Astronomy Study Set

Light travels 3 x 10^5 meters every second. That number in words is

300,000

Lunar Eclipse

FULL MOON, when it's farthest from the sun

The scientist who formulated the three laws of planetary motion by analyzing the data on the precise location of planets in the sky was

Johannes Kepler

The planet in our solar system with the shortest period of revolution is:

Mercury

Solar Eclipse

NEW MOON, when it's closest to the sun

Of these, which is the largest?

The Universe

Umbra

The darkest part of a shadow

What is Kepler's first law?

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

What's Kepler's second law?

The planets speed up as they get closer to the Sun, and slow down as they pull away

Universe

The sum total of all matter and energy; that is, everything within and between all galaxies

The 17th century astronomer who kept a roughly 20 year continuous record of the positions of the Sun, Moon, and planets was

Tycho Brahe

Which of the following has the greatest density?

a cubic meter of lead

Newton showed that to change the direction in which an object is moving, one needs to apply

a force

Galaxy Cluster

a group of galaxies being held together by gravity

The location of the Earth in the Milky Way Galaxy is

a little less than 30,000 LY from the center

constellation

a patch of sky (or sector) that gets the name, rather than the set of stars themselves

Asterism

a subset of stars that form a widely recognized shape (ex: Big Dipper)

From a particular location on Earth, why can we see many more total eclipses of the Moon than total eclipses of the Sun?

a total lunar eclipse is visible over a much larger part of the Earth's surface than a total solar eclipse

We now know that the orbit of a stable planet around a star like the Sun is always in the shape of

an ellipse

If you could see the new moon, at what time of day (roughly) would it rise?

at sunrise

Galaxy

big island of stars in space, all held together by gravity and orbiting a common center

When the authors of our textbook say that astronomers are like police detectives trying to solve crimes, they are explaining that

both astronomers and detectives must test their hypotheses against any evidence that they gather

How did Eratosthenes measure the size of the Earth?

by measuring the height of the Sun in the sky on the same day in two cities at different latitudes

The minimum speed required to launch an object so that it remains the same distance above the ground and just falls around the Earth is called:

circular satellite velocity

The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called

constellations

According to Kepler's third law, there is a relationship between the time a planet takes to revolve around the Sun and its

distance from the sun

The way scientists know that a hypothesis in astronomy is a reasonable description of nature is to

do experiments and observations about the predictions of the hypothesis

To leave the gravitational pull of the Earth, and explore other planets, satellites must have at least:

escape velocity

By the term universe, astronomers mean

everything that we can observe

Which of the following statements about eclipses of the Sun is true?

for a total eclipse of the Sun to happen, the Moon must get directly in front of the Sun, as seen from Earth

During what phase of the Moon is the Moon up only during the night hours and all night long?

full moon

What phase of the Moon must it be to have a lunar eclipse?

full moon

Angular Momentum

if the shape of an object changes while it is spinning, becomes more compact, it spins faster, momentum has to do with how spread out the object is (ex: figure skater)

Which of the following statements about the force of gravity is FALSE?

its strength is inversely proportional to the mass: the more mass, the less gravity

In Newton's Law of Gravity, the force of gravity goes up as the

more than one of the above

When a planet, in its orbit, is closer to the Sun, it

moves faster than average

For a person who lives at a latitude of +40°, when is the Sun directly overhead at noon?

never

What phase of the Moon must it be to have a solar eclipse?

new moon

What's Kepler's third law?

p^2=a^3

When a comet like Comet Hale-Bopp comes closest to the Sun in its orbit, we say that it is at:

perihelion

When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it

retrograde motion (ex: passing car on highway)

When the Sun and Moon are lined up and pull together, the tides they raise are called:

spring tides

A partial lunar eclipse occurs when

the Earth passes through part of the Moon's shadow

The south celestial pole and the north celestial pole lie in the sky directly above

the Earths axis

What causes the seasons?

the Earths tilt, when the sun is higher in the sky, the sunlight is more direct and the sun is in the sky for longer, (turn heat up higher and longer)

The Earth's escape speed (the speed you need to get away forever) is about 25,000 miles per hour. Escape speed depends on the gravity of the object trying to hold the spacecraft from escaping. Based on your understanding of gravity, how will the escape speed from the Moon compare to the escape speed from Earth?

the Moon's escape speed will be smaller than Earth's

Solar and lunar eclipses are rare because

the Moon's orbital plane is tipped by 5.2° relative to Earth's orbital plane

Which of the following is NOT an argument for showing that the Earth must be round

the Sun is seen blocking different constellations in the course of a year

Why does the Moon show phases in the course of a month?

the angle the Moon makes with the Sun changes and we see differing amounts of reflected sunlight

The Astronomical Unit (AU) as defined by astronomers is

the average distance between the Earth and sun

A light year is

the distance light travels in one year

In the Northern Hemisphere, the altitude (height in degrees above the horizon) of the North Star is always roughly equal to the

the latitude of the observer

What would happen if the Earth's tilt was at extremes

the more extreme the tilt, the more intense the seasons would be

Altitude of the celestial pole above the horizon always matches...

the observers latitude on Earth

Prograde

the planet looks like it's going forward

The celestial sphere turns once around each day because

the planet on which we live is rotating

In Ptolemy's system the planets orbit the Earth and not the Sun. How did the system explain the retrograde motion of planets like Jupiter?

the planets moved on a small circle whose center, in turn, circled a point near the Earth

Zenith

the point directly over your head

North Celestial Pole

the projection of Earths geographic North Pole into space

South Celestial Pole

the projection of Earths geographic South Pole into space

Celestial Equator

the projection of the Earth's equator into space

The period of the moon's rotation on its axis is

the same as its revolution around the Earth

Which of the following is NOT a result of the Earth's precession?

the stars twinkle when seen from the surface of planet Earth

Orbital Period

the time it takes to orbit

All molecules (like molecules of water or carbon dioxide) are made up of

two or more atoms

A solar eclipse occurs

whenever there is a NEW moon AND the moon is on the ecliptic

Horizon

where the dome of the sky that you can see meets the ground from your point of view

A single star in the process of forming starts by spinning slowly (while it is quite large and relatively cool.) As the star collapses under the pull of its own gravity, its size decreases. As a result, its rate of spinning

will increase

Earth is closest to the Sun when the Northern Hemisphere experiences

winter (think of the opposite)

The point in the sky directly above your head at any given time is called the

zenith