To find life elsewhere in the universe is the holy grail of science. But forget human life, signs of even the most plebeian bacterial life have proved elusive thus far. Still, the technology for discovering new solar systems has gone into hyperdrive in the last 15 years, much of this thanks to Nasa?s Kepler space telescope. Last month, the Kepler team announced a rich haul of habitable planets. As its principal investigator crowed, ?We went from zero to 68 earth-sized planet candidates and zero to 54 candidates in the habitable zone, some of which could have moons with liquid water.?
Modern astronomy fought back many centuries of geocentric and then heliocentric prejudices (whereby the Earth and then the Sun were considered the centres of the Universe) to establish the existence of orbiting planets around other stars. But through the 20th century, instruments remained too limited to actually spot alternative solar systems. It was not until 1995 that we saw the first confirmed detection of an extrasolar planet (one that orbits a star other than the Sun). If there are habitable planets like the Earth out there, we have come closer than ever to discovering them.
Nasa?s Kepler space telescope unblinkingly stares at 150,000 odd stars (out of the 70 sextillion odd known to exist in the universe); their dimming tells it of the passing of planets. As the Earth takes a year to orbit the Sun, Kepler will have to note at least three odd transits to confirm genuinely Earth-like behaviour (to be distinguished from the dimming occasioned by different planets sailing by a given star). Now, since the amount of light blocked gives a measure of the planet?s size and since Kepler can also figure out its mass, figuring out what it is made of gets a kick-start. By 2013, then, the Kepler observatory will should start churning out really good data about Earth-like planets. But the Kepler isn?t advanced enough to actually identify life. That technology is still said to be a couple of decades away, and even this will depend on how space programmes continue to be viewed by governments. This, in turn, will depend on public interest.
Back in 1961, then US president John F Kennedy pronounced an ambitious mission for Nasa, of landing a man on the Moon and returning him safely to Earth by the decade?s end. In 1966, the original Star Trek TV series made its d?but. William Shatner, who played Captain James T Kirk of the USS enterprise in the series, has said that he ?never thought it?d become a big deal, just 13 episodes and out?. Actually, it took three seasons before the series was cancelled, in 1969. Then Neil Armstrong delivered the Kennedy goal and Star Trek became a cult phenomenon. Nasa?s budget peaked at almost 5% of the total federal budget?more than the outlay on health and human services! But that figure is now down to 0.5% and mission-speak has become garbled. It?s been 38 years since any man walked the Moon and Barack Obama has cancelled the Constellation programme that would have taken Americans back there. This US president is urging Nasa to instead reach for milestones beyond the Moon, like sending humans to orbit Mars by the mid-2030s.
Here comes the catch. Even if the coming decades deliver the telescope technology needed to identify habitable planets, how are humans going to get there? Nasa?s manifest destiny is to move the human race beyond the Earth and the Moon into the yonder solar systems and galaxies. Other countries should be following in the same footsteps, whether for national glory or out of the spirit of adventure that drove Christopher Columbus ages ago. Stephen Hawking also reminds everyone, ?Life on Earth is at the ever-increasing risk of being wiped out by a disaster such as sudden global warming, nuclear war, a genetically engineered virus or other dangers… The human race has no future if it doesn?t go into space.? But the fastest rocket ever launched, Nasa?s New Horizons probe to Pluto, is travelling at a pace that would take it to the nearest star beyond the Sun in some 800 centuries. Our generation had better reconcile itself to living on a lonely planet.