Where Is Everybody?

Some of the greatest human minds are scanning the universe, with a range of increasingly powerful telescopes, in the search for extraterrestrial life. The universe is unimainably vast-how could we be both only ones?

- Amanda Riley-Jones

ARE WE ALONE IN THE UNIVERSE OR DO WE SHARE IT WITH CREATURES WE MIGHT ONE DAY MEET? It’s one of the most fascinating and puzzling questions out there. Either way, it’s a staggering thought. Lord Martin Rees, leading astrophysicist and the UK’s Astronomer Royal, says, “In the last 20 years (and especially the last five) the night sky has become far more interesting. Astronomers have discovered that many stars—perhaps even most—are orbited by retinues of planets, just like the Sun is.”

He continues, “There’s special interest in possible ‘twins’ of our Earth—planets the same size as ours, orbiting other Sun-like stars, on orbits with temperatures such that water neither boils nor stays frozen. The Kepler spacecraft has identified many of these, and we can confidently infer that there are billions in our galaxy.

“Within 20 years the next generation of telescopes will image the nearest of these planets. Will there be life on them?”

Of course, it’s intelligent life that we’re most fervently searching for. As Dr Stephen Webb, physicist at the University of Portsmouth, USA, puts it, “One recent estimate from an international team of astronomers suggested that the galaxy might contain as many as 100 billion habitable, Earth-like planets. There are about 500 billion galaxies in the universe, and so there might be as many as 50 sextillion potential homes for life. That’s a five followed by 22 zeros. Surely we can’t be the only intelligent species?”

In his book If the Universe Is Teeming with Aliens...Where Is Everybody?, Webb looks for an explanation for this paradox. He first considers whether intelligent aliens could already be here in our solar system.

Could E.T. already be home?