alien earths

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ALIEN EARTHS DR CRAIG O’NEILL DEPARTMENT OF EARTH & PLANETARY SCIENCE CCFS ARC NATIONAL KEY CENTRE MACQUARIE UNIVERSITY

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A recent talk I gave at the Newcastle Museum on exoplanets, and their chances for life.

TRANSCRIPT

Page 1: Alien Earths

A L I E N E A R T H S

D R C R A I G O ’ N E I L L D E PA R T M E N T O F E A R T H & P L A N E TA R Y S C I E N C E C C F S A R C N A T I O N A L K E Y C E N T R E M A C Q U A R I E U N I V E R S I T Y

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W H AT D O E S L I F E N E E D ?

M A R I N E TA R D I G R A D E

Page 3: Alien Earths

L I Q U I D W AT E R

T H E G O L D I L O C K S Z O N E

Page 4: Alien Earths

L I F E A R O U N D A B L U E S U P E R G I A N T ?

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T H E P E R I L S O F R E D D W A R F S

M-class stars

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L I Q U I D W AT E R

E V O L U T I O N O F T H E H A B I TA B L E Z O N E

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Life under a cold star

On Earth

And on Mars

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A N E V O LV I N G G R E E N H O U S EL I Q U I D W A T E R F O R 4 . 4 G A

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P L AT E T E C T O N I C SW H A T I S T H E E A R T H D O I N G R I G H T ?

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E A R T H ’ S T H E R M O S TAT

Plate tectonics

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S O U R C E O F V O L C A N I C G A S E S - M O S T LY C O 2 A N D W AT E R !R E C Y C L E S W AT E R A N D C O 3 I N T O T H E M A N T L E !C R E AT E S M O U N TA I N S A N D T O P O G R A P H Y - W E AT H E R I N G O F T H E S E ( T H E C O 2 - S I L I C AT E W E AT H E R I N G C Y C L E ) I S O N E O F T H E M A J O R C O 2 S I N K S O F G E O L O G I C A L T I M E S . !G E N E R AT E S H I G H C O R E H E AT F L U X - W H I C H P O W E R S T H E M A G N E T I C F I E L D - W I T H O U T W H I C H W E L O O S E AT M O S P H E R E FA S T. !S E E A L S O W A R D A N D B R O W N L E E , 2 0 0 0 ( R A R E E A R T H ) .

W H Y I S P L A T E T E C T O N I C S I M P O R TA N T ?

Page 12: Alien Earths

P L A T E T E C T O N I C S O N …

Mars? Venus? Kepler 186f?

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I N 2 0 0 7 . . . !VA L E N C I A , D . , R . J . O ’ C O N N E L L , A N D D . S A S S E L O V ( 2 0 0 7 ) ,

I N E V I TA B I L I T Y O F P L A T E T E C T O N I C S O N S U P E R - E A R T H S ,

A S T R O P H Y S . J . , 6 7 0 , L 4 5 , D O I : 1 0 . 1 0 8 6 / 5 2 4 0 1 2 . !P L A T E T E C T O N I C S O N G L I E S E 5 8 1 D ?

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A S U P E R E A R T H S I M U L AT I O N

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In 2007…

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- O ’ N E I L L , C . , A N D A . L E N A R D I C ( 2 0 0 7 ) , G E O L O G I C A L C O N S E Q U E N C E S O F S U P E R - S I Z E D E A R T H S , G E O P H Y S .

R E S . L E T T. , 3 4 , L 1 9 2 0 4 , D O I : 1 0 . 1 0 2 9 / 2 0 0 7 G L 0 3 0 5 9 8 .

“…thus super-sized Earths are likely to be in an episodic or stagnant lid regime.“

S U P E R V E N U S ?

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PA P E R S F O R P L A T E T E C T O N I C S

Page 19: Alien Earths

PA P E R S A G A I N S T P L A T E T E C T O N I C S

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W H AT I S N E P T U N E E V E N M A D E O F ?

What is the habitability of exoplanets?

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D O W E N E E D P L AT E T E C T O N I C S F O R H A B I TA B I L I T Y ?

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T H E A R C H A E A N

And then there was …

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H T T P S : / / W W W. FA C E B O O K . C O M / A L I E N E A R T H S