Ultimate Events. Galaxy clustering in ever deeper surveys. Models of universe and its fates

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ASTR 1040 Accel Astro: Stars & Galaxies Ultimate Events Prof.

edu/astr1040-toomre toomre Allen Telescope Array Review current big outstanding questions or issues in astronomy Look

7 Final review sheet available Graded Observing Projects B returned Homework 12 returned + answers Overview read Chap 24:

1 ASTR 1040 Accel Astro: Stars & Galaxies Ultimate Events Prof. Juri Toomre TA: Nicholas Nelson Lecture 30 Thur 28 Apr 2011 zeus.colorado.edu/astr1040-toomre toomre Allen Telescope Array Review current big outstanding questions or issues in astronomy Look briefly at Possibilities of Life Elsewhere and Extra-Solar Planets Final Exam Review tonight by Nick, here, 7-9pm. 7 Final review sheet available Graded Observing Projects B returned Homework 12 returned + answers Overview read Chap 24: Life beyond Earth INFLATION needed to explain uniformity of CMB REVIEW SIZE Models of universe and its fates OPEN CRITICAL (FLAT) WMAP 0.3 degree resolution Small temperature fluctuations used to test models of universe one degree scale in sky --> flat universe with early inflation NOW TIME CLOSED Galaxy clustering in ever deeper surveys Galaxies are always moving: Hubble flow + respond to local clustering Milky Way at center is moving toward Virgo cluster, then Coma supercluster 600 M ly across 1

The Big Mysteries What will be the fate of the universe?

Is the theory of inflation correct? What is the dark energy?

Science is not about belief, it s s about exploration Discussion

possible or is it nutty? A. Pretty unlikely (No) B.

Darned if I know (and why ask this in astronomy) D.

I prefer to sleep, wake me when its over Life in the Milky Way

life of any kind is present only on Earth B.

2 The Big Mysteries What will be the fate of the universe? What is the universe made of? What is the dark matter? Is the theory of inflation correct? What is the dark energy? Which of this, if any, should we believe? Science is not about belief, it s s about exploration Discussion Clicker Q Is Extra-Sensory Perception (ESP), or telepathy, possible or is it nutty? A. Pretty unlikely (No) B. Sure, I believe it (Yes) C. Darned if I know (and why ask this in astronomy) D. How could such communication be carried out? (Interested) E. I prefer to sleep, wake me when its over Life in the Milky Way galaxy Which do you think is most likely? A. life of any kind is present only on Earth B. primitive life exists elsewhere (Mars, other planetary systems), intelligent life is unique to Earth C. intelligent life developed elsewhere, but has since died out D. other civilizations exist, but are rare E. other civilizations are very common What is LIFE? Complex, complicated, delicate Building blocks for life forms How does life start? Three propositions Stanley Miller 2

3 Life on Earth: 4 ingredients Proteins: complex DNA RNA encoding Simple life form: nanobacteria Life in many forms some surprising Zones of habitability: requirements for carbon-based based life (ecospheres) Thermal pools in Yellowstone host life, despite very harsh conditions (high temperatures, acid water) Requirement for liquid water defines a habitable zone: range of distances from a star where the surface temperature is between freezing and boiling Not known observationally how often a rocky planet occupies the habitable zone Ecospheres to nurture and sustain life (on planets) Thought on theoretical grounds that habitable planets should be common 3

Our ECOSPHERE Varying zones of habitabilty

lifetime on MS? But maybe life on Titan?

Searches by several teams show that ~10% of

observer Most extra-solar planets detected

looking for transits (Kepler( Kepler) Debra

Earths are not yet detectable STAR First 77

4 Our ECOSPHERE Varying zones of habitabilty around stars A-type stars favorable, but lifetime on MS? But maybe life on Titan? How many stars host planetary systems? Searches by several teams show that ~10% of stars similar to Sun host giant gas planets Extremely hard to form images of extra-solar planets: faint, very close to bright host star Jupiter is ~10 9 times fainter than Sun as seen by distant observer Most extra-solar planets detected by radial velocity method,, many now by looking for transits (Kepler( Kepler) Debra Fischer Geoffrey Marcy Smaller extra-solar Earths are not yet detectable STAR First 77 planets, now about 300+ DISTANCE Neptune mass planet in short period orbit 4

$Multiple massive planets in Upsilon Andromeda Found that the planet frequency increases with the metallicity (i.e. the fraction of elements heavier than helium) of the star - presumably reflects more raw material for planet formation Jupiter masses Hot Jupiters: a < 0.$ 2 dy, circular orbits Broad range of eccentricity for all other planets No real overlap with Solar System distance Planet frequency is ~5 % in sample Late heavy bombardment ended about 3.

2 dy, circular orbits Broad range of eccentricity for all other planets No real overlap with Solar System distance Planet frequency is ~5 % in sample Late heavy bombardment ended about 3.

5 Multiple massive planets in Upsilon Andromeda Found that the planet frequency increases with the metallicity (i.e. the fraction of elements heavier than helium) of the star - presumably reflects more raw material for planet formation Jupiter masses Hot Jupiters: a < 0.1 AU P as low as 1.2 dy, circular orbits Broad range of eccentricity for all other planets No real overlap with Solar System distance Planet frequency is ~5 % in sample Late heavy bombardment ended about 3.8 billion years ago Primitive life got started on Earth quickly once conditions allowed One interpretation: expect life to start on any planet with the basic ingredients (liquid water, a source of energy) The Drake equation How many planets in Galaxy evolved intelligent life? N N * f planets f habitable f life f intelligent N * is number of suitable stars in the Galaxy, say 100 billion (10 11 stars) f planets is fraction of those that have planets f habitable is fraction of planetary systems that include habitable planets f life is fraction of habitable planets on which life of any sort gets started f intelligent is fraction of planets on which life becomes `intelligent 5

$Probability of more complex life emerging On Earth, the first evidence for multi-celled organisms dates back about 1 billion years For 3 billion years (significant fraction of Sun s s lifetime) there$ would evolve into a species capable of technology (and communication) How many civilizations are there? Let s estimate (guess!) some numbers: N N * f planets f habitable f life f intelligent 10 11 0.

would evolve into a species capable of technology (and communication) How many civilizations are there? Let s estimate (guess!) some numbers: N N * f planets f habitable f life f intelligent 10 11 0.

6 Probability of more complex life emerging On Earth, the first evidence for multi-celled organisms dates back about 1 billion years For 3 billion years (significant fraction of Sun s s lifetime) there were only single-celled organisms Modern humans and (especially) technology are only recent developments (only ~ last million years) Impossible to infer from this the probability that simple life would evolve into a species capable of technology (and communication) How many civilizations are there? Let s estimate (guess!) some numbers: N N * f planets f habitable f life f intelligent `astronomical parameters life is common but the chance of it becoming intelligent is very small Gives N = 5000 our Galaxy should be teeming with intelligent life! Some Thoughts on Civilizations Milky Way galaxy is about 10 billion years old -- or 5 billion years older than the Sun Many of those other civilizations could be millions or billions of years more advanced than us So why is not ET (or ET s s robot) here by now? A. intelligent life is really rare (10-9 ), or even unique B. civilizations are fragile - if they last only 1 million years, 5000 could have gotten started but at any time only one survives C. ET has better things to do than waste time communicating with primitive species (us) D. ET is keeping us in quarantine E. life of any kind is rare We wish you good fortunes with the Final Exam next Wed (4:30pm here) -- please bring pencils, crib sheets, ID and we hope you ve enjoyed this course that has touched the universe 6

Era of Atoms 5/3/18. Our Schedule and Topics

Era of Atoms 5/3/18. Our Schedule and Topics 5/3/18 ASTR 1040: Stars & Galaxies Cosmic Web Prof. Juri Toomre TAs: Peri Johnson, Ryan Horton Lecture 30 Thur 3 May 2018 zeus.colorado.edu/astr1040-toomre Our Schedule and Topics Final Exam on Wed May