Could the Milky Way be rippling with life

and intelligence

-worlds calling out to worlds-

while we on Earth are alive

at the critical moment

when we first decide to listen?

Our species has discovered a way to communicate

through the dark,

to transcend immense distances.

No means of communication is faster

or cheaper

or reaches out farther.

It's called radio.

We are now, on an unprecedented scale,

listening for radio signals

from possible other civilizations

in the depths of space.

This quest is called

the Search for Extraterrestrial Intelligence

SETI

Let me describe how far we've come.

The first SETI program

was carried out by Frank Drake

His great achievement was to show

that modern technology is fully able

to listen for signals from hypothetical civilizations

on the planets of other stars.

Meanwhile, the technology for detection

has been getting cheaper;

the sensitivity keeps improving;

the scientific respectability of SETI has continued to grow;

But our fear of the dark rebels.

The idea of alien beings troubles us.

We conjure up objections:

"It's too expensive."

But, in its fullest modern technological expression,

it costs less than one attack helicopter a year.

"We'll never understand what they're saying."

But, because the message is transmitted by radio,

we and they must have radio physics,

radio astronomy,

and radio technology in common.

The laws of Nature are the same everywhere;

so science itself provides a means

and language of communication

even between very different kinds of beings

provided they both have science.

"All through human history

advanced civilizations have ruined

civilizations just slightly more backward."

Certainly.

But malevolent aliens,

should they exist,

will not discover our existence from the fact that we listen.

The search programs only receive;

they do not send.

After billions of years of biological evolution

-on their planet and ours-

an alien civilization cannot be in technological lockstep with us.

There have been humans for more than twenty thousand centuries,

but we've had radio only for about

one century.

If alien civilizations are behind us,

they're likely to be too far behind to have radio.

And if they're ahead of us,

they're likely to be far ahead of us.

Think of the technical advances on our world

over just the last few centuries.

What is for us technologically difficult or impossible,

what might seem to us like magic,

might for them be trivially easy.

We could communicate today across much of the Galaxy.

They should be able to do much better.

If they exist.

En Abril del 2011 SETI anunció que debido a restricciones de presupuesto

el conjunto de radio-telescopios se pondría en estado de hibernación.

indefinidamente...