Class Notes (834,057)
Canada (508,304)

Habitable Planets.docx

3 Pages
Unlock Document

Life Sciences
Luc Bernier

Habitable Planets: Only earth? - Until now the only example of a known habitable planet - Earth orbits the sun within a regions … - Region where an earth analog planet can maintain liquid water on tis surface - The atmosphere provides a certain conc. Of greenhouse gases - Has the right mass to regulate plate tectonics Water: - The best solvent for life to emerge and evolve in o Has the ability to form h-bonds with other H2O molecules  This is ideal for proteins - Water is an abundant compound in our galaxy o Clouds and stellar clouds HZ: - The inner edge of the HZ zone, this is where we see runaway greenhouse conditions o All water is found as vapour, no liquid water present  Venus, mercury - The outer edge of the HZ the greenhouse effect fails to keep the planet above the freezing point o The water is frozen and found in the solid form  Neptune, Saturn - The earth is found in the HZ, the conditions are ideal o Distance from the sun is just right o Depending on the mass of the star the HZ might be closed (small star) or further (large star) Main factors: for life: - Long time span o Enough time for evolution to take place, the earth has been relatively stable in recent time - Liquid water in contact with building blocks - Environmental conditions that allow liquid water to exist Atmosphere: - Dense enough that can stabilize the surface temp - Greenhouse effect, caused by compounds that are very efficient absorbers in the infrared o CO2 o CH4 o N2O  These gases have caused our current temp with out them it would be about -16 degrees C Earths Radiation Budget: - The earth receives radiation form the sun - The earth also releases its own radiation (infrared) o Only a small fraction of this energy is actually lost o Most remains on earth Venus: - When the temperatures are exceeding a limit you end up with Venus o Earth may have looked like Venus when it was first forming - Surface pressure 9000 kPa - Surface temperature 480 degrees C - Has an atmosphere but very little water o Not sur
More Less

Related notes for LIFESCI 2H03

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.