The Universe

1
The Universe

• 8th Grade Science

2
Modern Calendar

• -Year time for Earth to orbit once around Sun.
• -Month time for moon to orbit once around
  Earth.
• -Day time for Earth to rotate once on axis.

3
(No Transcript)
4
Early Astronomers

• Ptolemy
• -Greek
• -140 CE
• -Earth-centered solar system
• -Incorrect, but believed for over 1500 years

5
Early Astronomers
Copernicus -Polish -1543 -Sun-centered solar
system -Afraid to publish theory -Copernican
Revolution
6
Early Astronomers

• Brahe
• -Danish
• -Late 1500s
• -Most detailed observations so far
• -Earth-centered Solar system but different
• -Sun moon orbit Earth
• -Rest of planets orbit Sun

7
Early Astronomers

• Kepler
• -German
• -Brahes assistant
• -Disagreed with Brahes idea of solar system, but
  realized value of his data
• -Sun-centered solar system
• -Planets elliptical orbits
• -3 laws of planetary motion

8
Early Astronomers

• Galileo
• -Italian
• -1609
• -One of the 1st people to use telescope
• -Discoveries
• -craters mts. on Luna
• -4 moons of Jupiter
• -sunspots on Sun
• -phases of Venus
• -House arrest

9
Early Astronomers

• Newton
• -English
• -early 1700s
• -Apple myth
• -Gravity
• -Explained why planets orbit Sun
• -Laws of Motion

10
Modern Astronomy

• Hubble
• -American
• -1920s
• -Galaxies beyond Milky Way
• -Universe expanding
• -Space telescope named in his honor

11
Modern Astronomy

• Chandrasekhar
• -Indian-born American
• -1930s-40s
• -structure evolution
• of stars
• -Chandrasekhar limit
• -White dwarfs
• -Nobel Prize in Physics

12
Modern Astronomy

• Sagan
• -American
• -1960s-70s
• -lead search for et (SETI)
• -Contact
• -missions to Mars other outer planets
• -coined term nuclear winter

13
Modern Astronomy

• Hawking
• -British
• -1980s-current
• -black holes emit radiation
• -universe infinite, theory of everything
• -ALS

14
Electromagnetic Spectrum

• -Wavelengths of electromagnetic radiation
• -James Clerk Maxwell, Scottish (whoo-hoo),1852

15
Tools of Astronomy

• Optical telescopes
• -gather focus VISIBLE LIGHT
• -reflecting (lenses)vs. refracting (curved
  mirrors)
• -on Earth dirty windshield
• -in Space MUCH better
• -Hubble ST

16
Tools of Astronomy

• Nonoptical Telescopes
• -Radio telescopesradio waves (VLA)
• -UV Telescopes
• -X-ray Telescopes
• -most in space due to atmosphere blocking.
• -all very powerful!

17
Sun in Different Wavelengths
18
Constellations

• -Regions of sky with recognizable star patterns
• -Navigation track of time
• -Different cultures different names/stories

19
Measuring Distance in Space

• -Astronomical Unit (AU) distance between Earth
  Sun (1AU)
• -about 150 million km (93 million miles)
• -distance in solar system only!
• -Light-year- distance light travels in 1 year.
• -about 9.46 trillion kilometers!
• -distance in galaxies or between
• -Parsec 3.26 light years
• -about the distance to the closest star.

20
(No Transcript)
21
Doppler Effect

• -Occurs with sound light waves
• -Sound train passing by
• -Light
• -Redshift object moving away, light looks
  redder
• -Blueshift object moving toward, light looks
  bluer

22
(No Transcript)
23
Moons

• -Satellite natural or artificial orbit around
  larger bodies.
• -moon- natural satellite.
• -All planets (except Mercury Venus) have moons.
• -Luna Earths moon.

24
Formation of Luna

• -Composition similar to Earths mantle.
• -moon rocks from Apollo mission analyzed.
• 4.6 bya, Mars-sized object hit Earth.
• -blasted part of mantle into orbit.
• -debris revolved, joined to form Luna.
• -Figure 2, page 111

25
Earth Luna
26
Moon Phases

• -Moon appears different due to changing
  positions.
• -waxing sunlit area we see is getting bigger.
• -waning sunlit area we see is getting smaller.
• -We always see same side of moon.
• -moons period of rotationits period of
  revolution.
• -Figure 3, page 112

27
(No Transcript)
28
Solar Eclipse

• -Moon comes b/t Earth Sun.
• -shadow of moon falls on part of Earth.
• -pg. 113
• -Annular moon farther from Earth.
• -disk of moon doesnt completely cover Sun.
• -Total moon closer to Earth.
• -disk of moon completely covers Sun.

29
Lunar Eclipse

• -Earth comes b/t Sun moon.
• -shadow of Earth falls on moon.
• -pg. 114
• -Why dont we see one every month?
• -moons orbit tilted about 5o.

30
Comets

• -Ice, dust, rock particles
• -dirty snowballs
• -Formed in outer solar system.
• -leftovers from formation of solar system.
• -Oort Cloud past Pluto
• -Kuiper Belt past Neptune

31
(No Transcript)
32
(No Transcript)
33
Asteroids

• -Rocky objects orbit Sun
• -few km more than 900 km!
• -Most orbit in asteroid belt
• -between Mars Jupiter
• -Larger than 10 km in diameter catastrophic
  global effects.

34
(No Transcript)
35
Meteoroids, ors, ites

• -Small, rocky bodies orbit Sun.
• -probably pieces of asteroids.
• -OIDS In Space
• -ORS Bright streak as it enters Earths
  atmosphere.
• -ITES If it strikes the ground.

36
(No Transcript)
37
Impacts

• -Planets/Moons with atmosphere not as many
  impacts..why????
• -atmosphere slows down/burns up meteoroids.
• -Why are there not many impact craters on Earth?
• -weathering, erosion, plate tectonics
• -

38
Earth Impacts

• -Impact - global catastrophe every few hundred
  thousand years.
• -Impact natural disaster every few thousand
  years.
• -Meteor Crater, Arizona
• -1 mile across
• -550 ft. deep
• -formed 50,000 yrs. ago

39
(No Transcript)
40
Torino Scale

• -Rates hazard level of space objects moving
  toward Earth.
• -numbered 0 10
• -0 being no worries 10 being worst case
• -also color coded
• -Developed by NASA
• http//neo.jpl.nasa.gov/torino_scale.html

41
Journey Out of Our Solar System
42
Stars

• -Composition gases, mainly H He.
• -Stars Color tells us Temperature
• -blue hotter
• -red cooler
• -Classified by how hot they are.

43

• -Orion Constellation
• -Betelgeuse
• Red Supergiant
• -Rigel
• Blue Supergiant

44
Classifying Stars

• -Oh, Be A Fine Girl (Guy), Kiss Me!
• -pg. 35 what does this mean???
• -Which class stars are hottest?
• -Which class stars are coolest?

45
Life Cycle of Stars

• -A Star is Born
• -Stellar nursery(nebula) - huge cloud of gas
  dust..
• -Material compresses heats up
• -Begins to glow with radiation
• -Temps in core reach 18 billion degrees F...
• -Begins nuclear fusion!!!

46
Rosette Nebula
47
Adulthood Main Sequence

• -Longest lasting stage
• -Stable existence no real turmoil
• -Core continues nuclear fusion

48

• -Our Sun
• Main
• Sequence
• Star

49
Crisis Old Age

• -How long a star live depends on its mass
• -smaller stars burn fuel less quickly longer
  life.
• -bigger stars burn fuel more rapidly shorter
  life.
• -All eventually run out move along the cycle

50
Death Begins

• -Outer layers grow turn reddish in color
• -can get as large as the orbits of Mars or
  Jupiter
• -Called red giants or red supergiants
• -Remainder of death can go one of 3 ways

51

• -Betelgeuse

52
3 Directions of Death

• Release of Outer layers Sun
• 2. Nova Stars bigger than Sun explosion
• 3. Supernova Most massive stars Chuck Norris
  of explosions.
• -can be as bright as an entire galaxy

53
(No Transcript)
54
In the Graveyard

• 1. White dwarf small, hot leftover center
• -stars the size of Sun or smaller
• 2. Neutron star collapses under gravity all
  particles are neutrons extremely dense
• -stars 5-20 times mass of Sun
• -Pulsar spinning Neutron star
• 3. Black Hole gravity so immense that nothing
  can escape not even light
• -stars 20 times or more massive than Sun

55
(No Transcript)
56
Galaxies

• -Large groups of stars, gas dust.
• -variety of shapes sizes
• -largest contain more than a trillion stars!
• -billions of galaxies in known universe
• -Classified by shape.

57
Spiral Galaxies

• -Central bulge spiral arms
• -arms made of gas, dust newer stars
• -Barred spirals bar-shaped bulge
• -Milky Way, Andromeda
• -Sagittarius arm, Orion spur

58

• -Milky
• Way

59

• -Arms of
• Milky Way
• -Side view

60
Elliptical Galaxies

• -Massive blobs of stars look sphere or
  oval-like
• -VERY bright centers
• -very little gas dust
• -Contain mostly OLD stars

61
(No Transcript)
62
Irregular Galaxies

• -Leftovers dont fit into the other groups
• -shape sometimes distorted by nearby large
  galaxies

63
(No Transcript)
64
Gas Clouds

• -Nebula cloud of gas dust
• -Found mostly in spiral galaxies
• -some reflect starlight, some absorb

65
Part of the Eagle Nebula
66
Horse head Nebula
67
Cats Eye Nebula
68
Star Clusters

• -Globular Cluster older stars.
• -may contain up to a million stars
• -located in halo that surrounds galaxies
• -Open Cluster closely grouped, younger stars
• -contain many bright, blue stars
• -a few hundred to a few thousand stars
• -located in spiral disk

69

• -Globular
• Cluster
• Omega
• Centauri

70
Open Cluster - The Pleiades
71
Quasars

• -Star-like sources of light extremely far away
• -most powerful energy sources in universe
• -may be caused by super massive black holes
  in cores of some galaxies.

72
(No Transcript)