Transcript What is a Red Shift?

Evidence of the
Big Bang Theory
What is the Big Bang Theory?
The theory that says that the universe
began with a super-powerful explosion
about 10-15 billion years ago.
What is a Red Shift?
http://www.youtube.com/watch?v=Fhfnqbo
acV0
Be ready to take notes!
What is a Red Shift?
Does red or blue light have a longer
wavelength? Circle One:
Red Light
Blue Light
How is an object moving if it is blue-shifted?
It is moving towards Earth.
How is an object moving if it is red-shifted?
It is moving away from Earth.
Do galaxies farthest away move slower or
faster than those that are closer?
Hubble’s Expanding Universe
/Red Shifts / Big Bang Theory
http://www.youtube.com/watch?v=hVApTL
E7Csc
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Hubble’s Expanding Universe /Red
Shifts / Big Bang Theory
Who discovered that the Milky Way is not the only
galaxy in our Universe?
Edwin Hubble
When do scientists think our Universe began?
Between 10 and 20 billion years ago.
What year was the Hubble telescope put into
orbit?
What advantage does the Hubble telescope have
over telescopes on Earth?
Hubble Ultra Deep Field 3D
http://www.youtube.com/watch?v=oAVjF_
7ensg
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Hubble Ultra Deep Field 3D
What did the telescope find after viewing a black
sky for 10 days?
What was one difference with the telescope the
second time they pointed it at a black area in
space?
Technology is defined as the use of knowledge
gained through science to make new products or
tools people can use. What role does technology
have in science?
Is there other evidence?
Scientists have found leftover cosmic
radiation in the form of microwaves that
has been around since the big bang
explosion.
http://www.youtube.com/watch?v=AfhRgh
1aqQk
Sun and Stars
Brain Thinkers
Compare our sun to other stars in the sky.
The sun plays a major role in our lives as
humans. Describe some situations where
the sun helps us as humans, with our
community, and our way of living.
What is our Sun?
Our sun is a medium-sized star near the
edge of a disc-shaped galaxy of stars.
The sun is many thousands of times
closer to Earth than any other star.
Characteristics of Stars
The Sun is an average star:
It’s not the hottest or coolest.
It’s not largest or smallest.
We can compare stars by color,
temperature, size, luminosity and
spectrum.
Color and Temperature
Color:
Stars range in color from red, orange, yellow, white,
to blue.
Red ----------- Yellow (Sun) ----------- > Blue
Temperature:
Stars range in temperature from 2000oC--50 000oC.
2 000oC ---------5 000oC (Sun)--------- > 50 000oC
Color and Temperature
Color and temperature are linked.
The 3,000oC stars are red in color.
The 50,000oC stars are blue in color.
Color and Temperature
Color
Temp. Range (oC)
Examples
Blue
25000 – 50 000
Zeta Orionis
Bluish-white
11 000 – 25 000
Rigel, Spica
White
7 500 - 11 000
Vega, Sirius
Yellowish-white
6 000 - 7 500
Polaris, Procyon
Yellow
5 000 - 6 000
Sun, Alpha Centauri
Orange
3 500 - 5 000
Arcturus, Aldebaran
Red
2 000 - 3 500
Betelgeuse, Antares
Luminosity
Luminosity is related to the distance
from the earth and the brightness of
the star
Apparent Magnitude – refers to the
brightness of a star as it appears to us.
Absolute Magnitude – refers to the actual
amount of light given off by a star at a
standard distance.
Spectrum
Spectroscope: Used to measure the chemical
composition of the stars. (also temperature
and direction the star is moving in relation to
the Earth.)
How? Set up a spectroscope with different
tubes; each gas has different spectras – light
patterns.
Questions
1. How is the color of a star related to its
temperature?
The color of a star depends on its temperature,
from red and orange (cool stars) to yellow and
white (hotter stars) to blue (very hot stars).
2. Explain why a cooler star could actually
appear brighter than a hotter star.
A cool star, such as a red giant, could be either
closer to us or much larger than a hotter star,
such as a white dwarf. (Could be closer and
larger)