Cosmic Inflation and the Horizontal and Flatness Problems

What is cosmic inflation? How does inflation solve the horizon problem? The flatness problem?

Four Layers in Distance-Measurement Ladder

Can I get help with describing the four layers in the distance-measurement ladder involved in determining the distance to a galaxy lying 5 Mpc away?

Active Galaxies

1. What is the significance of studying active versus normal galaxies? Explain. 2. Do you think that our galaxy has ever been an active galaxy? Could it have hosted a quasar when it was young? 3. How can collisions affect the shape of galaxies? What evidence can you cite that galactic cannibalism really happens?

Planet-Sized Objects Around Pulsars

Do you think that planet-sized objects discovered in orbit around a pulsar should be called planets? Why or why not?

Sunspot Activity

Given the unpredictability of sunspot activity and its ability to virtually shut down for extended periods of time, do you feel it is necessary to study sunspot activity? Why?

Voyager, Galileo, and Cassini Missions

Can I get examples and details of Voyager, Galileo, and Cassini missions?

The alignment of Phobos and Deimos from Mars.

Hi. 3. Phobos, the inner moon of Mars, has an orbital period of 0.32 days. Deimos the outer Martian moon has a period of 1.26 days. How often will Phobos and Deimos be aligned as seen from the surface of Mars? Please include the formula and units also. Thanks.

Semi-major axis, sidereal period and synodic period of a hypothetical planet

A hypothetical planet travels in an elliptical orbit around the Sun. The perihelion distance is 2.65 AU and the aphelion distance is 2.85 AU. For this hypothetical planet determine: a) the semi-major axis of its orbit. b) the sidereal period. c) the synodic period as seen from the Earth.

Determine the Mass of the Sun using Orbital Data from Venus.

Hi. Using the following orbital data for Venus, determine the mass of the Sun. a=1.08x10 11m p=224.68 days. Please include the formula and units. Thanks.

The Drake Equation

How many of the terms in the Drake equation are known with any degree of certainty and which factor is the least well known?

The Big Bang Theory and Cosmic Background Radiation

How does cosmic background radiation relate to the Big Bang theory? (Answered in approximately 100 words.)

How does the cosmic background radiation relate to the Big Bang Theory?

Explain cosmic background radiation and relation to big bang theory.

Do we know whether Mars ever had life at any time during its past? What argues in favor of the position that it may once have harbored life?

Explain whether or not life ever existed on Mars.

Why do astronomers think that quasars represent an early stage of galactic evolution?

Explain why quasars represent early galactic evolution.

Name two basic differences between normal and active galaxies. How do astronomers account for the differences in the spectra observed from active galaxies?

Over 200 word response with reference that compares normal and active galaxies.

Why is it so difficult to test the predictions of the theory of general relativity? Describe two tests of the theory.

Over 200 word response with reference that describes how to test the theory of general relativity.

Briefly describe the basic chain of events leading to the formation of a star like the Sun.

Over 200 word response with reference that explains how a star forms into a star like the Sun.

In general, is it possible to determine the life span of an individual star simply by noting its position on the H-R diagram?

Over 200 word response with reference that explains how astronomers determine the life span of a star using the H-R diagram.

Describe how energy generated in the solar core eventually reaches Earth.

Over 200 word response with reference that explains how energy reaches Earth from the solar core.

Over 200 word essay with reference that describes how the four Jovian planets get their colors.

Describe how the four Jovian planets get their colors.

How (and why) do the thickness of Saturn's various layers (clouds, molecular, and metallic hydrogen, core) compare to those in Jupiter?

Describe the various layers of Saturn in comparison to those of Jupiter.

What might be the consequences of a 10-km asteroid striking Earth today?

Over 200 word essay with reference that explains what would happen if a 10-km asteroid struck the Earth.

Why is the moon heavily cratered but Earth is not?

Over 200 word essay with reference that explains why the moon is heavily cratered and the Earth isn't.

What is interferometry and what problem in radio astronomy does it address?

Over 200 word essay with reference that covers the definition of interferometry and how it affects radio astronomy.

List three advantages of reflecting telescopes over refracting telescopes.

Over 200 word essay with reference in regards to three advantages of reflecting telescopes over refracting telescopes.

Contrast the sidereal and solar days. How, and by roughly how much, would the length of the solar day change if Earth's rotation were suddently to reverse direction?

Provides over 200 word essay and reference in regards to the length of the solar day and the process if the Earth's rotation was to reverse direction.

The role of collisions in the formation and evolution of galaxies

Describe the role of collisions in the formation and evolution of galaxies.

Kepler's Three Laws of Planetary Motion

Briefly describe Kepler's three laws of planetary motion. Explain how Kepler's laws allow us to use motion of an asteroid to find its average distance from the Sun.

Open and globular star clusters

Compare and contrast the properties of open and globular star clusters.

The death of stars

How do stars of low mass and high mass die?