NASA Space Artists Explain Their Exoplanet Illustrations

We are in the midst of the first great age of exoplanet exploration. Over the past few decades, the number of known exosolar planets has rocketed from zero into the thousands. But, unlike the New Horizons probe that took the fantastic new images of Pluto, the telescopes that help us find these far-off worlds can’t capture complete portraits. So, when NASA wants to show the world what it’s working on, the agency needs to get artistic.

Inverse caught up with astronomer Robert Hurt and animator Tim Pyle, who together form the visualization team at NASA’s Spitzer Space Telescope Station, to chat about how they create nudes of heavenly bodies billions of miles away.

What makes exoplanet visualizations so important?

Robert Hurt: We only know a tiny, tiny bit about these planets. They’re blips in the data. Perhaps we only have temperature estimates, or diameter estimates — what we don’t know will fill rooms. And what we do know can be summarized with a few bullet points. But if we can produce a piece of artwork that is completely consistent with what we do know, it serves as a visual shortcut for people who get attracted to the story.

Tim Pyle: If we find something that tells us that there’s a really hot Jupiter whose atmosphere is being blown off by its nearby star, it’s one thing to write that down on a page. It’s another thing to create an artist’s concept so the public can visualize it. Like, “Holy cow, this is what’s going on!” It makes it more real, more visceral.

How you walk the line between what we do know — and you’re definitely getting in the illustration — versus what we don’t, or maybe we have a more general idea?

TP: A lot of the public is interested in exoplanets because of the idea that we could find life outside of our solar system. Anything that might contribute to that [idea], we have to be very careful about how and when we introduce it. If we’re going to put water into the illustration, we have to feel confident that the science supports that there could be water: It’s close enough to the star that water is present, but it’s not frozen, so we now we have liquid water on the surface. We would only introduce that if science would back it up.

RH: A key element here is plausibility. Whatever we present in that — whatever choice we have to make — it at least has to be scientifically plausible for what the core research has indicated.

TP: But only for big things. I mean, if it comes to little things like how many clouds would there be, or what shape might they be? That doesn’t really matter one way or another. Then we have a lot more artistic license to determine what that looks like.

RH: In general, though, the process always begins and really ends with the principal investigators of the research. Any of these projects begins with a discussion with the researchers … I’ll go through the paper, the published journal article, and read through and find things that strike me that might be of visual interest for what we’re doing. Then we sit down and we talk to the scientists. We discuss the possibilities that things that they deal that they are most comfortable with emphasizing a given result. What I like to do is walk away from that conversation with a bullet list of two, three, four, five things that we have agreed that, yes, these are the good things to establish in the story. Then the artistry comes in in producing an illustration that encompasses all of those bits of information in the bullet list. And then everything else that we don’t know, that’s the part that gets filled up with art.

Where would you say your most creative or artistic choices come into play?

TP:It’s in the detail where we have a lot of freedom. For instance, one of the terrestrial planets, Kepler 186f, there were certain broad strokes that we had based on how big it is and it could have liquid water? (But it probably doesn’t have as much as Earth.) So the scientists came up with a percentage, which I think was maybe 25 percent of the surface was water and 75 percent wasn’t. But as far as what that looked like — is it one giant ocean or like lakes? How were they distributed? What’s the land topography look like? Since we don’t have any information about that, there’s a lot of freedom to make it look the way we want. That was actually kind of fun, sculpting lakes and rivers and things on the surface.

Do you now have increased information to work with when astronomers discover a new planet?

RH: Certainly what’s happened is, because of the explosion of known exoplanets and known systems and the varying conditions, there has been a lot more theoretical work that’s ongoing and continues to provide sort of a theoretical context for what conditions would be like on these. Teams working on exoplanet discoveries now, just by the nature of this research, have a lot more information at their disposal than even 5 years ago as what is likely to be a plausible set of models describing - is this going to have an atmosphere? Or is it going to be rocky? What would the surface temperature likely be? The chance of exposed magma? Or indications of things that could be volcanic activity. The very explosion of this field has actually given so much more context to interpret results than was available at the beginning.

Does that theoretical context make your jobs easier?

TP: From a purely artistic sense, I think that great art is achieved through constraint. If you’ve got a lot of interesting constraints on what can and can’t be there it actually drives more opportunities to really make a nice piece of artwork that all fits within that. Haiku is a more interesting poetry form than just free verse.

RH: If you say so.

TP: We’ll agree to disagree. Personally, the more that the scientists can give us as to what they think is going on, the happier I am. That really lets us focus on the subtle parts of the artwork…. It’s my understanding that a lot of these models are not going to advance too much until we actually get over and see some of these planets personally. Until then they’re still a theoretical model. I would imagine it would have been very difficult for us to have predicted what a Venus type of planet or a Mars type of planet would have looked like in another solar system if we didn’t have Venus and Mars to look at here. Neither of them, I believe, is uninhabitable and one of them is really close. We might have thought that it looked a lot different. We wouldn’t have known that Venus was so inhospitable if we discovered it around other stars.

RH: Venus is a nice case study in that naively one would potentially extend the habitable zone with fairly large boundary in our solar system, but we have a pretty clear demarcation that something the size of earth that’s 20 percent closer to the sun than earth clearly is not habitable. That really defines the habitable zone for us empirically.

TP: Well, it may not be habitable. Because we can’t even say that.

RH: Given all of things being equal … The trick with Venus is that just increasing the temperature of the surface that much more over Earth, we guarantee that much more water vapor in the air, which would be more greenhouse effect; Venus would be the defining example of the runaway greenhouse effect. And the more crap that’s in the air, the hotter it gets, causes more stuff to vaporize into the air, which accelerates the effect. The fact that Venus is only 20 percent closer to the sun than the Earth but that it’s surface temperature is 900 degrees kelvin is a vastly different surface.

Anything else about your work you’d like to mention?

RH: The opportunity to be in a position to really help take on the visual side of science communications, I think, is really just a lovely and exciting dream career to have. Astronomy, for me, has always been like a gateway drug to science. It lures them in with the pretty pictures to get them to actually learn the methodology of science and lots about it …. I think it’s just a wonderful challenge and it’s part of why we’re always trying to up our game. We always want that story to be clearer. We want that story to be better.

TP: When it comes to actually seeing what some of these planets really look like, we’re still a ways off from that happening. We’re on the cusp of actually being able to capture essentially the echo of a planet, whether it’s the 30 meter telescope, or some of these technologies that [the Jet Propulsion Lab] is doing, things that can block the star’s light so we can see the planet. But we’re still talking about little dots. And it’s going to be that way for a long time before we’re going to be able to see them large enough that we can see whether our artist’s concepts are accurate or not. Because of that, our artist’s concepts really are the only window into visualizing what these planets look like. It’s humbling to be able to be in that process of creating that art.