Astronomy Review

1. Describe the difference between apparent and absolute magnitude. Include an explanation of factors that cause the apparent magnitude.

Absolute magnitude is how bright a star really is.

Apparent magnitude is how bright a star looks from earth.

Apparent magnitude depends on:Absolute magnitude, which depends on:

Star color/heat/energyStar size

Distance

2. Explain the relationship between star color and temperature.

The color of a star indicates how hot a star is.

If you look at a H-R diagram, the cooler colors are to the right and they get hotter as you go left.

From cooler to hotter, you have red, orange, yellow, white, and blue.

For main sequence stars, as the temperature increases, the brightness increases.

3. Compare and contrast characteristics of the inner and outer planets.

The inner planets a terrestrial (rocky), while the outer planets are gaseous.

The inner planets have a shorter revolution period (Year Length). As the orbit gets further from the sun, the period of revolution increases.

The outer planets are larger. The outer planets have lower densities (as you

would expect since they are gas). There is no pattern of rotational periods (Day

Length). The outer planets all have rings and multiple

moons.

4. Place the following in a hierarchy from largest to smallest: star, planet, solar system, galaxy, universe, asteroid.

UniverseGalaxy

Solar System Star

Planet Asteroid

5. What is a light year? A light year is a measurement of

distance. It is how far a particle of light

could travel in one year’s time. It’s equal to 9,500,000,000 km! We use it to describe distances

in space because celestial objects are so far away.

As you can see in the example to the right, it makes the numbers much smaller!

6. Describe the main characteristics of the main galaxy types.

Galaxy types:Elliptical – Sort of a undefined blob!

Spiral – Has pinwheel arms and a central bulge.

Barred Spiral - A spiral with a bar across the middle.

Irregular – No identifiable shape!

Produced by galactic crashes!

7. Which galaxy are we in? Include the name and type of galaxy.

The Milky Way galaxy!

It’s a spiral galaxy.We are on the “Orion

Arm.”

8. Create sequence chains showing the life cycle of average mass stars and large mass stars. Sequence chains should start as a nebula.

9. Compare and contrast comets and asteroids. Comets

Dirty Snowballs Made of dust and frozen

material. Seen because it reflects

sunlight. Two tails! Melts as it approaches

the sun. Originate in the Oort

Cloud or Kuiper Belt.

Asteroids Flying Rocks Made of rocky or

metallic materials Seen because it reflects

sunlight. Mainly found between

Jupiter and Mars in the Asteroid Belt.

10. Where in our galaxy do most:Comets come from?Asteroids come from?

Comets come mainly from two locations: The Kuiper Belt, just beyond

Neptune. The Oort Cloud, which is much

further away. Most Asteroids come from the Asteroid

Belt, which is located between Mars and Jupiter.

11. Why do stars produce light but planets don’t?

Because of their tremendous mass and gravity, stars have incredible amounts of internal heat and pressure.

This causes nuclear fusion (combining atoms) to occur.

The nuclear fusion releases light energy.

12. What is the difference between a meteor, a meteoroid, and a meteorite?

Meteoroid: A chunk of debris in space.

Meteor: The flash of light produced by a

meteoroid entering our atmosphere at high speed.

The friction causes enough heat to produce the light.

Meteorite: A piece of the original meteoroid

that hits the ground.

13. When we look at any celestial object, are we seeing what is happening right now? Explain.

Although we don’t see it because it travels so quickly, all light takes time to go any distance.

Light travels at 3 x 108 m/s. To the right, are some light

travel times. Even when I look at you, I see

what was! The further away we look, the

further back in time we see.

14. Explain the difference between revolution and rotation. What is the period of time caused by each on Earth called?

Revolution refers to the amount of time taken to orbit around something (in our solar system’s case, this is the sun).This period of time is referred to as a year.

Rotation refers to how long it takes to spin around one complete time.We refer to this as a day.

Is there a pattern here? The further away from the sun, the slower

the orbit, so as you get further away, the period of revolution gets predictably longer.

Rotation seems to have no pattern at all! Here’s an interesting thought.

The same side of the moon always faces Earth.

That means that it rotates one time per month.

The lunar day is one month long!