1. SPACE INTRO LESSON
 Astronomy vs Astrology  Heliocentric vs Geocentric models  Celestial objects  Galaxy sorting  Black hole  Dark matter
Text section 8.1

2. Supermoon on Saturday May 5 2012
Moon is a celestial object
Hook: supermoon
Celestial object: any natural object seen in the sky. E.g. sun, earth, planets, comets

3. Astronomy vs. Astrology
Astrology
Astronomy
What it is
The study of how the positions of celestial bodies have influence on life events and behavior of people
The study of the origin, movement and behavior of the universe
Scientific basis
astrologist
Astronomer, cosmologist
Ability to predict future NO
YES, based on repeated observations, simulations and theories
Zodiac signs
YES
Constellations
12, first coined by Babylonians 88

4. Geocentric vs Heliocentric
Earth at the center
Sun at the center

6. The Universe = all existing matter and space considered as a whole; the cosmos.
How old is the universe?
13.7 billion years old
2. How do we know how old the universe is?
Edwin Hubble ( ) used two different methods:
Measuring speeds and distances of galaxies
Measuring the ages of the oldest star clusters.

7. Sorting Galaxies activity
In group of 4, come up with your own categories to classify these galaxies
What causes the difference in galaxies’ shapes?
Ignore sharp point in pictures; they are stars from our galaxy

8. Galaxies
A galaxy is a collection of hundreds of billions of stars held together by gravity
A star = a hot ball of plasma that shines because of nuclear fusion taking place at its core
Earth is part of the Milky Way which is an spiral galaxy
Color of galaxy depends on the age of the stars it contains
Lenticular galaxies are rather poorly understood objects. They simultaneously have properties similar to both Spiral galaxies and Elliptical galaxies. On the one hand this make them seem as if they are a transitional form of galaxy as they evolve from one type to another. Structure of Lenticular Galaxies
The defining features of Lenticular galaxies include a flat, disk-like shape. However, unlike Spiral galaxies, they lack the distinctive arms that wrap around the central bulge.
Shaped like spheres
or oval
Older & are largest galaxies
Fewer young stars than spiral galaxies
Flat & circular with curving arms
Have many young stars
Disc-shaped with a bulge in the middle
No particular shape

9. Properties of galaxies
1. Galaxies contain about 200 billion stars each and usually have a supermassive BLACK HOLE in their centre
2. At least 90% of the mass in the universe may be composed of dark matter

10. Black Hole
Space where gravity is so strong that it can pull anything right into it.
Masses of stars pulled into black hole increase the size and mass of the original black hole
The Milky Way’s black hole has been pulling stars for at least 7 billion years. Currently , the black hole has a mass equal to about 3 million stars that are of similar size to the Sun.
Its black hole is ly away from the Solar system
What about white hole?
A white whole is, roughly speaking, the opposite of a black hole. “A black hole is a place where you can go in but you can never escape; a white hole is a place where you can leave but you can never go back,”
Wormhole: a hypothetical connection between widely separated regions of space-time.

11. Dark matter explained: http://www.youtube.com/watch?v=nJN2X3NrQAE
Invisible matter that make up 90% of the matter in the universe.
Dark matter provides the gravitational force that holds the universe together
Evidence for presence of dark matter:
Stars around galaxy such as the Milky Way revolve around the galaxy’s centre at such high speed that they are expect to be flung off
But they are not.
Dark matter explained:
Tour of the universe: 3D atlas

12. Exit activities
Making crossword puzzle for today’s vocab