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Sorry Rosetta, Your Comet Stinks

To the surprise of scientists studying data from the European Rosetta mission, Comet 67P/Churyumov-Gerasimenko is venting chemicals associated with the smell of rotten eggs, urine, alcohol, bitter almonds and vinegar. Continue reading →

When asked to think up a bad smell, your mind will likely drift toward the putrid stench of rotten eggs. That tell-tail smell is caused by hydrogen sulfide and is produced by bacteria feasting on rotting organic matter.

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It also turns out that, to the surprise of scientists studying data from the European Rosetta mission, Comet 67P/Churyumov-Gerasimenko is venting hydrogen sulfide. But that's not all. Churyumov-Gerasimenko has gone all-out on the sniff-o-meter - it's also venting ammonia, methane, hydrogen cyanide and formaldehyde, chemicals that have smells associated with urine, alcohol, bitter almonds and vinegar.

In short, if we were to return a sample of this nasty cometary cocktail to Earth, it would not only bring a tear to the eye if you were unfortunate enough to sniff it, you'd also likely gag to death.

This delightful array of chemicals in the comet's coma (the comet's ‘atmosphere' surrounding the nucleus) were detected by Rosetta's mass spectrometer, the Rosina-DFMS instrument.

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"The perfume of 67P/C-G is quite strong," said Rosina's chief scientist Kathrin Altwegg in a Rosetta blog update. "With the odour of rotten eggs (hydrogen sulphide), horse stable (ammonia), and the pungent, suffocating odour of formaldehyde, this is mixed with the faint, bitter, almond-like aroma of hydrogen cyanide.

"Add some whiff of alcohol (methanol) to this mixture, paired with the vinegar-like aroma of sulphur dioxide and a hint of the sweet aromatic scent of carbon disulphide, and you arrive at the ‘perfume' of our comet."

Sounds delightful.

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The detection of these chemicals has surprised scientists; it was assumed that only the most volatile of ices - water and carbon dioxide - would be sublimated into space as the comet approaches the sun. Churyumov-Gerasimenko is currently over 250 million miles from the sun, but as it gets closer, solar energy heating the dusty surface will cause more ices to be released, generating more jets of gas and dust.

In new images sent back to Earth, an uptick in comet activity is being measured by Rosetta (pictured top).

"At this point, we believe that a large fraction of the illuminated comet's surface is displaying some level of activity," said OSIRIS scientist Jean-Baptiste Vincent from the Max Planck Institute for Solar System Research (MPS) in Germany.

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"Being able to monitor these emissions from up close for the first time gives us much more detailed insights," added OSIRIS Principal Investigator Holger Sierks. "But one image alone cannot tell us the whole story; from one image we cannot discern exactly where on the surface a jet arises."

The mission is continuing its detailed campaign as it circles Comet 67P/Churyumov-Gerasimenko, discovering not only how the comet is evolving as it approaches the sun, but also the cocktail of chemicals it's outgassing in the process.

Source: ESA Rosetta blog

OSIRIS image of Comet 67P/C-G on Oct. 20, 2014, showing jets of cometary activity along almost the entire body of the comet.

At 5:29 a.m. EDT (9:29 a.m. GMT) on Aug. 6, 2014, the European Space Agency's comet-chasing spacecraft Rosetta was a comet-chaser no more.

After 10 years and 3.7 billion miles, Rosetta reached its target, Comet 67P/Churyumov-Gerasimenko, to begin an unprecedented mission in cometary orbit -- the first mission to ever do so. Rosetta will remain in orbit as the comet swings past close approach of the sun, observing changes in the icy body's structure as they travel with one another. Comets possess some of the most pristine material in the solar system, having been in deep freeze since before the formation of the planets. So through Rosetta's instruments we'll not only be studying a fascinating celestial body, we'll be probing billions of years into the past. To help achieve this goal, in November Rosetta will even drop a small probe, called Philae, to attempt the first ever landing on a comet's surface.

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But for now, ESA has released the most detailed, and stunning, photos of 67P/Churyumov-Gerasimenko to date as Rosetta settles into orbit around the 2.5 mile-wide 'dirty snowball.' Shown in this image is 67P/Churyumov-Gerasimenko in its entirety taken by Rosetta's OSIRIS narrow-angle camera on Aug. 3 from a distance of 177 miles.

The comet is composed to two very distinct "lobes" -- a configuration that made the cometary nucleus look like a "rubber ducky" during Rosetta's approach to 67P/Churyumov-Gerasimenko. Astronomers believe that the object may be a "contract binary," where two separate objects collided and fused together as one. Shown here is an extreme closeup of a smooth region of the "body" (or the larger lobe) of the comet. The photo was captured on the day of rendezvous (Aug. 6) by Rosetta’s OSIRIS narrow-angle camera and it shows small boulders, cliffs and other, as-yet to be explained features. The resolution of this observation is 2.4 meters per pixel. Rosetta was a mere 81 miles from the comet.

Looking down on the comet's "body" from a distance of 177 miles on Aug. 3, 2014. Beautiful layering of material can be seen with big boulders breaking up large expanses of smooth terrain. This is a truly alien landscape and Rosetta has only just begun its mission to try to understand 67P/Churyumov-Gerasimenko's composition and dynamics.

Where the two lobes of 67P/Churyumov-Gerasimenko's mass meet, is a clearly defined "neck." As Rosetta was approaching the comet, a bright feature at the neck became clear, something that the mission will study to help us understand its nature. This photo was taken on Aug. 6, 2014, when the spacecraft was just 75 miles from the comet's surface, acquiring a resolution of 2.2 meters per pixel.

This earlier observation taken by the Rosetta probe as it was chasing the comet on Aug. 2, 2014, shows how active its nucleus is. The rays of light emanating from the top are jets of vapor forming the comet's coma, within which Rosetta is now orbiting. This cometary activity will increase as Comet 67P/Churyumov-Gerasimenko continues to approach the sun. And thanks to Rosetta, for the first time ever, we are going to have a ringside seat for the voyage.

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