This week, we as a species learned two important things about the building blocks of life - where they're lacking and where they could appear at any moment. I'm Hank Green, welcome to SciShow News.

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This week, a team of British and American scientists made a simple- sounding discovery that has some pretty big implications.

They found that amino acids, the organic compounds that make up proteins which control many biological functions, can occur just about anywhere in the solar system. Which means that life could potentially form anywhere - in the same way that having the ingredients to make tomato sauce means that pizza could form anywhere.

In Sunday's edition of the journal Nature Geoscience, the researchers said that by firing projectiles through a high speed gun at an icy surface, they imitated a comet hitting an icy planet. The impact, shock, and heat caused simple molecules like water and carbon dioxide to form more complicated molecules like glycine, alanine and isovaline amino acids. 

Now to be clear, this is just one step up in complexity from water and carbon dioxide, but it is a difficult step. The next step would mean even more complex molecules like proteins and then cell structures, and then cells, et cetera, until you've got bears, aardvarks and Emma Watson. So even though amino acids are called the 'Building Blocks of Life', they're really more like the building blocks of the building blocks.

But if cosmic impacts can make them, then they could theoretically exist anyplace where comets with water ice can crash into something. In fact, the scientists speculate that amino acids could have first formed on Earth because of such an impact. Plus, it maybe even likelier than we thought, that these acids could form on icy worlds like Europe and Enceladus, which means hope for life elsewhere in the Solar System.

Just not on Mars... at least for now because this week NASA made it doubly official that there is no methane - another potential indicator for life- on Mars.

To be fair, the Viking Lander told us this in the 1970's, but in the last decade of so, scientists have been questioning Viking's findings. Some researchers reported detecting what looked like plumes of methane in Mars' atmosphere, but ever since Curiosity has been wheeling around trying to get the record straight, it's gotten some confusing results. 

You might remember me telling you last Fall about some potentially Earth shaking findings from Curiosity's sample analysis when it seemed to detect a methane compound that's created by certain kinds of Earth bacteria. But then Curiosity measured again and detected no methane at all, so scientists thought the initial findings were a result of Martian chlorine reacting with Earth-borne carbon that was still inside the instrument.

Now there's some things that you want to be absolutely sure about, and whether or not there's life on Mars is one of them. So NASA used another instrument on board Curiosity - the Tunable Laser Spectrometer - which was specifically designed for measuring methane, and in Thursday's edition of the journal Science, they reported measuring less than 1.3 parts-per-billion by volume. That is a very, very small amount, and even that amount, scientists say came from somewhere other than Mars originally. The methane that Curiosity brought with it, for example, will take a least a few years to disappear.

So, definitively, there is not enough methane to suggest life on Mars, but don't be disheartened. No methane doesn't necessarily mean no life. It just means no life as we currently know it on Earth, and wouldn't finding a whole new flavor of life in the Solar System be infinitely cooler anyway?

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