Galaxies and the Universe

Chapter 24: Stars, Galaxies, and the Universe
Quarter 4 | Earth Science 7

https://www.youtube.com/watch?v=Vw_TBtAf1Bc

Video: The Universe

Guide Questions

Describe the universe in your own words.
How did the universe begin?
Why is it important to study the stars, galaxies, and the universe?

​What is the universe?

​all existing matter and space considered as a whole; the cosmos. The universe is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies; it has been expanding since its creation in the Big Bang about 13 billion years ago.

What lies beyond the solar system?

• Galaxies

• Stars

• Solar Systems

• Planets

• Black Holes

• Comets

• Much More...

There are three types of galaxies, Spiral, Irregular, and Elliptical. What shape is our galaxy?

Our galaxy, the Milky Way galaxy, is a spiral galaxy that looks somewhat like a pinwheel.

​Our Galactic Home

​The Milky Way Galaxy

​One of the spiral arms of our galaxy visible from Earth's surface.

How did the universe start?

There are several theories and they have developed over time as our scientific understanding has developed. The most widely accepted theory is the Big Bang Theory, the idea that the universe began from a single incredibly dense spot and exploded outwards.

​Planets are...

A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.​

​Exoplanets are...

​extrasolar planet, also called exoplanet, any planetary body that is outside the solar system and that usually orbits a star other than the Sun.

How Big is the universe?

https://youtu.be/nxs5wye0JXs

Multiple Choice

An exoplanet is a planet that orbits

• Another Planet

• Another Star

• Another Galaxy

• Another Moon

Multiple Choice

Choose the correct order listed from smallest body to largest.

• exoplanet, galaxy, star, asteroid

• asteroid, exoplanet, star, galaxy

• star, galaxy, exoplanet, asteroid

• galaxy, exoplanet, asteroid, star

Multiple Select

Check the galaxy shapes (that we know of) are in the universe

• Spiral

• Ellipse

• Oval

• Irregular

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Constellations

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​Parallax-effect when position or direction of an object appears to differ when viewed from different positions against a distant background

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CONSTELLATION

- a group or cluster of stars that appears to form a pattern or imaginary shapes.

​Parallax-continued

• Best used to measure nearby stars​

• When objects in space are super far away, the parallax is small (doesn't appear to move much) and not useful in determining an accurate measure of distance.

Poll

If you were to look at the nigh sky, how many constellations could you identify?

• none

• 1-3

• 4-6

• all of them!

Multiple Choice

Parallax is when you observe motion of an object across

• a distant background

• another moving object

• the sun

Multiple Choice

A constellation is a group of visible ____ that form a pattern when viewed from Earth.  

• planets

• stars

• patterns

• creatures

Multiple Choice

Parallax is only useful for observing

• nearby stars

• far away stars

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Circumpolar Constellations and Polaris

​Star Systems, Clusters & Galaxies-OH MY!

• Star system-two or more stars in a group

  • ​two-binary or double stars

  • ​three or more-multiple star system

• ​Star Cluster-stars in a larger grouping, formed from the same nebula at about the same time.

  • Open cluster-loose and disorganized​ (a few thousand stars)

  • Globular clusters-large groupings of older stars (more than a million)

• ​Galaxies-huge group of stars, star systems, star clusters, along with dust and gas held together by gravity (more than 100 billion stars)

Fill in the Blanks

The stars appear to revolve around the North Star, or

, the Pole Star, which is located at the north celestial pole.

Multiple Choice

Which has more stars, a star cluster or a galaxy?

• star cluster

• galaxy

Fill in the Blanks

Stars that appear to travel in a circle around the celestial poles are called

stars.

Multiple Choice

Which star cluster group is loose and disorganized

• Open

• Globular

Multiple Choice

Which star cluster grouping contains older stars and may have more than a million of them?

• open

• globular

​Binary Stars-two stars orbiting each other

• ​One is usually much brighter and more massive than the other.

• ​The dimmer one's gravity causes the brighter one to wobble

• ​Eclipsing Binary=one passes in front of the other/blocking its light

Multiple Choice

Binary star systems have how many stars?

• obe

• two

• three

• four

https://www.youtube.com/watch?v=LdgfUMT4TRc

Video: Constellations

​Galaxies

1. ​Spiral-middle aged stars/main sequence stars

2. ​Elliptical-old stars, no new stars forming

3. ​Irregular-young stars and new stars forming

4. ​Quasar-active, young galaxies with a black hole in the middle that gas spins around and glows

Draco the Dragon

Multiple Choice

The Milky Way Galaxy is a 

• spiral
• lenticular
• elliptical 
• irregular

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​Can you name

​the following

​constellations?

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Can you name the following

circumpolar constellations?

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Multiple Choice

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular
• Irrational

Multiple Choice

• little dipper

• draco the dragon

• big dipper

• orion

• Cassiopeia

Multiple Choice

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular 
• Irrational

Multiple Choice

• perseus

• draco

• orion

• cassiopeia

• Cepheus

Multiple Choice

What is not a galaxy?

• Optical Galaxy
• Spiral Galaxy
• Elliptical Galaxy
• Irregular Galaxy

Multiple Choice

• Cepheus

• Cassiopeia

• Orion

• Ursa Major

• Ursa Minor

Multiple Choice

How many stars are in a galaxy.

• millions or billions
• thousands
• hundreds
• Ten

Multiple Choice

Galaxies are composed of (best answer)

• stars
• stars and gas
• stars, dust, and gas
• stars, dust, and gas held together by gravity

​Lightyears

​Light travels 300,000,000 meters per second.

​Light travels 9,460,000,000,000 kilometers per year

​*Scientific notation=9.46 X 10 to the power of 12

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​Lightyear=unit of distance, not time.

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​Example: If you ride your bike at a speed of 10 km per hour and the mall is 10 km away, you could say the mall is "one bicycle hour away".

Multiple Choice

The universe is done expanding

• True

• False

Poll

Which type of lesson helps you learn best?

• Quizizz lesson

• Vocabulary

• Reading

• Hands on activity

Multiple Choice

When some giant stars explode gravity becomes so strong that they start pulling everything around it inwards. This is called a...........

• Nebula

• Black Hole

• Supernova

• White Dwarf

The Universe!

Where it has come from and what it looks like. We think!

Multiple Select

Check the galaxy shapes (that we know of) are in the universe

• Spiral

• Ellipse

• Oval

• Irregular