life in the universe l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Life in the Universe? PowerPoint Presentation
Download Presentation
Life in the Universe?

Loading in 2 Seconds...

play fullscreen
1 / 26

Life in the Universe? - PowerPoint PPT Presentation


  • 343 Views
  • Uploaded on

Life in the Universe? Rami T. F. Rekola Tuorla Observatory University of Turku Life? humans! dogs! lizards! bacteria! viruses? androids?? corpses??? mules?!?!?! Fig: Funny Pictures Fig: Purdue University Definition of definition

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Life in the Universe?' - JasminFlorian


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
life in the universe
Life in the Universe? by R. T. F. RekolaLife in the Universe?

Rami T. F. Rekola

Tuorla Observatory

University of Turku

slide2
Life in the Universe? by R. T. F. RekolaLife?
  • humans!
  • dogs!
  • lizards!
  • bacteria!
  • viruses?
  • androids??
  • corpses???
  • mules?!?!?!

Fig: Funny Pictures

Fig: Purdue University

definition of definition
Life in the Universe? by R. T. F. RekolaDefinition of definition
  • linguistical approach (Oliver & Perry 2006, Origins of Life and Evolution of Biospheres, 34, 323-356)
  • OED: definition = a statement of the meaning of a word or the nature of a thing
  • unmistakable definitions are difficult, if not impossible
slide4
Life in the Universe? by R. T. F. Rekola
  • Oliver & Perry 2006:
    • theoretical definitions
    • stipulative definitions
    • operational definitions
  • a good definition:
    • necessary and sufficient
    • universal and apply to all past, present and future cases
    • essence of the term (by describing its function)
    • able to settle ambiguous cases
slide5
Life in the Universe? by R. T. F. Rekola
  • existing life definitions often describe living systems rather than life itself
  • some definitions are totally earth-centric

?

Fig:

Dickinson and Schaller

slide6
Life in the Universe? by R. T. F. Rekola
  • Prof. Koshland 2002 (Science, 295, 2215-2216):
    • ingredients and interactions among ingredients
    • ability to change / adapt to changes (mutation)
    • cells and organs
    • energy to recycle chemicals
    • ability to regenerate
    • individual adaptability to changes in environment
    • seclusion of chemical pathways
slide7
Life in the Universe? by R. T. F. Rekola
  • Ruiz-Mirazo et al. 2004: a complex collective network
  • Zhuravlev & Avetisov 2006: a combination of a state, a structure and a process
  • whatever definition you use, it is difficult to separate living and non-living things
prerequisites of life
Life in the Universe? by R. T. F. RekolaPrerequisites of life
  • chemical abundances

Fig: New Holland Publishing

slide9
Life in the Universe? by R. T. F. Rekola
  • heavy elements

Fig: ITER

Fig: TheBest3D.com

Fig: Stephen Mason

slide11
Life in the Universe? by R. T. F. Rekola

Limits of survivability:

from 0 Gy (?) to 15000 Gy

  • radiation

Fig: Red Boiling Springs Florist

slide12
Life in the Universe? by R. T. F. Rekola
  • pressure

Limits of

survivability:

from 0 atm to

1000 atm

Fig: Panimpex

slide13
Life in the Universe? by R. T. F. Rekola

Limits of survivability:

from –250°C to +121°C (+150°C)

Limits of livability:

from –20°C to +121°C

  • temperature

Fig: Richard Pelisson and Roland Pelisson, SaharaMet

Fig: Her Majesty’s Armed Forces

slide14
Life in the Universe? by R. T. F. Rekola
  • salinity

Limits of survivability:

nearly saturated salts (e.g. rock salt)

Fig: CSIRO

slide15
Life in the Universe? by R. T. F. Rekola
  • acidity

Limits of survivability:

pH 0 – 12

(0 – 13.7)

Fig: webshots.net

habitable zones
Life in the Universe? by R. T. F. RekolaHabitable zones
  • water, organic molecules and amino acids are widespread in the universe
  • organic molecules in interstellar clouds
  • organic material in meteorites, comets and asteroids; and on planets and moons
  • distribution of heavy elements is quite universal
slide17
Life in the Universe? by R. T. F. Rekola
  • spectral type F and G, and possibly K and M type stars habitable
slide18
Life in the Universe? by R. T. F. Rekola

Fig: Kasting et al. 1993, Icarus, 101, 108

  • habitable zone is a distance range from the star – depending on radiation and where water stays liquid
galactic habitable zone
Life in the Universe? by R. T. F. RekolaGalactic Habitable Zone
  • Gonzalez et al. 2001 (Icarus, 152, 185-200): metallicity at least half that of the Sun required to build a habitable terrestrial planet
  • bulge: old stars, continued star formation, high rate of supernovae in the past
slide20
Life in the Universe? by R. T. F. Rekola

Fig: Swinburne University

  • thin disk: 360 pc thick, variety of stars and active star formation
  • GHZ, an annulus in the thin disk
  • innermost planets large, heavy iron cores, lots of radioactivity
  • outermost planets small, too little radioactive heating
  • annulus 4–18 kpc (or 7–9 kpc)
slide21
Life in the Universe? by R. T. F. Rekola
  • thick disk: 1.2 kpc thick, very old stars of low metallicity
  • halo: 100 kpc radius, oldest and metal-poorest stars
  • at least 10 million habitable planets in the Galaxy (von Bloh et al. 2002, in Lacoste H. ed., Proceedings of the First European Workshop on Exo-Astrobiology, pp. 503-504)

Fig: universe-review.ca

habitable zones in the universe
Life in the Universe? by R. T. F. RekolaHabitable Zones in the Universe
  • galaxy evolution is not the same everywhere
  • galaxy types have differences
    • habitability of spheroidals poorly known
    • spiral galaxies likely to match the Milky Way
slide23
Life in the Universe? by R. T. F. Rekola
  • early universe had too much radiation
  • late universe will have too little to build on
  • habitable age of the universe began 5 Gyr ago and will continue for 10-20 Gyr more

Fig: R. T. F. Rekola

the fermi paradox
Life in the Universe? by R. T. F. RekolaThe Fermi Paradox

“Where is everybody?”

N = R × fp× ne× fl× fi× fc× L

NS = 6000

NM = 22000

slide25
Life in the Universe? by R. T. F. Rekola
  • advanced civilisations
  • interstellar communication is not easy
  • life is rare or we are alone

On the other hand...

if N = 10000, average distances about 340 pc

conclusions
Life in the Universe? by R. T. F. RekolaConclusions
  • we need to know what is life
  • we need to find where it lives
  • we can then search for it
  • …and find it…

Figs from left:

- John Sarkissian

- Arecibo Observatory

- Brian Attebery

- NASA