1.3 - The Distribution of Matter in Space

Question 1

What is the Universe?

Answer 1

The totality of existence.
Includes everything in space (all matter and energy)
It’s size is unknown and possibly infinite.

Question 2

What is a star?

Answer 2

• A hot, glowing ball of gas (mainly hydrogen) that gives off light energy.
• Stars vary greatly in their characteristics: size, density, colour, surface temperature

Question 3

How does the Hertzprung-Russell diagram group stars?

Where do most stars fall within the diagram?

Answer 3

• The Hertzprung-Russell diagram groups stars according to surface temperature and brightness
• Most stars fall under the main sequence grouping

Question 4

True or False?

Stars do not have a lifecycle, as they are not living things.

Answer 4

False. Stars do have a lifecycle.

Question 5

Where do stars form? Describe the birthplace of a star.

Answer 5

• Stars form in regions of space where there are huge accumulations of gas and dust called nebulae.
• Nebulae are composed of interstellar matter, such as hydrogen, helium, oxygen, nitrogen, carbon and silicate dust.

Question 6

What is the first step in the formation of a Protostar?

Answer 6

• The gravitational force between gas and dust particles causes the nebula to collapse into a smaller, rotating cloud of gas and dust.

Question 7

What is the second step in the formation of a Protostar?

Answer 7

• As material is drawn into the spinning ball of gas and dust, the mass and temperature increase. When the core gets hot enough, it starts to glow, forming a protostar.

Question 8

What is the third step in the formation of a Protostar?

Answer 8

When the protostar’s core reaches 10 000 000 oC, hydrogen starts to change to helium. This process is called fusion and it releases large amounts of energy and radiation.

Question 9

What are constellations?

Answer 9

The groupings of stars we see as patterns in the night sky

There are 88 recognized constellations

Question 10

What are asterisms?

Answer 10

Unofficially recognized star groupings

Ex. The big dipper

Question 11

What is the galaxy?

Answer 11

• A grouping of millions of billions of stars, gas and dust that are held together by gravity
• Our galaxy is a spiral galaxy called the Milky Way
• Other types of galaxies include elliptical and irregular
• THere are an estimated billion billion galaxies in the universe