Here's What the Comet Looks Like Next to a Stadium

Images taken by Rosetta's navigation camera on October 26. Photo-illustration by Bloomberg, Source: ESA/Rosetta/NAVCAM

Humans just scored an interplanetary field goal. A really long one.

A few minutes after 10:30 a.m. New York time, a spacecraft named Philae ended a 10-year, 4-billion-mile journey to touch a comet. "We are sitting on the surface, and Philae is talking to us," Stephan Ulamec, the lander's project manager, said to cheers at the European Space Agency's operations center in Darmstadt, Germany.

It’s hard for us tiny Earth creatures to grasp the magnitude of a comet. Even the brightest one in recent history, Hale-Bopp in 1997, was but a single brushstroke against the canvas of night.

To give a sense of scale, we’ve taken the liberty of putting a professional football stadium on the comet's surface. The larger lobe of the comet, seen below, is about 2.5 miles (4 kilometers) across. The 220-pound Philae lander is roughly the size of a quarterback playing inside Kansas City’s Arrowhead Stadium, rendered here to scale using image dimensions provided by the European Space Agency.

Comet 67P/Churyumov-Gerasimenko's dimensions, as measured from images taken by Rosetta's OSIRIS imaging system. The images shown in the graphic were taken by Rosetta's navigation camera on 19 August The larger lobe of the comet measures 4.1 x 3.2 x 1.3 km, while the smaller lobe is 2.5 x 2.5 x 2.0 km. Source: ESA/Rosetta/NAVCAM; Dimensions-ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The successful landing is a triumph of space engineering. To get up to speed with the comet, Rosetta made fly-bys of Mars (2007) and Earth (2005, 2007 and 2009), using gravitational pulls to slingshot forward. After years in power-hibernation mode, the European Space Agency woke up Rosetta in time to rendezvous with the comet in August.

After receiving the final instructions from Earth, the mother ship, Rosetta, maneuvered into place and released the Philae lander at a delicate 2.2 miles per hour. That’s important, because the dusty comet has little gravitational pull; any miscalculation of angle, speed or landing site would have bounced Philae back into deep space.

To prevent that, the lander had a roof thruster to pin it to the comet and harpoons to lock it in place. Both malfunctioned. Luckily, after a double bounce on the powdery surface, the lander has come to rest and is communicating with mission control.

Next will come a battery of tests to examine, for the first time, the precise makeup of a comet. Scientists hope the mission will shed light on the role of comets in seeding planets with water, or even with life.

In the words of project scientist Matt Taylor, it’s “the sexiest space mission there ever has been.”


Rosetta itself will continue observations through the end of 2015, giving it time to watch the comet's tails burst into life as its orbit approaches the sun. The minimum planned mission time for the Philae lander is a week but could last longer.

Philae will be hard at work as the Kansas City Chiefs take on the Seattle Seahawks on Nov. 16, some 300 million miles away.

Four-image montage comprising images taken by Rosetta's navigation camera on 18 October from a distance of 9.8 km from the centre of Comet 67P/Churyumov-Gerasimenko (about 7.8 km from the surface). The image scale is 66.5 cm/pixel, so each 1024 x 1024 pixel frame making up the montage is about 680 metres across. Photo-illustration by Bloomberg, Source: ESA/Rosetta/NAVCAM

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