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Molecular oxygen in comet's atmosphere not created on its surface
- sidcool 8y agoDidn't know comets have atmosphere.
- manicdee 8y agoaka Coma
- baxtr 8y agoI really like the educative style of the article. It explains things assuming almost no level of pre-knowledge. I’d wish more scientific articles were written like this.
- sitkack 8y agoThe author also has a podcast, http://www.imperial.ac.uk/people/h.dunning http://www.imperial.ac.uk/people/h.dunning
- DoctorOetker 8y agoHas the spectrumm of individuaal shooting stars been measured? Do we know their distribution of compositions?
- drjesusphd 8y agoFirst of all, a shooting star is a meteor, not a comet. So we can do better, we can recover individual meteorites themselves. A comet looks stationary in the sky when you see one, only moving noticeably day by day, like a fast planet.
- DoctorOetker 8y agoI knew a comet is not a meteorite, I just had the question lingering around in my head and was waiting for a tangentially related topic to pop up on HN, in the hopes that someone who knows would answer if or if not ever the spectrum of a shooting star aerobraking had been measured. I ask because the composition of what remains lumped together, and the actual physical finds of remains may not be representative of the bulk mass originally entering the atmosphere. So has distribution of optical spectra of shooting stars been measured? (this seems hard to me because one would need accurate tracking before it enters in order to aim the telescope+spectrometer in the right direction for the short duration it passes the atmosphere) The reason I ask is because I have an idea on how to try detecting very faint objects, which may nevertheless be dangerous as rare impacts, or valuable if it turns out the material would be valuable in bulk before it evaporates in the atmosphere..
- rikkipitt 8y agoFascinating! Last Friday I was closing some curtains on a full (ish) bright moon, my other half asked what the star beside it was. I told her it was Jupiter. She then asked what the very dim star beside Jupiter was... I didn't know so I opened the "Star Walk" iOS app to find out. It was 67P/Churyumov-Gerasimenko! We couldn't believe we could see it with the naked eye in a major city. Quite surreal to think that something mankind made is sitting on it...
- jcims 8y agoThanks for the heads up! I had no idea it was visible either, will look for it tonight before the fireworks!
- jhpankow 8y agoYou could see a magnitude 23 comet outside of Jupiter with your naked eye?
- dotancohen 8y agoWhatever star you saw, it was not the comet. You would have an easier time squinting and seeing the streptococcus on your teeth in the mirror than you would see the comet. The bacteria are both larger (angular diameter) and higher contrast against the background. You saw another star, in the same general direction of the comet. But it's cool knowing in what direction that comet is, with our little robot on it.
- rimliu 8y agoInteresting… Last Friday (jun 30th) Mars and Saturn were both much closer to the moon than Jupiter, and depending on the time Jupiter could be below horizon already. The bright star next to Jupiter could be Zubenelgenubi. As other pointed out there is no way you could see madnitude 22 object with a naked eye. You won’t be able to see it even with 10 meter telescope, unless you use something that lets you to integrate the light.
- ianai 8y agoI could swear Asimov (or someone else) hypothetized that finding oxygen in a planets atmosphere would indicate the presence of life. Oxygen reacts so readily with other things that there would have to be a “someone” producing it. Guess he was wrong. I wonder what would suggest life if found in an atmosphere.
- scrumbledober 8y agoWell, birds for one
- whatshisface 8y ago>The new analysis is consistent with team's original conclusion, that molecular oxygen is most likely primordial. This does not prove that theory wrong. On the surface of an earthlike planet there would be plenty of reactive material to turn in to oxides. On the surface of the comet, that wouldn't necessarily be the case.
- ianai 8y agoReally good point. Comets wouldn’t typically have volcanic activity, enough gravity to generate an atmosphere, nor much energy from the sun.