Rotten eggs, horse pee, alcohol and bitter almonds: this is the bouquet of odours you would smell if a comet in deep space could be brought back to Earth, European scientists said Rotten eggs, horse pee, alcohol and bitter almonds: this is the bouquet of odours you would smell if a comet in deep space could be brought back to Earth, European scientists said on Thursday. 
 
 An instrument aboard the probe Rosetta has detected some intriguing chemical signatures from Comet 67P/Churyumov-Gerasimenko since their rendezvous in deep space in August, they said. 
 
 Molecules include ammonia, methane, hydrogen sulphide, hydrogen cyanide and formaldehyde. 
 
 "If you could smell the comet, you probably wish that you hadn't," the team said wryly in a blog posted on the European Space Agency (ESA) website. 
 
 The device, called Rosina-DFMS, is a mass spectrometer—it has been analysing the signature of gas given off by the "coma," the comet's head, as the distance closes with the Sun. 
 
 "The perfume of 67P/C-G is quite strong, with the odour of rotten eggs (hydrogen sulphide), horse stable (ammonia) and the pungent, suffocating odour of formaldehyde," said Kathrin Altwegg, Rosina's chief scientist. 
 
 "This is mixed with the faint, bitter, almond-like aroma of hydrogen cyanide. 
 
 "Add some whiff of alcohol (methanol) to this mixutre, 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." 
 
 The detection of so many different molecules at this stage has been a surprise, ESA said. 
 
 The Rosina team believed only the most volatile molecules—carbon dioxide and carbon monoxide—would be released as the comet's icy surface started slowly to warm. 
 
 On a 6.5-year orbit, 67P/C-G is the target of an ambitious mission to shed light on the origins of comets, ancient travellers of the Solar System. 
 
 Rosetta caught up with it after a six-billion-kilometre (3.75-billion-mile) trek that required four flybys of Earth and Mars, using the planets' gravity as a slingshot to build up speed. 
 
 It is now in close orbit around the comet at a distance of around 400 million kilometres from the Sun. The scout will send down a robot lander, Philae, on November 12 to carry out on-the-spot scientific tests. 
 
 On August 13 next year, the comet and Rosetta will be 185 million kilometres from the Sun, their closest approach to our star. 
 
 Explore further: Comet-chasing probe closes in on target ||||| With inputs from Kathrin Altwegg, ROSINA science team, University of Bern. 
 
 Since early August, the Rosetta Orbiter Sensor for Ion and Neutral Analysis (ROSINA) has been ‘sniffing the fumes’ of 67P/C-G with its two mass spectrometers. 
 
 As reported previously in this blog, even though the comet is still more than 400 million kilometres from the Sun, the mixture of molecules detected in the comet’s coma is surprisingly rich already. Before arriving at 67P/C-G, the ROSINA team thought that at these vast distances from the Sun, its relatively low intensity would only release the most volatile molecules via sublimation, namely carbon dioxide and carbon monoxide. 
 
 However, ROSINA has detected many more molecules. Indeed, as of our 11 September report, ROSINA’s inventory of detected gases 67P/C-G looked like this: 
 
 Water (H 2 O) 
 
 Carbon monoxide (CO) 
 
 Carbon dioxide (CO 2 ) 
 
 Ammonia (NH 3 ) 
 
 Methane (CH 4 ) 
 
 Methanol (CH 3 OH) 
 
 But today we can report that the following have also been detected: 
 
 Formaldehyde (CH 2 O) 
 
 Hydrogen sulphide (H 2 S) 
 
 Hydrogen cyanide (HCN) 
 
 Sulphur dioxide (SO 2 ) 
 
 Carbon disulphide (CS 2 ) 
 
 If you could smell the comet, you would probably wish that you hadn’t 🙂 
 
 As the Kathrin Altwegg, principal investigator for ROSINA, put it: “The perfume of 67P/C-G is quite strong, 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.” 
 
 While this is unlikely to be a particularly attractive perfume, remember that the density of these molecules is very low, and that the main part of the coma is made up of water and carbon dioxide, mixed with carbon monoxide. 
 
 The key point, however, is that a detailed analysis of this mixture and how it varies as 67P/C-G grows more active will allow scientists to determine the comet’s composition. Further work will show how 67P/C-G compares with other comets, for example by revealing differences between comets originating from the Kuiper Belt (like 67P/C-G) and comets that hail from the distant Oort cloud (like Comet Siding Spring, which recently flew past Mars). The goal is to gain insights into the fundamental chemical make-up of the solar nebula from which our Solar System and, ultimately, life itself emerged. 
 
 *For a simple explanation of mass spectra and associated units, see Wikipedia’s entry: http://en.wikipedia.org/wiki/Mass_spectrum 
 
 For more detailed information on ROSINA, see our description here. ||||| That heady bouquet, according to Swiss researchers, is the 'perfume' of comet 67P/Churyumov-Gerasimenko. 
 
 Scientists at the University of Bern said Thursday they have determined what the comet would smell like by analyzing the chemicals in its coma, the fuzzy head surrounding the nucleus. 
 
 For this, they used one of the instruments aboard the European spacecraft Rosetta that is preparing to drop a lander onto the comet's icy surface Nov. 12. 
 
 Project leader Kathrin Altwegg of the University of Bern said the aroma will get stronger as 67P gets closer to the sun, causing it to release more gas and form the coma characteristic of comets. ||||| Image copyright Esa/Rosetta /Navcam 
 
 The Philae lander has detected organic molecules on the surface of its comet, scientists have confirmed. 
 
 Carbon-containing "organics" are the basis of life on Earth and may give clues to chemical ingredients delivered to our planet early in its history. 
 
 The compounds were picked up by a German-built instrument designed to "sniff" the comet's thin atmosphere. 
 
 Other analyses suggest the comet's surface is largely water-ice covered with a thin dust layer. 
 
 The European Space Agency (Esa) craft touched down on the Comet 67P on 12 November after a 10-year journey. 
 
 Dr Fred Goessmann, principal investigator on the Cosac instrument, which made the organics detection, confirmed the find to BBC News. But he added that the team was still trying to interpret the results. 
 
 It has not been disclosed which molecules have been found, or how complex they are. 
 
 There's a trade off - once it gets too hot, Philae will die as well. There is a sweet spot Prof Mark McCaughrean, Senior science adviser, Esa 
 
 But the results are likely to provide insights into the possible role of comets in contributing some of the chemical building blocks to the primordial mix from which life evolved on the early Earth. 
 
 Preliminary results from the Mupus instrument, which deployed a hammer to the comet after Philae's landing, suggest there is a layer of dust 10-20cm thick on the surface with very hard water-ice underneath. 
 
 The ice would be frozen solid at temperatures encountered in the outer Solar System - Mupus data suggest this layer has a tensile strength similar to sandstone. 
 
 "It's within a very broad spectrum of ice models. It was harder than expected at that location, but it's still within bounds," said Prof Mark McCaughrean, senior science adviser to Esa, told BBC News. 
 
 "People will be playing with [mathematical] models of pure water-ice mixed with certain amount of dust." 
 
 Media playback is unsupported on your device Media caption Philae has gone into standby because of low power 
 
 He explained: "You can't rule out rock, but if you look at the global story, we know the overall density of the comet is 0.4g/cubic cm. There's no way the thing's made of rock. 
 
 "It's more likely there's sintered ice at the surface with more porous material lower down that hasn't been exposed to the Sun in the same way." 
 
 After bouncing off the surface at least twice, Philae came to a stop in some sort of high-walled trap. 
 
 "The fact that we landed up against something may actually be in our favour. If we'd landed on the main surface, the dust layer may have been even thicker and it's possible we might not have gone down [to the ice]," said Prof McCaughrean. 
 
 Scientists had to race to perform as many key tests as they could before Philae's battery life ran out at the weekend. 
 
 On re-charge 
 
 A key objective was to drill a sample of "soil" and analyse it in Cosac's oven. But, disappointingly, the latest information suggest no soil was delivered to the instrument. 
 
 Prof McCaughrean explained: "We didn't necessarily see many organics in the signal. That could be because we didn't manage to pick up a sample. But what we know is that the drill went down to its full extent and came back up again." 
 
 "But there's no independent way to say: This is what the sample looks like before you put it in there." 
 
 Scientists are hopeful however that as Comet 67P/Churyumov-Gerasimenko approaches the Sun in coming months, Philae's solar panels will see sunlight again. This might allow the batteries to re-charge, and enable the lander to perform science once more. 
 
 "There's a trade off - once it gets too hot, Philae will die as well. There is a sweet spot," said Prof McCaughrean. 
 
 He added: "Given the fact that there is a factor of six, seven, eight in solar illumination and the last action we took was to rotate the body of Philae around to get the bigger solar panel in, I think it's perfectly reasonable to think it may well happen. 
 
 "By being in the shadow of the cliff, it might even help us, that we might not get so hot, even at full solar illumination. But if you don't get so hot that you don't overheat, have you got enough solar power to charge the system." 
 
 The lander's Alpha Particle X-ray Spectrometer (APXS), designed to provide information on the elemental composition of the surface, seems to have partially seen a signal from its own lens cover - which could have dropped off at a strange angle because Philae was not lying flat. 
 
 Follow Paul on Twitter.
– Comets stink, and not just because they have the potential to cause cataclysmic devastation if they ever came hurtling through our atmosphere and made impact with Earth. These "cosmic snowballs of frozen gases, rock, and dust roughly the size of a small town" (as described by NASA) literally stink to high heaven, according to scientists at Switzerland's University of Bern. One comet does, anyway: Researchers analyzed the "perfume" of comet 67P/Churyumov-Gerasimenko and said that its BO is apparently a combo of "rotten eggs, horse urine, formaldehyde, bitter almonds, alcohol, vinegar, and a hint of sweet ether," the AP reports. "If you could smell the comet, you would probably wish that you hadn't," reads a blog post on the European Space Agency site. The scientists were able to surmise what the comet would smell like by examining the gas emitted by the "coma," the comet's head, Phys.org reports. Luckily, instead of a squeamish human, a mass spectrometer aboard the space probe Rosetta was assigned the task of parsing out the perfumed molecules of 67P, including ammonia, methane, hydrogen sulfide, hydrogen cyanide, and "the pungent, suffocating (odor) of formaldehyde," notes the ESA post. The probe caught up to the comet in August after chasing it nearly 4 billion miles; it will be sending its Philae robot lander onto the comet proper on Nov. 12, NASA reports. And it appears the comet's odoriferous odyssey is just beginning: The lead scientist on the project says that as 67P gets closer to the sun, it will start stinking up the cosmos even more. (Whatever happened to NASA's plans to harpoon comets?)