1. The Components and Origin of the Universe

2. Earth in the Universe

3. Formation of the Solar System
Solar Nebula Theory:
Solar system formed 5 billion years ago from a massive cloud of gas and dust that began to contract

4. Evidence
Theory explains observations that the planets orbit the Sun in the same direction, the planets are all in the same plane, Sun is at the centre, most planets rotate the same way, terrestial are closer than gas

5. The Organization of the Universe
Stars and Solar Systems
most common type of celestial object
Star Clusters
groups of stars that formed in the same nebula and are gravitationally bound
Open star clusters – groups of 6 to 1000’s of young stars
Globular star clusters – groups of 1000’s to millions of older stars

6. The Organization of the Universe
Galaxies
collections of star clusters, planets, gas and dust measuring up to light years across.
there are different kinds
Elliptical - contain the oldest stars but little gas or dust
Spiral (like the Milky Way) - many bright, young stars with lots of gas and dust

7. The Organization of the Universe
Galaxies
Lenticular – central bulge but no spiral arms
Irregular – no definite shape

8. The Organization of the Universe
Galaxy Clusters
galaxies, like stars, are grouped together
the Milky Way and our closest neighbouring galaxy Andromeda are part of the Local Cluster
local clusters are then grouped into Super Clusters and so on
How many stars are in the universe? Well…
300 billion stars x
1.0 x 1022 stars (20 sextillion stars)
200 billion galaxies =

9. The Organization of the Universe

10. Our Expanding Universe:
we know the universe is expanding due to the phenomenon of the Doppler Effect
as a fire truck goes past you, its pitch changes (click)

11. The Doppler Effect and Light
the same thing happens with light energy
energy travelling towards you has a shorter wavelength because it is compressed (bluer light)
energy going away from you has a longer wavelength (redder light)
this is called the RED SHIFT
we see a red shift in the light from distant stars therefore, they are moving away from us

12. The Doppler Effect and Light

13. Hubble’s Law
based on this evidence, Edwin Hubble proposed HUBBLE’S LAW
the farthest galaxies are moving away the fastest and the closest are moving away the slowest
think of raison bread dough…….you are sitting on a single raison and so it appears you are sitting still
The red shift and expanding universe are part of the evidence of the Big Bang – a theory explaining how the universe originated.

14. Dark Matter and Dark Energy
scientists were puzzled when some galaxies appeared to be moving away faster than they should be
the deduced there must be upwards of 10x more mass in a galaxy than we can see
they called this mass dark matter
we now know it is the most abundant matter in the universe but we don’t know much about it
before 1998 scientists thought the pull of gravity would eventually slow the expansion of the universe down
however, in 1998, they discovered that not only is the universe expanding but it gets faster as it goes
this strange energy working against the force of gravity was called dark energy

15. Origin of the Universe The Big Bang:
Universe began in an incredibly hot, dense expansion approximately 13.7 billion years ago

16. No, not this one

17. This one…

18. The Big Bang Theory
the Big Bang Theory suggests that all matter and energy expanded from a hot dense mass with an incredibly small volume
at first, the universe was hot (10 32 C) and energy went rushing out in all directions
energy became cooled enough to become matter
matter then cooled enough to form protons, electrons and neutrons (subatomic particles)
subatomic particles combined to form mostly hydrogen but some helium nuclei

20. Evidence of the Big Bang
the universe is filled with gas and as a gas expands it cools  the universe is cooling
the red shift shows that galaxy’s are moving away from us universe if growing
we have detected cosmic background radiation that was left over from the intense radiation created during the Big Bang  we can hear it
we have found no stars that are older than the age we think the universe is  we’re smart

22. Your Task
P. 391 #5 -8
P. 397 #1-6, 8-10