Astronomy Exam I

What is astronomy

the branch of science that deals with celestial objects in space and the physical universe as a whole

what is a nebula?

a ball of gas throughout space that gives off color and shapes

what is a supernova

a star whose life just recently ended, and the aftermath is what’s left of the star/planet

what is a blackhole?

an enormous amount of mass in a tiny pocket of space that creates a gravity well to where anthing that enters it, won’t come out, including light

how big is a blackhole?

6 ½ solar masses (or 6.5 times the size of our sun)

what is the difference between a star and a planet?

a star is a large, glowing ball of gas that generates energy through nuclear fusion in its core, while a planet is a big rock that orbits a star

on what horizon do stars rise and set?

rise in the east, set in the west

in the observable universe, how many stars are there?

10 billion trillion stars

how fast is the speed of light

186,000 miles per second

a star and all the objects that orbit it

solar system

the group of galaxies to which the milky way belongs

local group

the distance light can travel in one year is called a

lightyear

the largest known structures in the universe, consisting of many clusters of galaxies

supercluster

the average distance of earth from the sun

astronomical unit

the orbital motion of one object around another

revolution

a relatively small, icy object that orbits a star

comet

a cluster of galaxies

galaxy cluster

an object that orbits a star but is too small to qualify as a planet or dwarf planet

small solar system body

the plane of earth’s orbit around the sun

ecliptic plane

the amount by which a planet’s axis is tilted with respect to a line perpendicular to the ecliptic plane

axis tilt

the name given to the event thought to mark the birth of the universe

the big bang

the process which two or smaller nuclei slam together and make one larger nucleus

nuclear fusion

the portion of the milky way galaxy that is located relatively close to our sun

local solar neighborhood

the portion of the entire universe that, at least in principle, can be seen from earth

observable universe

the spinning of an object around its axis

satelite

the supercluster of galaxies to which the local group belongs

local supercluster

an object that orbits the sun and is massive enough for gravity to have made it a round shape but does not qualify as a planet because it’s not cleared its orbital neighborhood

a dwarf planet

alternative name for the universe

cosmos

local sky

the sky viewed from a particular location on earth

the portion of a total lunar eclipse during which the moon is fully within Earth’s umbral shadow

totality

the small circle upon which a planet moves while simultaneously going around a larger circle

epicycle

a lunar eclipse in which the moon becomes fully covered by earth’s umbral shadow

total lunar eclipse

a lunar eclipse during which the moon becomes only partially covered by earth’s umbral shadow

partial lunar eclipse

both the point on the celestial sphere where the ecliptic is farthest south of the celestial equator and the moment in time when the sun appears at that point each year (around december 21)

december solstice

the sun’s apparent annual path among the constellations

ecliptic

the gradual wobble of the axis of a rotating object around a vertical line

precession

a region of the sky

constellations

a solar eclipse during which the sun becomes only partially blocked by the disk of the moon

partial solar eclipse

what is the september equinox referred to as?

fall equinox

direction around the horizon from due north, measured clockwise in degrees

azimuth

the set of phases in which more and more of the visible face of the moon is becoming illuminated; the phases that come after new moon but before full moon

waxing

the apparent motion of a planet

apparent retrograde motion

the set of phases in which less and less of the visible face of the moon is illuminated;

waning

the dark central region of a shadow

umbra

a measure of the angle formed by extending imaginary lines outward from our eyes to span an object

angular size

both the point on the celestial sphere where the ecliptic is farthest north of the celestial equator

june solstice

the angular distance between the horizon and an object in the sky

altitude

periods during which lunar and solar eclipses can occur because the nodes of the moon’s orbit are aligned with the earth and the sun

eclipse seasons

a phase of the moon or a planet

lunar phase

what is the march equinox referred to as

spring equinox

an event that occurs when the moon’s shadow falls on earth, which can occur only at new moon

solar eclipse

1/60 of an arcminute

arcsecond

the point directly overhead, which has an altitude of 90 degrees

zenith

both the point in Pisces on the celestial sphere where the ecliptic crosses the celestial equator and the moment in time when the sun appears at that point each year (around march 21)

march equinox

the constellations on the celestial sphere through which the ecliptic passes

zodiac

the extension of earth’s equator onto the celestial sphere

celestial equator

a solar eclipse during which the sun becomes fully blocked by the disk of the moon

total solar eclipse

the time required for earth to complete exactly one orbit as measured against the stars

sidereal year

what is the december solstice referred to as?

winter solstice

an event that occurs when the moon passes through earth’s shadow, which can occur only at full moon

lunar eclipse

the two points in the moon’s orbit where it crosses the ecliptic plane

nodes

the apparent shifting of an object against the background, due to viewing it from different positions.

parallax

the period over which the basic pattern of eclipses repeats, which is about 18 years

saros cycle

the point on the celestial sphere directly above earth’s south pole

south celestial pole

a lunar eclipse during which the moon passes only within earth’s penumbral shadow and does not fall within the umbra

penumbral lunar eclipse

motion that is backward compared to the norm.

retrograde motion

the lighter, outlying regions of a shadow

penumbra

the point on the celestial sphere directly above earth’s north pole

north celestial pole

both the point in virgo on the celestial sphere where the ecliptic crosses the celestial equator and the moment in time when the sun appears at that point each year

september equinox

24 hours, which is the average time between appearances of the sun on the meridian

solar day

the circle on earth with latitude 23.5 degrees north, which marks the northernmost latitude at which the sun ever passes directly overhead

tropic of cancer

1/60 of 1 degree

1 arcminute

the apparent shift in the position of a nearby star that occurs as we view the star from different poitions in earth’s orbit of the sun each year

stellar parallax

the phase of the moon in which just a small portion of the visible face is illuminated by sunlight

crescent

the time of 23 hours 56 mins 4.09 secs between the successive appearance of any particular star on the meridian;

sidereal day

the meridian of longitude that passes through greenwich england; defined to be longitude 0 degrees

prime meridian

the angular north-south distance between earth’s equator and a location on earth surface

latitude

the imaginary sphere on which objects in the sky appear to reside when observed from earth

celestial sphere

a half-circle extending from your horizon due south, through your zenith, to your horizon due north

meridian

the rotation of an object that alwats shows the same face to an object that it is orbiting because its rotation period and orbital period are equal

synchronous rotation

the phase of the moon in which more than half but less than all of the visible face is illuminated by sunlight

gibbous

a boundary that divides what we can see from what we cannot see

horizon

the angular east-west distance between the prime meridian and location on earth’s surface

longitude

a principle used in science, that scientists should prefer two simpler of two models that agree equally well with observations

Occam’s Razor

the principle that, in the absence of net force, the total momentum of a system remains constant

conservation of momentum

the acceleration of a falling object

acceleration of gravity

a general pattern of thought that tends to shape scientific study during a particular time period

paradigm

the potential energy of mass (E = mc²)

mass-energy

energy that an object has by virtue of its position in a gravitational field

gravitational potential energy

the most commonly used temperature scale in science

kelvin

momentum attribute to rotation or revolution.

angular momentum

the sum of an orbiting object’s kinetic and gravitational energies

orbital energies

what is force?

anything that can cause a change in momentum

the speed necessary for an object to completely escape the gravity of a large body such as a moon, planet or star

escape velocity

the geocentric model of the universe developed in about 150 A.D.

Ptolemaic Model

Kepler’s First law

how planets move in elliptical orbits with the sun

Kepler’s second law

a planet covers the same area of space in the same amount of time no matter where it is in its orbit

Kepler’s third law

a planet’s orbital period is proportional to the size of it’s orbit

thermal energy

the collective kinetic energy

kinetic energy

energy of motion,