In August, the European Space Agency's (ESA) Rosetta spacecraft will arrive at its destination comet, orbiting and then landing on the surface. This close approach will give scientists a detailed picture of this primordial piece of the solar system.
But before Rosetta arrives, you can guess the comet's shape and size in the form below for a chance to win the "What will Rosetta find?" contest.
On January 20, 2014, the European Space Agency's (ESA) Rosetta spacecraft woke from a 31-month-long deep sleep. ESA launched Rosetta 10 years ago, sending it on a path that ends at a "nearby" comet: the deep-space visitor called Comet 67P/Churyumov-Gerasimenko.
Comet 67P goes around the Sun once every 6.5 years, so scientists have been able to witness seven of its close encounters with the Sun since its discovery in 1969. When the comet is far from the Sun, it's too dim for even powerful telescopes to discern details. And when it approaches our star, it heats up and forms a bubble of sublimated ice and blown-off gases that block the surface from our view. So to see 67P clearly, scientists had to send their instruments to the comet, rather than merely observing when the comet comes to them.
That's where Rosetta comes in. But the spacecraft hasn't arrived yet, and the comet still looks like a distant dot, nearly indistinguishable from the background stars. While you wait for Rosetta to take close-up snapshots of the comet's surface, you can make educated guesses about what those pictures will show.
Fill out the form below with your best ideas about Comet 67P/Churyumov-Gerasimenko's shape and size, and tell us what you think about the Rosetta mission. The best answers will win signed copies of Editor David J. Eicher's book Comets! Visitors from Deep Space (Cambridge University Press, 2013) and ESA swag, like water bottles and posters.
Send your answers before June 23 for a chance to win!