AST1002 Final FRQ

Name one reason why the study of asteroids is very important to planetary scientists.

Very old, give clues to early solar system

What are the most important locations where icy bodies similar to asteroids are found in the Solar System? Name two locations.

Kuiper Belt; Oort Cloud

Asteroids are found in three places in the Solar System. Describe two.

Main Asteroid Belt; Jupiter’s Trojan Points; Near Earth orbits

Describe one observation of the current state of the Solar System that supports the Solar Nebula theory.

All orbits are in the same plane

Describe one change that happens to a comet as it approaches the Sun.

Coma develops

Describe one change you will notice due to the Earth's revolution about the Sun.

Different constellations visible at different times of year

All of our studies of Venus have been carried out by orbiting satellites. Why have we hardly ever explored Venus with landers and rovers?

Venus has high atmospheric pressure and temperature that satellites on the surface cannot survive

How did the temperature in the early Solar System affect the chemistry of the planets?

Different chemicals are available depending on reaction to solar temperature

Describe the most widely accepted theory for the formation of the Moon.

Large mars-sized body struck earth and the debris formed the moon

What is convection? Describe one process that we have studied that is a result of convection.

Convection is the flow of heat through the movement of a gas or liquid. Examples include tectonic plate motion, bands on Jupiter, granules on surface of Sun

Why does the Moon show different phases?

The angle between the Earth Moon and Sun only allows us to see a portion of the lit side.

What important feature did Copernicus’ model of the Solar System change to improve the accuracy of predictions?

He placed the sun in the center.

How does a given planet generate a magnetic field?

A spinning, electrically conductive core

What are the most important processes that add and remove carbon dioxide from a terrestrial planet's atmosphere?

Added by volcanism, removed by chemical reactions with rocks and open water.

Describe clearly the positions of the Earth, Moon and Sun during a Lunar Eclipse? What phase is the Moon in during the eclipse?

Earth between moon and sun. Full

Name one similarity between the atmospheres of Venus and Mars. Name one difference.

They are both carbon dioxide; Very different environment due to different atmospheric pressure

The surface of Venus displays three types of volcanic features. Name two of them.

Corona; Pancake dome; Volcano

Describe clearly the positions of the Earth, Moon and Sun during a Solar Eclipse? What phase is the Moon in during the eclipse?

Moon between earth and sun, new

Name one rover that has explored the surface of Mars.

Perseverance

Describe one reason why we believe there is water on Mars.

Outflow channels resemble water features; Phoenix dug up snow in north pole

What process creates spots on Jovian planets

Bands moving different directions above and below the spot: differential rotation or zonal flow

Why are the colors on the surface of Saturn more muted than on Jupiter

Saturn has thicker cloud layers and a cover of haze

Why are the atmospheres of Uranus and Neptune blue, while Jupiter and Saturn are more red/green?

They contain methane, which absorbs red light.

Why does convection make different bands on Jupiter have different colors?

Different chemical condense into cloud at different altitudes due to changes in temperature

Why is Io the most volcanic object in the solar system?

It is constantly flexed by gravitational tides from Jupiter and Europa

Name two moons of the outer solar system that are considered to have liquid water which may possibly support life.

Europa; Ganymede

Describe the size and composition of the material making Saturns rings.

Chunks of ice or ice covered rock the size of a snowball

Describe one significant feature that makes Titan unique among moons of the Solar System.

Permanent dense atmosphere

What is unusual about Triton?

It orbits in retrograde

What do visible light, radio, infrared, ultraviolet, X-rays and Gamma rays have in common? What makes them different?

They are all electromagnetic radiation. They have different wavelengths/frequencies.

An astronomer is observing a hot blackbody in space. What kind of spectrum is observed?

A continuum spectrum

What information can be determined from a continuous spectrum?

temperature

An astronomer is observing a hot blackbody object in space using a spectroscope. A cool cloud of hydrogen gas is between the object and the astronomer. What will the image on the spectroscope look like?

A rainbow crossed by dark lines

An astronomer is observing a diffuse cloud of gas being ionized by a nearby hot star. What will the image in the spectroscope look like?

Narrow colorful lines against a black background

Briefly describe the process of nuclear fusion including the elements that start the reaction, the necessary temperature for the reaction and the elements that are produced by the reaction.

Hydrogen nuclei at temperatures of 10,000,000K fuse to make helium

What physical effect links sunspots and prominences?

Magnetic fields

How does the number of sunspots on the surface of the sun change over time?

It varies between no sunspots and many on an 11 year cycle

What is the Solar wind?

A stream of charged particles lifted off the sun by magnetic fields and pushed through the solar system

Name the three layers of the Sun’s atmosphere.

Photosphere; chromosphere; corona

Describe how parallax is determined.

A star is observed from Earth once, then again six months later. This gives the baseline for detecting parallax.

Name two properties that a star in the upper right of the HR diagram must have.

Bright; cool; large

How does the Sun compare to other stars in size? Is it average, below average, or larger than average? Explain.

Above average. The sun is larger than 88% of other stars. Most stars are less than half the size of the sun.

Describe the mass of the most common stars.

Most stars are red dwarfs with masses of between 0.25 and 0.5 solar masses

Describe the process that creates an emission nebula.

An O star emits UV radiation that ionizes the hydrogen gas in nearby clouds

Identify two effects, visible in telescope images, that mark the birth of a new star.

TTauri stars; jets; dust cocoons

Why are O stars important for star formation?

O stars’ strong radiation and stellar winds compress gas triggering star formation

Where do emission nebulae form?

Around O stars, generally near large dust clouds in the galactic spiral arms

What event makes a main sequence star begin evolving into a red giant?

When helium builds up in the center hydrogen fusion becomes more intense in a shell around the helium core.

Why is the death of stars important for life on Earth?

Life on Earth requires heavy elements that are only produced in dying stars.

What is the significance of iron in the life of a high-mass star?

Iron does not produce energy when it fuses. When a star produces iron it triggers a core collapse

What is a white dwarf?

The core of a low-mass star that has died and ejected a planetary nebula

What process creates a planetary nebula?

Large red giant stars have unstable power output which ejects material from the outside of the star in a massive solar wind.

What process causes a Type I supernova?

A white dwarf accumulates so much mass from a companion that it starts carbon fusion and burns itself up

List three properties that all neutron stars have.

Small size; High density; Fast rotation; Strong magnetic fields

Explain what a pulsar is.

A pulsar is a neutron star that sends out beams of radiation from hot spots on its surface. If the Earth is crossed by the beams, we see a pulsing signal

What causes an X-ray burst?

When material drawn from a companion builds up on a neutron star, it will eventually fuse in an explosion.

In direction and distance, where are gamma ray bursts found?

In every direction at very long distances.

Describe one model for the generation of a gamma ray burst.

Two neutron stars collide and merge

List the two conditions that are used to decide if a star is in a binary system with a black hole.

The visible star moves as if it orbits an unseen companion; Flickering x-ray emission from the accretion disk is observed

Describe two differences between the galactic halo and the galactic disk.

No gas and dust vs. lots; Only old stars vs. a mix of young and old; No star formation vs. lots of star formation

What did astronomers observe that led to the theory of dark matter?

The rotation speeds of stars in the outer galaxy do not match the predictions.

List two observed phenomena in our galaxy that suggest there is a supermassive black hole in the galactic center.

Fast orbit of stars around the BH; X-ray source from accretion disk;

What is a globular cluster?

A group of some millions of stars in a spherical shape orbiting the galaxy in the halo.

Describe how you would use a Cepheid variable to determine distance.

If you measure the period you know the actual luminosity. By measuring the apparent luminosity, the inverse square law determines the distance.

Describe three properties of the galactic disk relative to other parts of the galaxy.

Orbits are in the same sense; revolution about the center; Lots of cool gas and dust; Mix of young and old stars

Hubble’s sequence lists four types of galaxies. Name three.

Spiral; Barred Spiral; Elliptical; Irregular

Describe two differences between spiral and elliptical galaxies.

Old stars vs. mix; No gas and dust vs. lots; No star formation vs. lots; Shape; Presence of a disk

List two properties common to all Active Galaxies.

Intensely luminous cores; Broad emission lines; Jets and other explosive features

What is Hubble’s Law?

Galaxies are redshifted with further galaxies displaying more redshift.