'J' marks the spot for historic Rosetta comet landing

The European Space Agency (ESA) unveiled Monday the spot on a comet in deep space where in November it will attempt mankind's first-ever landing on one of these ancient wanderers of the Solar System.
The landing site is one of five that ESA shortlisted after its Rosetta spacecraft met up with rubber duck-shaped Comet 67P/Churyumov-Gerasimenko in August, following a marathon chase.
Codenamed "J", the site offers the best chance for a safe landing on an exceptionally difficult target, while also offering conditions for meeting scientific goals, ESA said.
"The comet is a beautiful but dramatic world -- it is scientifically exciting, but its shape makes it operationally challenging," said Stephan Ulamec, in charge of the landing.
On November 11, Rosetta is scheduled to let down a robot lab called Philae to carry out experiments on the comet's surface that scientists hope will shed light on the origins of these icy bodies -- enigmatic voyagers born along with the Solar System itself.
The 100-kilo (220-pound) lab will use harpoons to anchor itself, and then drive screws into the surface for better grip. Its experiments will include drilling up to 30 centimetres (18 inches) into the comet to extract pristine material for onboard chemical analysis.
Mission scientists had scrutinised five potential sites, named A, B, C, I and J, vetting each for the scientific return they offered, landing risks and the amount of light from the Sun for Philae's solar cells.
Comet "67P" comprises two lobes joined by a narrow neck, resembling the shape of a rubber duck -- though one that is pitch-black, darker even than charcoal.
Three of the candidate sites were on the smaller lobe, or head of the "duck", and two on the larger lobe, or body. The oval-shaped landing site called "J" is roughly where the duck's forehead would be.
Comets have in the past been considered iconic portends of good or evil.
Doomed to orbit the Sun, their outer layers are stripped by solar heat as they draw nearer, leaving a trail of dust and ice crystals that is reflected in sunlight and looks like a tail from Earth.
Astrophysicists say they are balls of ancient ice and dust left from the building of the Solar System some 4.6 billion years ago.
This cosmic rubble is essentially a time capsule -- the oldest, least-touched material in our stellar neighbourhood  -- and understanding them may advance knowledge of how Earth came to bear life.