Joel Levine – TEDxNASA November 2009 TRANSCRIPT
I want to talk about 4.6 billion years of history in 18 minutes. That’s 300 million years per minute.
Let’s start with the first photograph NASA obtained of planet Mars. This is fly-by, Mariner IV. It was taken in 1965. When this picture appeared, that well-known scientific journal, The New York Times, wrote in its editorial, “Mars is uninteresting. It’s a dead world. NASA should not spend any time or effort studying Mars anymore.”
Fortunately, our leaders in Washington at NASA headquarters knew better and we began a very extensive study of the red planet. One of the key questions in all of science, “Is there life outside of Earth?” I believe that Mars is the most likely target for life outside the Earth. I’m going to show you in a few minutes some amazing measurements that suggest there may be life on Mars.
But let me start with a Viking photograph. This is a composite taken by Viking in 1976. Viking was developed and managed at the NASA Langley Research Center. We sent two orbiters and two landers in the summer of 1976. We had four spacecraft, two around Mars, two on the surface — an amazing accomplishment.
This is the first photograph taken from the surface of any planet. This is a Viking Lander photograph of the surface of Mars. And yes, the red planet is red. Mars is half the size of the Earth, but because two-thirds of the Earth is covered by water, the land area on Mars is comparable to the land area on Earth. So, Mars is a pretty big place even though it’s half the size.
We have obtained topographic measurements of the surface of Mars. We understand the elevation differences. We know a lot about Mars. Mars has the largest volcano in the solar system, Olympus Mons. Mars has the Grand Canyon of the solar system, Valles Marineris.
Very, very interesting planet. Mars has the largest impact crater in the solar system, Hellas Basin. This is 2,000 miles across. If you happened to be on Mars when this impactor hit, it was a really bad day on Mars. This is Olympus Mons.
This is bigger than the state of Arizona. Volcanoes are important, because volcanoes produce atmospheres and they produce oceans. We’re looking at Valles Marineris, the largest canyon in the solar system, superimposed on a map of the United States, 3,000 miles across.
One of the most intriguing features about Mars, the National Academy of Science says one of the 10 major mysteries of the space age, is why certain areas of Mars are so highly magnetized. We call this crustal magnetism.
There are regions on Mars, where, for some reason — we don’t understand why at this point — the surface is very, very highly magnetized. Is there water on Mars? The answer is no, there is no liquid water on the surface of Mars today.
But there is intriguing evidence that suggests that the early history of Mars there may have been rivers and fast flowing water. Today Mars is very very dry. We believe there’s some water in the polar caps, there are polar caps of North Pole and South Pole.
Here are some recent images. This is from Spirit and Opportunity. These images that show at one time, there was very fast flowing water on the surface of Mars. Why is water important? Water is important because if you want life you have to have water. Water is the key ingredient in the evolution, the origin of life on a planet.
Here is some picture of Antarctica and a picture of Olympus Mons, very similar features, glaciers. So, this is frozen water. This is ice water on Mars. This is my favorite picture. This was just taken a few weeks ago.
It has not been seen publicly. This is European space agency Mars Express, image of a crater on Mars and in the middle of the crater we have liquid water, we have ice. Very intriguing photograph. We now believe that in the early history of Mars, which is 4.6 billion years ago.
4.6 billion years ago, Mars was very Earth-like. Mars had rivers, Mars had lakes, but more important Mars had planetary-scale oceans. We believe that the oceans were in the northern hemisphere, and this area in blue, which shows a depression of about four miles, was the ancient ocean area on the surface of Mars.
Where did the ocean’s worth of water on Mars go? Well, we have an idea. This is a measurement we obtained a few years ago from a Mars-orbiting satellite called Odyssey. Sub-surface water on Mars, frozen in the form of ice. And this shows the percent. If it’s a blueish color, it means 16% by weight. Sixteen percent, by weight, of the interior contains frozen water, or ice. So, there is a lot of water below the surface.
The most intriguing and puzzling measurement, in my opinion, we’ve obtained of Mars, was released earlier this year in the magazine Science. And what we’re looking at is the presence of the gas methane, CH4, in the atmosphere of Mars. And you can see there are three distinct regions of methane.
Why is methane important? Because on Earth, almost all — 999 percent — of the methane is produced by living systems, not little green men, but microscopic life below the surface or at the surface.
We now have evidence that methane is in the atmosphere of Mars, a gas that, on Earth, is biogenic in origin, produced by living systems. These are the three plumes: A, B1, B2. And this is the terrain it appears over, and we know from geological studies that these regions are the oldest regions on Mars. In fact, the Earth and Mars are both 4.6 billion years old.