Planetary Smell Test

When I was younger a friend started a conversation about steak.  He was related to the owner of a local restaurant noted for its steaks. The gist:  You need to age steaks well before cooking to get the best from them, and aging steaks is stinky business.

Our sense of smell is cool.   As one of our five major senses, the unique aspect of smell is it is tuned to our Earth’s organic petri dish aromas.  Many of those aromas are caused by the metabolisms of living things.  NASA uses sensors on exploration vehicles to detect gases in extraterrestrial atmospheres.  I wonder if the sniff test might be useful.

The September issue of Astronomy Magazine features an article about what Saturn’s moon Titan might smell like.  I’ll come back to that, but first to other places, starting with our Moon.

Astronauts exploring the lunar surface reported the regolith clinging to their space suits smelled vaguely like burnt gunpowder.  There is no way an astronaut could smell it outside, even if a nose could be poked out of their space suit.  The severe pressure differential would cause air to escape from their lungs with no way to breathe in.  That would be stupid dangerous.

Venus has a mostly CO2 atmosphere, with a little sulfur dioxide and sulfuric acid clouds.  It’s so thick it would feel like being 3000 feet under water on Earth.  The USSR sent several Venera probes there, hardened to withstand that pressure and the nearly 900-degree F temperature.  The longest survivor…2 hours.  If you could take a whiff before being incinerated and/or crushed into a puddle, it might smell like being inside a volcano.  In part of Venus’s upper atmosphere conditions are more Earthlike but the sulfur dioxide and/or hydrogen sulfide gasses present would still make it stinky. A recent discovery of phosphine there, a toxic and stinky gas, has scientists scratching their heads.  It’s the metabolic byproduct of anaerobic life on Earth.

Mars’s atmosphere is predominantly CO2 but super thin, like being 115,000 feet above Earth’s surface.  Again, it would be dangerous to attempt a sniff.  Its surface contains compounds of iron, magnesium, and some sulfur, all baked by solar radiation.  The atmosphere doesn’t likely have an odor, but a dirt devil might send particles into your nose and possibly smell like acrid corrosion mixed with lit gunpowder.

The giant planets have somewhat similar atmospheres of hydrogen, helium, traces of water vapor, ammonia, and hydrocarbons.  They might smell a little like your mom’s kitchen after moping with ammonia in water.

Getting back to Titan.  Its predominant gasses (nitrogen, methane, hydrogen) are odorless, but it has some trace gasses (ammonia, benzene, methylamine, hydrogen cyanide) that do smell.  You might pick up hints of dead fish mixed with gasoline and urine.  Aah…the marina.

What’s in the Sky?

September 21; dusk; southwest horizon:  Watch the crescent Moon eventually cover up bright double star Beta Scorpii.  Binoculars make it better.