Quarter 1 Quiz 2 Redo Flashcards
Existence of dark matter
Galaxies simply do not have enough mass to be held together by gravity
Based on our observations, stars would be scattered randomly throughout the universe based on the gravity of observable matter
Dark matter exists - weird, mysterious, and probably vital to the existence of the universe as we know it
Irregular galaxies
These galaxies have an irregular shape
fesult of the collisions of galaxies
generally contain a complex mix of interstellar gas and dust, young stars, and old stars
Spiral galaxies
These galaxies are disk-shaped width either a round central hub (unbarred) or a hub shaped like a bar (barred)
They rotate with spiral arms that contain interstellar dust and gas, as they rotated gas and dust gets swept into nebulas, promoting star formation and an abundance of young stars
Elliptical galaxies
little to no structure, rotation, or interstellar matter
minimal star formation and dominance of the long lived, red stars
ellipsoid-shaped
most common type of galaxy
Chicxulub crater
300 km diameter ringed basin
About 65 million years old
Buried beneath Yucatan Peninsula and Gulf of Mexico
evidence of asteroid impact that killed dinosaurs
DART mission
wanted to knock an asteroid off its course, was successful
Systems used in DART could be used to knock an asteroid off course if it is going to hit Earth
What are the three types of meteorites?
Stones, irons, and stony-irons
Characteristics of stones (stone meteorites)
largest group, and they once formed part of the outer crust of a planet or asteroid
Characteristics of irons (iron meteorites)
once part of the core of a long vanished planet or large asteroid
believed to have originated within the Asteroid Belt
Characteristics of stony-irons (stone and iron meteorites)
very rare ( less than 2% of all known meteorites)
roughly equal amounts of nickel-iron and stone
thought to have formed at the core/ mantle boundary of their parent bodies
What is the kinetic energy equation
KE =(½)(m)(v^2)
Meteoroid
A small piece of asteroid or other debris in the solar system, measures less than 1 meter to be considered a meteoroid (but must be at least as large as a small grain)
Meteor
The term “meteor” refers to the fiery aerial display created by a falling meteoroid or asteroid
Meteorite
A meteorite is if the meteoroid survives the atmosphere and lands on Earth
Asteroid
Rocky/metallic objects that orbit the sun
Mostly made of rock
typically cratered and irregularly shaped
Most asteroids are within asteroid belt
Nebula
a cloud of interstellar dust and gas
Planetesimal
one of the small bodies that formed from the solar nebula and eventually grew into protoplanets
Protoplanetary body
a relatively large clump of material, formed in the early stages of solar-system formation, which later formed into planets
Nuclear fusion
nuclear process that releases energy when lightweight nuclei combine to form heavier nuclei
terrestrial planet
any of the planets Mercury, Venus, Earth, or Mars, or a planet similar in size, composition, and density to Earth. A planet that consists mainly of rocky material
Kepler’s 1st law
The orbit of every planet is an ellipse with the Sun at one of the two foci (focal points)
Kepler’s 2nd law
Kepler’s 2nd law
A line joining a planet and the Sun sweeps out equal area during equal intervals of time (planet is faster when closer to the Sun and slower when further)
Kepler’s 3rd law
The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit (the further from the Sun, the longer a planet’s revolution, year is proportional to th distance from the Sun)
Ellipses
elongated circles, the set of points such that the sum of the distance to the foci for any point on the ellipse is constant
Eccentricity
describes how elongated an ellipse is, ranges from 0 to 1
Higher eccentricity means an ellipse is more elongated, farther from a circle
Calculating eccentricit
Eccentricity = distance between foci / length of major axis
Higher eccentricity means an ellipse is more elongated, farther from a circle
Aphelion
the point in an object’s orbit when it is farthest from the Sun
Perihelion
the point in an object’s orbit when it is closest to the Sun
What a comet is
Small icy bodies that originate from the outer edges of our solar system
Comets have low densities (< 1)
Orbit the sun, some orbits as short as 100 years or less, some orbits upwards of 30 million years
Orbits follow Kepler’s laws
What are the parts of a comet?
nucleus, coma, 2 tails
parts of a comet and how they form
Nucleus - about 10km, center made of frozen gases, mixed with bits of rock, at the center may be rock
Coma - 10^3 to 10^5 km, forms when comet is closer to the Sun, gases sublimate and form a weak atmosphere, making coma grow
Comets have 2 tails, 10^5km to 1 AU long, one formed by dust and the other from gas, solar winds push dust and gas away from coma to form tails
Where comets come from (short and long period comets)
Comets are thought to be the left over debris from during the time of formation of the solar system.
Comets have shorter orbits (~200 yrs or less) known as short period comets, and longer ones (~30 million years), known as long-period comets
Short period comets come from Kuiper Belt
Long period comets come from Oort Cloud, long period comets are evidence for Oort Cloud’s existence
Process of Outgassing
The process by which gases that are frozen or trapped inside an object are released, heat from the sun allows gases to escape from a comet as it nears its perihelion
Happens when distance comets made of ice and gas approach the Sun, highly eccentric orbit means they get very close
orbits of comets
Comets have higher eccentricity
Focal points are further from each other and closer to the edges, the difference between aphelion and perihelion is large, getting really close to the Sun and really far from the Sun based on where it is in its orbit
Elliptical in shape
Not oriented to ecliptic plane, randomly oriented
Orbits follow Kepler’s laws
evidence for 10km asteroid impact (dinosaur killer)
Evidence for 10 km asteroid impact in
Worldwide 65 million yr old clay layer with:
Iridium (element #77) rare in crust, but in clay
Shocked quartz—indicates heat & pressure
Soot—global wildfires
what did the impact of the 10km asteroid have on Earth
Impact caused extinction
Disappearance of 70% species from the fossil record, including dinosaurs
What happens when a large (10km) asteroid or comet strikes
A
Object explodes (energy = billion megatons) on impact
vaporizes a portion of crust
Molten rock is thrown into atmosphere, it falls back down as a fiery rain igniting forests
Lighter dust stays suspended=>dark & cold
Photosynthesis & food chain disrupted
Soot, shocked quartz, iridium dust settles creating 65 million year old clay layer exposed at over 100 places on Earth
earth impacts
Small bodies can produce very large impact craters because velocity has such a big impact, it is squared in the equation
Meteor crater, Arizona
50000 years old
Projectile was 50 meter diameter, metallic asteroid
Crater diameter is 1.2km, 200m deep
