Astronomers have spent decades scouring the heavens for signals from aliens on other planets, but to no avail.
Rather than being too far away, or too technologically advanced for us to spot, however, researchers now believe there is a much simpler reason our efforts have been met with deafening silence – ET is already extinct.
A group of astrobiologists has claimed that life on other planets, if it managed to get going at all, would likely be brief and would die out quickly.
And they said that while many planets could have potentially been habitable, and may have once teemed with microbial life, runaway heating or cooling would have left their surfaces inhospitable.
In their new theory, the researchers looked at the role life can play in helping to control the climate of a planet, making it more habitable in the process.
They argue that while both Mars and Venus may once have been planets that could have hosted life four billion years ago, any life there failed to stabilise the environment.
The researchers argue that life may well have emerged multiple times on other planets following the heavy bombardment of wet rocky worlds by asteroids.
But they said almost all of this life would go rapidly go extinct unless it was able to evolve fast enough to regulate greenhouse gases and so maintain stable surface temperatures.
‘To produce a habitable planet, life forms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable.’
This is where life plays a key role in modifying and regulating its environment to ensure its survival.
Earth provides a classic example of this as early organisms began regulating the amount of carbon dioxide in the atmosphere and eventually produced enough oxygen for other new organisms to emerge.
Source: Daily mail
N.H.Khider