question

hypothesis

answer

educated guess

question

Hallmark of Science #1

answer

a scientific model cannot just include divine intervention: should rely solely on natural causes

question

Hallmark of Science #2

answer

Occam's Razor: the simplest explanation that predicts the phenomenon equally well

question

Hallmark of Science #3

answer

a scientific model must make *testable predictions* about natural phenomena that would force us to revise or abandon the model if the predictions do not *agree with observations*

question

A scientific theory must:

answer

1) explain a wide variety of observations with simple principles 2) supported by a large, compelling, body of evidence 3) must not have failed any crucial test of validity

question

Astrology v Astronomy

answer

astrology: search for hidden influences on human lives based on the positions of planets and stars in the sky astronomy: learning about how stars, planets, other celestial objects work

question

sidereal

answer

relative to the stars

question

sidereal day (time?)

answer

- the time it takes *any star* to make a circuit of the local sky *(23 hr, 56 min)* - takes for the Earth to complete one rotation about its axis with respect to the 'fixed' stars.

question

solar day (and time?)

answer

- the time it takes the *sun* to make a circuit of the local sky *(24 hours)* - the time it takes for the Earth to rotate about its axis so that the Sun appears in the same position in the sky.

question

difference between sidereal and solar day

answer

- one full rotation of the Earth represents a sidereal day and returns you to pointing in your original direction, but you need to rotate a little extra to return to pointing at the Sun - so because Earth travels about 1 degree per day around its orbit, so a solar day requires about 361 degrees of rotation ( one more degree to face the sun to make it 1 solar day )

question

synodic month

answer

the amount of time it takes the moon to repeat it's phases (29.5 days)

question

sidereal month

answer

the amount of time it takes the Moon to complete one orbit around the Earth with respect to the background stars *(27.3 days)*

question

Earth travels about ... degrees per month around it's orbit. so from one new moon to the next, the moon must complete a ... orbit

answer

30; full 360 degree

question

sidereal year

answer

the amount of time it takes the Earth to orbit the Sun once with respect to the background stars

question

tropical year (time difference between sidereal year?)

answer

the amount of time it takes the Earth to go from the March equinox one year to the March equinox the next year *(20 min difference between sidereal year)*

question

sidereal period

answer

the amount of time it takes any planet (other than Earth) to orbit the Sun, measured with respect to the background stars

question

synodic period

answer

the time it takes for a planet to be aligned with the Sun in our sky until it is again aligned similarly

question

inferior conjunction with an inferior planet

answer

the planet is located in between the sun and the earth

question

superior conjunction with an inferior planet

answer

more distance conjunction.. the planet is located on the opposite side of the sun, but in line with the Earth and Sun

question

greatest eastern/western elongations

answer

*see the planet at it's greatest angular distance away from the sun*; there is a right angle between the planet and the sun: a triangle between the sun, planet, and Earth (straight line is between sun and earth)

question

conjunction with a superior planet

answer

the planet is on the opposite side of the sun, in line with the sun, and Earth

question

opposition with a superior planet

answer

the Earth is in between the sun and the other planet

question

quadrature

answer

the earth and sun make a 90 degree angle, the other planet and Earth make a straight line that is the "height" of the triangle, the "base" is the straight line between the sun and the Earth

question

transit

answer

when mercury or venus passes in front of the sun

question

Apparent solar time and it's negatives

answer

Noon is the time when the shadow on a sundial is shortest. - can't tell at night - can't tell someone in any other location than you

question

Mean solar time

answer

Noon is set to the average time when the shadow on a sundial is shortest. (Accounts for subtle differences in day lengths.)

question

Standard time

answer

Mean solar time in the center of your time zone.

question

Universal time

answer

- Mean solar time at 0 degrees longitude (Greenwich, England) - Useful standard for navigation and astronomy

question

When and why do we have leap years?

answer

- Because there are about 365.25 days in a year, a calendar based on 365 days will get out of synch with the seasons - Solution: Add one day every four years! - they are apart of the Julian calendar

question

... adds even more subtle corrections to stop the equinoxes from drifting.

answer

The Gregorian calendar

question

we use ... and ... to pinpoint locations in the local sky

answer

altitude and direction

question

we use ... and ... to pinpoint locations on Earth

answer

latitude and longitude

question

we use ... and ... to pinpoint locations on the celestial sphere

answer

declination and right ascension

question

Declination

answer

"longitude" on the celestial sphere. 0 degrees at celestial equator, +/- rather than north/south.

question

Right ascension

answer

"latitude" on the celestial sphere. 0 degrees at March equinox, measured in hours and minutes east/west

question

The Sky at the North Pole: Stars move .. A star's declination is ... ... of stars are circumpolar

answer

- Stars move parallel to your horizon. - *A star's declination is equal to its altitude.* - 100% of stars are circumpolar

question

The Sky at the Equator Stars move... ... stars are circumpolar

answer

- Stars move perpendicular to your horizon. - no stars are circumpolar

question

Stars with dec = 0 degrees rise due ..., cross the meridian at the ..., and set due ...

answer

east; zenith; west

question

Stars with dec > 0 degrees rise ... of due ... and set ... of due ...

answer

north; east; north; west

question

what fraction of the stars in the sky are visible at the equator?

answer

all of them over the course of the year

question

what range of declination can we see at the equator? what are endpoints of declination?

answer

all ranges; 90 degrees

question

Stars at high dec will be ...

answer

circumpolar.

question

Stars at low dec will ...

answer

rise and set at an angle to your horizon.

question

intermediate latitudes...

answer

both circumpolar and non circumpolar stars

question

how to find latitude if given celestial equator altitude

answer

- on the equinox's we know that the sun crosses the celestial equator... so use this number and add it to zenith (90) then subtract from 180 to find the latitude you're at - or if you're just given path of solstice for ex) 73.5 degrees - 23.5 degrees = 50 degrees .. then do the same procedure

question

Over the course of the year, the Sun's ... changes.

answer

declination

question

Because the Earth's axis tilt is roughly 23.5o, there are several "special" latitudes.

answer

North pole latitude +90 degrees Arctic circle latitude +66.5 degrees Tropic of cancer latitude +23.5 degrees equator 0 degrees tropic of capricorn latitude -23.5 degrees antarctic circle latitude -66.5 degrees south pole latitude - 90 degrees

question

The Sun circles the ... on the equinoxes. The Sun circles the sky at an altitude of ... on the summer solstice. The Sun circles ... below the horizon on the winter solstice.

answer

horizon; 23.5; 23.5

question

The Arctic and Antarctic circles represent the latitudes above (Arctic) or below (Antarctic) which there will be more than ... during the summer and ... during the winter.

answer

24 hours of consecutive sunlight; darkness

question

You can also determine your latitude from the altitude of any star or the Sun...

answer

as it crosses the meridian

question

- star x has declination +10 degrees - star has angle up from the south of 60 degrees (meridian altitude = 60) (find latitude)

answer

- *meridian altitude = altitude of CE + star's declination * - answer = 50 degrees

question

how can you determine longitude?

answer

1. suppose your apparent solar time is 1pm, meaning the sun crossed your meridian 1 hour ago 2. you learn that it is 3pm right now in Greenwich, meaning your local time is 2 hours behind greenwich 3. because each hour represents 15 degrees of longitude you are at longitude 2x15 = 30 degrees W ( you know it's west because it's *an earlier time* - the further west you are the further you are towards an earlier time)

question

To determine your longitude, you need to know both...

answer

the apparent solar time and the time at your known longitude.

question

1. june solstice 2. sun on meridian at 50 degrees in the south 3. universal clock tells you time is 15 hours *if you already have the altitude of the celestial equator just add to 90 and subtract to 180... if you're given this type of information you must use formula to find the altitude of CE*

answer

1. (tells you where sun is on celestial sphere) sun's declination = +23.5 degrees 2. meridian altitude of object - tells you that local time is 12:00 if on the meridian 3. meridian altitude = alt of CE + star's declination (50 - 23.5 = 26.5) 26.5 is altitude of celestial equator - now that we know how high celestial equator is.. we can find latitude = 63.5 degrees (90 +26.5 = x 180 -x = 63.5) - if UT is 3 hours ahead of us (because on meridian when sun is directly over head it is 12:00), we must be 3 hours to the West of their location, or 45 degrees to the west 15 degrees/hr = 45 W (west because their time is ahead of ours)

question

Consider the statement "there is no gravity in space." True or False and WHY?

answer

Completely false because there is always gravity at some point from the center of earth, stars, solar system, the Milky Way, etc.

question

True or false, suppose you can enter a vacuum chamber on earth, that is, a chamber with no air inside it. Inside this chamber, if you dropped a hammer and a feather from the same height at the same time, both was at the bottom at the same time.

answer

True being there is no air friction or anything in the way of both objects they will hit at the same time

question

6 gees of acceleration = how many m/s^2

answer

6 x 9.8 m/s^2 = 58.8 m/s^2

question

Speed

answer

Rate at which object moves speed = distance/time

question

velocity

answer

speed and direction

question

acceleration

answer

rate of change in speed/time (m/s^2)

question

All falling objects accelerate at the same rate not counting...

answer

friction of air resistance

question

On earth g = (Which means what?)

answer

10 m/s^2 (speed increases 10 m/s with each second of falling.)

question

Galileo showed the g is the same for...

answer

all falling objects, regardless of their mass

question

Momentum =

answer

mass x velocity

question

A net force changes ..., which generally means...

answer

momentum; an acceleration (change in velocity).

question

angular momentum

answer

Rotational momentum of a spinning or orbiting object

question

is net forced described here? 1. A car coming to a stop 2. A bus speeding up 3. An elevator moving up at constant speed 4. A bicycle going around a curve 5. A moon orbiting Jupiter

answer

1. Y 2. Y 3. N 4. Y 5. Y ( speed or direction must change )

question

mass

answer

a measure of the amount of matter in an object

question

weight

answer

the force that a scale exerts upon an object

question

You are ... in free-fall!

answer

weightless

question

On the moon... (Weight/mass)

answer

My weight is less, my mass is the same.

question

Is there gravity in space?

answer

Yes

question

Weightlessness is due to...

answer

constant free fall

question

Angular momentum describes ...

answer

objects that are spinning or moving in circles.

question

torque

answer

needed to change an object's angular momentum.

question

your weight under 6 g's v. 1 g

answer

weight increases by 6x

question

weight =

answer

mass x gravity

question

force =

answer

mass x acceleration

question

Newton realized the same physical laws that operate on Earth also ...

answer

operate in the heavens

question

Newton discovered laws of ... and ...

answer

motion; gravity

question

Newton's first law of motion

answer

An object moves at constant velocity unless a net force acts to change its speed or direction

question

Newton's Second Law of Motion

answer

There are two equivalent ways to express Newton's Second Law of Motion - Force = mass x acceleration - Force = rate of change in momentum

question

Newton's Third Law of Motion

answer

For every force, there is always an equal and opposite reaction force

question

How does the force the Earth exerts on you compare with the force you exert on it?

answer

Earth and you exert equal and opposite forces on each other

question

A compact car and a Mack truck have a head-on collision. Are the following true or false? 1. The force of the car on the truck is equal and opposite to the force of the truck on the car. 2. The momentum transferred from the truck to the car is equal and opposite to the momentum transferred from the car to the truck. 3. The change of velocity of the car is the same as the change of velocity of the truck.

answer

1. The force of the car on the truck is equal and opposite to the force of the truck on the car. T 2. The momentum transferred from the truck to the car is equal and opposite to the momentum transferred from the car to the truck. T 3. The change of velocity of the car is the same as the change of velocity of the truck. F

question

Objects continue at constant velocity because of

answer

conservation of momentum.

question

The total momentum of interacting objects cannot change unless ...

answer

an external force is acting on them.

question

Interacting objects exchange momentum ...

answer

through equal and opposite forces.

question

Angular momentum is conserved as

answer

Earth orbits the sun

question

distance is greater so (velocity?)

answer

velocity is smaller

question

distance is smaller so (velocity?)

answer

velocity is greater

question

Angular momentum =

answer

mass x velocity x radius

question

The angular momentum of an object cannot change

answer

unless an external twisting force (torque) is acting on it.

question

Earth experiences no twisting force as it orbits the Sun, so

answer

its rotation and orbit will continue indefinitely.

question

Where do objects get their energy?

answer

Energy makes matter move. Energy is conserved, but it can: transfer from one object to another and change in form

question

Kinetic (...) Radiative (...) Potential (...)

answer

motion. light. stored

question

thermal energy

answer

The collective kinetic energy of many particles (for example, in a rock, in air, in water)

question

Thermal energy is related to .. but it is NOT the same

answer

temperature

question

Temperature

answer

the average kinetic energy of the many particles in a substance.

question

thermal energy depends on

answer

temperature AND density because a higher average kinetic energy for the particles means a higher total energy and the more dense the more molecules that the substance contains

question

gravitational potential energy on earth depends on..

answer

object's mass (m) strength of gravity (g) distance object could potentially fall

question

In space, an object or gas cloud has more gravitational energy when

answer

it is spread out than when it contracts.

question

A contracting cloud converts...

answer

gravitational potential energy to thermal energy

question

Mass itself is a form of...

answer

potential energy called mass-energy (E=Mc^2)

question

3 rules of conservation of energy

answer

- Energy can be neither created nor destroyed. - It can change form or be exchanged between objects. - The total energy content in an isolated system is always the same.

question

The universal law of gravitation:

answer

1. Every mass attracts every other mass. 2. Attraction is directly proportional to the product of their masses. (Doubling mass, doubles gravity) 3. Attraction is inversely proportional to the square of the distance between their centers. (Doubling distance, weakens force of gravity - inverse square law)

question

Kepler's laws apply to..., not just planets.

answer

all orbiting objects

question

Bound orbits

answer

Orbits in which an object goes around another object over and over again

question

Unbound orbits

answer

Paths that bring an object close to another object just once

question

Because of momentum conservation, orbiting objects orbit around ...

answer

their center of mass.

question

Newton's laws of gravity and motion showed that the relationship between the ... and ... of a system tells us ...

answer

orbital period; average orbital distance of a system; the total mass of the system.

question

what is total orbital energy

answer

gravitational energy + kinetic energy

question

Total orbital energy (gravitational + kinetic) stays constant if

answer

there is no external force

question

Gravitational encounter

answer

Two objects pass each other enough that each can feel the effects of the other's gravity

question

Atmospheric drag

answer

Friction causing objects to lose orbital energy

question

Escape velocity

answer

An object that gains orbital energy moves out of one orbit and into another orbit with a higher average altitude

question

Total orbital energy stays...

answer

constant

question

farther from the sun (orbital distance and gravitational potential energy?)

answer

larger orbital distance means more gravitational potential energy

question

slower orbital speed means (kinetic energy)

answer

less kinetic energy

question

faster orbital speed means (kinetic energy)

answer

more kinetic energy

question

smaller orbital distance means (gravitational potential energy?)

answer

less gravitational potential energy

question

what can make an object gain or lose orbital energy?

answer

- Friction or atmospheric drag - A gravitational encounter

question

If an object gains enough orbital energy, it may ...

answer

escape (change from a bound to unbound orbit).

question

Moon's gravity pulls harder on ...

answer

near side of Earth than on far side.

question

difference in moon's gravitation pull stretches...

answer

Earth

question

The ... also has a small tidal effect on Earth.

answer

Sun; but because it's so distant, it isn't very much

question

Tidal friction gradually slows ... (and makes the Moon...)

answer

Earth's rotation; get farther from Earth

question

spring tides occur at

answer

new and full moon

question

neap tides occur at

answer

first and third quarter moon

question

The Moon once orbited faster (or slower); ... caused it to ''lock'' in synchronous rotation.

answer

tidal friction

question

Conservation of momentum

answer

States that there are no external forces, the total momentum is conserved

question

Momentum =

answer

Mass x velocity

question

Conservation of angular momentum

answer

As long as there is no external torque, the total angular momentum of a set of interacting objects cannot change

question

Torque

answer

Twisting force

question

Angular momentum =

answer

M x v x r (Mass, orbital velocity, and radius of orbit or distance to sun)

question

Angular momentum explains why

answer

We see so many spinning disks in the universe

question

Law of conservation of energy

answer

Energy cannot appear out of nowhere; objects can gain or lose energy only by exchanging energy with other objects

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