SCIENCE fiction movies and novels have long regaled us with fantastic tales about space. A good many of those sci-fi offerings revolve around comets, those interstellar travellers whose rare appearances brought dread and fascination to ancient and modern stargazers alike.
For centuries comets were looked upon as harbingers of disasters, plagues, wars and other dark events that have been foisted on humankind. Today, science has torn down that long-held belief, and astrophysicists study comets to pick up clues about the origin of the universe and the beginnings of life on Earth.
Last Wednesday, science fiction entered the realm of science fact. A robot probe the size of a washing machine has landed on a comet hurtling at 18 kilometers per second, 510 million kilometers from Earth.
The touchdown of the Philae lander on the craggy surface of comet 67P/Churyumov-Gerasimenko is the high moment of a $1.6-billion mission that started more than 10 years ago. It also marks an exciting new chapter in space exploration.
Rosetta, the mother ship from which Philae was launched, was sent into space by the European Space Agency (ESA) to chase after and make contact with 67P. Last August, after travelling almost 6.5 billion kilometers, Rosetta was close enough to the comet to initiate the tricky descent.
The drama, which rivalled Arthur Clarke’s “2001: A Space Odyssey,” and the classic 1998 space thriller “Armageddon,” played out for seven hours as Philae left Rosetta for its rendezvous with 67P.
The landing was a rough one. Philae’s anchoring hooks failed to deploy, and the lander tumbled along the comet’s surface before settling into a deep crevice. Mission controllers in Darmstadt, Germany, held their breath, worried that Philae was too damaged to transmit data to Rosetta. After some anxious minutes, the robot came to life, streaming information to its mother ship.
“Science from an alien world” ESA tweeted. “Info now flowing from @ Philae2014.”
The exhilaration did not last long. Philae’s position hid most of its solar panels from the sun. Starved of power, Philae will die a slow death as its 10 onboard systems shut down.
There is a faint chance that Philae could reawaken when the comet swings by the sun on its way out of the Solar System, but ESA is not keeping its fingers crossed.
What scientists are pinning their hopes on is that the probe would finish several tasks before it signs off. It already has transmitted spectacular photos taken on a comet, and recorded its surface density, temperature and composition.
Philae also carried out one momentous task: Drilling into the comet’s surface to help shed light on how the Solar System began 4.6 billion years ago.
Equally significant, the Rosetta mission could provide key pieces of the puzzle that has been fascinating scientists: Did comets seed Earth with the primal components of life?
The Rosetta mission will no doubt provide a rich trove of information that will keep scientists busy decoding for the next few years. But beyond the scientific bonanza, Philae’s historic “piggyback” ride on a comet has also come up with an intriguing development. The lander has picked up what ESA described as a strange “song” coming from 67P.
ESA believes the comet emits the sound as it releases particles into space, which become ionized.
Still, the space agency said “the precise physical mechanism behind the oscillations remains a mystery.”
Ionized particles or music from an extraterrestial? Your guess is as good as ours.