Greg Brennecka

all the meteorites that we have on Earth have passed through Earth's atmosphere and have landed on Earth.

And that in itself contaminates that sample.

And particularly for this mission, it was really important to have an uncontaminated sample because what they were looking at, in addition to the chemical and isotopic compositions that Livermore was involved in,

was some of the organic biologic precursors, ingredients that may lead to the emergence of life later on.

Those ingredients already exist on Earth, so if you have a meteorite that's flying through the atmosphere and lands in a bog, of course it's going to be contaminated.

There's a great handshake between nuclear forensics and cosmochemistry because we are always pushing the boundary on what we can measure and getting better at it by looking at these really small samples that we see oftentimes in cosmochemistry.

You want to find out where it came from.

You want to find out how old it is.

You want to find out what it's made from.

Those are also the same types of questions that we ask in nuclear forensics.

When the sample returned back to Earth and they were able to open the canister, it became pretty obvious just with the naked eye that you could see there were slight differences in different lithologies, which is basically rock type that we're seeing in the sample.

And of course, this gave everyone pause and we thought, OK, well, we need to measure each individual rock type to see how different they are.

Each lithology could carry a slightly different history, and each one needed to be decoded.

Isotopes are different versions of an element.

What that tells us is that those different isotopes behave slightly differently in conditions like in outer space or on Earth.

A story that's being told by looking at the isotopic composition.

So much like a very large dog is going to be able to make a different type of cut than a very small dog.

If a Great Dane and a Chihuahua are running around a corner, the Chihuahua is going to be able to make that corner earlier.

So we know how those behave because we've seen it in the past.

And so we can make predictions on how different isotopes behave in different environmental situations.