Studied by 39 PeopleTags & Description
when did the universe form
13.77 bya
what elements were around in the early universe
hydrogen and helium
what is gravity
a force that attracts things with mass or energy to one another
what is gravity proportional to
weight and distance
chemical bond
the sharing of electrons
fusion
fusion of the nuclei in two elements
other than the big bang, how are elements formed
in stars when they continue to create chemical bonds of elements up to Iron, 26. the stars would then become heavy and explode and the heat fused other elements to create the rest.
how are nebulae formed
gravity brings elements together, in the early world it was only made of hydrogen and helium gas
what subatomic particle determines an atom's atomic number
the number of protons
atom
basic unit of matter
big bang nucleosynthesis
the big bang generated a lot of heat, so when it got super hot, there was fusion
electron
negative energy
element
a type of atom that has a specific number of protons and chemical characteristics
neutron
neutral energy
nucleosynthesis
the fusion between two nuclei
nucleus
contains protons and neutrons
proton
positive energy
what is the difference between chemical bond and fusion
fusion is created through intense heat and it creates new elements chemical bonds do not create new elements
what elements are made in stars
only up to the 26th element, Iron
what elements are made in supernovas
all elements
why do supernovas happen
once a star has fused a lot of iron, it becomes heavy and explodes
what is the difference between the first nebulae and the ones after supernovas occurred
the first nebulae were only made of hydrogen and helium but after supernovas they consist of lots of different elements
how do elements get distributed throughout the universe
through supernovas, when they explode and spread elements
stellar nucleosynthesis
fusion in stars that can only go up to iron
supernova
occurs when a star gets too heavy of iron and explodes, creating heat
supernova nucleosynthesis
heat from supernovas making fusion happen, creating all the elements
how do we know there was a supernova before our solar system
there are many kinds of elements on our planet
what was earth like during the Hadean Eon
lots of radioactive elements which caused a molten earth from their heat 4.6-4.0 bya
why do the different layers of the earth have different chemical compositions
heavier elements sank and lighter ones stayed at the top
why is the the center of the earth so hot
the radioactive elements still have particles breaking off generating heat
what is the favored hypothesis of the formation of the moon
giant-impact hypothesis because the elements are similar
giant-impact hypothesis
theia, a possible planet, crashed into earth which caused a chunk that broke off but stayed in because of gravity
did the moon or ocean form first
the moon formed around 4.5 bya and the oceans formed 4.3 bya
where do we think most of earth's water is from
carbonaceous chondrite
carbonaceous chondrite
a watery asteroid
three ways earth's water may have been formed
orbiting cloud water had water vapor and grains of dust let droplets form
rocks in the crust reacted with chemicals to create more water molecules
from asteroids and comets
how old is the universe's oldest water
12.7 bya
why is the origin of water important to study
because there may be other planets out there that could support life
gravitational collapse
the implosion of a star resulting from its own gravity; the result is a smaller and denser celestial object
radioactive decay
particles not being stable break apart into smaller particles and it releases energy and heat
hydrosphere
the water layer on earth
atmosphere
layer of gasses around the earth
biosphere
layer of life on earth
magma
molten rock in the earth's crust
igneous rock
rock formed by the solidification of molten magma
silicon tetrahedron
the sharing of electrons between 4 oxygen and 1 silicon, make up a large part of crystals
rock
naturally occurring solid aggregation of minerals.
mineral
naturally occurring, inorganic, crystalline solid with a relatively consistent composition
why is obsidian not a mineral
does not have a crystalline form
when is ice a mineral
when it is naturally occurring
sheet silicates
the atoms are arranged in a sheet rather than a framework
salt
is not a silicate but is a mineral
what is the difference between crust and mantle
chemically different
oceanic crust
denser but thin because of sediments
continental crust
less dense but thick
what layer is rigid
crust and upper mantle
what layer is ductile
inner mantle
lithosphere
"rock sphere" rigid
asthenosphere
"weak sphere" ductile NOT liquid
what types of crust have ocean on top of them
oceanic crust always has ocean on top and continental sometimes has ocean on top
polar ice's impact on sea level
determines the amount of water that covers continental crust
when do magnetic field reversals occur
hard to predict and can happen at any interval
what happens to make a magnetic field reverse
the field weakens until it is almost gone and then gradually builds in the opposite orientation
what are impacts of a weakened magnetic field
we are not protected against asteroids, tectonic plates can break off into the core, magma could come up from the core, and a mass imbalance could happen
continental margin
not a plate boundary but is where two types of crust meet
ductile
able to be deformed
dynamo
rotating, convecting, and electrically conducting fluid that can maintain a magnetic field
metallic bonds
electrons are not associated with any specific atoms, "sea of electrons"
rigid
unable to bend
plate tectonics
14 plates that is driven by the churning of the mantle. not made of crust but of lithospheric plates
difference between crust vs. mantle and lithosphere vs. asthenosphere
chemical difference, physical difference
hypothesis
a proposed explanation on the basis of limited evidence as a starting point for further investigation
theory
a well-substantiated explanation that is based on repeated confirmed experiments
how did the ideas of seafloor spreading start
through the use of a sonar during WWII
supporting evidence of seafloor spreading
seafloor sediment
magnetic polarity changes
radiometric dating
half-life
every half life is half of whatever parent atoms were there the previous half-life
continental drift
a hypothesis that our lands used to be one piece but drifted due to plate tectonics
glacial striations
striations in rocks from glaciers that would scrape along rocks and would even polish them
isotope
one of two or more atoms with the same atomic number but with different numbers of neutrons
magnetite
FeO rock that forms from magma and aligns to that current magnetic field
mid-ocean ridges
volcanic valleys with magma in the middle
pangaea
a hypothesis of a supercontinent ~300 mya
seafloor spreading
ridges are higher because of magma injections. ocean crust is being formed as the magma cools and as they cool they sink down and move away
what happens to plates as they move apart
more crust is formed but the other edges of the plates can hit other plates