What will life on other planets look like, and would we even know it if we saw it? 

Astrobiologist Betül Kaçar studies how life might appear elsewhere by looking at how microbes survive in extreme places on Earth. With better telescopes, scientists are now able to search for chemical signs that life might leave behind. To find these signs, scientists are learning to recognize a wider range of clues and ultimately rethink what life can be.

BETÜL KAÇAR: It's actually quite an exciting time to be looking for life in the universe.

I don't think we know for sure how life will look like, right? I mean, we don’t know that.

We are absolutely biased by what is around us. I mean, we are a form of life searching for itself.

Earth is our north star. We have to find analogs on this planet that may resemble an ancient Mars surface, an ocean that may resemble the ice ocean of Europa.

This is very important for the search for life in the universe. This is also good for understanding human exploration of different planets too, as we may be close to visiting these planets ourselves.

The more our telescopes are able to resolve more clear pictures, the further we are able to see. And what we are truly seeking is some sort of signature that is created by life. And by that what we mean is microbes.

What is missing in our knowledge, however, is knowing what kind of different signatures can microbes release into the atmosphere that could be detectable. And that will be the next challenge for the field—connecting the observables with the producers of that observable.

It's very optimistic to assume that a single smoking gun will be enough, that there will be one thing, and then we'll say, oh, there it is. That's life.

The complexity of biology shows us that over and over again that it's not going to be the case. But that's not a bad thing. That means that we will have to look at multiple levels of evidence. We have to develop multiple levels of observations—what it eats may be different, and how its poops may be different.

That's going to be the fun time, right? That's going to be so amazing for any biologists who want to know how this thing does what it does. I mean, it's really exciting to think about this.

Regardless of the composition of the planets or the moon, regardless of the stuff that is on this floating rock, if there is life, that means there's some chemistry on this planet.

That's, I think, the biggest shift in our minds. It is not just the stuff, but it is the relationship between the chemistry and the remainder of the planet.

If, or maybe I should say when, we discover life elsewhere, I hope that it would not be anything like we've ever thought of or imagined.