Imagine you were stranded on a desert island. How would you get yourself rescued? 

Obviously, it would make no sense to start swimming in one direction in the hope of finding someone. Instead, you would encourage them to come to you - by scrawling a message in the sand or lighting a beacon for planes to spot.

Scientists are taking the same approach in the search for extraterrestrial life. They have devised a new message, the Beacon in the Galaxy (BITG), which will soon be beamed out into space.

It contains digital images of human beings, along with information about life on Earth and the location of our solar system. And it invites any sentient being that finds it to respond.

This is not the first time we have tried to contact aliens. In 1974, a coded radio message with some of the same information was emitted from the Arecibo ObservatoryAn observatory in Puerto Rico. Its telescope was the largest single-aperture telescope in the world from 1963 until 2016. It collapsed in 2020..

And in 1977, the two Voyager spacecraftTwo interstellar probes launched in 1977 towards Jupiter and Saturn. They transmit information back to Earth but can never be brought back, so they will spend the rest of eternity traversing the universe. sent to study the planets of the outer solar system were fitted with "Golden RecordsTwo gold-coloured vinyl-style records mounted on the Voyager spacecraft that play sounds on one side and feature diagrams and images on the other. They have been compared with a message in a bottle. ", which store a variety of natural sounds, greetings in 55 languages and diagrams and written messages.

But neither of these represented very serious efforts at contact. The Golden Records are not due to pass another star for 40,000 years.

The BITG, in contrast, is being beamed directly at the part of space where we think it is most likely we will find extraterrestrial life.

Some think this may be unwise. Physicist Michio KakuAn American theoretical physicist and public scientist. has compared us with the AztecsThe most powerful Central American civilisation in 1492, when Europeans first made sustained contact with the Americans. Their civilisation was destroyed by the Spanish, who enslaved what was left of their people., warning that aliens may wipe us out and colonise the Earth just as the Spanish did in central America.

And scientists have to overcome another problem: how can we make ourselves understood?

The philosopher Ludwig Wittgenstein wrote, "If a lion could speak, we could not understand him." He showed that words are not just symbols representing things in the world that we string together in a familiar order. We communicate with others via "language games" that give our words meaning.

For example, if someone shouts "Water!", this might mean they have found an oasis after weeks in the desert, or that there is a fire that must be put out. It could be a warning that some water is poisoned - or even a secret code. We cannot know for sure without using the "rules" of ordinary language.

This mostly works amongst human beings because these language games are familiar to us: we can instinctively work out from our context what "game" we are playing. But aliens would have completely different points of reference. Like lions, they might be unable to take part in the same language games as us, leaving us incapable of communicating.

Scientists hope to get around this with maths. They are transmitting the BITG in binary codeText made up entirely of two symbols, usually 0 and 1., along with some basic mathematical concepts to establish terms of communication they hope will be universal. But if the aliens have a different understanding of physics, this could still fail. 

It might be that we have no idea what we are actually telling them. Or it could be that we are telling them more than we realise.

Yes: There are probably aliens elsewhere in the galaxy. As such, we should make it clear that we want peace and communication. That way, they are less likely to attack.

No: There is no way of stating our intentions clearly to a civilisation that might have no means of understanding us. The BITG is nothing more than an invitation to come and conquer the Earth.

Or...? The BITG is probably just a waste of time. The chances of it actually reaching an alien civilisation are minuscule, and unless their technology is far more advance than our own they will struggle to return an answer.