So way out, towards the center of our galaxy there’s a pretty huge gas cloud that probably tastes like raspberries.
I know that seems like a crazy thing to say--but we know this because radio astronomers at the Max Planck Institute in Bonn, Germany used radio waves to figure out that the cloud--called Sagittarius B2--contains a whole bunch an organic molecule called ethyl formate, which is what gives raspberries their awesomely tang-tastic flavor.
And that's cool and everything--but its BAFFLING that we know it. I mean, SERIOUSLY, how the heck could we possibly know that some gas cloud 26-freakin-thousand light years away tastes like raspberries? Its not like we can just drive up to Sagittarius B2 and take a spoonful of the stuff out there. If its SO FAR AWAY--how could we ever KNOW its composition?
Well--we've got enough evidence to know for certain that ethyl formate is out there. And we've got this knowledge thanks to a totally kickass science called Spectroscopy.
Spectroscopy is the study of spectra. I'm sure you've heard the word "spectrum" before. But what the HECK is a spectrum, anyway?
The basic idea is this: throw a bunch of different atoms into a flame--and that flame changes color. Sodium ions from salt make flame go bright yellow, strontium ions make a deep red flame, boric acid makes a crazy yellow-green, and so forth. You can make a whole rainbow of fire using nothing but salts and alcohol.
[FOR SCIENCE: show a CAREFULLY SET UP demonstration with 6 petri dishes in a row. Each petri dish should contain a small amount of methanol (roughly 30ml) with amounts of different salts mixed in. From left to right, each petri dish should have: 1. Strontium Chloride, 2. Calcium Chloride, 3, Sodium Chloride, 4. Boric Acid, 5, Ethanol (no methanol) and 6. Potassium Chloride. Lighting each petri dish CAREFULLY in a cool, ventilated room (preferably a fume hood) will create a full rainbow of Red, orange, yellow, green, blue, and violet flames (all in proper rainbow order.) For the sake of simplicity, we ask that you just not worry about Indigo. Indigo is for chumps. This set up is A LOT OF WORK for like, four and a half seconds of footage. So its optional. But awesome. ]
Incidentally, this is how fireworks manufacturers make all those crazy colors in your fireworks. But there's a way more sciencey application for this. You take that same light from methanol burning with salt in it and put it through a prism, and BAM--you've got something called an emission spectrum M. A prism is just any piece of glass that can STRETCH out white light into a rainbow. And its that concept of STRETCHING thats really important. You're essentially magnifying the light--taking a detailed look at it and what its made of. And this lets us see what kind of elements are in a thing that's emitting light.
Put that bright yellow light from our sodium fire through a prism and you'll see that a certain part of where the yellow in a rainbow should be is one really bright line.
[MEDIA: a sodium emission spectrum.]
This is the chemical signature for sodium. Because when sodium atoms or ions get REALLY HOT, they emit YELLOW LIGHT because of the way the one electron in the outer shell of sodium is arranged. ! And EVERY SINGLE element and molecule that can possibly exist will have its own unique spectrum, so we can use the light coming out of objects to find out what they're made of. AWESOME.
