Earth and Mars Book

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Although Earth and Mars were created together five billion years ago, our planet has evolved with life, while Mars is a cold, mostly dry planet. “Earth and Mars: A Reflection,” is a fusion of art and science, with images and essays that celebrate the life-sustaining nature of our planet and the mystery of Mars. Stephen Strom, a Harvard-educated astronomer, will talk about the book he helped create.

TED SIMONS: Earth and Mars may have been created together some 5 billion years ago, but they evolved and developed in very different ways. A new book, Earth and Mars, A Reflection, celebrates the life-sustaining nature of earth and the mystery of Mars with striking images and essays. Stephen Strom, a Harvard-educated astronomer, is here to tell us about the book that he helped create. Welcome to "Arizona Horizon," good to have you here.

STEPHEN STROM: Thanks, Ted, I'm very pleased to be here.

TED SIMONS: There's a lot of ways I could describe this book. You describe this book.

STEPHEN STROM: Well, the book is a combination of images of Mars taken by the high-resolution camera on the Mars reconnaissance orbiter. The camera orbits Mars at a height of about 100 kilometers or 60 miles above the surface and takes photographs of selected regions on Mars. Those photographs are combined with images that I took on the earth and what the book aspires to do is to compare the surfaces of earth and Mars and to try to explain how the surfaces of each planet were shaped by forces, such as volcanic activity, wind, and water.

TED SIMONS: And it looked to me, and I think as well as the description of the book, looking at it as an artist as much as a scientist, correct?

STEPHEN STROM: That's right. I've had two passions in life. The first is research in astronomy and my work focused on how stars and planetary systems formed. But in the late 1970s, I found myself seduced to photograph, particularly in the southwest, and while continuing my astronomical research career, I have been photographing in the four corners region and more recently, on the pacific northwest and have created during the last 30 years six books.

TED SIMONS: My goodness. Well, let's get to this one now and the opening photograph of this book kind of says it all doesn't it? One of these things looks like life and the other doesn't.

STEPHEN STROM: That's right. Mars and earth were formed, as you said over 4.5 billion years ago and both planets at one point in their life were rich in water but only one, earth, is at present. Our planet, as you know, as we all know since we're sitting here, is a life-bearing planet. Mars may once have had life, that's still an unknown. But it certainly did have water and that has been emphasized by recent work which has shown that not only is there water at the poles and under the surface in the form of ice on Mars but there appeared to be regions in which water is still flowing on the planet but there are no oceans anymore.

TED SIMONS: Interesting. We have talked about the seasonal kind of idea, seasonal water. You mentioned your book separated into four sections. The first section is entitled earth. And this photograph -- we're going to see a photograph. These are craters, the one on the left is Mars and the one on the right is I think in Namibia. Is that ice I'm seeing on Mars?

STEPHEN STROM: That is carbon dioxide ice that you're seeing in the -- in the hollow of the crater as well as a few specks on some of the high regions surrounding the crater. And the pairing, of course, is to try to demonstrate that on both earth and Mars, a bombardment by either comets or asteroids have been a crucial part of the planets' history from its formation to the present.

TED SIMONS: And it sounds like dune fields and sand dunes also a similarity. Good luck to anyone trying to figure out which one is Mars and which one is earth but it's the one on the left is Mars.

STEPHEN STROM: The one on the left happens to be Mars and it has that characteristic iron-rich soil that covers the very surface of Mars. And the right-hand image happens to be taken in Death Valley but both were shaped by wind. Winds on Mars can achieve speeds as high as 150 miles an hour and although the atmosphere on Mars is very thin, nevertheless winds do in fact, have enough -- can shape dunes.

TED SIMONS: Well, those are gorgeous photographs there. The next one shows polar ice caps and again, we've got one on Mars and the one on the right is in Norway, Correct?

STEPHEN STROM: That's correct. It's on one of the fjords in Norway, happened to select a small fraction of the image which I believe was taken by the astronauts in the international space station but yes that's right the picture on the left is of the south pole of Mars.

TED SIMONS: So we have ice at the poles and we have dry riverbeds, images in here and again, this is just amazing. They both look like earth.

STEPHEN STROM: Well, on the left was an image taken by the curiosity rover on Mars. It's on the edge of a crater and on the right is an image taken just east of Flagstaff and yes, the comparison is pretty remarkable.

TED SIMONS: The second section of your book is entitled fire and I guess you look at interiors and crusts and tectonic and volcanic activity. I was interested to know, no moving plates on the crust of Mars?

STEPHEN STROM: There may have been some movement early on in Mars' history. There have been some studies which suggest that there -- was some early displacement of plates on Mars but tectonic activity was modest compared to what happened on earth. On Mars it ceased perhaps a few hundred million years after the formation of the planet.

TED SIMONS: That being said what we're looking at, cinder cones and volcanic rock and that's Mars on the left, Mars I guess is always going to be on the left?

STEPHEN STROM: On most pages. [ Overlapping Speakers ] I've forgotten whether I put in a few to fool you but generally speaking, yes.

TED SIMONS: Cinder cones on Mars and volcanic rock on earth?

STEPHEN STROM: That's correct. The picture on the right was taken in the Pacific Northwest. In fact, in the San Juan islands.

TED SIMONS: Beautiful area. My goodness. Next photograph same thing. Cinder cones from Mars and volcanic rock, and I think that's Idaho?

STEPHEN STROM: Yes, it's taken in craters of the moon national park or monumental, I can't remember which.

TED SIMONS: And one more I think with Mars and Idaho as it adjust to position. Again, one of them looks a little drier not quite as colorful but they sure look the same.

STEPHEN STROM: They were chosen for morphological similarity and also I mean I had hoped that they would also evoke -- well, an esthetic response.

TED SIMONS: I'm sure, they definitely do. Third section of the book is entitled air, how the atmosphere reshapes surfaces and we're looking back at dunes that can be anywhere.

STEPHEN STROM: Right on the left is a dune on Mars and what you're looking at is half a mile on the side picture of Mars and on the right-hand side is a picture taken in Colorado. And you're looking at about oh, three feet or so of -- of sand dunes. So that was taken at grand sand dunes national monument in Colorado.

TED SIMONS: Our next one has a shot from Arizona there on the right and that's a sandstone wall but what a gorgeous photograph there on the left. That's Mars.

STEPHEN STROM: It is Mars and again, it's about half a mile on the side, those are dunes on Mars and the reason that I've chosen a bit of sandstone on the right is that the sandstone on earth was also molded partly by wind and partly by water.

TED SIMONS: More dune patterns coming up here, this time New Mexico gets a play on the right. But again, I've got to tell you, the one from Mars, the photograph from Mars seems more striking.

STEPHEN STROM: Well, I tend in my photographs to emphasize subtle patterns rather than dramatic patterns but nevertheless they both illustrate the effects of wind on the surface of each of planets.

TED SIMONS: And that is the result of wind on Mars, what we're looking at?


TED SIMONS: My goodness. Fourth section is water, Mars was what like one third covered with water they think?

STEPHEN STROM: That's right. And there's clear evidence of what looked to be now-dried ocean bottoms. There's evidence that water once flowed vigorously on the surface of Mars. You see features that look like river deltas on the planet. And as I said, there's evidence, direct evidence of water in the form of ice at the poles, water subsurface in the form of ice, water that flows when meteors strike the surface of Mars, and now, evidence of very briny flowing water on the surface, as well.

TED SIMONS: What we just saw was ice patterns, I think they were ice patterns on Mars compared to Utah, is that Utah?

STEPHEN STROM: That's right.

TED SIMONS: And that's your photograph on the right.


TED SIMONS: The next photograph has water eroded channels. Gorgeous on Mars and where's that other one? Is that Oregon?

STEPHEN STROM: The other one was taken on the mid-coast in Oregon, and it's interesting. Again, the scale on the one on the left is about a half a mile. The one on the right is a few feet and yet the water can form those same fractal patterns that you see that are so characteristic of river deltas.

TED SIMONS: Fractles play a big part in a lot of this doesn't it. The last thing we have here, is that frozen co2 from Mars?

STEPHEN STROM: That is correct. That's frozen carbon dioxide, peaking up in the interstices of a cracked surface. On the right hand side happens to be the Dirty Devil river in Utah.

TED SIMONS: Absolutely gorgeous. Why did Mars, the oceans and the rivers on Mars they disappeared, why there, not here?

STEPHEN STROM: Well, a crucial difference between earth and Mars is the fact that the earth is more massive, the pull of gravity on earth is stronger. So when water evaporates from the surface of either planet, on earth, water molecules are held in by gravity but water molecules on Mars are light enough so that Mars' gravity can't hold them in so over time, over time, water molecules evaporate from the surface and then eventually the water vapor is lost to space. Helping that process along is the fact that Mars no longer has a magnetic field. Our magnetic field shields our planet from the incoming solar wind. In the case of Mars, the magnetic field is very weak and as a result, high-energy particles from the sun, the solar wind, can penetrate and collisions between water molecules and the solar wind can accelerate those water molecules and accelerate them to speeds so that they escape from Mars' relatively slight gravitational pull.

TED SIMONS: I think I followed that, too.


TED SIMONS: It's all right. Last question on the book. Yes, there's science in there, yes, there's discovery in there but I found that it really does encourage contemplation, doesn't it?

STEPHEN STROM: I hoped so. I hope that the book could be read in two ways. One as a story told in images. And they're meant to evoke the feeling of similarities and differences between the planetary surfaces and the second part, the text that was largely written by brad smith, the planetary astronomer, provides some background so that those that are interested in pursuing the "why" behind the images can find that information, as well.

TED SIMONS: And we do want to thank the U.S. geological survey, the Mars reconnaissance orbiter high-rise camera, the NASA space station, NASA opportunity, and you as well for the great photographs and just a great effort. Thank you so much for being here.

STEPHEN STROM: And thank you, Ted for giving me the opportunity to talk about the book.

TED SIMONS: You bet. Thank you.

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Stephen Strom: Harvard-educated astronomer

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