MIT reveals how today’s lasers could turn Earth into an alien lighthouse

5 Nov 2018

Image: © marcel/

Instead of trying to find a way of locating any potential extraterrestrial civilisations, maybe we should turn Earth into a giant laser lighthouse?

Despite claims that our solar system may have been ‘buzzed’ by an extraterrestrial object, we still have yet to find any solid evidence for the existence of alien life, intelligent or not.

Aside from trying to collect microbe samples from Mars and other planets, for decades, groups such as SETI have been searching for traces of radio signals emitted deep in space. This has yielded nothing but the famous ‘Wow!’ signal, which is increasingly likely the result of some natural cosmic emission. But perhaps we have been going about it the wrong way?

According to MIT, instead of us trying harder to hear signals from deep space, we should make it easier for an intelligent alien species to hear us instead. In a paper published to The Astrophysical Journal, researcher James Clark proposed that if a high-powered laser up to 2MW in power was focused through a 30-45-metre telescope, it would produce a beam powerful enough to stand out from the intensity of the sun.

If an alien species was giving a cursory glance towards our part of the Milky Way – and especially if they were in a neighbouring system such as Alpha Centauri – they could clearly detect it. On top of that, the same laser telescope could be used to send a brief message in the form of pulses, similar to Morse code.

“If we were to successfully close a handshake and start to communicate, we could flash a message, at a data rate of about a few hundred bits per second, which would get there in just a few years,” Clark said.

‘If ET is phoning, we will detect it’

Although a little outlandish, what makes the idea encouraging is the fact that existing laser technology could be used to make this feasible.

“The kinds of lasers and telescopes that are being built today can produce a detectable signal, so that an astronomer could take one look at our star and immediately see something unusual about its spectrum,” he added. “I don’t know if intelligent creatures around the sun would be their first guess, but it would certainly attract further attention.”

However, when considering whether an alien species could take the same approach to help us spot them easier, Clark said that while the laser could be spotted by a telescope as small as one metre in size, it would have to be looking at the exact direction the beam was being emitted from. The odds of this, he said, were “vanishingly unlikely”.

“However, as the infrared spectra of exoplanets are studied for traces of gases that indicate the viability of life, and as full-sky surveys attain greater coverage and become more rapid, we can be more certain that, if ET is phoning, we will detect it.”

Colm Gorey was a senior journalist with Silicon Republic