European Space Agency's Rosetta spacecraft meets up with comet 67P after ten years

After traveling through the dark and cold of deep space for ten years and 4 billion miles, the European Space Agency's Rosetta spacecraft has arrived at its destination, the comet 67P.

The European Space Agency released photos of the comet to commemorate the arrival. The photos were taken at a distance of around 180 miles. The ESA hopes that Rosetta will eventually be able to get as close as 18 miles from the comet.

When Rosetta finally caught up with 67P, the comet was midway between the orbits of Mars and Jupiter, moving at over 34,000 miles per hour.

The comet has an elliptical orbit that takes it past Jupiter when it is farthest from the sun. The closest it comes to the sun is between the orbits of Earth and Mars. Rosetta will follow 67P for a year as it makes its way back toward Jupiter and the outer solar system.

In order to catch 67P at the proper moment, the satellite had to use the gravity of both Earth and Mars to put itself in the proper location to intercept the comet. It had to use the Earth's gravity three times and Mars' gravity once.  

Rosetta is the first spacecraft to rendezvous with a comet, meaning that it will most likely produce new, exciting, and unexpected findings about comets.

On August 6, the ESA undertook a series of 10 maneuvers to perfectly position Rosetta for the interception of 67P. Started in May, if any one of the 10 moves had failed to be executed perfectly, Rosetta would have just flown by the comet and into the depths of space.

One of Rosetta's first findings was the discovery that the comet's tail's brightness varies. In the first six weeks since Rosetta was able to photograph the comet, its tail brightened and darkened variably.

Readings also suggested that the comet was emitting water vapors, an unexpected find in deep space.