It could be a blow for those hoping to make contact with an alien species within their lifetime – researchers estimate it could be 1,500 years before we hear from life on another planet.
Astrophysicists have calculated that under one per cent of our own galaxy has been reached by human radio signals leaking out into space so far.
If a similar principal is applied to alien planets, it means it is highly unlikely extraterrestrial communications will reach Earth for another 1,500 years.
While this is doubtless disappointing for those scouring the heavens for messages from outer space, it may also comfort others who fear what may happen if we encountered intelligent alien beings.
Waiting another millennium and a half could give our civilization the chance to develop the technology it needs to counter any threat intelligent extraterrestrials may pose.
The researchers, based at Cornell University, used mathematical modelling to examine something known as the Fermi paradox.
This says that billions of Earth-like planets exist in our galaxy, yet no aliens have contacted or visited Earth that we know of.
The scientists, who are presenting their findings at the Americal Astronomical Society's annual meeting later this week, said this should perhaps not be unexpected.
They argue that TV and radio signals produced by mankind have only penetrated 80 light years into our galaxy.
This means they have probably reached around 8,531 stars and 3,555 Earth-like planets, the scientists said, but this is too small a number to expect to get a response.
The researchers based their conclusions on something known as the Mediocrity Principle – which says the Earth is not physically special or unique and so will not be deliberately sought out by aliens.
Instead alien signals will leach out across the galaxy much like our own.
Based on this, the researchers estimate that it could be about 1,500 years before we are in range of communications from enough distant worlds for us to receive a signal from intelligent alien life.
Evan Solomonides, an astronomy student at Cornell who worked on the research with Professor Yervant Terzian, said: 'This is not to say that we must be reached by then or else we are, in fact, alone.
'We simply claim that it is somewhat unlikely that we will not hear anything before that time.
'Even our mundane, typical spiral galaxy – not exceptionally large compared to other galaxies - is vast beyond imagination.
'Those numbers are what make the Fermi Paradox so counterintuitive.
'We have reached so many stars and planets, surely we should have reached somebody by now, and in turn been reached. This demonstrates why we appear to be alone.'
Mr Solomonides and Professor Terzian estimate we should not expect to be reached until our own communications have reached approximately half of the stars and planets in our galaxy.
There are an estimated 200 billion stars in the Milky Way alone and it is more than 100,000 light years across.
Our own solar system lies on an arm about 26,092 light years from the centre of the galaxy.
Yet despite the time it will take before we are contacted by alien life, Mr Solomonides said we should not stop listening.
Organisations like the Search for Extra Terrestrial Intelligence have been searching intensely for radio signals from deep space that may indicate an alien origin.
They also recently announced a new project to begin beaming deliberate signals designed to communicate with intelligent life. (DM reports.