Download 186,000 miles per second

186,000 miles per second
Electromagnetic Spectrum
It’s not just a good
idea…
It’s the law!
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What is a light year and what does it
measure?
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The distance light travels in a year’s
time
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How many miles in 1 light year?
186,000 x 60 = min x 60 = hr x 24 = day x 365 = year
=5.87 x 1012 miles!
= 5,870,000,000,000 miles
How long does it take for sunlight to reach Pluto which is 3.6 billion miles
away?
3.6 x 109 mi = 1 sec
= 1 min = 1 hour
186,000 mi
60 sec
60 min
= 5.37 hours (.37 x 60 = 22 min) so 5 hr 22 min.
How many miles to the star Sirius which is 8.7 light years away?
5.87 x 1012 miles x 8.7 = 5.1 x 1013
= 51,000,000,000,000 miles!
How many miles to the Andromeda galaxy which is 2.9 million light years
away?
5.87 x 1012 mi x 2.9 x 106 = 1.7 x 1019
17,000,000,000,000,000,000 miles!!
And that is a NEARBY galactic neighbor!!
So how do astronomers know all of
this?
It all starts with an understanding of
the electromagnetic spectrum
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Speed = wavelength x
frequency
speed
or
= 186,000 mi/sec
300,000 km/sec
wavelength=
crest to crest
frequency = # of waves/sec.
If you increase wavelength, then the frequency decreases
If you decrease wavelength, then the frequency increases
 Called an inverse relationship
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Optical Telescopes
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Where would be the best place to build your telescope? Why?
Two purposes: gather light and magnify objects
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The larger the opening, the greater the light gathering ability
A= ∏(r)2
So, if you double the size of the telescope, it increases its light gathering
potential by ____?
Refractor
Reflector
Multiple-Mirror Telescopes (MMT)
Schmidt- reflecting mirror and refracting lens = wide angle view
Charge-Coupled Devices (CCD’s)
Reflecting telescope
Yerkes
Observatory,
Wisconsin
102 cm refractor
(the world’s
largest refracting
telescope)
Hale Telescope, Mt Palomar CA
mirror is 508 cm!
Keck MMT: Mauna Kea, HI
two telescopes work together to equal 85 meter
mirror!
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Hubble
Radio Telescopes and others
 Utilizes
different wavelengths
can they be wire mesh?
 Wavelengths are so long
 Other types are infrared, gamma, x-ray
 Why
Very Large Array: Socorro, NM
Radio telescopes linked to equal a diameter of 34
kilometers!!
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