ASTR Midterm

any life that originates from outside Earth

• -Organic molecules form naturally everywhere
• -Extremophiles
• -Life appeared early

studying conditions that began and support life on earth, looking for other places with these conditions, and looking for evidence of life in other places.

• Atomists
• Aristotelians

• the earth and sky are made of invisible atoms (4 kinds – earth, air, water, fire)
• ET life: maybe

• the 4 elements (maybe atoms, maybe not) make up the earth and the 5th element (quitessence) makes up the sky
• ET life: NO

Aquinas

early middle ages 500-1000 AD

Atheism; caused it to go into decline

• -not 4 elements
• -Earth isn't that special
• -not enough evidence

• -can be proven scientifically
• -consistency in testing
• -credible source
• -testable, measurable
• -mathematically explainable
• -physical, tangible

scientifically, a well-sustained explanation of some aspect of the natural world (like a model, but more thoroughly tested)

NO (new info comes in all the time)

a back-and-forth motion in stars

the sun and stars orbit the earth

was supposed to predict positions of planets, but the planets were never in their spots

facts and statistics collected together; often used as evidence

moment when everything started in the universe, not an explosion, and nothing existed before it

used a large telescope to discover all galaxies are moving apart

• -farther away= moving faster
• -Galaxies are not expanding
• -some nearby exceptions are moving closer because of gravity
• -the universe itself is expanding, meaning it was closer together in the past and must have been one point at one time

• -hydrogen
• -helium
• -lithium

within first 3 seconds of Big Bang

as soon as the universe expanded and cooled enough, protons, neutrons, and electrons combined to make these elements

in the center of stars by fusion (byproduct is light)

made in supernova when they explode

previous generation stars die and give some contents back to space to form more stars

sometimes described as an electromagnetic wave or as particles called photons

YES

• -called a photon
• -has no mass
• -only thing in universe to travel at the speed of light
• -photons have different energies

• 1) Gamma
• 2) X-ray
• 3) Ultraviolet
• 4) visible
• 5) Infrared
• 6) microwave
• 7) Radio

energy intensity

using a different telescope for the specific kind of light

• -high energy radiation
• -used in medicine to tell ho dense something is

objects that are warm or hot emit IR ratiation (heat waves); the hotter the object, the more heat waves it emits

• -how far away things are in space
• -what elements are emitted
• -how hot the place is (temp. and radiation)
• -density of planet
• -speed the objects are apporaching or receding
• -how fast they spin

• more heat= more light emitted
• more heat= more high energy light emitted

the nuclei of some isotopes spontaneously break apart, relasing particles, energy, and daughter isotopes

fission or radioactive decay

NO

it breaks the DNA strands

it does penetrate DNA, but our bodies can repair it quickly

rocks and fossils get less radioactive over time; this is what is used to tell the ages

time it takes for an element to decay to exactly half of the origional sample

• -impacts
• -differentiation (dense stuff sinks to the bottom)
• -radioactivity

flowy, gooey part between crust and mantle

• 1) inner core (solid metal)
• 2) outer core (liquid)
• 3) mantle (solid)
• 4) crust

the core's convection cells

the core convection moving around the charged particles creates a magnetic field that shields the atmosphere

it prevents solar wind from stripping away the atmosphere

• -correct temperature
• -correct pressure (needed for liquid form)

convection in the aesthenosphere

plate tectonics

the more greenhouse gases, the hotter Earth gets

water vapor (H₂O)

• complex and organized
• reproduces
• grows and develops
• taking and using energy
• responds to environment
• evolution and adaptation

NO

Cell

cells, DNA, protein

sulfur, carbon, hydrogen, nitrogen, oxygen, phosphorus (SCHNOPs)

hydrogen

• -Protein
• -Lipid
• -Nucleic Acid
• -Cabohydrates

workhorses of cells; enzymes, antibodies, hormones

fats, oils, cholesterol; long term energy storage, cell structure, and hormones

DNA and RNA; info storage and transfer

sugar and polysaccharides; short-term energy storage

• -very abundant
• -can bond up to 4 other elements at a time
• -very strong bonds
• -can make double bonds with itself

protein

protein

• -source of carbon and other raw materials
• -source of energy
• -water (liquids)

"life arising from non-life"

• -biologists use this model knowing it's incomplete
• -not all steps are reproducible in the lab

deep-sea vents

• 1) molecular building blocks form
• 2) RNA becomes self-replicating
• 3) pre-cells arise
• 4) true cells with RNA genomes appear
• 5) modern cells with DNA genomes evolve

RNA came first and may have assembled itself by sticking to rock or clay or assembled in icy water

NO

replicase

DNA; stonger, copies more reliable, encode more.

icy asteroids that were formed in the colder regions of the solar nebulas

ice being subliminated to gas by the sun's heat

shooting star

meteor that hit the ground

NO

residue from comets

the huge meteorite that hit the earth 65 mil. years ago and caused the extiction of the dinosaurs by climate change

• Impacts: 2
• Volcanism and global warming: 1
• Poisoning: 1
• Sea level change: 1

• appendix
• body hair
• tailbone
• extra ribs
• goosebumps
• male nipples
• third eyelid
• wisdom teeth

ancestors needed extra organ to digest tough veggies

ancestors had bigger mouths and used them for grinding tough plants

ancestors had tails and the modern tailbone is several tiny fused bones