Life in the Universe part 6: How many intelligent life forms will develop the ability and desire to communicate?

This is part of the Life in the Universe series of posts. Go here for the first one.

Part 5 discussed how many life-bearing planets will support the development of intelligence in one or more of its resident species. This post carries on from that and asks how many of the life forms that develop intelligence will go on to develop the ability and desire to communicate across the stars.

What does 'communication' mean in this context?

The Arecibo radio telescope - sender of the Arecibo message in 1974

In order for beings from different planets to get in touch with one another they must have developed some pretty serious technology. Within the confines of one planet, it doesn't take much for a member of one tribe to walk to within waving distance of another- waving could qualify as 'communicating'. To do even the most basic analogy of this on a planetary scale takes considerably greater scientific achievement: to do something as simple as waving you have to be able to either get there yourself or send the message electronically.

Therefore, in this context, communication is most likely to be electronic in nature, and sending messages over the distances required takes a lot of power and accuracy. Any civilisation that wanted to achieve this would have to be pretty clever and pretty determined.

What about 'desire'?

The Arecibo message

It is conceivable that an race of intelligent beings may get to the point at which they are perfectly capable of communicating across the massive distances between populated planets but lack the motivation to do so. This could happen for a number of reasons, some of which can be drawn from our own experiences:

Here, on Earth, the human race has developed the technological ability to communicate across the stars, but we are not yet doing so. Why not?

• We don't have anyone to talk to yet: we don't know where to aim our message should we wish to send one.
• We don't know what to say: first contact with an extra-terrestrial intelligence could be crucial, and we have to be careful. We wouldn't want to appear confrontational or cause offence with our very first directed message to the stars.
• A number of people, including possibly the world's most famous physicist Stephen Hawking, have said that we shouldn't be trying to contact E.T. at all. Hawking himself has urged caution at the idea of advertising our whereabouts to advanced alien civilisations, citing human behaviour in similar situations: "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."*
• Communicating requires costly equipment and power usage and issues closer to home are often considered to be more worthy of the funds. It must be remembered that these costs will be compounded by the necessity of setting up, running and maintaining receiving equipment for centuries afterwards in order to catch any possible response.

So how many intelligent civilisations are trying to communicate?

Remember that our own civilisation wouldn't be included in this statistic, so are we a typical intelligent civilisation or not? It is impossible to know for sure, but current estimates are that somewhere between 1 in 100 and 1 in 1000 intelligent species will be trying to communicate.

Life in the Universe

This is the sixth in a series of posts about Life in the Universe, culminating in a discussion about the Drake Equation. The first post concentrated on the number of suitable stars formed each year. The next one will follow on from this and discuss how long an intelligent race will remain able and willing to communicate with other alien races.

<-- Part Five | Part Seven -->

* In his Into the Universe series for the Discovery Channel.