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Astro 101 Exam 1: Introduction to Astronomy - University of Michigan, Exams of Astronomy

A comprehensive overview of key concepts in introductory astronomy, covering topics such as the solar system, planetary motion, stars, galaxies, and the universe. It includes multiple-choice questions and answers, making it a valuable resource for students preparing for an exam in introductory astronomy.

Typology: Exams

2023/2024

Available from 02/19/2025

lenah-smith
lenah-smith šŸ‡ŗšŸ‡ø

632 documents

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Astro 101 - Exam 1 UMich with 100%
correct answers
What is our planet in the solar system
part of the solar system, in the milky way galaxy, in local group of galaxies, in local supercluster
how did we come to be
the Big Bang which produced hydrogen and helium
where did elements come from
the big bang produced H and He, which are the base of other elements constructed in stars
how old are we in comparison to the universe
human civilization is a second of a year, and our own life is a fraction of a second
how is earth moving
earth rotates on an axis once a day and orbits the Sun at 1 AU (150 million kilometers)
how can we specify the position of an object in the local sky
altitude above the horizon and direction along the horizon
why do stars rise and set
because of Earth's rotation
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Astro 101 - Exam 1 UMich with 100%

correct answers

What is our planet in the solar system

part of the solar system, in the milky way galaxy, in local group of galaxies, in local supercluster

how did we come to be

the Big Bang which produced hydrogen and helium

where did elements come from

the big bang produced H and He, which are the base of other elements constructed in stars

how old are we in comparison to the universe

human civilization is a second of a year, and our own life is a fraction of a second

how is earth moving

earth rotates on an axis once a day and orbits the Sun at 1 AU (150 million kilometers)

how can we specify the position of an object in the local sky

altitude above the horizon and direction along the horizon

why do stars rise and set

because of Earth's rotation

why do the constellations we see depend on latitude and time of year

your location determines which constellations are hidden by earth

the time of year determines the location of the Sun and the celestial sphere

what causes the seasons

the tilt of the Earth's axis

what are the summer and winter solstices

when the Northern hemisphere gets its most and least direction sunlight

what are the spring and fall equinoxes

when both hemispheres get direct and equal sunlight

how does the orientation of Earth's axis change with time

the tilt remains about 23.5 degrees (so the season pattern is not affected) but the the cycle slowly and subtly changes the orientation of earth's axis every 26,000 years

why do we see phases of the moon

half the Moon is lit by the Sun, half is in shadow, and its appearance to us is determined by the relative positions of the Sun, Moon, and Earth

each planet orbits the sun in a path called an ellipse with the sun at one focus

Kepler's Second Law of Planetary Motion

As a planet moves around its orbit it sweeps out equal areas in equal times.

a planet travels faster when it is nearer to the sun and slower when it is farther form the sun

Kepler's Third Law of Planetary Motion

The square of the orbital period of any satellite is proportional to the cube of its average distance from its central mass

More distant planets orbit the Sun at slower average speeds: p2 = a3 (p= orbital period in years and a= average distance from Sun in AU)

Galileo

his experiments and observations overcame the remaining objections to the Sun-centered solar system model

what is a scientific theory

A model that explains a wide variety of observations in terms of a few general principles and that has survived repeated and varied testing

how is astrology different from astronomy

  • Astronomy is the scientific study of the universe

and the celestial objects within it

  • Astrology assumes that the positions of celestial

objects influence human events

speed

distance/time

rate at which objects move

velocity

Speed in a given direction

Acceleration

rate of change of velocity

Momentum

mass x velocity

force

causes change in moment, produces acceleration

mass

the quantity of matter in an object

conservation of angular momentum

keeps a planet rotating and orbiting the Sun

conservation of energy

Energy cannot be created or destroyed, but it can be transformed from one form to another

types of energy

kinetic, potential, radiative

How do gravity and energy together allow us to understand orbits

Change in total energy is needed to change orbit

Add enough energy (escape velocity) and object leaves

How does gravity cause tides?

Moon's gravity pulls harder on near side of Earth than on far side

Difference in Moon's gravitational pull stretches Earth

the moon's gravity stretches earth and its oceans

Why do all objects fall at the same rate?

Mass of object in Newton's second law exactly cancels mass in law of gravitation

light is

a form of energy

light comes

in many colors than combine to form white light

how do light and matter interact

Matter can emit light, absorb light, transmit light, and reflect (or scatter) light.

Interactions between light and matter determine the appearance of everything we see

light emission

matter releases energy as light

light absorption

matter takes energy from light

light transmission

matter allows light to pass through it

light reflection (scatter)

matter repels light in another direction

what is light

As temperature rises, a substance transforms from a solid to a liquid to a gas, then the molecules can dissociate into atoms

Stripping of electrons from atoms (ionization) turns the substance into a plasma

how is energy stored in atoms

the energies of electrons in atoms correspond to particular energy levels

atoms gain and lose energy only in amounts corresponding to particular changes in energy levels

what are the three basic type of spectra

Continuous spectrum, emission line spectrum, absorption line spectrum

how does light tell us what things are made of

chemical fingerprints

-- each type of atom has a unique set of energy levels

-- each transition corresponds to a unique photon energy, frequency, and wavelength

-- downward transitions produce emission lines; upward transitions produce absorption lines

how does light tell us the temperature of planets and stars

Nearly all large or dense objects emit a continuous spectrum that depends on temperature

The spectrum of that thermal radiation tells us the object's temperature

blue light

hotter, closer

red light

cooler, further

light spectrum from shortest to longest wavelength

gamma rays, x-rays, ultraviolet, visible light, infrared, microwaves, radio waves

how does light tell us the speed of a distant object

the Doppler effect tells us how fast an object is moving toward or away from us

closer = higher pitch (blue light)

further = lower pitch (red light)

star

large, glowing ball of gas that generates heat and light through nuclear fusion

planet

a moderately large object that orbits a star, Ade spherical by gravity, (mostly) shines by reflected light

moon (or satellite)

light year

the distance light travels in one year, about 6 trillion miles (10 trillion km)

atoms

Building blocks of all chemical elements

where do we come form

we are "star stuff"

how we came to be

Big Bang, first stars, stellar death, 2nd gen stars

Big Bang

birth of universe, creation of H and He

first stars

fusion creates heavy elements

stellar death

seeds space with heavy elements

2nd gen stars

solar systems with planets

the earth rotates around its axis...

once every day (rotation)

Earth orbits around the sun

once every year (orbit)

How do galaxies move within the universe?

Galaxies are carried along with the expansion of the universe

Hubble discovered that

all galaxies outside our Local Group are moving away from us

the more distant the galaxy, the faster it is racing away

(we live in an expanding universe)

distant galaxies are

moving away from us

the further away galaxies are

the faster they are moving away from us

celestial equator

the extension of Earth's equator onto the celestial sphere

we measure the sky using

angles

An object's angular size appears ___ if it is farther away

smaller

altitude

(angle) above horizon

direction

along horizon

meridian

line passing through zenith and connecting N and S points on horizon

zenith

the point directly overhead

horizon

all points 90 degrees away from zenith

why do stars rise and set

Earth rotates west to east, so stars appear to circle from east to west

earth's daily motion

As the Earth rotates, the sky appears to rotate in the opposite direction around the celestial poles

If you are standing at the poles, nothing rises or sets

If you are standing at the equator, everything rises & sets 90 degrees to the horizon

We cannot see stars near the

south celestial pole

Stars near the north celestial pole are

circumpolar and never set

latitude

position north or south of equator

Longitude

the moon we see comes from

the moon's orbit (months)

Seasons are caused by

The tilt of the Earth's axis and how it affects the directness of sunlight

Summer Solstice

June (highest path)

winter solstice

december (lowest path)

spring equinox

march (precisely due)

fall equinox

September (precisely due)

eclipse

when either passes through the other's shadow

when the moon's orbit intersects the ecliptic (node)

new moon

solar eclipse

must be in the moon's shadow to see it

full moon

lunar eclipse

retrograde motion

The apparent motion of the planets when they appear to move backwards (westward) with respect to the stars from the direction that they move ordinarily

scientific thinking is based on

everyday ideas of observation and trial-and-error experiments

How did the Greeks explain planetary motion

earth at the center

objects move on perfect spheres or circles around earth

the Ptolemaic model