In the 1970s, NASA built an interstellar map to guide aliens to Earth

The universe may or may not be filled with aliens. People believe that NASA is on the verge of announcing they’ve found alien life, and we’ve even got a protocol in place in the instance we do actually find alien life. While we hunt endlessly for extraterrestrial life, we may just have to face the fact that perhaps they’re already all dead or stranded on a set of exoplanets that could be boiling them alive.

But, if there is just a slim chance there is alien life out there, it turns out that we’ve actually already sent them a map to find Earth so they can come and say hello. In an insightful feature by Nadia Drake on National Geographic, it turns out we strapped a star map to the twin Voyager spacecraft that launched in the late 1970s.

Both spacecraft are now venturing into the complete unknown, with one Voyager craft exploring interstellar space and the other just on the fringe. Having sent back images from Pluto for the first time, Voyager now has a second purpose, to help aliens find their way to Earth and to our solar system.

Aliens won’t find a copy of the galactic A to Z stapled to the side of Voyager, though: instead, both crafts carry a cipher that leads to Earth. Creating the map was a puzzle unto itself, without a shared language, nor knowledge of how they read or write – if at all – a visual guide is all that can be created. Drake goes into greater detail in her post, but essentially it maps the Sun inside the Milky Way by using 14 pulsars from the spinning remnants of exploded stars as navigation posts.

A replica of the Voyager I spacecraft carrying the pulsar map

Because pulsars spin for billions of years emitting electromagnetic waves, an extraterrestrial could work out how much these pulsars have slowed since the map was created, in order to work out – on their own timescale – how long it’s been since the map was sent from Earth. In a weird, somewhat dark way, it could help them look towards our planet and discover if we’re even worth visiting; after all, by then we could have become extinct due to global warming or Donald Trump’s goading of nuclear war with North Korea.

Back in the 1970s, extraterrestrial life was a topic more unknown than it is today – humans didn’t even know if exoplanets even existed. It was a shot in the dark and, back before we knew about potential other home worlds, nobody thought aliens could be nefarious. These days, we might have concerns about how safe it is to send a map out into space, but in reality, this whole endeavour could all be for nought.

As map creator, and the author’s father, Frank Drake explains, both Voyagers are “going something like 10km per second, at which speed it takes – for the typical separation of stars – about half a million years to go from one star to another”. In the inky vastness of space, chances are it won’t ever stumble across another life form. Throw in the various nearby gravitational pulls, and it may never end up on a planet or near one with habitable life. As Drake summarises, “it’s not aimed at any star, it’s just going where it’s going”.

Perhaps one day we’ll be visited by extraterrestrials who were drawn to Earth by a map sent out on a spacecraft in the 1970s. Then again, perhaps we won’t. Ultimately, what really matters is that NASA has already designed and sent out an interstellar map to guide people through the vastness of space.

You can read the full story about the creation of the map to Earth over on National Geographic.