#### Transcript Astronomy Review - Cockeysville Middle

```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/energy
 Star 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.



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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.

Universe

Galaxy
 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
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?

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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.
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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!
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