PHYS 005 Lecture Notes - Lecture 20: Radial Velocity, Extremophile, Rich Mix
5 Jul 2018
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5/25 Beginning of the Universe
Water needs to be around for at least 2 Billion years before life can start existing
●Did water on mars stay long enough for life to form?
Circumstellar Habitable Zone
Too cold
●Water freezes into crystals that puncture cell wall
Too hot
●Boiling water will kill off life
Keeping water in habitable zone
●Blue/white (hotter stars)- zone is further away
○Cooler stars- zone is closer in proximity
You also need to STAY in goldilocks (habitable zone) at all times
Metallicity of Host Star
●Compared to the sun- in the middle of the graph
○stars with more metal content than sun > stars with less, but
○Stars with SIMILAR metal content to sun DOMINATES
●METALLICITY IMPORTANT TO FORM PLANETS
Characteristics required to be a Habitable body
○Metals- IRON (in core)
■To have GRAVITY
●Envelope of gas that turns into atmosphere
○Atmosphere- to breathe & shield fr star radiation
●Planet too big- atmosphere will collapse into planet
○Planet is too small- no metals, iron in core, ENVELOPE OF GAS
WILL FLY AWAY
○Continents AND oceans
■Regulates temperature
○Geological activities
■Life is based on water
●Needs WATER CYCLE to happen
○https://ilearn.ucr.edu/webapps/blackboard/execute/content/fil
e?cmd=view&content_id=_3232622_1&course_id=_268211_1
slide 19
○Continents allow cycle to happen- difference of temp between
water & land masses
■Geological activities helps replenish minerals
○Atmosphere
Document Summary
Water needs to be around for at least 2 billion years before life can start existing. Water freezes into crystals that puncture cell wall. Blue/white (hotter stars)- zone is further away. Cooler stars- zone is closer in proximity. You also need to stay in goldilocks (habitable zone) at all times. Compared to the sun- in the middle of the graph. Stars with more metal content than sun > stars with less, but. Stars with similar metal content to sun dominates. Envelope of gas that turns into atmosphere. Atmosphere- to breathe & shield fr star radiation. Planet too big- atmosphere will collapse into planet. Planet is too small- no metals, iron in core, envelope of gas. Continents allow cycle to happen- difference of temp between. Geological activities helps replenish minerals water & land masses. Every week, found new planet that may support life. 900 that are apprx in size to earth.
