# Presentation: 465470

## Searching for Habitable New Worlds

**Searching for Habitable New Worlds**
**and**
**Life in the Universe**

**Hosted by  **
***Night  Sky Network***

**Notes:**
Series of talks
First of 5 monthly December through April
Feature  four of the world’s greatest discoverers.
 What’s happening today in astronomy is as exciting as anything that has come before
Hope by evening’s end you’ll feel that excitement, too.

## Universal Laws of Biology ?

- Lawrence Hall of Science

- Liquid  Water

- DNA

- Intelligence

**Notes:**
Fund. Quest. Of biology not know.  Life on earth depends on water;  Do all forms of life in the universe also depend on water?
This basic question of biology is not known.   Is the DNA molecule the only possible molecular code of life?  Other replicating molecules possible.
And what about intelligence?  Does evolution always drive toward higher and higher intelligence?  Or is intelligence just
One twig on the tree of life, with millions of other life-form twigs that are fit to survive.

## Is there life 

***Is there life ***
***elsewhere in our***
***Solar  System?***

- The Only  Known Site of Biology
- In  the  Universe.

## Mars

***Mars***

- Liquid  Water
*Impossible*

**Pressure **
**= 0.01  of Earth**
** **
**. . . too low  for**
**Liquid  water.**

## Jupiter  and Two Moons

*Io*

*Europa*

## Surface  of Jupiter’s  Moon: :Europa

**Fractures in**** **
***Floating Ice***

***Icebergs***

## Jupiter’s  Moon:  Europa

**Jupiter’s  Moon****:**  *Europa*

*Sub-Crust*
*Ocean*

- .

***.***

***Life  in the ***
***Ocean?***

***.***

***.***

***Hydrogen-Carbon***
***compounds likely:***
***Amino acids***

***First New Ocean***
***Since Balboa***

##  The Milky Way Galaxy

**Now Exiting  our  Solar System to ...**

-  *The* *Milky Way Galaxy*

- .   .
-   .

**.     .**
** ****.  .**

** ****.**

**  ****.  **
** ****.**

**.     **
**  ****.**

-      .

***Meanwhile, we are hunting for abodes***
***Beyond our Solar System***

## The Discovery of Other

**The Discovery of Other**

- &  Implications

- Planetary  Systems

**Collaborators:****           **
** ****Paul  Butler,****  ****Debra Fischer,  Steve  Vogt**
** ****Chris Tinney,  Greg Laughlin, Hugh Jones**
**         **
** ****Andrew Cumming, Greg Henry, **
**    ****Jack Lissauer  Jason Wright, Brad Carter, **
** ****Eugenio Rivera, Chris  McCarthy, John Johnson**

***www.exoplanets.org***

**Notes:**
I am delighted to be here today,
Because of the wonderful
Bank of the West tennis tournament
That occurs here every July.

## Planet  Detection

***Wobble of Star:***
***Gravitational pull***
***by the planet***

##  WobbleVelocity

**V****PL****2  ****=****  ****G M****Star**** / r****                ****V****PL ****~ 10 ****km/s**
** ****V****Star**** =  ****     ****     ****V****PL****                     ****V****STAR**** ****~ 10 **m/s**  **
**                                                 **x (MPL /MJUP)

- Momentum:

** ****Wobble****Velocity**

***  ******M******PL***
***  ******M******STAR***

- Energy Equipartition:

-  (*** ***

- )

**12 years**

**. . . Jupiter **

***(Meters/sec)***

***Need  Telescope . . .***

## World’s most Successful Planet Search

-   1997 – Present

**Survey:  1300  **
**Nearby Stars**

*Keck 1*

## Echelle  Spectrometer

**CCD**

**Echelle**
**Grating**

- Collimator

**Starlight**
**From Telescope**

**High  Resolution ``Echelle”**

***Spectrometer***

## Spectrum of Star:Doppler  Effect

**Spectrum of Star:****Doppler  Effect**

***Doppler  Precision:***
***v / c ~ 10******-9***
********* ******~ 10******-9***

***4096  Pixels***

## 16 Cygni B

**16 Cygni B**

***Mass = 1.7 M******JUP   ****** ******(Min)***

**Orbit Period**

**2.2 yr**

***Not  Sinusoidal***

**Velocity**
**Wobble**

## Orbit of Planet around 16 Cygni

## 16 Cygni:  Planet & Moon

## Life on Gas  Giant  Planets ?

- Unlikely

- ?

***Floaters***

***Earth-Like  Moon***

## 70  Days

**Mass = 0.62 M****JUP**

***Upsilon  Andromedae******:***
***Velocity  Residuals***

## 4 MJup

- <date/time>

- 0.6 MJUP

- 2 MJUP

- 4 MJup

**Upsilon Andromedae:**
**Triple  Planet  System**

*Planets  have*
*No  Names*

***.***

***.***

***.***

***.***

***.***

***.***

***.***

***.***

## Upsilon Andromedae

***Upsilon Andromedae***

## 7.5 Earth-Masses

**Per = 1.94 d**
**M = 7.5 M****Earth**

**Gliese 876 d**
**Lowest  Mass Exoplanet :*****  ***
***7.5 Earth-Masses***

***1.94 Days***

***5 m/s***

***Three  Planets Orbiting Gliese 876***

***7 ******1/2****** Earth-masses***

## Ring in Between: 
 Lukewarm   

**Ring in Between:***** ***
*** ******Lukewarm******   ***

***Hot:***
***370 C***

***Cold:***
***-100 C***

***7.5  Earth-Mass Planet *****Orbiting  Gliese  876**

**Tides:***** ***
***One Planet Side ***
***always Faces Star***

## Milky  Way  Galaxy

**200  billion  stars**

** **
**     ****~10% of all Stars **
**  ****have *****detected***** planets.**

- 20  Billion  Planetary  Systems

- Detected so far:
-  Jupiter-mass
-  Saturn-mass
-  Neptune-mass

***~ Earth-Mass ?***

## More Low-Mass

- Planets

***Planet  Mass***

## Only Known Abode of Life

**But are they**
**Habitable ?**

**Must ****Environments**
**Be *****“Just Right”***
**For Life ?**

***Conclusion:  Many  Earth-******mass******  Planets ***

## Yellowstone  National Park :

**Suitable for Life ?**

-   ***Boiling Geysers***
***  ******Freezing winter***
***  ******Sulfuric acid.***

***One of the  Least  Hospitable  Places on Earth:***

## YellowstonePinwheel  Geyser

- Bacteria
- Thrive

**Near Boiling:**
**T ~ 80 C**

***Water:  Acidic***
***as battery acid***

- Each color
- a different
- species of
- bacterium

## Life at High Temperatureand High Acidity

**Temp = 65 C**
** ****pH = 2 **

- Yellowstone

## YellowstoneChurning  Cauldron

- Boiling  Temp

## YellowstoneChurning  Cauldron

- Yellowstone***Churning  Cauldron***

- Boiling  Temp,
- pH = 2

**Bacteria &**
**Algae Thrive **

**Algae**

-  **pH = 2**

**Corrosion**

## Cyanidium  Calderium

**Life  at**
**Extreme  Temp**
**&**
**Extreme  Acidity**

***Lives only at***
***T  > 60 C***

## Extremophiles Show that Life

-   Tolerates heat or cold

-   Takes food from a variety of sources

-   Thrives in acidic or alkaline environments

***  ******Copes with Intense Solar Radiation - - or none!***

***Liquid Water                     Life***

**Primitive Life:*****   Common in the Universe***

## Is our Milky  Way Galaxy Teeming  with Intelligent Life ?

** ****Galaxy is **
**     ****10 Billion Years Old**
**   ****- - - Twice the Age of Earth**** **
**50%  of  Stars are**
**     ****as Old as the Sun & Earth **
**   ****Many stars & planets older by  billions of  years!**
**How Many Civilizations ?**

## Is our Milky  Way  Teemingwith Intelligent Life ?

- Is our Milky  Way  Teemingwith Intelligent Life ?

**20 Billion **
**    ****Planetary Systems:**
**      ****1/2 are older than Earth**** **
**   ****What fraction have **
**       ****Intelligent  Life? **
**    **
**Pessimist****:  1 in a Million**

***There must be Thousands of Civilizations ***
***In the Milky Way Galaxy. . .***

- Advanced

- .               .

- .

- .

- .

- .

- .

- .

- .
-          .

- .

- .

- .

- .

## Where  is  Everybody?Why  Didn’t  They Come Here?

**Moon:  ****No Alien Spacecraft, Crash Debris, Obelisk**
**Mars:   Same Story**
**Earth:  ****Lovely Planet for 4 Billion Years . . .**
**                 *****Yet, no Alien Settlement.***
**100’s of Telescopes:  No Alien Ships spotted**
**Night Sky:  No Exotic Rocket Exhaust**
**No  Robotic  Probes Visit Solar System**
**SETI:  No Radio Signals  in  40 years.**

## Where  Is  Everybody?

- Hypothesis:  - **Thousands of Civilizations in Galaxy**
**                              ****- Head Start of Billions of years.**
***                              ******They should be Near!***
- Migration Throughout Galaxy:  Easy with robotic spacecraft
- =================================================
- Observation:  No Aliens Detected, and no Traces.
- Conclusion:  ***Hypothesis possibly  flawed.******                    ***
***                                    ***
***                                       ******( Ants eventually   find  your Kitchen)***
***  ***

- How Long do
- Technological
- Civilizations  Last?

**Expect:  1000**** ****Civilizations**
**              ****in  5 Billion Years**

**For Multiple Civilizations Today, *****Lifetimes Must Overlap:***
**Lifetime  >  5 Million yr**

***Recipe  for ***
***Exobiology:***
-  Planets
-  Chemicals
-  Water
-  Energy - - -
-     **Stars, Tidal, Geothermal**

**Life:**
***Probably Common ***
***in  the Universe.***

- Primitive  Life, at least

***February 5, 1996***

## SETIATA: Proposed Radio Telescope Array

##     Life in our Milky Way Galaxy:Primitive Life:  CommonIntelligence:     Rare ?

- Intelligence

***Semi-Intelligent Life forms***

- ..

## www.exoplanets.org