Stars & Disks
What nearby region shows thousands of young stars with disks actively forming planets?
The Orion Nebula
Which 3 planets are closest to our sun?
Mercury, Venus, Earth
Name two places meteors are commonly found
Deserts & Antarctica
Where is all of the water on Earth found?
The surface
Where was cosmochemistry invented?
UChicago
What climate process defines the inner edge of the habitable zone?
Runaway greenhouse effect
What natural outcome of star formation explains why planets are so common?
The formation of protoplanetary disks
Which telescope gives images in greater detail than the Hubble Space Telescope?
JWST
What feedback process helps regulate Earth's climate by stabilizing CO2 levels?
The carbon-silicate cycle
Who lectured this week?
RJ Graham & Fred Ciesla
What percentage of a protoplanetary disk is dust vs gas?
1% dust, 99% hydrogen and helium
On average, how many planets does each star in the Milky Way host?
~1
Why are meteorites considered time capsules of planet formation?
They preserve early ingredients. Tells us about diff environments and conditions when planets form
Roughly what percentage of Earth's total mass is water?
<0.1%
What happens at the outer edge of the habitable zone even with high CO2?
CO2 can no longer prevent global freezing (maximum greenhouse limit)
What physical law explains why collapsing molecular clouds form rotating disks around young stars?
Conservation of angular momentum
What general trend describes planet size and composition with distance from a star in our solar system?
Smaller rocky planet closer in, larger gaseous planet farther out
Why are meteorites insufficient for explaining habitability?
They do not record later climate and geological evolution
Why can't we study Earth's earliest formation directly?
Geological activity has erased early evidence
What boundary in the disk determines where water ice can exist as a solid?
The snow line
The dust bunnies under your bed are an example of what?
Coagulation (planet growth)
Ciesla's 4 words to describe planet formation
Hit, stick, grow, repeat
Why do we use radio and infrared wavelengths to study planet formation?
They can see through dust that blocks visible light
Why didn't Earth freeze over when the Sun was dimmer in its early history?
Higher atmospheric CO2, stronger greenhouse warming
Why is being in the habitable zone not sufficient for habitability?
Planets may lack atmosphere retention, proper mass, geological activity, or climate regulation