YouTube

Got a YouTube account?

New: enable viewer-created translations and captions on your YouTube channel!

English subtitles

← Why we need to go back to Mars | Joel Levine | TEDxNASA

In this talk, planetary scientist Joel Levine shows some intriguing - and puzzling - new discoveries about Mars: craters full of ice, traces of ancient oceans, and compelling hints at the presence, sometime in the past, of life. He makes the case for going back to Mars to find out more.

Get Embed Code
6 Languages

Showing Revision 8 created 05/14/2015 by TED Translators admin.

  1. I want to talk about two planets
  2. the title is really,
    "A tale of two planets" -
  3. Earth and Mars.
  4. I want to talk about
    4.6 billion years of history
  5. in 18 minutes.
  6. That's 300 million years per minute.
  7. Let's begin the talk.
  8. Let's start with the first photograph
    NASA obtained
  9. of planet Mars.
  10. This is fly-by, Mariner IV.
  11. It was taken in 1965.
  12. When this picture appeared,
  13. that well-known scientific journal,
  14. The New York Times,
    wrote in its editorial,
  15. "Mars is uninteresting.
  16. It's a dead world.
    NASA should not spend
  17. any time or effort studying Mars anymore."
  18. Fortunately, our leaders in Washington
  19. at NASA headquarters knew better
  20. and we began a very extensive study
  21. of the red planet.
  22. One of the key questions
    in all of science,
  23. "Is there life outside of Earth?"
  24. I believe that Mars
    is the most likely target
  25. for life outside the Earth.
  26. I'm going to show you in a few minutes
  27. some amazing measurements that suggest
  28. there may be life on Mars.
  29. But let me start with a Viking photograph.
  30. This is a composite
    taken by Viking in 1976.
  31. Viking was developed and managed
  32. at the NASA Langley Research Center.
  33. We sent two orbiters and two landers
    in the summer of 1976.
  34. We had four spacecraft, two around Mars,
  35. two on the surface -
  36. an amazing accomplishment.
  37. This is the first photograph taken
  38. from the surface of any planet.
  39. This is a Viking Lander photograph
  40. of the surface of Mars.
  41. And yes, the red planet is red.
  42. Mars is half the size of the Earth,
  43. but because two-thirds
    of the Earth is covered by water,
  44. the land area on Mars
  45. is comparable to the land area on Earth.
  46. So, Mars is a pretty big place
    even though it's half the size.
  47. We have obtained topographic measurements
  48. of the surface of Mars.
  49. We understand the elevation differences.
  50. We know a lot about Mars.
  51. Mars has the largest volcano
    in the solar system,
  52. Olympus Mons.
  53. Mars has the Grand Canyon
  54. of the solar system, Valles Marineris.
  55. Very, very interesting planet.
  56. Mars has the largest
  57. impact crater in the solar system,
  58. Hellas Basin.
  59. This is 2,000 miles across.
  60. If you happened to be on Mars
  61. when this impactor hit,
  62. it was a really bad day on Mars.
  63. (Laughter)
  64. This is Olympus Mons.
  65. This is bigger than the state of Arizona.
  66. Volcanoes are important, because volcanoes
  67. produce atmospheres
    and they produce oceans.
  68. We're looking at Valles Marineris,
  69. the largest canyon in the solar system,
  70. superimposed on a map
    of the United States,
  71. 3,000 miles across.
  72. One of the most intriguing features
    about Mars,
  73. the National Academy of Science says
  74. one of the 10 major mysteries
    of the space age,
  75. is why certain areas of Mars
  76. are so highly magnetized.
  77. We call this crustal magnetism.
  78. There are regions on Mars, where,
    for some reason -
  79. we don't understand why at this point -
  80. the surface is very,
    very highly magnetized.
  81. Crustal magnetism.
  82. Is there water on Mars?
  83. The answer is no, there is no liquid water
  84. on the surface of Mars today.
  85. But there is intriguing evidence
  86. that suggests
    that in early history of Mars
  87. there may have been rivers
  88. and fast flowing water.
  89. Today Mars is very very dry.
  90. We believe there's some water
    in the polar caps,
  91. there are polar caps
    of North Pole and South Pole.
  92. Here are some recent images.
  93. This is from Spirit and Opportunity.
  94. These images that show at one time,
  95. there was very fast flowing water
    on the surface of Mars.
  96. Why is water important?
    Water is important
  97. because if you want life
    you have to have water.
  98. Water is the key ingredient
  99. in the evolution,
    the origin of life on a planet.
  100. Here is some picture of Antarctica
  101. and a picture of Olympus Mons,
  102. very similar features, glaciers.
  103. So, this is frozen water.
  104. This is ice water on Mars.
  105. This is my favorite picture.
    This was just taken a few weeks ago.
  106. It has not been seen publicly.
  107. This is European space agency
  108. Mars Express, image of a crater on Mars
  109. and in the middle of the crater
  110. we have liquid water, we have ice.
  111. Very intriguing photograph.
  112. We now believe
    that in the early history of Mars,
  113. which is 4.6 billion years ago,
  114. 4.6 billion years ago,
    Mars was very Earth-like.
  115. Mars had rivers, Mars had lakes,
  116. but more important
    Mars had planetary-scale oceans.
  117. We believe that the oceans
    were in the northern hemisphere,
  118. and this area in blue,
  119. which shows a depression
    of about four miles,
  120. was the ancient ocean area
  121. on the surface of Mars.
  122. Where did the ocean's worth
    of water on Mars go?
  123. Well, we have an idea.
  124. This is a measurement
    we obtained a few years ago
  125. from a Mars-orbiting satellite
    called Odyssey.
  126. Sub-surface water on Mars,
  127. frozen in the form of ice.
  128. And this shows the percent.
    If it's a blueish color,
  129. it means 16 percent by weight.
  130. Sixteen percent, by weight,
    of the interior
  131. contains frozen water, or ice.
  132. So, there is a lot of water
    below the surface.
  133. The most intriguing
    and puzzling measurement,
  134. in my opinion, we've obtained of Mars,
  135. was released earlier this year
  136. in the magazine Science.
  137. And what we're looking at
    is the presence of the gas methane,
  138. CH4, in the atmosphere of Mars.
  139. And you can see there are three
    distinct regions of methane.
  140. Why is methane important?
  141. Because on Earth, almost all -
  142. 99.9 percent - of the methane
  143. is produced by living systems,
  144. not little green men, but microscopic life
  145. below the surface or at the surface.
  146. We now have evidence
  147. that methane is in the atmosphere of Mars,
  148. a gas that, on Earth,
  149. is biogenic in origin,
  150. produced by living systems.
  151. These are the three plumes: A, B1, B2.
  152. And this is the terrain it appears over,
  153. and we know from geological studies
  154. that these regions
    are the oldest regions on Mars.
  155. In fact, the Earth and Mars
  156. are both 4.6 billion years old.
  157. The oldest rock on Earth
    is only 3.6 billion.
  158. The reason there is a billion-year gap
  159. in our geological understanding
  160. is because of plate tectonics,
  161. The crust of the Earth has been recycled.
  162. So the oldest rock on Earth
  163. is a billion years after the Earth formed.
  164. We have no geological record prior
  165. for the first billion years.
  166. That record exists on Mars.
  167. And this terrain that we're looking at
  168. dates back to 4.6 billion years
  169. when Earth and Mars were formed.
  170. It was a Tuesday.
  171. (Laughter)
  172. This is a map that shows
  173. where we've put our spacecraft
    on the surface of Mars.
  174. Here is Viking I, Viking II.
  175. This is Opportunity. This is Spirit.
  176. This is Mars Pathfinder.
  177. This is Phoenix,
    we just put two years ago.
  178. Notice all of our rovers
    and all of our landers
  179. have gone to the northern hemisphere.
  180. That's because the northern hemisphere
  181. is the region of the ancient
  182. ocean basin.
  183. There aren't many craters.
  184. And that's because the water
    protected the basin
  185. from being impacted
    by asteroids and meteorites.
  186. But look in the southern hemisphere.
  187. In the southern hemisphere
    there are impact craters,
  188. there are volcanic craters.
  189. Here's Hellas Basin,
  190. a very very different place, geologically.
  191. Look where the methane is,
    the methane is in a very
  192. rough terrain area.
  193. What is the best way to unravel
  194. the mysteries on Mars that exist?
  195. We asked this question 10 years ago.
  196. We invited 10 of the top Mars scientists
  197. to the Langley Research Center
    for two days.
  198. We addressed on the board
  199. the major questions
    that have not been answered.
  200. And we spent two days deciding
  201. how to best answer this question.
  202. And the result of our meeting -
  203. two day meeting, on the best way
    to solve these questions on Mars -
  204. was a robotic rocket-powered airplane
    we call ARES.
  205. It's an Aerial Regional-scale
    Environmental Surveyor.
  206. There's a model of ARES here.
  207. No speaker has made mention to it before,
  208. but it's been here
    since last night when I brought it,
  209. This is a 20-percent scale model.
  210. This airplane was designed
    at the Langley Research Center.
  211. If any place in the world
  212. can build an airplane to fly on Mars,
  213. it's the Langley Research Center,
  214. for almost 100 years
  215. a leading center of aeronautics
    in the world.
  216. We fly about a mile above the surface.
  217. We cover hundreds of miles,
  218. and we fly about 450 miles an hour.
  219. We can do things that rovers can't do
  220. and landers can't do:
  221. We can fly above mountains,
    volcanoes, impact craters;
  222. we fly over valleys;
  223. we can fly over surface magnetism,
  224. the polar caps, subsurface water;
  225. and we can search for life on Mars.
  226. But, of equal importance,
  227. as we fly through the atmosphere of Mars,
  228. we transmit that journey,
  229. the first flight of an airplane
    outside of the Earth,
  230. we transmit those images back to Earth.
  231. And our goal is to inspire
    the American public
  232. who is paying for this mission
    through tax dollars.
  233. But more important we will
  234. inspire the next generation of scientists,
  235. technologists, engineers
    and mathematicians.
  236. And that's a critical area
    of national security
  237. and economic vitality, to make sure
  238. we produce the next generation
  239. of scientists, engineers,
    mathematicians and technologists.
  240. This is what ARES looks like
  241. as it flies over Mars.
  242. We preprogram it.
  243. We will fly where the methane is.
  244. We will have instruments aboard the plane
  245. that will sample, every three minutes,
    the atmosphere of Mars.
  246. We will look for methane
  247. as well as other gasses
  248. produced by living systems.
  249. We will pinpoint
    where these gases emanate from,
  250. because we can measure the gradient
    where it comes from,
  251. and there, we can direct the next mission
  252. to land right in that area.
  253. How do we transport an airplane to Mars?
  254. In two words, very carefully.
  255. The problem is we don't fly it to Mars,
  256. we put it in a spacecraft
  257. and we send it to Mars.
  258. The problem is the spacecraft's
  259. largest diameter is nine feet;
  260. ARES is 21-foot wingspan, 17 feet long.
  261. How do we get it to Mars?
  262. We fold it,
  263. and we transport it in a spacecraft.
  264. And we have it in something
    called an aeroshell.
  265. This is how we do it.
  266. And we have a little video
    that describes the sequence.
  267. Video: Seven, six. Green board.
    Five, four, three, two, one.
  268. Main engine start, and liftoff.
  269. Joel Levine: This is a launch
    from the Kennedy Space Center in Florida.
  270. This is the spacecraft taking nine months
  271. to get to Mars.
  272. It enters the atmosphere of Mars.
  273. A lot of heating, frictional heating.
  274. It's going 18 thousand miles an hour.
  275. A parachute opens up to slow it down.
  276. The thermal tiles fall off.
  277. The airplane is exposed
    to the atmosphere for the first time.
  278. It unfolds.
  279. The rocket engine begins.
  280. We believe that in a one-hour flight
  281. we can rewrite the textbook on Mars
  282. by making high-resolution measurements
    of the atmosphere,
  283. looking for gases of biogenic origin,
  284. looking for gases of volcanic origin,
  285. studying the surface,
    studying the magnetism
  286. on the surface, which we don't understand,
  287. as well as about a dozen other areas.
  288. Practice makes perfect.
  289. How do we know we can do it?
  290. Because we have tested ARES model,
  291. several models
    in a half a dozen wind tunnels
  292. at the NASA Langley Research Center
    for eight years,
  293. under Mars conditions.
  294. And, of equal importance
  295. is, we test ARES
    in the Earth's atmosphere,
  296. at 100,000 feet,
  297. which is comparable
    to the density and pressure
  298. of the atmosphere on Mars where we'll fly.
  299. Now, 100,000 feet, if you fly
    cross-country to Los Angeles,
  300. you fly 37,000 feet.
  301. We do our tests at 100,000 feet.
  302. And I want to show you one of our tests.
  303. This is a half-scale model.
  304. This is a high-altitude helium balloon.
  305. This is over Tilamook, Oregon.
  306. We put the folded airplane
    on the balloon -
  307. it took about three hours
    to get up there -
  308. and then we released it on command
  309. at 103,000 feet,
  310. and we deploy the airplane
    and everything works perfectly.
  311. And we've done
  312. high-altitude and low-altitude tests,
  313. just to perfect this technique.
  314. We're ready to go.
  315. I have a scale model here.
  316. But we have a full-scale model
  317. in storage at the NASA
    Langley Research Center.
  318. We're ready to go.
  319. All we need is a check
    from NASA headquarters
  320. (Laughter)
  321. to cover the costs.
  322. I'm prepared to donate
    my honorarium for today's talk
  323. for this mission.
  324. There's actually no honorarium
    for anyone for this thing.
  325. This is the ARES team;
  326. we have about 150 scientists, engineers;
  327. where we're working
    with Jet Propulsion Laboratory,
  328. Goddard Space Flight Center,
  329. Ames Research Center
    and half a dozen major universities
  330. and corporations in developing this.
  331. It's a large effort.
  332. It's all led
    at NASA Langley Research Center.
  333. And let me conclude by saying
  334. not too far from here,
  335. right down the road in Kittyhawk,
    North Carolina,
  336. a little more than 100 years ago
  337. history was made
  338. when we had the first powered flight
    of an airplane on Earth.
  339. And in Anna McGowan's talk,
  340. you heard about
    where we're going in the next 100 years.
  341. We are on the verge right now
  342. to make the first flight of an airplane
  343. outside the Earth's atmosphere.
  344. We are prepared to fly this on Mars,
  345. rewrite the textbook about Mars.
  346. If you're interested in more information,
  347. we have a website
    that describes this exciting
  348. and intriguing mission,
    and why we want to do it.
  349. Thank you very much.
  350. (Applause)