earth sci chapter 2&3

Question 1

How do we measure distances in space (2 different units of measure)?

Answer 1

• Light years: distance light will travel in one year

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Question 2

Explain how you can use trigonometric parallax to tell the distance of nearby stars

Answer 2

When an object appears in a different place relative to a background based on
your viewpoint

Question 3

What is our nearest neighbour galaxy as found by Hubble?

Answer 3

Andromeda Galaxy

Question 4

What is the Hubble law? Explain the terms? V = Hd

Answer 4

A relationship between star/galaxy’s distance and the “redshift” of light from
star/galaxy

v= speed in km/s
h= Hubble constant (rate of expansion of universe)
d= distance

Question 5

What are the 3 ways to determine distance?

Answer 5

Trigonometric parallax for near distances (500 light years or less)

Hertzprung-Russell Diagram, uses colour and temperature to determine brightness. Also uses marker stars called Cepheids, determines its brightness period and then uses same as before (500 to 500 million
light years)

Hubble’s Law for far distances (beyond 500 million light years)

Question 6

Will the Milky Way ever crash with the Andromeda galaxy?

Answer 6

• Andromeda is hurtling towards the Milky Way at 500,000 km/h
• Expected to crash or merge in 3 billion years

Question 7

Formation of elements from light to heavy. Which ones form in the big bang, a star or a
supernova?

Answer 7

• Supernova is the explosive death of a massive star

- Supernovas can produce all the heavy elements

Question 8

Describe the nebular hypothesis for the formation of our solar system

Answer 8

Suggests solar system formed in a brief span of time from a nebula or interstellar gas

Question 9

describe collapase

Answer 9

• some external force causes a portion of
  the cloud to condense and begin to
  contract
• this snowballs until the entire cloud condenses and heat no longer escapes
  ­- the heat builds up and becomes very hot, allows for fusion reactions to occur
  ­- the release of energy from the fusion reactions creates a star

Question 10

describe flattening

Answer 10

• The cloud started with very likely had a net rotation or swirling motion
  ­- As the collapsing occurred, the net rotation would have sped up due to increase of attraction
  ­- This causes cloud to flatten out

Question 11

growth of planets

Answer 11

• Lots of small masses orbiting sun in same direction
  ­- Collisions were more or less gentle and the pebbles would collide and stick together
  ­- This occurred a lot and they accumulated into larger lumps until they became planetesimals (small planets)
  ­- This process continued, yet at a slower rate since number of masses decreases, until large planets resulted

Question 12

Why is the Sun hot?

Answer 12

• Fusion reactions release energy and this is in the form of heat and light
• Very hot since there are tons and tons of fusion reactions happening all the time,
  massive energy output

Question 13

Why is the solar system a flat disc?

Answer 13

Since the cloud that created the solar system had a rotational movement about it,
when it condenses, this rotation became faster and flattened the cloud

Question 14

Why did all planets originally move in the same direction around the Sun?

Answer 14

• Also due to the rotational motion of the cloud
• When the atoms around the sun condensed, they continued their circular motion
  because of the conservation of angular momentum

Question 15

The interior planets are made from condensed refractory materials, what happened to the more volatile gases?

Answer 15

The heat from the sun does not allow the lighter atoms to condense, therefore planets closer to the sun are made solely of heavier elements and those further away are made up of a lot of volatile gases

Question 16

What is the solar wind?

Answer 16

• An outflow of charged particles (mostly electrons) at a high velocity
• A solar flare or eruption increases flow and this is what causes northern lights

Question 17

Explain how changes in bombardment rates support the nebular hypothesis

Answer 17

• The nebular hypothesis predicts that the bombardment rates would decrease over
  time
• Studies on the Moon showed that early on, it was hit by many large chunks and then the bombardment rate dropped off

Question 18

How will our solar system likely be destroyed?

Answer 18

• In 5 billion years, the sun will run out of fuel and become a red giant destroying
  most of the planets (including earth)
• However, in 3 billion years the Andromeda Galaxy is expected to collide with our
  solar system which may change things