Download Unit 8 Chapter 26 Studying Space

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Unit 8 Chapter 26
Studying Space
Section 1 Viewing the Universe
Astronomy __________________________________________________
Astronomer _________________________________________________
The Value of Astronomy
As new things are discovered in space like Black Holes, new planets, stars
and nebula, scientists can use that information to learn about Earth.
Scientists have been able to piece together the processes that involve the
formation of our planet, the solar system and the universe.
Characteristics of the Universe
Cosmology is _________________________________________________
____________________________________________________________
The Universe began approximately __________________ ago in what we
feel was a “Big Bang”.
Organization of the Universe
Our nearest part of the universe is our solar system. Our solar system is
part of a galaxy which is a collection of stars, dust, gas and other objects
bound together by gravity.
Our galaxy name is the _________ (candy named after it).
Measuring Distances in the Universe
Astronomical Unit (A.U.) is the average distance from the earth to the sun
which is 149,597,870.691 km (150 million)
Light Year measures the distance that a ray of light travels in one year,
which is approximately 9.46 X 1012 km
1 light year = 9.5 X 1012 km
1 A.U.
= 1.5 X 108 km
This means that there are 6033 X 104 A.U.’s per light year.
The next closest object to us aside from out sun is approximately 4.22 light
years away.
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Observing Space
The light that is emitted by the object in space allows us to see them.
Planets do not emit light, they reflect, starts emit a light.
Electromagnetic Spectrum
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It is an instrument that uses prisms to split light, a special telescope and a
special camera to look at stars. Each star emits its own spectrum because
each star is made of different elements and each element emits a different
wavelength.
___________________They are an unbroken band of color which shows that the source is
emitting all visible wavelengths. It can be either a glowing solid (hot
filament of light bulb) or a glowing liquid (molten iron, lava) or a hot
compressed gas.
_________________These are unevenly spaced lines of different colors and brightnesses.
Bright lines mean light of only certain wavelengths can be glowing thin
gasses (Florescent bulbs).
____________________
It is a continuous spectrum crossed by dark lines. This happen when
light passes through a cooler gas, actually the elements in the gas
absorb exactly the same wavelengths that they would emit if they
were hot and glowing.
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Visible Electromagnetic Radiation
Visible Spectrum is the part of the electromagnetic spectrum that human
eyes can see. We see the colors of a rainbow, Red (longest), Orange,
Yellow, Green, Blue and Violet (shortest). White light is made up of all of
the colors in the spectrum.
Color shifts are used to visualize the movement of objects toward and
away from the observer. We use this when we work with meteorological
maps and viewing objects in space. In labs the changes are either to the
red or the blue side of the spectrum.
RED SHIFT- __________________________________________
There is a wavelength increase
BLUE SHIFT- _________________________________________
There is a wavelength decrease
Erwin Hubble discovered that most stars are red shifted. It means that all
stars are moving apart and the universe is expanding
Invisible Electromagnetic Radiation
Invisible radiation is the radiation that we can not see but we can feel it
and experience it. It will usually involve a temperature rise. In the 1800
William Heschel discovered that there was a rise in temperature in the red
end of the spectrum if you placed a thermometer in it, hence the name
Infrared, which means below red.
Doppler Effect is ______________________________________________
____________________________________________________________
Example- The sound of a siren as it comes towards you and then
moves past you. The pitch grows higher as the vehicle
approaches it compresses and makes the wavelength shorter
(higher pitched) as the vehicle goes away from you the
wavelengths increase in size and the pitch drops.
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Telescopes
A Telescope is used to help our eyes see further and more clearly into
space. Although he was not the first to make it, Galileo was the first to use
it to see the “heavens”, since it was originally used to look for ships and
pirates. They gather more light than our eye can and can magnify images.
The best place to use a telescope is in a place that is away from light and
as high as possible. Why?
Refracting Telescopes
Refracting Telescopes ___________________________________________
The bad thing about them is that it is hard to make big lenses for the
instruments, so they tend to be smaller. Also if you focus in on one color,
you will be out of focus in another.
Reflecting Telescopes
Reflecting Telescopes ___________________________________________
_________________________. Sir Isaac Newton first introduced this.
These telescopes are usually about 10 meters in diameter. The Keck
telescope in Hawaii is the largest of these so far. If smaller multiple mirrors
are used instead of one big one it is called a Multiple Mirror Telescope
(MMT).
Astronomers are planning are making larger ones. An ELT, Extremely
Large Telescope at about 50meters and the OWL, Overwhelmingly Large
Telescope at about 100 meters are in the works.
Telescopes for Invisible Electromagnetic Radiation
A Radio telescope uses radio waves instead of light. It collects the sound
waves from space and transmits them into an instrument that looks like a
dish. In New Mexico there is an array of them able to act as one, the Very
Large Array (VLA). This enables astronomers to hear radio waves from
outer space (like the movie Contact).
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Space Based Astronomy
In Space, Earth’s atmosphere can not interfere with the detection of
electromagnetic energy.
Space Telescopes
Hubble Telescope
A telescope launched in space from the space shuttle that enables us to
see 12 billion light years away. Named after Erwin Hubble who discovered
that most (all) stars is red shifted
Other Spacecraft
Since the 1960’s we have been sending things into space to do the
exploring for us.
1977 Voyager 1 and Voyager 2 investigated Jupiter, Saturn, Uranus & Neptune
1995-2003 Galileo orbited Jupiter
2004 Cassini orbited Saturn
2004 Huygens studied the surface of Titan
2004 Mars rovers Spirit and Opportunity landed
2008 Phoenix found ice on Mars
Human Space Exploration
The first humans went into space in the 1960’s. Between 1969 and 1972
12 humans have landed on the moon. NASA is still researching and
sending crews out to space stations now.
Spin-offs of the Space Program
We have satellites that we use to help us see and hear things better, for
commercial or government use. Medical equipment is also being
experimented on in the space station for use on earth.
Section 2 Movement of the Earth
If we can understand the motions of the Earth, we can understand the
motions of other bodies in our solar system.
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The Rotating Earth
The earth rotates counter clockwise as seen from above the North Pole
(from west to east).
The earth rotation and its tilt also cause:
changes in the amount of sunlight per day
length of the day (24 hours)
direction of the sunset;
Summer – north of West
Winter – south of West
direction of sunrise;
Summer – north of East
Winter – south of East
Apparent movement of the sun across the
Sky
The earth is 40,074 km at the Equator, it rotates 15o/hr therefore it must
rotate 1670 km/hr. At the north and South Pole, it rotates at the grand
speed of 0 km/hr. At 41o N Lat. It is approximately 1325 km/hr.
The Foucault Pendulum
In 1851 Jean Foucault constructed a freely swinging pendulum that
appeared to change its direction in a very predictable manner.
The pendulum appeared to move 15o per hour.
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The Coriolis Effect
Objects in the Northern Hemisphere ____________________________
Objects in the Southern Hemisphere ____________________________
The Revolving Earth
As Earth spins on its axis, it also travels around the sun. The average
speed of the orbit is approximately 29.8km/s which takes us about 365 ¼
days to go around the sun.
Earth’s Orbit
Because the earth’s orbit isn’t a perfect circle we are closer in the
winter and further away in the summer.
Aphelion-_____________________________________________
Perihelion_____________________________________________
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Constellations and Earth’s Motions
Evidence of Earth’s motions can also be seen in the motions of the
constellations.
Constellations
________________________________________________________
_____________________________________________________________
_____________________________________________________________
Evidence of Earth’s Rotation
All stars appear to move in an arc in the sky except for Polaris. Why
______________________________________________________
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Evidence of Earth’s Revolution
Not only does the daily position of celestial objects change, the position
changes throughout the year, why?
____________________________________________________________
Measuring Time
Earth’s motion provides the basis for measuring time. Each day is divided
into 24 hours.
A year is divided into 365 ¼ days and a month was based on the cycle of
the moon which was approximately 29.5 days. Now it is based on being
1/12th of the year.
Formation of the Calendar
A calendar is a system created for measuring long intervals of time by
dividing time into periods of days, weeks, months, and years.
Because the year is about 365 1/4 days long, the extra 1/4 day is usually
ignored to make the number of days on a calendar a whole number. To
keep the calendars on the same schedule as Earth's movements, we must
account for the extra time. So, every four years, one day is added to the
month of February. Any year that contains an extra day is called a leap
year.
The Modern Calendar
Because the year is not exactly 365 days long, over centuries, the calendar
gradually became misaligned with the seasons. In the late 1500s, Pope
Gregory XIII formed a committee to create a calendar that would keep the
calendar aligned with the seasons. We use this calendar today. In this
Gregorian calendar, century years, such as 1800 and 1900, are not leap
years unless the century years are exactly divisible by 400. Thus, 2000 was
a leap year even though it was a century year. However, 2100, 2200, and
2300 will not be leap years.
Time Zones
Standard time zones - the world is divided in 24 different time zones each
15o of longitude, called time meridian.
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International Date Line
International Date Line – because of the changes of time either ahead or
back, people can lose or gain a whole day. This line (imaginary)
represents where the date will change.
West – one day ahead
East – one day earlier
Daylight Savings Time
Because there is a different amount of day light hours in the winter and
summer, the United States decided to adjust out clocks to accommodate
this. We turn our clocks ahead in the spring, in which we lose an hour of
time, and then we fall back, in which we gain an hour. This was due to
help with the energy crisis.
The Seasons
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Since our axis is tilted about 231/2o off of perpendicular this which means
that a different area of the earth receives different amounts of light each
day. And since it takes us 12 months to complete a revolution around the
sun, it takes approximately 3 months to change the area being exposed.
Seasonal Weather
As the Earth moves, it causes changes in the area exposed which creates
different weather in areas on the earth. So the seasons are caused by the
tilt of Earth's axis and not by Earth's distance from the sun.
Equinoxes
Equinox
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Summer Solstice
Summer Solstice (June 21st)
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Winter Solstice
Winter Solstice (December 21st)
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