TOPICS > Science

Mars’ Close Encounter

August 27, 2003 at 12:00 AM EDT

TERENCE SMITH: Today, Mars made its closest pass to Earth in nearly 60,000 years, giving people a chance to get their best look at the red planet. Normally, Mars is about 140 million miles away from Earth. But today, it orbited a mere 34 million miles away. In countries around the world, people flocked to telescopes to catch a glimpse of the tiny ball in the sky. And today NASA released images taken by its Hubble telescope providing the most detailed look.

For more on this special moment and on our continuing fascination with Mars, I’m joined by Neil DeGrasse Tyson, an astrophysicist and the director of the Hayden planetarium at the American Museum of Natural History.

Mr. Tyson, welcome. Is this a scientific event, a media event, a big party? What is it?

NEIL DEGRASSE TYSON: It’s a little of all of the above but it’s primarily a media event and a big party, because every couple of years, every 26 months, Earth and Mars are on the same side of the sun when you combine what their orbits are doing in the ballet of the solar system.

And about every 15 or 17 years it’s at about this distance from us. And so to make a big deal over this as a record, yes, it’s because we like records, but I’ll give you an example — 79 years ago, in 1924, Mars was almost as close as it is today and yet no one is reflecting back on that time. And it’s almost like me taking a few steps to my left, entering New Jersey here from Manhattan and saying, you know, I’ve never been this close to Japan before. Yes, technically I’m close to Japan but that difference is not much compared to how often Mars has been close.

TERENCE SMITH: How close is close? I mean relate it in terms of distance to the moon, to the other planets.

NEIL DEGRASSE TYSON: Well, moon is only 240,000 miles away. Mars this morning was 34 million miles. Now, that’s a long way.

And, by the way, had we never been there, we could view this as a special moment for never having seen it this close. But of course we’ve landed on Mars before. We’ve got spaceships going to Mars now that are about to deploy rovers. So to gather around and look at the Hubble picture and say, wow, look how close Mars is, I’m waiting for the rovers to land to get an even closer view.

TERENCE SMITH: In fact, you have, do you, a meteorite with you?



NEIL DEGRASSE TYSON: From the meteorite collection of the American Museum of Natural History. I’d like to thank my [museum] colleague … who is our meteorite curator, for supplying this for me for this interview. This is a Martian meteorite, this was a rock that was minding its own business on the Martian surface when a larger meteorite struck, thrusting this up to escape velocity, having it enter inter-planetary space wandering not quite aimlessly but in response to gravity of other planets, it landed on Earth .

And, in fact, it was seen to hit in Egypt in 1911. We know it’s from Mars because you can analyze trapped gases within it and it matches bang on to the gases of the Martian atmosphere. And this rock, what makes it kind of interesting is, in fact, very interesting, is it’s a reminder that planets are not isolated orbs in the solar system. There’s communication between planets by this very process.

And we happen to know that there are some kinds of bacteria that can survive trips through inter-planetary space. So if any of these rocks had a crevice in it and if Mars once had life, which we strongly believe, then you could have stow-away bacteria coming from Mars to Earth . It may be that all Earth lings are descendents of Martians, Martian bacteria that is.

TERENCE SMITH: There are all sorts of things I want to ask you about here. Those who go out tonight or in the next few nights and they look up without a telescope, with naked eye, what are they going to see?

NEIL DEGRASSE TYSON: Well, by the way it’s not only tonight. Just to set the record straight — the moment when we were closest to Mars was Wednesday morning, this morning, at 5:51 Eastern Time, but Mars, these days, are close enough so if you missed it tonight because it was cloudy or you fell asleep, it’s not as though there’s not going to be another chance. You have weeks to do this.

Mars rises at sunset and sets at sunrise. So it’s ideally positioned for anybody to see it, no matter your work schedule. And all you have to do is look towards the Southeast after sunset. And there’ll be this glowing thing, it will be the brightest thing in the sky. Mars right now is the third brightest thing in the sky after the sun and the moon. So you’ll have no excuse if you can’t find it.

I worry that maybe you’ve never looked up before. A lot of city people have never looked up. So it’s a challenge to city people to move out from behind buildings, get a view of the eastern horizon in the evening. And you’ll see a glowing orb there, an object, that once you confirm it’s not a plane coming in for a landing that’s going to be Mars. It will have this amber reddish hue to it.

TERENCE SMITH: I went out last night and, in fact, looked, saw it immediately. No question — the brightest light in the southeastern sky. But it was at least to my eye white, not red.

NEIL DEGRASSE TYSON: Well, the problem is the cones in your retina require a higher threshold of light to start triggering color so the best way to see color is to get an inexpensive pair of binoculars, spend $50 or $60 on a pair of binoculars – you could use it for sporting events the next day. Look at Mars through those binoculars and the color will become that much more apparent to you. Even with a simple telescope you’ll get the color for free but you’ll also notice among — at the poles of Mars you get icecaps and so it’s a reminder that Mars goes through seasons just like Earth.

TERENCE SMITH: You know, we’ve been fascinated, we Earthlings, have been fascinated with Mars for a long time. Why?

NEIL DEGRASSE TYSON: I could name a hundred reasons. Let me start with the top three. First it rotates in 24 hours just like Earth, 24 hours 30 something minutes. Its axis is tilted just like Earth . It has polar icecaps like Earth . It has seasons like Earth . It has a record of there once having been liquid water moving on its surface. There are meandering river beds, dry today but nonetheless meandering river beds, river deltas, flood plains.

There is no doubt that Mars was once an oasis, but it isn’t today and nobody knows why. We’re worried about that because we don’t know what we’re doing to our own Earth that might end up having all the water go away. So the more we study Mars not only is it fascinating in its own right it will surely give us clues as to what knobs we are inadvertently turning here on Earth that could have a dramatic effect of the future of life on this planet.

TERENCE SMITH: Is it your belief that there was life on Mars if there is not life there now?

NEIL DEGRASSE TYSON: Every place we look on Earth where there’s liquid water there’s life. You know, it’s the old pond drop under the microscope experiment. It’s teaming with life. In fact, Leeuwenhoek, the one who invented the microscope called those “little animals.”

And so it’s tantalizing to suggest that wherever you might find liquid water in the solar system you would have life. And so that is driving our interest in this planet. By the way, we’re not the first generation to have this interest.

Percival Lowe, 100 years ago, was fascinated by Mars, so fascinated that it kind of affected his brain and he started inventing things that he believed he saw. He imagined colonies and civilizations and cities and canals; it’s the origin of the canal myth on Mars. And then Orson Wells and H.G. Wells wrote the story, Orson Wells personified it on the radio program where they re-enacted an invasion by evil aliens from Mars. So Mars has been in our literature, it’s been in our fears, and today it’s on our frontier of science.

TERENCE SMITH: Very briefly, if you will, what do you expect to learn from these missions that are en route to Mars? What are you going to learn and when?

NEIL DEGRASSE TYSON: It’s almost like Earth attacks with this flotilla of probes en route to Mars. Right now — in the old days you would just sort of land on Mars and look around and take pictures.

Now we’re very sophisticated with miniaturization of electronics. There are rovers that will now go out, go up and cut into rocks, and with a microscope take a look at the freshly exposed surface deep within and analyze it for its composition, its chemical composition, its mineral composition. There’s a camera that will get a panoramic view that will be beamed back here to Earth so that we can all be vicarious explorers through the eyes of these rovers.

So science in this modern age has become democratized in a way that we can all sort of participate on that frontier of discovery right there with those who are conducting the mission themselves.

TERENCE SMITH: Neal DeGrasse Tyson, thanks so much for telling us about it.