Exam One - Survey of the Universe

The scientist who first devised experimental tests to demonstrate the validity of the heliocentric model of the solar system was:

Galileo

Who used a telescope to look at celestial bodies starting in 1609?

Galileo

Who was the first person to see the moons of Jupiter?

Galileo

What was Kepler's Third Law?

The square of the time period for an orbit of a planet is proportional to cube of its average distance from Sun (in other words P2 is proportional to a3).

What color is our Sun?

White Appears white to the human eye because it is giving off equal amounts of all the visible colors of light.

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

YES OR NO: Are orbits ellipses?

YES

What is Newton's Law of Gravitation?

Two objects with mass will attract each other with this strength: F=(G)Mm/r^2

What specific event really made it possible for the three laws of planetary motion to be discovered?

Tycho Brahe died and his assistant was able to get full access to his data.

What two waves are the only waves that can travel through the atmosphere?

Visible and Radio

Imagine that Earth's orbit was changed to be a perfect circle around the Sun so that the distance to the Sun never changed over the course of one year. How would this effect our seasons?

We would experience seasons in essentially the same way we do now.

Valles Marineris is a:

large canyon on Mars.

What can we learn by analyzing starlight?

- A star's temperature - A star's chemical composition - How big a star is - If it is moving toward or away from you, and how fast

What are the characteristics of the Inner Planets?

- Small - Rocky - No rings - Orbit very close to the Sun - Has few moons

Things you can tell about stars by looking at their light include:

- Temperature - Size - Composition

There are three things waves can do that particles cannot:

- Transfer energy without transferring matter - Overlap (called interference) - Bend around corners (called diffraction)

Planets move 1. _____ when closer to the Sun and 2.______ when farther away.

1. Faster 2. Slower

Planets orbit the Sun, which is located at one of the 1. _______ of this figure. The line across the widest part of this figure is called its 2. ______.

1. Foci 2. Major Axis

Order the planets:

1. Mercury 2. Venus 3. Earth 4. Mars 5. Jupiter 6. Saturn 7. Uranus 8. Neptune

If you were to use 1 foot basketball to represent Sun, how far would it have to be from Earth to be accurate scale model?

110 feet

When England and the American colonies finally adopted the Gregorian calendar in 1752, what dramatic change had to be made?

12 days had to be dropped to bring the date and the seasons back into accord.

How long does it take to go from one noon to the next noon?

24 hours

About how far apart must the objects be placed to represent an accurate scale model of the Earth-Moon system?

30 feet

The MORE mass there is, the GREATER the force of ______.

ATTRACTION

An astronomer observes two ordinary stars that are the same size. The first one turns out to be twice as hot as the second. This means that the first one radiates:

About 16 times the energy of the second

f you can identify our north star, Polaris, in the night sky and measure it to be 50 degrees up from the horizon, what is your latitude?

About 50 degrees north

How long does it take to complete the full cycle of moon phases?

About one month

To go from a lower level in an atom to a higher level, an electron must...

Absorb a photon of energy

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

An ellipse

How big is Valles Marineris?

As big as the entire United States

There are two classes of smaller objects in heliocentric orbits:

Asteroids and Comets

What is Newton's Third Law?

For every action there is an equal and opposite reaction (or: the mutual actions of two bodies upon each other are always equal and act in opposite directions).

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

Force

Newton concluded that FORCE was:

GRAVITY

Big and hot objects have a _______ luminosity than small, cool objects.

GREATER

Who demonstrated a telescope with a magnification of 9× to government officials of the city-state of Venice?

Galileo

Where does light come from?

Light comes from the acceleration of charged particles (such as electrons and protons)

How do astronomers learn what elements are present in a given star?

Look at the absorption lines in its spectrum

Using the inverse-square law for light, if we know a star's distance and can easily measure its apparent brightness, we can determine the star's...

Luminosity

The widest diameter of the ellipse is called its:

Major Axis

What is the smallest of the Inner Planets?

Mercury

The Inner Planets:

Mercury, Venus, Earth, Mars - (terrestrial planets)

When is the full moon highest in the sky and most noticeable?

Midnight

The distance from the center of the ellipse to one end is called its:

Semimajor Axis

How long does it take to go from Sunrise to Sunset?

12 hours

What pair of objects would make a good scale model of the Earth and the Moon?

A basketball and a baseball

"Blackbody Curve"

A graph of an object's energy output versus wavelength.

Celestial Equator

A great circle on the celestial sphere 90° from the celestial poles; where the celestial sphere intersects the plane of Earth's equator

The time it takes for the Sun to return to the same place in our sky after the Earth has rotated once is called:

A solar day

Same brightness, but cooler temperature =

BIGGER STAR

Same wavelength, but more luminosity =

BIGGER STAR

Can any combinations of the following items be used to make an accurate scale model of Earth and the Sun?

Baseball for sun, grain of sand for Earth

Light behaves like:

Both a particle and a wave depending on how you observe it.

Who was considered the "greatest naked eye astronomer"?

Brache

Dwarf Planets:

Ceres, Pluto, Eris, Makemake

Who devised the first comprehensive heliocentric model to successfully explain retrograde motion?

Copernicus

What direction does the Earth rotate?

Counter-clockwise (eastward)

What was Kelper's First Law?

Each planet moves around the Sun in an orbit that is an ellipse, with the Sun at one focus of the ellipse.

What is the biggest of the Inner Planets?

Earth

What direction does the moon move each day?

Eastward

Some of the planets' orbits are almost circles and others are more stretched out. _________ is a measure of how round or squashed the shape of the orbit is.

Eccentricity

Even though ancient thinkers considered the circle to be the perfect form and thus imagined that the planets followed orbits that were circles, in fact the orbit of a planet is in the shape of an _______.

Ellipse

What is Newton's First Law?

Every object will continue to be in a state of rest or move at a constant speed in a straight line unless it is compelled to change by an outside force (pushing or pulling).

What is the Electromagnetic Wave Theory of Light?

Every vibrating charged object creates a disturbance (wave) in its own electromagnetic field. This disturbance spreads outward through the field at lightspeed (300,000 km/s)

TRUE OR FALSE: All the planets in the solar system are similar in terms of what materials they are mostly made of.

FALSE

TRUE OR FALSE: Infrared telescopes, which detect heat rays from the universe, must be kept as warm as possible.

FALSE

TRUE OR FALSE: The eight planets may be different in size, but they all have roughly the same density.

FALSE

TRUE OR FALSE: The smaller the ellipse, the slower the overall planet moves.

FALSE *The LARGER the ellipse

Mercury must have the shortest orbital period (88 Earth-days); thus, it has the ______ orbital speed.

HIGHEST

When it comes to our place in the solar system today, which model do we accept?

Heliocentric

Typically, astronomers express the right ascension of a star on the sky in what units?

Hours, Minutes, and Seconds

What scientist formulated three laws of motion and the law of gravitation - these laws describe the motion of our physical world?

Isaac Newton

What gives us our sense of weight?

It is this force of gravity on the surface of Earth

The Earth is closest to the Sun in which month of the year?

January

The Outer Planets:

Jupiter, Saturn, Uranus, Neptune - (gas giants)

The first radio telescope was built in the 1930's by...

Karl Jansky

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

New Moon

If we used a basketball to represent the Sun and a ping pong ball to represent Earth, and separated them by the distance, would we have an accurate scale model of Sun-Earth system?

No; Ping pong ball used for earth is too large.

What is the name of the largest volcano in the solar system that has a base larger than the state of Arizona.

Olympus Mons

How long does it take for the Sun to complete a circle around our sky on the ecliptic?

One year

Who developed a model that would account for retrograde motion?

Ptolemy

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

A writer of mystery novels wants to portray something gruesome happening just as the full moon is at its highest point in the sky. What time of day will the gruesome event occur?

Roughly midnight

TRUE OR FALSE: Light is an electromagnetic wave that is visible. There are other EM waves that are invisible.

TRUE

TRUE OR FALSE: The more craters we can count on the surface of a moon, the older that surface must be.

TRUE

TRUE OR FALSE: To improve the resolution of telescopes on Earth, astronomers use adaptive optics.

TRUE

TRUE OR FALSE: Today, when astronomers use the term constellation, they mean one of 88 boxes into which they divide the sky.

TRUE

TRUE OR FALSE: We define a planet's orbital period, (P), as the time it takes a planet to travel once around the Sun.

TRUE

What causes the phases of the moon?

The Sun is lighting up different fractions of the part of the Moon we see from Earth.

The strip of the sky through which the Sun, the Moon, and the bright planets appear to move in the course of a year is called:

The Zodiac

The Astronomical Unit (AU) as defined by astronomers is...

The average distance between the Earth and the Sun

What is Newton's Second Law?

The change of motion of a body is proportional to and in the direction of the force acting on it. Force = mass x acceleration

A light-year is...

The distance that light travels in one year

Wien's Law

The higher the temperature of a body the shorter the wavelength of it's maximum radiation. (hotter = shorter wavelength)

Why do we have a regular day and night cycle on Earth?

The planet rotates on it's axis

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

What is NOT one of Kepler's Three Laws of planetary motion?

The planets orbit the Sun at a speed that is proportional to its mass.

Zenith

The point on the celestial sphere opposite the direction of gravity; point directly above the observer

Stefan-Boltzmann Law:

The relationship stating that an object emits energy at a rate proportional to the fourth power of its temperature, in Kelvins.

What is retrograde motion?

The retrograde motion is the apparent motion of a planet to move in a direction opposite (westward) to that of other bodies within its system.

What was Kelper's Second Law?

The straight line joining a planet and the Sun sweeps out equal areas in space in equal intervals of time.

Which of the following statements is true about the location of the Sun at sunrise on the days of the Spring and Autumn equinoxes?

The sun will rise directly to the East.

What is Lumonsity?

The total energy (light) emitted by an object in each second

Gravitational attraction between two bodies must be proportional to _________.

Their MASS

Does this mean two Sun's place side by side would fit inside Moon's orbit around Earth, or that two moon orbits placed side by side would fit across sun?

This means two Moons would fit side by side inside the Sun.