#8 A: Vocabulary from Topic 4
8 B: Green Review books
#9 : Constellation - DRAW Big and Little dipper with "North Star" Polaris
Remember the Constellation worksheet.... where we see the stars at NIGHT.
So now in Dec 21 we would see GEMINI, not Sagittarius... This is ASTRONOMY not Astrology!
Can you shade in the area of earth that would be night time?
or
but actually
#10: Draw the orientation of the SUN - Earth - moon for the following phenomenon
Lular eclipse vs Solar Eclipse
Spring Tide vs. Neap tide
end of 2012
Happy New Year!
2013
#11: Green Review Book
Do the following Read pg 254-255
Answer Q's 1,3,4,6,7,8,9,10,11,15,16
on pg 260-261 # 17,18,20,21
Pg 266 #1
The review books are in! you are given your own copy and you need to keep it NEW, No marking in the book. you will have to return them in June before the Regents.
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HW#8
Read pg 272 to 278
Do the following questions & answer pg 276 to 278 #2, 4to 15 then pg 294 #8
(copy the question then answer)
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Angular Measure: Degrees, Minutes, and Seconds of Arc
Degrees, minutes, seconds
The apparent sizes of distant objects and things in the sky are measured by the angle they subtend at the eye. (It's a common error to suppose that the Sun, say, looks about as big across as a dinner plate; to some people, it seems bigger than that, but to others, it's smaller. So such attempts to describe apparent sizes in linear terms lead to misunderstandings and confusion. Angular sizes can be measured with instruments, and are a standard we can all agree on.) If you are unfamiliar with angular measure, there are 90° in a right angle; 60 minutes of arc in one degree; and 60 seconds of arc in a minute. (We say “minutes of arc” to distinguish them from minutes of time.) Minutes of arc are designated by a (') sign; so “ 30' ” is read “30 minutes”. To give some familiar examples:
The width of your thumb, seen at arm's length, is about 2°. The angular diameter of the Sun or the Moon is only about 1/4 of that, or just over 1/2 degree, which is 30 minutes of arc. (Yes, they look bigger than that near the horizon; the increased apparent angular size is an optical illusion.) A person with normal vision can just distinguish two points separated by about 1' of arc. (That means you can forget about seconds of arc unless you're using a telescope.)
The angular height of mirages is always less than a degree. But, because of the horizon illusion mentioned above, people often suppose they are bigger than that.
Distant objects
Because the distances of miraged objects are always much greater than their sizes, the angles they subtend are always small. Small angles are readily related to the sizes and distances of the objects: the ratio of the size to the distance is the angular size measured in radians.
The final meteor shower of the year is going
to take place tonight and if you are lucky to have clear skies this
should be quite the show. Across much of the northeast and back into
the northern Rockies skies will be clear and perfect for viewing. There
is a "new moon" tonight and this means no moonlight to spoil the show.
While you will be able to see a few shooting stars after sunset the
display really gets going after 10PM and will peak a couple of hours
after midnight. However, you will definitely see some shooting stars
well before peak. I circled in blue areas of the country that will have
the best viewing tonight on the map below. I'd love to hear your experience on the meteor shower or on this blog. Please follow and chat with me on Twitter at @growingwisdom and check out my latest videos at GrowingWisdom.com
A brand new meteor shower possible
Astronomers are particularly excited about tonight's Geminid meteor
shower as there could be even more shooting stars added to the mix. The
earth may pass through comet Wirtanean in the next few days. Most
meteor showers are caused when the earth passes through the debris of a
comet. As of yet, the Earth hasn't run into comet Wirtanean's debris
field. However, tonight may be different. If the earth passes through
the debris it would result in a new shower of meteors that would combine
with the Geminid's. That means we could be looking at 60-100 meteors
per hour. The additional meteors would be coming from the constellation
Picses (The Fish), so the shower could be called the Piscids.
The Geminids will appear to emanate from the constellation Gemini
(The Twins) and are a result of the Earth hurling through debris shed by
the huge, enigmatic asteroid 3200 Phaethon. This makes this meteor
shower unusual because it isn't caused by comet particles.
Remember, the most important thing about viewing the event is get away
from as much light as possible. The darker your surrounding the better
your viewing will be and the more meteors you will see. Jupiter
If you are looking up tonight you might spot Jupiter as well. Jupiter
is one of the brightest objects in the sky rising after sunset to the
southeast and remaining in the sky most of the night. If you want to
see Mars look to the southwestern sky at sunset as the reddish object
will be that planet setting for the night. If you are up super early
you can catch Venus rising in the eastern sky about 2 hours before the
sun.
axis (of rotation) Foucault pendulum Phases (of the moon) constellation geocentric model tides Coriolis effect heliocentric model time zone eclipse local time
Our universe contains an amazing array of
celestial objects, sometimes referred to as celestial
bodies or astronomical objects. Though most of the
observable cosmos is composed of empty space, this cold, dark void that is
sparsely populated by a number of astronomical objects that range from the
common to the bizarre. Known collectively by astronomers as celestial objects,
celestial bodies, astronomical objects, and astronomical bodies, they are the
stuff that fills the empty space of the universe. Most of us are familiar with
the stars, planets, and moons. But beyond these everyday celestial objects, lies
an amazing collection of other wondrous sights. There are colorful nebulae,
delicate star clusters, and massive galaxies. Pulsars and quasars add to the
mystery, while black holes swallow up every bit of matter that comes too close.
And now, the search is on to identify the mysterious, invisible objects known as
dark matter. Join Sea and Sky for an intriguing journey as we discover these
amazing celestial objects. Click on any image below to find out more, or use the
icons on the left side of the page to navigate your way through the celestial
objects.
Stars
Planets
Moons
Asteroids & Comets
Nebulae
Star
Clusters
Galaxies
Pulsars
Quasars
Black
Holes
Dark
Matter
All images in
this section are copyrighted 1999 by J.D. Knight.
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Let's say you are sending a spacecraft to Mars. You'd like your spacecraft to help you figure out what the rocks on Mars are made of. Or, let's say you'd like to know what gases are in the planet Jupiter's atmosphere. Or, maybe a strange gas has entered your school building and you'd like to figure out if it's dangerous or not. A spectrometer will help you in all these cases. It turns out that different substances absorb or emit light at different wavelengths in the Electro Magnetic (EM) Spectrum. If you shine the light you get from burning sodium into a prism or diffraction grating or other spectrometer, you'll find that the light comes out in bands of color at different places on the spectrum.
The amazing thing is, every time you see burning sodium, you'll see this same pattern of light if you send it through a spectrometer. You will always see those same bright aqua and green lines by themselves in the middle of the spectrum. These lines are called spectral lines, and they are related to the way the atoms in the material are arranged.
**************************************************************************** Variations in Air Pressure and Corresponding Waveform
Suppose that there is a happy bug in the center of a circular water puddle. The bug is periodically shaking its legs in order to produce disturbances that travel through the water. If these disturbances originate at a point, then they would travel outward from that point in all directions. Since each disturbance is traveling in the same medium, they would all travel in every direction at the same speed. The pattern produced by the bug's shaking would be a series of concentric circles as shown in the diagram at the right. These circles would reach the edges of the water puddle at the same frequency. An observer at point A (the left edge of the puddle) would observe the disturbances to strike the puddle's edge at the same frequency that would be observed by an observer at point B (at the right edge of the puddle). In fact, the frequency at which disturbances reach the edge of the puddle would be the same as the frequency at which the bug produces the disturbances. If the bug produces disturbances at a frequency of 2 per second, then each observer would observe them approaching at a frequency of 2 per second. Now suppose that our bug is moving to the right across the puddle of water and producing disturbances at the same frequency of 2 disturbances per second. Since the bug is moving towards the right, each consecutive disturbance originates from a position that is closer to observer B and farther from observer A. Subsequently, each consecutive disturbance has a shorter distance to travel before reaching observer B and thus takes less time to reach observer B. Thus, observer B observes that the frequency of arrival of the disturbances is higher than the frequency at which disturbances are produced. On the other hand, each consecutive disturbance has a further distance to travel before reaching observer A. For this reason, observer A observes a frequency of arrival that is less than the frequency at which the disturbances are produced. The net effect of the motion of the bug (the source of waves) is that the observer towards whom the bug is moving observes a frequency that is higher than 2 disturbances/second; and the observer away from whom the bug is moving observes a frequency that is less than 2 disturbances/second. This effect is known as the Doppler effect. The Doppler effect is observed whenever the source of waves is moving with respect to an observer. The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding. It is important to note that the effect does not result because of an actual change in the frequency of the source. Using the example above, the bug is still producing disturbances at a rate of 2 disturbances per second; it just appears to the observer whom the bug is approaching that the disturbances are being produced at a frequency greater than 2 disturbances/second. The effect is only observed because the distance between observer B and the bug is decreasing and the distance between observer A and the bug is increasing. The Doppler effect can be observed for any type of wave - water wave, sound wave, light wave, etc. We are most familiar with the Doppler effect because of our experiences with sound waves. Perhaps you recall an instance in which a police car or emergency vehicle was traveling towards you on the highway. As the car approached with its siren blasting, the pitch of the siren sound (a measure of the siren's frequency) was high; and then suddenly after the car passed by, the pitch of the siren sound was low. That was the Doppler effect - an apparent shift in frequency for a sound wave produced by a moving source.
The Doppler effect is of intense interest to astronomers who use the information about the shift in frequency of electromagnetic waves produced by moving stars in our galaxy and beyond in order to derive information about those stars and galaxies. The belief that the universe is expanding is based in part upon observations of electromagnetic waves emitted by stars in distant galaxies. Furthermore, specific information about stars within galaxies can be determined by application of the Doppler effect. Galaxies are clusters of stars that typically rotate about some center of mass point. Electromagnetic radiation emitted by such stars in a distant galaxy would appear to be shifted downward in frequency (a red shift) if the star is rotating in its cluster in a direction that is away from the Earth. On the other hand, there is an upward shift in frequency (a blue shift) of such observed radiation if the star is rotating in a direction that is towards the Earth. http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/redshift.html
Redshift
Astronomers often use the term redshift when describing how far away a distant object is. To understand what a redshift is, think of how the sound of a siren changes as it moves toward and then away from you. As the sound waves from the siren move toward you, they are compressed into higher frequency sound waves. As the siren moves away from you, its sound waves are stretched into lower frequencies. This shifting of frequencies is called the Doppler effect.
A similar thing happens to light waves. When an object in space moves toward us it light waves are compressed into higher frequencies or shorter wavelengths, and we say that the light is blueshifted. When an object moves away from us, its light waves are stretched into lower frequencies or longer wavelengths, and we say that the light is redshifted.
In the visible portion of the electromagnetic spectrum, blue light has the highest frequency and red light has the lowest. The term blueshift is used when visible light is shifted toward higher frequencies or toward the blue end of the spectrum, and the term redshift is used when light is shifted toward lower frequencies or toward the red end of the spectrum. Today, we can observe light in many other parts of the electromagnetic spectrum such as radio, infrared, ultraviolet, X-rays and gamma rays. However, the terms redshift and blueshift are still used to describe a Doppler shift in any part of the spectrum. For example, if radio waves are shifted into the ultraviolet part of the spectrum, we still say that the light is redshifted - shifted toward lower frequencies.
The light from most objects in the Universe is redshifted as seen from the Earth. Only a few objects, mainly local objects like planets and some nearby stars, are blueshifted. This is because our Universe is expanding. The redshift of an object can be measured by examining the absorption or emission lines in its spectrum. These sets of lines are unique for each atomic element and always have the same spacing. When an object in space moves toward or away from us, the absorption or emission lines will be found at different wavelengths than where they would be if the object was not moving (relative to us).
The change in wavelength of these lines is used to calculate the objects redshift. Redshift is defined as the change in the wavelength of the light divided by the wavelength that the light would have if its source was not moving (called the rest wavelength).
The cosmological redshift is a redshift caused by the expansion of space. As a result of the Big Bang (the tremendous explosion which marked the beginning of our Universe), the Universe is expanding and most of the galaxies within it are moving away from each other. Astronomers have discovered that all distant galaxies are moving away from us and that the farther away they are, the faster they are moving. This recession of galaxies away from us causes the light from these galaxies to be redshifted. As a result of this, at very large redshifts, much of the ultraviolet and visible light from distant sources is shifted into the infrared part of the spectrum. This means that infrared studies can give us much information about the ultraviolet and visible spectra of very young, distant galaxies.
Doppler Shift Interactive (70.0K) Astronomers use the Doppler Effect to determine the motion and speed of galaxies and other distant objects. This Interactive shows you what the Doppler Effect is: how the frequency and wavelength of light or sound waves change as the source or the observer (or both) move relative to each other. Click on the buttons to make the Observer, the Source or Both approach, and observe the waves on the graph. Or take matters into your own hands by clicking and dragging on the spaceship to change its velocity.
also on Nov 16 , Friday you can observe the Leonid Meteor Shower Webcast at NASA!
This sky map for the Leonid meteor shower of 2012 shows the
location of the radiant (center) before dawn on Saturday, Nov. 17 - the
peak viewing time. CREDIT: StarDate.org
The annual Leonid meteor shower will peak overnight tonight (Nov. 16)
and early Saturday (Nov. 17), and you can watch the celestial fireworks
show live via a NASA webcast.
Scientists at NASA's Marshall Space Flight Center in Huntsville, Ala., will provide a live views of the Leonid meteor shower from an all-sky camera beginning late Friday afternoon and running through early Saturday morning.
The webcast will be embedded below when it begins by 7 p.m. EST (0000 Nov. 17 GMT):
legs in order to produce disturbances that travel through the water. If these disturbances originate at a point, then they would travel outward from that point in all directions. Since each disturbance is traveling in the same medium, they would all travel in every direction at the same speed. The pattern produced by the bug's shaking would be a series of concentric circles as shown in the diagram at the right. These circles would reach the edges of the water puddle at the same frequency. An observer at point A (the left edge of the puddle) would observe the disturbances to strike the puddle's edge at the same frequency that would be observed by an observer at point B (at the right edge of the puddle). In fact, the frequency at which disturbances reach the edge of the puddle would be the same as the frequency at which the bug produces the disturbances. If the bug produces disturbances at a frequency of 2 per second, then each observer would observe them approaching at a frequency of 2 per second.
the same frequency of 2 disturbances per second. Since the bug is moving towards the right, each consecutive disturbance originates from a position that is closer to observer B and farther from observer A. Subsequently, each consecutive disturbance has a shorter distance to travel before reaching observer B and thus takes less time to reach observer B. Thus, observer B observes that the frequency of arrival of the disturbances is higher than the frequency at which disturbances are produced. On the other hand, each consecutive disturbance has a further distance to travel before reaching observer A. For this reason, observer A observes a frequency of arrival that is less than the frequency at which the disturbances are produced. The net effect of the motion of the bug (the source of waves) is that the observer towards whom the bug is moving observes a frequency that is higher than 2 disturbances/second; and the observer away from whom the bug is moving observes a frequency that is less than 2 disturbances/second. This effect is known as the Doppler effect.
