1
Q
What did Newton believe about light?
A
- that light is a stream of particles
2
Q
What did Hooke believe about light?
A
- light is a process like sound (waves)
3
Q
What did Newton find about prisms
A
- newton found that the prism itself does not add the colour to the light but that the colour is an intrinsic property of light
4
Q
What does a prism split white light into?
What happens when you shine the light through a second prism?
Who found this out?
A
- a prism breaks light into its spectrum (ROYGBV)
- though using screens and a second prisms newton found that depending on the screen using, only certain color will pass, but the second prism only changes the direction
- different colours correspond to different types of light particles (newton)
5
Q
Who predicted and confirmed electromagnetic waves?
A
- James Clerk Maxwell predicted them in 1860
- 20 years later this was confirmed by Heinrich Hertz
6
Q
What is wavelength ?
A
- the distance between two peaks in a wave
7
Q
What differentiates electromagnetic waves from other types of waves like sound waves and water surface
A
- electromagnetic waves can propagate through an empty space (vacuum)
8
Q
What wavelengths are visible to humans
A
- 400 to 700 nm
9
Q
What is the speed of light referred to
A
C
C= 300,000 km/s = 180,000mils
10
Q
What is one of the fundamental principles of physics
A
- nothing can move faster than light
- the fitness of the speed of light
11
Q
If the sun went out, how long would it take for us to know?
A
8 minutes
12
Q
Is light particles or waves?
A
- its both
13
Q
What is the order of waves starting with the longest
A
- radio waves
- microwaves
- infrared radiation/ light
- visible/ white light
- ultraviolet radiation/ waves
- x-ray waves
- gamma rays
14
Q
What is the Doppler Effect?
What is a Red shift?
What is a Blue shift?
A
- Evidence of a wave behaviour of light
- the change in wavelength of light and sound waves due to the relative motion between the source and the observer along the line of sight
- for example, when a cop drives by the sound is the loudest when it is closest or most in line with you
- red shift= moving away from observer, longer, behind
- blue= moving toward observer, shorter, infront
15
Q
What was Albert Einsteins contribution to light properties
A
- he showed that light also behaves as particles called photons
- the energy of a photon decreases as it’s wavelength increases
16
Q
Does a photon of red light carry less or more energy than blue
A
- less
17
Q
According to Quantum Mechanics, photons have what properties
A
- the properties of particles and waves at the same time
- particle-wave dualism
18
Q
What does the transparency of a material depend on?
Which waves can pass through and which cannot?
A
- wavelength of light “windows” in the earth’s atmosphere
- radio, visible waves can travel through
- x rays, gamma, cannot (easier to observe )
- UV and infrared are partial
19
Q
What are the two basic telescopes
A
- reflecting
- refracting
20
Q
What are reflecting telescopes
A
- they use a concave mirror to gather and collect light
- creates focal point
- concave parabolic mirror
- gather and focus
21
Q
what is the newtonian reflecting telescope
A
- primary and secondary concave mirrors
- primary mirror focuses light on flat secondary mirror into lens eyepiece
22
Q
What are the 3 properties and functions of a telescope
A
- light gathering power
- angular resolution
- magnification
23
Q
What are the light gathering powers of a telescope and how does diameter affect this
A
- telescopes brighten objects by collecting light. the ability of a telescope to collect light is called its light gathering power
- smaller diameter means less light gather power, blurred or dimmed image
- larger diameter means more light gathering power, brighter, sharper image
24
Q
What is the resolution property of a telescope
How does diameter affect this
A
- the clarity of the image and the amount of detail revealed is called angular resolution
- smaller diameter telescopes have less resolution, meaning less details are seen
- larger diameter telescopes have more details and more resolution
25
What is magnification
- making objects appear larger
26
Why is the human eye not very good as light detectors
- they become tired
| - eyes cannot take photos, must sketch what u see
27
Photographic plates
- glass plates covered In silver salts
- light sensitive emulsion
- hard to store
28
Charge-Coupled Devices (CCDs)
- gather more light efficiently than photographic plates
| - they produce images with incredible detail
29
What are refracting telescopes
- a convex lens converges parallel light rays at a focal point, just like reflecting telescopes
- they use an objective lens to gather light and an eyepiece through which the image is viewed.
- this is the telescope that produces an image that is upside down but there is no up and down in space so it doesn't matter
30
What are the limitations of a refracting telescope
1. chromatic aberration- different colours of light have different focal points
2. spherical aberration - not all parallel rays converge at a single focal point
3. the weight of a lens can cause the lens to sag and distort the image
4. air bubbles in glass distort the image
5. glass is opaque due to certain wavelength's of light, meaning they do not go through the mirror
31
What is the main problem with reflecting telescopes
| How do ew fix this
- spherical aberration
not all parallel rays converge at a single focal point
-problem - spherical mirror
- how to fix this? use a parabolic mirror so there is one focal point for all light rays
32
Where is the largest refracting telescope
- yerkes observatory near chicago
| - the objective lens is 102 cm or 40 inch in diameter and the telescope tube is 19 1/3 m or 63 1/2 ft long
33
How to make a large parabolic mirror
- 40,000 pounds of glass are loaded into a rotated furnace and heated to 1200 degree Celsius
- after melting, spinning, and cooling, the surface is ready to be coated with a highly reflective material
34
Why are many observatories located on mountain tops
- starlight appears less distorted in the thin atmosphere on mountain tops
- at high altitudes there is less atmosphere to absorb infrared energy
- mountain tops also have unobstructed views of the horizon in all directions
- light from cities scatter in our atmosphere reducing the visibility of celestrial objects (light pollution)
35
What is the ultimate solution
- space based telescopes
36
Why are space-based telescopes better
- the moon has no atmosphere
37
What is the oldest outer space telescope
the hubble space telescope
- launched in 1990
- its primary mirror is about 2 meters in diameter
- it has solar panel's to power and is expected to work for 30 years (till 2020)
38
Who is james webb
- successor , It has a mirror thats about 14 ft to be able to see way further and will be way further away from earth
39
What speed do light waves move at in space
- speed of light
40
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What is Nonoptical Astronomy
Whats an example
What is it used for
Where is it located
what is the diameter
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- the Arecibo radio telescope
- the huge dish is 305 m in diameter mounted in a crater of an extinct volcano
- the surface is made of almost 40,000 aluminum panels
- now we only use it to search for extraterrestrial life
41
What is the very large aray (VLA)
- in central new Mexico combines the signals from 27 radio telescopes
- the radio telescope in green bank west virginia
- radio waves: we use false-colour images when displaying data from non-visible light
42
What is the Spitzer space telescope
| what did nonoptical images find
- will examine infrared cosmos
| - nonoptical images of the sun reveal detail that other wise cannot be seen
Astronomy
flashcards
Decks in class (10)
# Cards
-
Unit 1: Discovering the Night Sky74
-
Unit 2: Gravitational Forces40
-
Unit 3: Light and Telescopes42
-
Unit 4 Solar System39
-
Unit 5: Moon and other Terrestrial Planets27
-
Unit 6: The outer Planets56
-
Unit 7: Light and Matter- The Sun46
-
Unit 8: Characterizing Stars41
-
Unit 9: The lives of stars from birth through middle ages88
-
Unit 10: Black Holes and Galaxies Cosmology58
