BB guns, comets, and the origins of life?

By Casey Frye, CCNN Writer

comet science
Researchers from three different universities shot steel balls into ice to simulate comets crashing into Earth.

Where do you think life began? I know, I know, it’s a tough question to answer. If I asked high school students, they’d probably say life on Earth began as single cells that eventually evolved into the complex life forms we have today. But, if I were to ask scientists from Imperial College London, the University of Kent, and Lawrence Livermore National Laboratory, they’d say life on Earth came from comets. Sounds crazy, right? Well, what’s even wackier is the scientists basically used BB guns to prove it!

For years, researchers have provided evidence that amino acids – one of the basic building blocks of life – came crashing down to Earth in a comet. In fact, several scientists have run computer simulation tests that support their theory. However, according to Nir Goldman, the co-author of the latest study, this is the first research “that looks at a cometlike mixture under high pressures and temperatures.”

In a perfect example of how cool science can be, the researchers took a gas-powered gun and loaded the “scientific tool” with tiny steel bullets (just like a BB gun!). From there, they fired at two different blocks of ice, which were supposed to model a cold planet. One block was filled with carbon dioxide, mixed with “ammonium hydroxide” and “methanol” – two key chemicals found in comets. The other was basically just a gigantic ice cube. When the researchers fired at the cold chunks, the bullets sped to around 16,000 miles per hour before they hit! Would the experiment simulate a comet crashing into Earth and making life?

In order to find out, the researchers quickly heated up the chemical-laced ice cube and evaporated the water away. Much to their surprise, they were left with a type of… gooey substance. “The result is, you get this kind of goop, and that goop is actually hard to analyze,” said Goldman. When the researchers did analyze the residue, they discovered several amino acids!

“This process demonstrates a very simple mechanism whereby we can go from a mix of simple molecules, such as water and carbon dioxide ice, to a more complicated molecule, such as an amino acid,” said Mark Price, one of the leaders of the experiment. “This is the first step toward life. The next step is to work out how to go from an amino acid to even more complex molecules such as proteins.”

Featured image courtesy of Laurence Livermore National Lab. Image of falling comet courtesy of Imperial College London.