Recently, when I was researching material for my latest science fiction book, I came across some extraordinary facts about the number of exoplanets that were discovered during 2014. For those of you not familiar with the term, an exoplanet is a planet outside of our solar system.
The first of these exoplanets was discovered back in 1992 orbiting a pulsar. But since the launch of the Kepler space telescope in 2009, there has been a huge growth in the number of discoveries of these planets, with over 850 discovered in 2014. As of February 2015, some 1890 planets in 1189 planetary systems have been discovered.The Kepler space telescope has also identified a few thousand further candidate planets, which are still to be confirmed.
The Kepler space telescope is focused on a relatively narrow field of view covering some 3000 light years of the milky way. It sounds a lot, but it’s not. The diameter of the milky way is 100,000-120,000 lightyears in diameter and contains over 100-400 billion stars.
Kepler found that on average there was at least one planet per star and that 20% of sun-like stars have an earth-sized planet in the ‘goldilocks’ zone similar to earth. This is the zone around a star that is likely to provide planet temperatures that could support life as we know it. That could mean 11-40 billion potentially habitable planets in the milky way. And of course, that’s just one galaxy. The observable universe contains hundreds of billions of galaxies in different shapes and sizes.
So potentially there could be a huge number of planets similar to Earth. But what we don’t know of course is how many of these planets could have developed intelligent life. In later years, new telescopes may be able to detect more about these planets, (for example, whether there water present in their atmosphere). But for now we only have speculation.
The earlier discoveries of exoplanets tended to be super Earths since they were the most easy to spot orbiting a star. However, Kepler has now identified 47 Earth-sized planets. The best prospect so far being Kepler 186f, which is a mere 10% larger than the Earth. The drawback is that is 500 light years away (2,939,249,910,000,000 miles). So even if we sent a message to it at the speed of light it would take almost a thousand years to get a reply.
So maybe Gene Roddenberry, the creator of Star Trek, was right that space is populated by lots of potential intelligent civilisations. But communicating with them or travelling to them would take forever, unless there was a technology that allowed travel or communication at speeds substantially faster than the speed of light.
Of course, in a lot of science fiction, faster than light travel (FTL) is a common assumption, even though the physics would seem a little shaky. But without FTL space opera would not be able to exist. So I for one will still be using it in my current novel.
But in reality such drives would be only practicable for inter stellar distances if they could achieve speeds thousands of times faster than the speed of light. In Star Trek terms, we would need drives that could achieve warp 1000+ just to get around our own galaxy. To get to Andromeda, 2.5 million light years away would require something altogether faster. Even Captain Kirk, struggled to get to Warp 10 without the Enterprise shaking apart.