at Jodrell Bank in the UK. (Photo: Paul Sutherland).

• Discover space for yourself and do fun science with a telescope. Here is Skymania’s advice on how to choose a telescope. We also have a guide to the different types of telescope available.

Paul Sutherland

Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.
Paul Sutherland

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Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.

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