Big bang midterm

Order of planets

sun, mercury, venus, earth, mars, jupiter, saturn, uranus, neptune, pluto

Mercury

The closest planet to the sun; fastest moving, named after the messenger god Hermes

Venus

Second planet from the sun; thick atmosphere (93x Earth's), 96% CO2, volcanic activity - sulfuric acid clouds, surface temp near 1000°F, named after the goddess Aphrodite

Earth

largest terrestrial planet; supports life, has 1 moon, atmosphere suitable for water and life

Mars

Fourth planet from the sun; polar ice caps, rust-colored surface, changing seasons, evidence of past water and possibly life, named after Ares

Jupiter

Largest planet; gas giant, hundreds of years-old storm 3x Earth's size (Great Red Spot), possible moon with life, 5 AU from Sun, named after Zeus

Saturn

Gas giant; famous for prominent rings, has moons (one may have developing life), 9 AU from Sun, named after Kronos

Uranus

Gas giant; discovered in the 1700s, slow-moving, barely visible, named after the creator god Ouranos

Neptune

Outermost traditional planet; discovered in the 1800s, 30 AU from Sun, blue color due to methane, named after Poseidon

Pluto

Dwarf planet in the Kuiper belt; formerly classified as a planet, has a moon (Charon), 40 AU from Sun, named after Hades

Charon

Pluto’s largest moon, named after the mythological ferryman to the underworld; shares its name with the discoverer's wife

Moon

Earth's only natural satellite; controls tides, shows phases, only one side is visible due to synchronous rotation;

acutal size (diameter) = 2000 miles, r = 1000 miles

Sun’s mass

m☉=1.94x10^33 grams

Alpha Centauri

Closest star system to Earth;

contains three stars (A, B, C/Proxima);

visible from southern hemisphere;

brightest star centaurus constellation

Astronomical Unit (AU)

about 149 million km/94 million miles; standard unit in astronomy

Jovian planets

largest, outermost planets in solar system (Jupiter, Uranus, Neptune, Saturn); made of gas

Terrestrial planets

Earth-like worlds with rock/solid surfaces (Earth, Mercury, Venus, Mars)

Moon’s distance from earth

d = 238,000 miles

Sun’s distance from Earth

d = 1 AU; 149 million km; 94 million miles

How many arcminutes in 1 degree?

60

How many arcseconds in 1 arcminute?

60

how many arcseconds in 1 degree?

3600

Light

Atoms - protons (2 up quarks, 1 down quark) & neutrons (1 up quark, 2 down quarks)

Quarks

components of protons/neutrons (up, down, top, bottom, charge, strange)

mass of electrons

m = 9.10910^-28 grams

light travel problem

can’t see things contemporaneously because of light travel - light travel causes delay

*The further we look, the further back in time we see

Sun’s light distance from Earth; duration of Sun’s light travel

d = 8.5 mins - we see Sun’s light as it was 8.5 mins ago

Speed of light’s travel around Earth

6.5x around Earth/second

Light speed (constant)

c = 299,792,458 meters/second - finite, noninstantaneous

How far back (in light years) can we see?

13.8 billion light yrs. away (because the Big Bang (creation of the universe) occurred only 13.8 billion yrs ago)

James Webb telescope

6.5m fragmented mirror (folds, expands upon launch);

shows how stars/planets form, finds life in the universe, gives structure of universe as a whole

Scintillation

stars light coming through Earth’s atmosphere– stars’ sparkle

Hubble space telescope

1990;

1.5m mirrors;

orbits around earth in 90 mins;

built to better understand what’s outside of milky way (gave previously unrealized images of universe);

$1 million/day to run

Sun as a star

100 billion stars over 120,000 light yrs. across;

Formed 4.5 billion yrs ago

Alpha centauri A

biggest star in alpha centauri;

similar (but more massive) than the Sun;

~1 billion yrs older than the sun;

Alpha centauri B

slightly smaller than the Sun;

what the sun will look like in ~1 billion yrs

Alpha centauri C (proxima)

Closest alpha centauri star to Earth (d = ~300,000 AU);

3 ½ light yrs away from Earth

Aristarchus of Samos

discovered you can’t see a shadow unless it falls on something (shadow is much bigger than actual object, but gets smaller with added distance);

saw relative size of moon with respect to Earth through exclipses–saw moon was ¼ of Earth’s size through its shadow

How do we know the Sun is further away from Earth than the moon?

Solar eclipses (moon PASSING IN FRONT OF the sun & going through Earth’s shadow); 

ASSUMPTION: Shadow cast by the Earth = cone (if sun were close, the earth’s shadow would be a cylinder)

Solar eclipse - contact times

Contact time 1 = moon touching earth’s shadow;

Contact time 2 = moon fully consumed by earth’s shadow (t 1→2 = ~15 min);

Contact time 3 = moon touching opposite side of earth’s shadow (t 2→3 = ~1 hr)

Moon’s size compared to Earth

¼ of the Earth - Shadow of earth takes 15 mins to go across diameter of the moon/moon takes 1 hr to go across diameter of earth

why is 15 mins ¼ of an hour?

Shadow of earth takes 15 mins to go across diameter of the moon/moon takes 1 hr to go across diameter of earth

Aneximander’s universe model

believed Earth is a flat disc in the center of a circular surrounding universe 

Babylonian universe model

believed we lived on the ground with a hemisphere dome above us (firmament) where stars/planets sat–snowglobe

How fast does the Earth go to complete a rotation on its axes?

800MPH

How long does it take Earth to rotate on its axes?

23 hrs, 56 mins

Procession

the motion of an object’s rotational axes

how long does it take for Earth’s rotational axis to form a complete circle?

26,000 yrs

How many constellations does Earth travel through every year?

12 - ZODIAC constellations (technically 13 (Ophiucus));

constant

Planet (in latin)

“wandering star”

What proved that Earth rotates on its axes

the Foccault Pendulum;

Coriolis effect;

direction of hurricanes (COUNTERCLOCKWISE MOTION);

cyclones (in southern hemisphere—clockwise motion);

setting/rising of Sun & Moon

Nova

new stars

Supernova

star gets brighter due to a catastrophic explosion–makes sky temporarily brighter;

100 billionx brighter than Sun’s eventual explosion

Asterism

a prominent pattern of stars that is NOT a formal constellation

Sirius

biggest star in the sky;

Sun is cloest to Sirius in August - warmer temps; DOG DAYS OF SUMMER

Aldeberean

“the eye of the bull”;

biggest star of taurus constellation

Betelguese

Ancient Persian(?);

big, old star - bigger than Sun

Orion constellation

soldier with shield/weapon in hand;

fighting taurus to protect the 7 sisters

Ursa major constellation

"big bear”;

Ursa Major was originally a woman with a son (Ursa Minor), ursa major gets turned into a bear, her son comes back from hunting and gets scared by her as a bear, sends Hermes (mercury) down, son drags ursa major to heaven by the tail to get her immortalized in the sky - tail gets stretched long on the journey;

big dipper;

Big dipper constellation

Ursa Major’s body and long tail

Ursa major eye test

BINARY STARS (2nd star on the tail) - only 20/20 vision or better can see it

What did Issaac Newton discover?

Force

Force

accelerating a mass (ma); 

measured in Newtons (N)

Fundamental forces of nature

1. Gravity

2. Electricmagnetic

3. Strong nuclear

4. Weak nuclear

Gravity (Fgrav)

force that accelerates mass (Fgrav = ma = W);

9.81 m/s² OR 32.2 ft/s²

WEIGHT (W);

objects accelerate due to gravity at the same rate, regardless of mass—doesn’t account for friction

electromagnetic

unlike charges attract, like charges repel

strong nuclear

unlike charges repel, like charges attract

position

x;

distance & direction in space

velocity

change in position with respect to time (m/s);

v = Δx/Δt;

v = gt

acceleration

change in velocity with respect to time (m/s²);

a = Δv/Δt

average velocity (speed)

distance travelled/elapsed time (m/s);

Vavg = Δv/Δt

distance (vector)

d = ½at²; ½gt²

d = vt

d = gt/at

moon phase diagram

sunlight = EAST;

ORBIT = perfect circle because the size of moon and distance from earth stays constant–COUNTERCLOCKWISE/EAST

waxing phase = progressively more illumination (MOON RISING IN THE EAST/NIGHTFALL);

waning phase = progressively less illumination (MOON SETS IN THE WEST/DAYBREAK);

Full moon (midnight) = light side of moon facing earth (WEST);

New moon (noon) = dark side of moon facing earth (EAST);

equinox

“equal night”;

sun is above horizon for 12 hrs/is below horizon for 12 hrs

gravity (FREE FALL (m))

g = 9.8 m/s

Gravity between two masses

Fgrav = g(m1)(m2)/d²

Gravity and the distance between Sun and Moon

Double one mass → F(grav) WOULD DOUBLE–MASS EFFECTS GRAVITY LINEARLY;

Double both masses → F(grav) WOULD INCREASE 4x;

Double distance → F(grav) DECREASES 4x–INVERSE SQUARE

Static motion (forces)

ALL FORCES BALANCED;

Fn + Fgrav = 0

distance (arch length) (s)

s/θ = 2πR/360° → s = θ (2πR/360°)

Measuring planet radius (arc length): R = radius (degrees); θ/a = relative size (degrees); s = arch length/distance

s/θ = 2πR/360° ; R = 180(s)/πθ

dynamic motion

FORCES = UNBALANCED (tension, etc)

GUESS method

Givens

Units

Equation

Substitue

Solve

gravity (FORCE (ft))

tan(θ)

opp(θ)/adj(θ)

sin(θ)

opp/hyp

cos(θ)

adj/hyp

forces & formulas

Fbal² = (Fx)² + (Fy)²

θ (angle) → trig functions

Coriolis effect

deflection of a moving object's path caused by the rotation of the Earth or another rotating system

• veering Eastward from equator

• veering westward from North pole

What direction is earth’s motion?

COUNTERCLOCKWISE

Foucault pendulum - how it works

Pendulum hanging 4 stories down;

Pendulum stays in motion, area around it shifts with earth’s rotation

• 12 hrs = 180 degree rotation

Earth’s radius

4000 miles

Earth’s circumfrance

24,000 miles

Apex (top of motion) velocity

v = 0

Net force

difference between (unbalanced) opposing forces

• use when solving for acceleration in motion problems—Fnet=ma

Friction in motion problems (v and a)

acceleration (a) = CONSTANT

velocity (v) is NOT constant

Friction

force that opposes/resists motion–drag; air

• the faster objects move, the sronger it gets

intertia

object’s tendency to resist change in motion (mass)

• Smaller mass = faster acceleration

• More mass = more inertia

Earth’s diameter

8000 miles

Proofs the Earth orbits the sun

1. parallax

2. abberation of starlight

3. tides

4. seasons

What was Aristotle’s proof that the Earth orbits the Sun?

parallax