Upload
metta
View
41
Download
0
Embed Size (px)
DESCRIPTION
Thursday September 6, 2012. ( The Study of Light; Doppler Shifts; Videos HTUW: The Big Bang , Part 3 ). The Launch Pad Thursday, 9/6/12. Can you name the seven basic colors of visible light from lowest to highest frequency?. R O Y G. B I V. Announcements. - PowerPoint PPT Presentation
Citation preview
ThursdaySeptember 6, 2012
(The Study of Light; Doppler Shifts; Videos
HTUW: The Big Bang, Part 3)
The Launch PadThursday, 9/6/12
Can you name the seven basic colors of visible light from lowest to highest frequency?
ROY G. BIV
Announcements• Please remember that we will
have our next Quiz tomorrow.
Assignment Currently Open
Summative or
Formative?Date Issued Date Due Date Into
GradeSpeed Final Day
ESS Class Information Sheet F1 8/27 8/28
ESS Class Procedures and
ExpectationsF2 8/27 8/29
Quiz 1 S1 8/31 8/31 8/31 9/14
Lab - Hubble’s Law - the
Expanding Universe
F3 9/4 9/6
??
Recent Events in ScienceHubble Captures a Collection of Ancient Stars
The NASA/ESA Hubble Space Telescope has produced this
beautiful image of the globular cluster Messier 56 (also known as M 56 or NGC 6779), which is
located about 33,000 light years away from the Earth in the constellation of Lyra (The
Lyre). The cluster is composed of a large number of stars,
tightly bound to each other by gravity.
http://www.nasa.gov/mission_pages/hubble/science/ancient-stars.htmlRead all about
it!
How the Universe
Works: The Big Bang
Part 3 Gravity
Video
The Study of Light • The Doppler Effect is the apparent change in __________
of waves caused by the relative _______ of the source and observer. It is used to determine:» ________ of motion.• increasing distance – wavelength is ________
(“stretches.”)• decreasing distance – makes wavelength
________ (“compresses.”)» velocity – larger Doppler shifts indicate ______
velocities.http://www.youtube.com/watch?v=Kg9F5pN5tlI
wavelengthmotions
directionlonger
shorterhigher
• So, the Doppler Effect is the change in the wavelength of light emitted by an object due to its motion.
Movement away stretches the wavelength Longer wavelengthLight appears redder
Movement toward “squeezes” the wavelengthShorter wavelengthLight shifted toward the blue
The Study of Light
The Electromagnetic Spectrum
Figure 23.2
Doppler Shifts
The amount of the Doppler shift indicates the _____ of movement .
… a large Doppler shift indicates a ________ velocity
… a small Doppler shift indicates a ________ velocity
rate
greater
lesser
Doppler Shifts The Expanding Universe
Most galaxies exhibit a ____ Doppler shift, meaning they are moving ___________ us.
Far-away galaxies exhibit the greatest shift, therefore the greater __________.
This phenomenon was discovered in 1929 by _________________.
“_____________” states that the recessional speed of galaxies is proportional to their __________.
redaway from
velocity
Edwin HubbleHubble’s Law
distance
Doppler Shifts If a star (or galaxy) is stationary relative to us
here on Earth, the light waves it emits are neither bunched together nor stretched out;
therefore, it appears yellow.If a star or galaxy is approaching us rapidly, its
light waves will be bunched together; therefore, it appears blue.
If a star or galaxy is receding from us rapidly, its light waves will be stretched out; therefore,
it appears red.
Please note at this point that there are other factors that influence the color of a star. We
will discuss this at a later date.
Question: Name two compelling pieces of evidence that support the Big Bang
Theory?
In 1929, astronomer Edwin Hubble discovered that most galaxies are moving away from one
another. Hubble’s discovery indicated that the Universe is expanding in all directions.
Diffuse cosmic background radiationhttp://www.astrosurf.com/luxorion/audiofiles-misc-natural.htm