EPSS 9 - Solar Systems and Planets Final

Olber's Paradox

A paradox pointing out that if the universe were infinite in both age and size, then the sky would not be dark at night. ( the universe is finite)

Archmides

10^63 grains of sand to fill universe, proved exponential math ( the universe is large)

1 AU

The distance from the Earth to the Sun

Parallax

the apparent change in position of an object when seen from different places

Cepheid variables

A variable star that brightens and dims regularly, or pulses, and whose distance can be determined from its period of pulsation

Edward Hubble

used Cepheid variables to obtain distances. Things moving away = reddening of light. Farther things move faster ( the universe is expanding)

Hubble constant

the rate of expansion of the universe 1/time ( velocity versus distance)

Doppler effect

lengthening of wavelength due to motion and velocity

Super Nova

a star that suddenly gets very bright and explodes

Age of universe

~13 billion years ( hubble constant slope: age/rate of expansion)

volume

4/3 pi r^2

velocity

distance/time

Kepler Telescope

Help see that we are not the only solar system and that other solar systems are different than ours

Aristotle

Earth was prime mover causing astronomical motions, planets closer to horizon = closer to sun

Ptolemy

tried to explain retrograde motion using epicycles from a geocentric system

Epicycles

along with orbiting earth, each planet had its own cycles around another fixed point along the orbit

Retrograde

Earth's orbit moves faster than orbits of other planets, makes it seems like other planet is moving backwards for a while

Copernicus

proposed heliocentric model, earth around sun once yearly; all planets have circular orbits; retrograde motion was only apparent

Galileo

early adopter of telescope; planets are disks; venus has phases; moons of jupiter; sunspots; moon craters

Tycho Brahe

Saw new star, nova, made planet position error bars smaller

Kepler

proposed elliptical orbits; planets sweep equal area in equal time.

Kepler's First Law

The orbit of each planet around the Sun is an ellipse with the Sun at one focus.

Kepler's Second Law

As a planet moves around its orbit, it sweeps out equal areas in equal times. closest to star = perihelion, farthest to star = aphelion. T^2 = R^3

Kepler's Third Law

The square of the orbital period of a planet is directly proportional to the cube of planets avg distance from sun. P = sqroot(r^3/A)

Newton

Introduced 3 new laws of motion. Proposed force between all objects in universe with mass ( gravity )

Newton's laws

Everything in motion remains in motion, force = mass*acceleration, action => equal and opposite reaction

force between two objects is proportional to product of their mass

f = G mM/r^2

Stellar Nursery

gaseous pillars of star formation

rotational motion

planetary systems form in disks, planets turn counter clockwise

plane of the ecliptic

The plane of Earth's orbit around the Sun

Obliquity

The tilt of the planet's axis

inner planets

Small, rocky planets that orbit closest to the sun including Mercury, Venus, Earth, & Mars

outer planets

Jupiter, Saturn, Uranus, & Neptune made of gases and ices with irregular satellites

asteroid

planetesimals broken and reassembled by multiple collisions

Comets

small icy bodies from far reaches of solar system with a gas tail pointing away from sun, dust tail curves from orbit

angular velocity

2 pi / T(time of one orbit)

Angular momentum

lies within the planets due to molecular cloud viscosity and friction. Inner disk slows down, outer disk speeds up

Isotope

same number of protons, different number of neutrons

Safronov

planetesimal hypothesis: dust to planetesimals, planetesimals to protoplanets, protoplanets to planets

N-body simulation

Approximates the motion of particles that are interacting with one another through physical force (usually gravity)

Isolation Mass

feeding zone mass

Pebble Accretion

material slow down and spiral into planetesimal; inside gaseous protoplanetary disk

Hutton and Lyell

said earth was formed by regular processes rather than catastrophic events

Kelvin

calculated earth was molten for 20-40 million years; didn't consider convection

Becquerel

discovered radioactivity (through uranium)

Joly

measured salt in ocean to estimate earth to be 90-100 million years old

Rutherford

suggested used radioactivity as geological clock

Boltwood

said lead is final product of Uranium decay

Holmes

got age of 3 bys from coniferous samples

Patterson

measured minerals in meteorites and first established age of earth and solar system

Age of Solar System

4.567 billion years old

Mass spectrometry

a technique that separates particles according to their mass

Titius- Bode law

predicts regular spacing b/w planets in solar system; led to discovery of Uranus; suggested asteroid belt is exploded planet

1 Ceres

Largest body in the main asteroid belt; 1/3 total mass of all asteroids. Discovered 1801, never melted, malleable, spherical

Kirkwood gaps

gaps in the asteroid belt

E-type asteroids

chondrite

S-type asteroids

ordinary chondrites

C-type asteroids

Carbonaceous asteroids...they are the most common variety, forming around 75% of known asteroids.

JAXA Mission

evidence for rubble pile concept

Dawn Mission

got good pictures of Vesta and Ceres

4 Vesta

made of basalt and shown to have been once melted, metal core, spherical. Like HED meteorites

white spots on Ceres

salt

Cryovolcano

saltwater, mud, ice volcano driven by liquid water and ammonia

Pysche

M type asteroid- Metal, represents metal core with silicate worn away

Heat to melt asteroids

radioactive decay. Heat from accretion not enough

Harold Urey

proposed decay of Al 26 as source of heat within planets

Comet IP / Halley

elliptical orbit, short period comets from Kuiper belt

Jan Oort

proposed comets reside in cloud of icy/rocky material (oort clout)

Tempel 1

It was the target of the Deep Impact space mission. shown to have equal rocky and ice

chondrites

a stony meteorite containing small mineral granules

chondrules

a spheroidal mineral grain present in large numbers in some stony meteorites. Melted and help date universe

undifferentiated meteorites

never melted, preserve proportions of silicate and metal inherited from solar nebula

Fireballs

very bright meteors, can help track meteorite's orbit

SNC meteorites

Meteorites that appear to have formed on Mars and have managed to make their way to a variety of locations on the Earth. May show signs of life on mars (small bacteria)

Moon composition

silicate crust, mantle, maybe core

Imbrium Basin

ridges and groves on near side of moon

simple crater

small, bowl-shaped craters with a fairly uniform blanket of ejecta distributed around the rim

complex crater

A crater that has central peaks and ejecta thrown out in long rays

Tycho

youngest large impact crater on moon's nearside

lunar cataclysm

Nice model suggested that planets migrate largely, causing increased scattering of planetesimals that impacted the moon

second suggestion for lunar craters

just the end of planet formation

Porcellarum

rift volcano basin on moon

Formation of moon

Earth and Theia collision

SPLAT

a second moon plastered itself to far side, creating a thicker crust there

Moon and Tides

Moon pulls on Earth and slows down rotation of earth, increasing lunar orbit speed

snow line

liquid water within, solid water outside

light and gravity

1/r^2

Tranquility

Serenity

Imbrium

Crisium

Fertility

Tycho crater

Mercury

dense with no atmosphere, most models dont make this planet, dramatic topography range; 59 moons; larger than moon

Mercury's spin orbit resonance

3:2

Caloris Basin

big impact feature on Mercury filled with Lava; chaotic terrain on other side of planet shows effect of shock wave; sun is attracted to this side.

Venus

Planet in retrograde rotation; large, sulphuric atmosphere. Intense volcanism.

Surface of venus

has basalt and continental terrain

how old is the surface of venus

young ( very low cratering ), no magnetic field

Tessera terrain

contains a strike slip fault and corona volcanic flows, pancake domes