Why extremophiles bode well for life beyond Earth - Louisa Preston
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0:06 - 0:07We've all seen movies
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0:07 - 0:10about terrible insects from outer space
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0:10 - 0:12or stories of abduction by little green men,
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0:12 - 0:14but the study of life in the universe,
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0:14 - 0:17including the possibility of extraterrestrial life,
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0:17 - 0:20is also a serious, scientific pursuit.
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0:20 - 0:23Astrobiology draws on diverse fields,
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0:23 - 0:24such as physics,
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0:24 - 0:25biology,
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0:25 - 0:26astronomy,
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0:26 - 0:27and geology,
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0:27 - 0:29to study how life was formed on Earth,
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0:29 - 0:31how it could form elsewhere,
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0:31 - 0:33and how we might detect it.
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0:33 - 0:35Many ancient religions described
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0:35 - 0:38other worlds inhabited by known human beings,
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0:38 - 0:40but these are more like mythical realms
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0:40 - 0:42or parallel universes
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0:42 - 0:43than other planets existing
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0:43 - 0:45in the same physical world.
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0:45 - 0:46It is only within the last century
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0:46 - 0:48that scientists have been able
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0:48 - 0:49to seriously undertake the search
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0:49 - 0:51for extraterrestrial life.
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0:51 - 0:53We know that at the most basic level
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0:53 - 0:55organisms on Earth need three things:
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0:55 - 0:56liquid water,
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0:56 - 0:58a source of energy,
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0:58 - 1:00and organic, carbon-based material.
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1:00 - 1:01We also know that the Earth
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1:01 - 1:03is just the right distance from the Sun,
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1:03 - 1:06so as not to be either frozen or molten.
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1:06 - 1:08So, planets within such a habitable range
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1:08 - 1:10from their own stars
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1:10 - 1:12may be able to support life.
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1:13 - 1:14But while we used to think
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1:14 - 1:16that life could only exist
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1:16 - 1:17in such Earth-like environments,
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1:17 - 1:20one of the most amazing discoveries of astrobiology
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1:20 - 1:23has been just how versatile life is.
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1:23 - 1:24We now know that life can thrive
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1:24 - 1:26in some of the most extreme environments
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1:26 - 1:29that'd be fatal for most known organisms.
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1:29 - 1:30Life is found everywhere,
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1:30 - 1:33from black smoke of hydrothermal vents
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1:33 - 1:35in the dark depths of Earth's oceans,
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1:35 - 1:37to bubbling, hot, acidic springs
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1:37 - 1:38on the flanks of volcanoes,
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1:38 - 1:41to high up in the atmosphere.
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1:41 - 1:43Organisms that live in these challenging environments
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1:43 - 1:45are called extremophiles,
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1:45 - 1:47and they can survive at extremes
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1:47 - 1:48of temperature,
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1:48 - 1:48pressure,
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1:48 - 1:49and radiation,
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1:49 - 1:50as well as salinity,
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1:50 - 1:51acidity,
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1:51 - 1:54and limited availability of sunlight,
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1:54 - 1:54water,
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1:54 - 1:56or oxygen.
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1:57 - 1:59What is most remarkable about these extremophiles
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1:59 - 2:01is that they are found thriving in environments
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2:01 - 2:04that mimic those on alien worlds.
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2:04 - 2:06One of the most important of these worlds
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2:06 - 2:09is our red and dusty neighbor, Mars.
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2:09 - 2:12Today, astrobiologists are exploring places
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2:12 - 2:14where life might once have existed on Mars
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2:14 - 2:17using NASA's Curiosity rover.
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2:17 - 2:18One of these is Gale Crater,
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2:18 - 2:20an impact crater created
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2:20 - 2:22when a meteor hit the surface of Mars
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2:22 - 2:24nearly 3.8 billions years ago.
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2:24 - 2:28Evidence from orbit suggest past traces of water,
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2:28 - 2:29which means the crater
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2:29 - 2:31might once have supported life.
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2:31 - 2:33Planets are not the only places
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2:33 - 2:35astrobiologists are looking at.
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2:35 - 2:38For example, Europa, one of the moons of Jupiter,
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2:38 - 2:39and Enceladus and Titan,
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2:39 - 2:40two of Saturn's moons,
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2:40 - 2:43are all exciting possibilities.
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2:43 - 2:45Although these moons are extremely cold
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2:45 - 2:47and two are covered in thick ice,
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2:47 - 2:50there is evidence of liquid oceans beneath the shell.
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2:50 - 2:53Could life be floating around in these oceans,
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2:53 - 2:55or could it be living around black smoker
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2:55 - 2:57vents at the bottom?
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2:57 - 2:59Titan is particularly promising
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2:59 - 3:00as it has an atmosphere
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3:00 - 3:03and Earth-like lakes, seas, and rivers
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3:03 - 3:04flowing across the surface.
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3:04 - 3:06It is very cold, however,
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3:06 - 3:08too cold for liquid water,
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3:08 - 3:09so these rivers may instead be flowing
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3:09 - 3:11with liquid hydrocarbons
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3:11 - 3:13such as methane and ethane.
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3:13 - 3:15These are composed of hydrogen,
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3:15 - 3:17and, more importantly, carbon,
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3:17 - 3:18which is the basic building block
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3:18 - 3:20of all life as we know it.
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3:20 - 3:23So, could life be found in these lakes?
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3:23 - 3:25Although instruments are being designed
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3:25 - 3:27to study these distant worlds,
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3:27 - 3:28it takes many years to build them
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3:28 - 3:30and even longer to get them
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3:30 - 3:31where they need to be.
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3:31 - 3:33In the meantime, astrobiologists work
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3:33 - 3:36in our own natural laboratory, the Earth,
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3:36 - 3:37to learn about all the weird
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3:37 - 3:39and wonderful forms of life that can exist
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3:39 - 3:41and to help us one day answer
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3:41 - 3:43one of humanity's oldest questions:
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3:43 - 3:45Are we alone?
- Title:
- Why extremophiles bode well for life beyond Earth - Louisa Preston
- Description:
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View full lesson: http://ed.ted.com/lessons/why-extremophiles-bode-well-for-life-beyond-earth-louisa-preston
Life on Earth requires three things: liquid water, a source of energy within a habitable range from the sun and organic carbon-based material. But life is surprisingly resilient, and organisms called extremophiles can be found in hostile living conditions (think extreme temperatures and little access to oxygen). Louisa Preston argues why extremophiles give astrobiologists hope for life in the universe.
Lesson by Louisa Preston, animation by Emanuel Friberg.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:01
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