Download Big Bang Theory Scientific origin of the Universe

Structure of the Universe
Unit 1 Lesson 1
Big Bang Theory
Scientific origin of the Universe
1. All matter in the universe began moving
together to a single point.
2. At that time the universe was small, hot
and dense.
3. 10-15 billion years ago there was an
enormous explosion that sent all matter
moving outward.
4. Since then all matter in the universe has
continued expanding outward.
Evidence for the Big Bang
Red Shift/Blue shift
• Redshift and blueshift describe how light
changes as objects in space (such as stars or
galaxies) move closer or farther away from us.
The concept is key to charting the universe's
expansion.
Redshift/blueshift
Visible light is a spectrum of colors, which is
clear to anyone who has looked at a rainbow.
When an object moves away from us, the light is
shifted to the red end of the spectrum, as its
wavelengths get longer. If an object moves
closer, the light moves to the blue end of the
spectrum, as its wavelengths get shorter.
Example
Everyone has heard the increased pitch of an
approaching train and the sharp decrease in
pitch as the train passes by and recedes. The
effect arises because the sound waves arrive at
the listener's ear closer together as the source
approaches, and further apart as it recedes.
Doppler Effect
This sound effect was first described by Christian
Andreas Doppler and is called the Doppler
effect. Since light also travels in wavelengths,
this means that the wavelengths can stretch or
crunch together depending on the relative
position of objects.
Evidence
In the universe scientists have found that the
galaxies are moving away (redshift) from a
central point (where the explosion originated).
The universe is still expanding.
The Universe - All space, energy and matter
• What is in the Universe?
1. Earth
* Water in all 3 states
* If no water, no evaporation, no clouds, no oxygen, no
plants, no animals, no humans
* Has the right combination of gases in the atmosphere
that animals need to breathe.
* Has ozone that absorbs harmful radiation.
2. Solar systems
* A collection of large and small bodies
that orbit a central star.
* Our solar system has one star, the sun
and 8 planets.
* Planet – spherical body that orbits a star
*Terrestrial planets – rocky, dense and
relatively small bodies
* Mercury, Venus, Earth, Mars
*Gas giant planets – large planets with
thick , gaseous atmospheres
*Jupiter, Saturn, Neptune, Uranus
* Natural satellites (moons) – smaller bodies that
orbit planets
* Smaller objects – meteoroids, comets, asteroids
3. Stars
* Star - is a large celestial body that is
composed of gas and emits light
*Most stars are mainly composed of
hydrogen and helium.
*Nuclear fusion – stars fuse lighter
elements into heavier elements (ex.
Hydrogen into helium)
*Fusion takes place in the center of the
star and energy leaves the core and
moves outward giving of radiation
3. Galaxies
* Galaxy is a large collection of stars, gas
and dust held together by gravity
* Dwarf galaxies – small galaxies
containing 100 million stars
*Giant galaxies – contain hundreds of
billions of stars
*3 types of galaxies
*Spiral – our galaxy the Milky Way
*Elliptical galaxy
*Irregular galaxy
How are distances in the universe measured?
• Light-year – the distance that light travels in one year
going at the speed of light
• Speed of light – 300,000 km/second
• Speed of light – 186, 000 miles/second
• 9.5 trillion km in one year
• Closest star (other that sun) is Proxima Centauri is 4.3
light years away
• It would take 4.3 year to get there traveling at the
speed of light.
• Sun is 8 light-minutes from Earth
• Fastest inter-planetary spacecraft moves
58,000km/hour
• At that speed it would take 75,000 years to reach
nearest star
What is the structure of the Universe?
*Clusters or Superclusters – areas of densely
concentrated galaxies
• Voids – large areas where very little matter
exists
* Between galaxies are huge voids. Most of the
universe is made of voids.