Astrophysics Final

What is retrograde motion?

the apparent motion of a planet to move in the opposite direction

Polaris

North Star

Sirius

the brightest star in the night sky

How many times a year would an upright flagpole cast no shadow at equator because theSun is directly above it?

Twice a year at the equinoxes

Earth is closest to the sun in

In the winter in the northern hemisphere

What is the shape of Mars' obit around the Sun?

An ellipse

The gravitational force of Earth on the Moon is __________ the gravitational force of the Moon on Earth.

Equal

T/F The moon has a dark side

False

How long is the orbital period of the moon?

About 1 month.

True/False: The Moon is moving away from Earth at a rate of few cm per year.

True

If the Earth orbit were change to a perfect circle about the Sun how it would affect theseasons?

We would continue to experience the seasons in the same way we do now

What color are the hottest stars?

blue

Compared to visible light, ultraviolet light has

Shorter wavelength and higher energy

How does the speed of radio waves compare to the speed of visible light in vacuum?

They are the same

What type of star is the Sun?

main sequence

During what event are elements heavier than iron produced by nuclear reactions?

During a supernova explosion of a massive star.

Can a white dwarf explode?

Yes, but only if it is in a binary star system.

What type of galaxy is our galaxy?

spiral galaxy

Where is our solar system located within our galaxy?

Near to halfway to the edge.

How was the mass of our Galaxy determined?

Measuring the rotation of the Galaxy

How was the location of the center of the galaxy first correctly determined?

Using the locations of globular clusters

Star formation in the Milky Way is happening mostly in what area?

the spiral arms

Where is the supermassive black hole Sag A* is located?

In the nucleus of our galaxy

What type of galaxies have the lowest star formation rate?

Elliptical galaxies

What is dark matter?

Matter that does not give off electromagnetic radiation

What famous astronomer discovered four moons orbiting Jupiter?

Galileo Galilei

What observation confirmed Newton's Theory?

The discovery of Neptune.

Why do astronauts inside the Space Shuttle float around as it orbits the Earth?

Because they are falling the same way as the space station.

What is the central bright nucleus of a very distant active galaxy powered by material falling into its supermassive black hole?

Quasar

What does the Orion Nebula do?

Form new stars.

How long ago was our solar system formed?

About 5 billion years ago.

What did our solar system form from?

a cloud of gas, ice, and dust

What was the important contribution of the astronomer Eratosthenes?

The circumference of the Earth.

What was the important contribution of the astronomer Aristarchus?

The heliocentric model

What was the important contribution of the astronomer Ptolemy?

Geocentric Model.

What was the important contribution of the astronomer Newton?

Three laws of motion

What was the important contribution of the astronomer Maxwell?

Electromagnetism

What was the important contribution of the astronomer Edwin Hubble?

The universe is expanding.

What was the important contribution of the astronomer Henrietta Leavitt?

Cepheid variable stars

What was the important contribution of the astronomer Cecilia Payne-Gaposhkin?

Stars are made of hydrogen and helium.

What was the important contribution of the astronomer Antonia Maury?

Stellar classification system.

What was the important contribution of the astronomer Max Planck?

Quantum theory

What was the important contribution of the astronomer Albert Einstein?

Theory of relativity

What was the important contribution of the astronomer Zwicky?

Dark matter

What are epicycles?

a small circle whose center moves around the circumference of a larger one

What is the scientific method?

A logical, systematic approach to the solution of a scientific problem

What is the Doppler Effect?

Change in frequency due to velocity

What is Kepler's third law?

Orbital period depends on distance and mass

What is an HR Diagram?

A plot for stars mapping luminosity with temperature.

What is a "standard candle"?

an object for which we are likely to know the true luminosity

What is a black hole?

An incredibly dense region of space with an escape velocity faster than the speed of light.

What is dark energy?

An energy that counteracts gravity causing the universe to expand

What is the hottest planet?

Venus.

How big is our Solar System?

About 3 light years

What is the boundary of our Solar System?

The Kuiper Belt.

What kind of shift occurs when an object is moving away?

Redshift

What kind of shift occurs when an object is moving closer?

Blueshift

What technique is used to measure distances for nearby stars?

Parallax.

What is a parallax?

An apparent shift in position with respect to background

What technique is used to measure distances for farther stars?

Standard candles.

What technique is used to measure distances for the farthest stars?

Hubble's Law.

What are the most common types of telescopes?

Reflective telescopes.

What can a spectra tell us?

Distance and chemical composition.

What star is the closest to our Solar System?

Proxima Centauri

What are the most useful stars?

Cepheids Variable stars

What type of star is Polaris?

Binary star.

What important measurement is derived from Polaris?

Latitude

How long does it take for the Sun to complete a rotation?

One month.

What will the Sun end its life as?

White dwarf

Where does the Sun's energy come from?

nuclear fusion

What is the Sun's stellar classification?

G2

What is the stellar evolution of a large star?

Supernova Type II -> Black Hole -> Neutron Star

What is the stellar evolution of a smaller star?

HB Star -> AGB Star -> Planetary Nebula -> White Dwarf

Who observed the phases of Venus and thus the Heliocentric Model?

Galileo

What direction do stars rotate in the night sky?

Counter-clockwise.

Name three circumpolar stars.

Draco, Ursa Major, Cassiopeia

Name three season stars.

Orion, Canis Major, Crux

How can you find Polaris in the night sky?

From the Tip of the Big Dipper, move up and right to the very tip of an upside down Little Dipper's handle.