Wonder over New Horizons' finds about Pluto will only grow

This view of Pluto is dominated by Pluto’s “heart,” a region of icy plains.

Members of the New Horizons team gather around a laptop as they review newly processed images being sent from the New Horizons spacecraft.

Alan Stern, who pushed and promoted a visit to Pluto for more than two decades and led the NASA New Horizons mission that produced the first pictures of the ninth planet last month, was in Tucson this weekend.

He talked about the surprises revealed in just 3 percent of the data gathered by New Horizons in its flyby of Pluto, and the surprises yet to come as the spacecraft slowly downloads its data from more than 3 billion miles away.

That global portrait of the red-tinged planet with its heart-shaped region of icy plains, for instance, will be five times clearer when the tiny spacecraft unloads the rest of its computer storage in the coming months.

As you waited for New Horizons to signal that it had gathered all the data on its flyby, was there ever a doubt?

There is always some doubt when you’re dealing with the unknown about the things you can’t control. But I knew the spacecraft was rock solid and that the flyby sequence was very well tested, and I was very confident.

You told me earlier this year that you would temporarily name one of the new moons you found “Arizona” to honor the state where Pluto was discovered, but you didn’t find additional moons.

That was one of my biggest surprises after we kept finding moons from the Hubble (Space Telescope). Every time we’d look harder, we’d find another — and then we get out there and the system is clean as a whistle. I lost a big dinner bet over that.

We now know what Pluto looks like. Does the picture get better?

Quite a bit better. Right now the best resolution imagery is 2 kilometers per pixel, more than a mile per pixel.

The best global that we will have will be at about 400 meters per pixel, five times better, and the best regional will get down to 100 meters per pixel and the very best stuff will be 100 meters per pixel, so you could see the football stadium here in town at that resolution.

Talk about the science surprises so far.

The two biggest surprises I believe we’ve found so far are, No. 1: that Pluto is so complex.

Even having worked on this for a long time and expecting it to really knock our socks off, it’s way beyond my expectations and we have a lot of work ahead to understand that geology — all the volatile transport and everything that’s taking place there. I think it pretty much universally surprised people how intricate this small planet is and how complicated it is.

And then the fact that we found areas the size of Texas, specifically Sputnik planum, that have no craters and that must have formed recently in a geologic sense — less than 1 percent of the age of the solar system. They may have been formed 100 years ago for all we know, but certainly less than 100 million years.

That means small planets are capable of generating geologic change billions of years after they have formed. It’s got to be doing it on its own, and we don’t know how to make that work.

That’s going to be a major, lasting contribution of this mission. It’s going to send the geophysicists to the drawing board to figure out how you do that.

When do we see even better pictures of Pluto?

It will probably be a slow reveal. What you really want to make in the end is the best composite of all the imagery. … It’s going to take us a year to do that, beginning in September.

Along the way, we’ll be showing you much more variety than we’ve been able to, at high resolution, and then there will be stages at which our map is twice as good and then four times as good and then even better still.

We’re going to be in the news and that’s a chance to inspire and to teach about science and to interest kids in STEM education, and we’re going to take full advantage of that.

New Horizons may have another mission — visiting another one or two Kuiper Belt objects. Where does that stand?

We have permission to choose the target and to fire the engines to go in that direction. We’re going to do that this year, then apply for funding and NASA will make that decision next year.

You did get to honor Pluto’s discovery in Flagstaff by naming regions for Percival Lowell, who established the observatory there, and Clyde Tombaugh, who discovered Pluto.

I’m glad we could do that. I think we made a lot of people happy.

Frankly, I think what the IAU (International Astronomical Union) did (in classifying Pluto a dwarf planet) disrespected some very important work and diminished the importance of, not just that planet, but the unbelievable accomplishment of Clyde Tombaugh in doing that in an age, by today’s comparison, of Stone-Age technology.

So the biggest and brightest feature on the planet, which we can see from 100 million miles away like a shining beacon, will be forever Tombaugh Regio.

Doesn’t the name have to be ratified by your friends at the International Astronomical Union?

I’m not worried about that. They wouldn’t dare ...