Astronomy Midterm Study Guide

Put 6.438 x 10^2 in standard notation.

643.8

Why does a bowling ball and a feather fall at the same rate when air resistance is removed?

Because the force of gravity is stronger on the bowling ball.

Which of the following in not a conservation law in our universe?

Conservation of Matter.

Residents of the Southern Hemisphere cannot see the same stars as we do because

Earth itself is in the way.

Which of the following is NOT a unit of length?

Kilogram

The Solar System is:

One of many star systems in the Milky Way galaxy.

Which of the following objects is accelerating?

a ball moving at a constant rate around a circular hoop

The Big Bang Theory:

our understanding of the beginning of the universe.

Astronauts on the ISS in orbit around Earth feel weightless because

they are free falling around Earth.

Two objects of different mass are dropped simultaneously from the same height and land at the same time. This happened because:

they both have the same acceleration due to gravity and have negligible wind resistance.

Chris, a space shuttle astronaut, is involved in repairing a satellite while in Earth orbit, but he becomes separated from the space shuttle. He has a massive wrench in his hand. What should he do to return to the space shuttle?

throw the wrench in exactly the opposite direction from the space shuttle

The driver of a car who suddenly brakes for a stoplight is

undergoing acceleration because the car is slowing down.

If it is 6:00 pm where you live and you see a full Moon, it is

"rising" from the eastern horizon.

If Earth were twice as far from the Sun as it is now, the gravitational force between Earth and the Sun would be

0.25 times as great.

A light wave has frequency 3 × 1019 Hz. What is its wavelength?

1 × 10-11 m

List the following objects in order of increasing thermal energy (from lowest to highest).

1) The air in an oven at 322 degrees Celsius 2)A pot of boiling water 3)The Earth 4)The Sun 5)Venus

List the following astronomical objects in order of their size from smallest to largest.

1) The comet that killed the dinosaurs 2) Pluto 3) The Moon 4) The Earth 5) The orbit of the Moon around the Earth 6) The Sun 7) The Solar System 8) The Milky Way 9) The Virgo Cluster 10) The Laniakea Supercluster

An astronaut travels to a planet 100 light years away at a speed of 99.99% the speed of light (v = 0.9999 c, gamma = 71). How many years does this trip take according to the astronaut?

1.41

In the not so distant future we can conceivably build a space ship that will travel 0.25 times the speed of light. How long would it take this ship to reach the Andromeda galaxy?

10 million years

The age of the Universe is:

13.7 billion years old.

Careful analysis of the orbits of asteroids and comets far from the sun, suggests that there is ninth planet in our solar system (nicknamed Planet-X). The data predicts the orbit of Planet-X to be and average distance of 600 AU away from the Sun (20x further than Neptune!). How long is it estimated to take Planet-X to make one full orbit around the Sun?

15,000 years.

What will be the acceleration of a 40-kilogram object that is pushed with a net force of 80 newtons?

2 m/s^2

There are an estimated 1 trillion galaxies in our observable universe. The Milky Way galaxy contains about 200 billion stars. Using this data, estimate the number of stars in the observable universe.

2 x 10^23

The number 384,000,000 can also be written as

3.84 x 10^8

The age of the Earth and Solar System is:

4.5 billion years.

The Juno spacecraft is currently in orbit around Jupiter. We communicate with Juno using radio waves. It is 817 million km away from Earth. How many minutes does it take a radio wave signal to reach it? (calculate it, don't just look it up).

45.4

The infrared light emitted by Venus is strongest at a wavelength of 3.86um what is the temperature of Venus (in Kelvin)?

750.7

How fast are you moving with respect to the center of the Earth when you are sitting in your chair in Chicagoland?

800 miles per hour.

Tycho Brahe's major contribution to the development of modern astronomy was

?

Which law of physics led Einstein to develop the Theory of Relativity.

?

Which of the following are true about Aristotle's theory of the Universe. (One or more answers may be correct).

?

Which of the following are true about a spaceship traveling near the speed of light? (one or more answers may be correct).

?

Who developed the modern scientific method?

?

Why must the clocks on GPS satellites be corrected in order to be in sync with clocks on Earth (more than one answer may be correct).

?

Which of the following is not one of Galileo's many contributions to astronomy.

A fundamental understanding of gravity.

A scientific theory is

A model explaining something that is backed by a large body of evidence and hasn't failed a single test.

The following is a list of "theories." Three are defined by the everyday meaning of the word "theory." Which one is the scientific theory?

A model that explains how gravity works, which has been tested many times by many different people, who have so far found that all of its predictions have come true.

How is an idea different from a hypothesis?

An idea can be anything, but a hypothesis is specifically an idea that leads to testable predictions.

Which scientist was the first to propose a heliocentric model of the Solar System?

Aristarchus

Why don't Newton's laws predict the precise orbit of Mercury?

Because they only work in flat space-time and the space-time around Mercury is distorted due to the mass of the Sun.

Which of the following could be a scientific hypothesis?

Birds navigate using Earth's magnetic field.

Which law of physics explains why the nebula that formed the solar system started to rotate faster as it collapsed.

Conservation of angular momentum.

In six months, you will be able to see a different set of stars in the night sky because

Earth will move.

Our complete cosmic address is

Earth, Solar System, Milky Way Galaxy, Local Group, Virgo Cluster, Laniakea Supercluster, Our Universe

What is the significance of Planck's constant? (one or more answer may be correct).

Energy is not continuous, it comes in discrete packets called quanta.

The lack of knowledge of what fundamental aspect of nature distorted Aristotle's theories of motion and the universe?

Friction.

How fast does light travel?

From Earth to the Moon in 1.25 seconds.

Copernicus's heliocentric theory was very successful, but it was also incorrect in one major aspect. What was this aspect?

He assumed that the planetary orbits were circular.

How did Galileo solve the stellar parallax objection to the heliocentric model?

He saw that the stars did not get larger in his telescope, so they must be too far away to observe parallax.

Where were the heavy elements in your body originally formed?

Inside of stars, and in supernova explosions, and in collisions between neutron stars.

Which of the following statements are true about a light year? (one or more answers may be correct).

It is about 6 trillion miles. It is the distance light travels in one year.

How was Neptune discovered?

It was predicted to exist by Le Verrier to explain the discrepancies of Uranus's orbit, and was soon after observed by Galle.

Which of the following statements about light is true? (one or more answer may be correct).

Light is both a particle and a wave. X-ray photons have smaller frequencies than gamma rays and they travel at the same speed.

In the course of a night the stars appear to rotate in a circular motion from east to west. What causes this?

The Earth spinning on its axis.

What insight allowed Newton to finally formulate his Universal Law of Gravity?

The Moon is falling towards the Earth because of gravity.

Why don't we see stars during the daytime?

The Sun is much closer than the stars, so its light is much brighter and its light overwhelms the light from the stars.

Sandy, a space shuttle astronaut, pushes on a bowling ball twice as hard as Doug, another space shuttle astronaut.

The acceleration of the ball that Sandy causes is twice as great as Doug's acceleration.

Which of the following is not explained by Newton's third law?

The gravitational force between the Sun and the Earth.

The gravitational pull of the Sun on the Earth causes the Earth to orbit around Sun, why does the Earth only cause the Sun to wobble a very small amount?

The gravitational force is the same, but the Sun is much more massive so it is accelerated less.

What causes the Moon to go through phases?

The relative positions of the Moon, Sun, and Earth as the Moon orbits Earth.

The speedometer of a car reads 30 mph (miles per hour). One minute later it reads 40 mph. Which of the following is true?

The speedometer is giving the car's speed at each moment, and the car is accelerating.

When is the Northern Hemisphere of the Earth most tilted away from the Sun?

The winter solstice.

The hydrogen-alpha emission line from a nearby star is measured at a wavelength of 630.3 nm. This line occurs at 656.28 nm in our stationary laboratory. What can we stay about this star?

This star is moving toward us.

Which of the following are true about space-time (more than one answer may be correct).

Time and Space are on equal footing. Matter distorts space-time. Space-time tells matter how to move

Kepler's second law, the law of equal areas, tells us that

a planet moves its fastest when closest to the Sun.

How long does it take the light from the closest star (besides the Sun) to reach the Earth?

about four years.

Which of the following terms describes the event in which the Moon is directly centered over the disk of the Sun from the vantage point of Earth but is relatively far away from Earth in its orbit, so it is not large enough in our sky to cover the entire Sun?

an annular solar eclipse

Light can be generally described as

an electromagnetic wave that causes charged particles to vibrate.

In reality, the Celestial Sphere is

an imaginary surface on which distant objects appear to lie, which rotates because Earth is spinning on its axis.

Adaptive optics is a technique used to correct telescope images for

atmospheric distortion.

If you are located at a position of latitude 42° north (you are), Polaris

can be found at an altitude of 42°.

The Milky Way galaxy:

has a supermassive black hole at its center.

The tilt of Earth's axis causes seasons by changing the

inclination of sunlight upon your location on Earth as the year progresses.

Suppose you are transported to a planet with twice the mass of Earth, but the same radius of Earth. Your weight would __________ by a factor of __________.

increase; 2

If a satellite is orbiting Earth at constant speed,

its orbit is circular.

Compared to blue light, red light has a

longer wavelength and lower energy.

According to Newton's first law, a space probe traveling through interplanetary space will

maintain its motion in the absence of any net outside force.

If a test of the prediction of a hypothesis supports that hypothesis, the next step in the scientific method is to

make and test more predictions of that hypothesis.

The connection between gravity and orbits enables astronomers to measure the __________ of stars and planets.

masses

If Earth's axis were tilted twice as much as it currently is, we would experience

more extreme seasons.

When using the scientific method, a hypothesis that would explain a particular observation

must be able to be tested.

Apparent retrograde motion in our sky

occurs when a planet appears to move temporarily "backward" in our sky.

A partial solar eclipse occurs when

only part of the Sun's disk is covered by the Moon from the vantage point of an observer on Earth.

The Sun is directly overhead (at the zenith) at noon

only twice a year at locations within the Tropics.

A lunar eclipse is possible

only when a full Moon's orbit intersects Earth's orbital plane around the Sun.

A solar eclipse is possible

only when a new Moon's orbit intersects Earth's orbital plane around the Sun.

Scientific knowledge is reliable because

predictions are tested with experiments and observations.

The Cosmological Principle is the

proposition that natural laws should behave the same everywhere in the Universe.

The correct order of steps in the scientific method after making an observation is to

suggest a hypothesis, make a prediction, perform a test.

Which of the following objects are not found inside our Solar System?

the Milky Way galaxy

The Moon is in synchronous rotation with Earth because

the Moon rotates on its axis once per revolution around Earth.

Compared to the winter, in the summer:

the Sun is higher in the sky at noon.

In the geocentric model,

the Sun, planets, and stars orbit Earth.

Galileo observed that Venus had phases, with the full phase occurring when Venus appeared smaller. This showed that

the heliocentric model of the Solar System was correct.

On the surface of the Earth, the gravitational force between you and Earth depends on

the mass of Earth. your mass. the radius of Earth.

The likelihood of your seeing a particular phase of the Moon depends on

the time of day or night where you are located on Earth. the position of the Moon in its orbit around Earth. the angular separation between the Moon and the Sun.

Astronomical blurring is due to

the turbulent distortions of Earth's atmosphere.

Astronomy dates back to

the very first human records.

In what part of the electromagnetic spectrum is light with a wavelength of 500 nm?

visible

When the moon appears more than half lit, and is becoming more lit every day, which phase is it in?

waxing gibbous