Astro Section 1 Flashcards
(79 cards)
1
Q
What is the star
A
Going bald gas that generates heat through nuclear fusion
2
Q
What is a planet
A
Large Object that orbits a star shines by reflected light maybe Rocky icy or gaseous
3
Q
What is a moon or satellite
A
An object that Orbits of planet
4
Q
What is an astroid
A
Small and rocky object that orbits the star
5
Q
What is a comet
A
Relatively small icy object that orbits a star
6
Q
What is a solar or Star system
A
a star And all the material that orbits it
7
Q
What is a nebula
A
An interstellar cloud of gas and dust
8
Q
How far away is the Orien nebula
A
1500 ly
9
Q
What is a galaxy
A
Great island of stars and space hope together by gravity
10
Q
Where is the Andromeda galaxy
A
2.5 million light-years away
11
Q
What is a galaxy group
A
A few dozen galaxies together, usually a few million light-years across
12
Q
What is a galaxy cluster
A
A few hundred to a few thousand galaxies
13
Q
What is the universe
A
The sum of all matter and energy
14
Q
When did we first discover that the speed of light is finite
A
Olaf Romer when looking at the revolution of Jupiter’s moons
15
Q
What is a light-year
A
The distance light can travel in one year. About 10 trillion km
16
Q
On the 1 to 10 billion scale how big is the sun? How big is the earth?
A
Grapefruit. The earth is the size of a ball point pen.
17
Q
On this scale how far is the earth from the sun
A
15 m
18
Q
On the scale how far is Pluto from us
A
A few minutes walk
19
Q
How many stars are in the Milky Way
A
100 billion
20
Q
How many galaxies are in the universe
A
100 billion
21
Q
What is an AU
A
Astronomical unit. Distance from Earth to sun. 150 Million kilometers.
22
Q
How are galaxies moving in respect to one another
A
They are expanding apart and more distant galaxies are receding faster
23
Q
How fast are we moving through the cosmic rest frame
A
1,330,000 km an hour
24
Q
How long does it take to do one orbit around the Milky Way
A
230 million years
25
What did ancient societies use astronomical observations for
Practical purposes like agriculture or hunting navigation, religious or ceremonial purposes
26
What could ancient people of Africa do
Predict seasons using the orientation of the Moon Crescent
27
Tell me about Stonehenge
At summer solstice Sunrose at the Keelstone. At winter solstice it's set at the other end.
28
What happened at the Mayan temple
At equinox Sunrose exactly between the two buildings
29
What's important about anasiva kiva
's exactly aligned north-south
30
What does the Sun dagger tell
Marks summer solstice with a line through the middle and winter solstice with two lines on either side. Also marked equinoxes with one line not through the center
31
What did ancient societies achieving astronomy
Track the seasons, daily timekeeping, calendar, monitor lunar cycles and planets and stars, predict eclipses.
32
Why does modern science trace its roots to the Greeks
They were the first to make models or theories to explain patterns that they saw.
33
What did Eratosthenes measure
The circumference of the earth using the shadows of towers in two different cities
34
What Was involved in the Greeks geocentric model and who was involved with it.
they thought the earth was at the center of the universe and that the heavens must be perfect so objects must move in perfect spheres. Aristotle and Plato were key in this idea.
35
This did not explain retrograde motion. What is retro grade motion
Over a period of 10 weeks Mars appears to stop back up then go forward again
36
Who created the most sophisticated geocentric model
Ptolemy created the Ptolemaic model. It was impressively accurate, enough to remain in use for 1500 years. His model proposed that planets going to series of smaller circles around greater circle Around earth.
37
Who is Copernicus and what did he do
Proposed a sun centered model and using the model determined the layout of the solar system. But his mother was no more accurate than the Ptolemaic model.
38
Who is tycho Brahe and what did he do
Make the most accurate naked eye measurements. Believed in the geocentric model because he could not see stellar parallax. Hired Kepler.
39
Who is Kepler And what did he do
Noticed that there is an eight arc minute discrepancy and so he studied it for years. He made Kepler's three laws of planetary motion.
40
What are Kepler's three laws of planetary motion
One – the orbit of each planet around the sun is an ellipse with the sun at one focus. 2- As a planet moves around its orbit it sweeps out equal areas in equal time, so chattels faster when it's nearest of the sun and slower when it's far from The sun. 3- More distant planets orbit the sun at lower average speeds.
41
What were the three objections to the Copernican view
One – earth could not be moving because objects in here would get left behind. Two – noncircular orbits are not perfect as heaven should be. Three – if the earth where orbiting the sun we would see stellar parallax
42
Who proved these objections wrong and how
Objection one – Galileo show that all objects will stay in motion unless a force acts on them. Objection two – Galileo saw sunspots on sun so it's not perfect. Objection three – Galileo figured out that we don't see stellar parallax because the stars are so far away.
43
What also solidified Kepler's laws
Newtons discovery of the laws of motion and gravity. They confirm Kepler's laws especially the first two.
44
Who is Hans orsted
Electric currents generate magnetic fields
45
Who is ampere
Figured out mathematically how currents generate magnetic fields
46
Gauss
Examined earths magnetic field and formulated absence of magnetic charges mathematically
47
Faraday
Changes in magnetic Fields generate eclectic fields
48
Maxwell
Final form of the laws of classical electromagnetism
49
Hertz
Built first antennas to generate and observe EM waves.
50
What is energy
Ability to do work. Measured in joules
51
How do we measure the flow of energy
Watts
52
How does light interact with matter
Emission, absorption, transmission – transparent objects transmit light and opaque objects absorb it – reflection.
53
What are particles of light called
Photon
54
What is a wave
Pattern of motion that carries energy without caring matter with it
55
The speed of light equals
Wavelength times frequency
56
What are the four phase changes
Melting(Solid into liquid) Evaporation(Liquid into gas) Dissociation(Breaking molecules into Atoms) Ionization(Stripping electrons and changing atoms into plasma)
57
Phase depends on what
Temperature and pressure
58
There are three types of Spectra what are they
Continuous, emission line, absorption line
59
What is continuous spectrum
The spectrum of a common light source for example lightbulb that spans all visible wavelengths without interruption
60
What is an emission line spectrum
A sin or low-density cloud of gas emits light only at specific wavelengths depending upon its composition and temperature. This produces a spectrum of bright emission lines
61
What is an absorption line spectrum
When there is a cloud of gas between us and the light source the cloud absorbs specific wavelengths of light leaving dark absorption lines in the spectrum
62
What is a chemical fingerprint
How each Adam has a unique set of energy levels producing a unique pattern of emission lines. This can tell us what types of atoms are present in a cloud of gas.
63
Molecules have additional energy levels because they can....
Rotate and vibrate as well. This makes their energy level spectra more complicated.
64
Thermal radiation depends on what property
Temperature only! So we can use thermal radiation to tell us the temperatures of stars and planets
65
What are the two properties of thermal radiation
One – hotter objects emit more light at all frequencies. Two – hotter objects emit photons with a higher average energy.
66
Using the Doppler effect we can tell whether distant objects are moving towards or away from us. If an object is blueshifted what does that mean? If an object is red shifted what does that mean
Blueshift equals Moving toward us
| Red shift equals moving away from us.
67
Broadening or widening of spectral lines means what
An object is rotating faster
68
What is refraction
The bending of light as it passes from one substance into another. In our eyes it causes parallel rays converge At a focal point.
69
What are the two Important properties of the telescope
One – light collecting area ( larger the area the greater the amount of light) Two – angular resolution (the better the angular resolution the clear the image)
70
What is angular resolution
The minimum angle separation that the telescope can distinguish. (As two separate objects. )
71
The limit on angular resolution is known as
Diffraction limit
72
What are the two basic designs of telescopes
Refracting telescope(Focuses light with lenses) Reflecting telescope(Focuses light with mirrors). Reflecting telescopes have much greater diameter. Refracting telescopes have to be really long with large heavy lenses. Most modern telescopes are reflectors.
73
What do astronomers do with telescopes
Imaging( Taking pictures of the sky) Spectroscopy(Breaking light into spectra, gives better data and better resolution) Timing(Measures how light output varies with time)
74
What is a good place for a telescope
Calm ( not too windy that stirs up dust) high ( less atmosphere to see through) dark( less light pollution) dry ( fewer clouds to see through)
75
Why do we put telescopes into space
Because there is less disturbance (Turbulence) from the atmosphere and because then they can gather forms of light that cannot pass-through earths atmosphere.
76
Tell me about radio telescopes
Have to be big. Because the wavelength is big.
77
Tell me about infrared and UV telescopes
They operate like visible light telescopes but they need to be above the atmosphere to see all wavelengths. Example of infrared is Sophia and Spitzer.
78
Tell me about x-ray telescopes
Also need to be above the atmosphere. Hard to focus because x-rays are so powerful. You can't shoot it at a lens you have to deflect the rays and funnel them to a focus. I.e. Shandra Observatory
79
Tell me about GammaRay telescopes
Also are defocus because they are the highest energy. I.e. Fermi GammaRay Observatory
