Term
| If the sun were the size of a grapefruit, how big would the solar system be? |
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Definition
| The size of the University or a few kilometers |
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Term
| Where should ultraviolet telescopes be placed? |
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Definition
| They should be placed in outer space because UV rays are blocked by the Earth's atmostphere |
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Term
| Do Lyman absorption lines begin with the electron in a hydrogen atom in the ground state (level number 1) |
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Definition
| Yes, that is true because Remember, the Balmer series (optical) start from level 2, while the Paschen series (infrared) start from level 3. The Lyman series are in the ultraviolet, and start from level 1. |
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Term
| Atoms in a thin hot gas, according to Kirchoff's laws, emit light |
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Definition
| at specific wavelengths, the pattern depending on the element, because Remember the other two of Kirchoff's Laws : a thick hot gas emits a continuous spectrum; and a thin gas in front of a hotter thick gas produces absorption lines. |
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Term
| How many stars does the Milky Way Galaxy have? |
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Definition
|
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Term
| How are galaxies grouped? |
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Definition
Galaxy: Billions of Stars
Local Cluster: the group of about 40 galaxies to which the Milky Way Galaxy belongs.
Galaxy Cluster: Groups of galaxies with more than a few dozen members
Super Cluster: Groups of galaxy clusters |
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Term
| How and when did the Universe form? |
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Definition
| The Big Bang about 14 billion years ago |
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Term
| Is the Universe expanding? |
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Definition
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Term
| If the Universe is expanding, why isn't the space between the Earth and the Sun expanding? |
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Definition
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Term
| What two elements did the early Universe contain? |
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Definition
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Term
| How did elements other than hydrogen and helium come into being? |
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Definition
| They were manufactured by stars. These stars shine with nuclear fusion and it is during this process that the other elements were created. |
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Term
| How are stars born and how do they die? |
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Definition
| Stars are born out of gravity which compresses material into a star. This star then beings to shine and burn energy through nuclear fusion. After it has burned all the available fuel the star dies. Massive star deaths are called supernovae |
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Term
| What is an Astronomical Unit |
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Definition
| The distance between the Sun and Earth. About 150 million km |
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Term
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Definition
| The distance light can travel in one year |
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Term
| Approximately when did the Solar System form? |
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Definition
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Term
| Approximately how much of the galaxy's hydrogen and helium has been converted to heavier elements? |
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Definition
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Term
| How can we look back in time at space |
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Definition
| It takes time for light from distant bodies to reach earth, therefore, we see a body 8 light years away as it was 8 years ago |
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Term
| How far away is the Andromeda galaxy from earth? |
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Definition
|
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Term
| How by is the observable universe |
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Definition
| The observable universe is 14 billion ly. Trying to look beyond that is trying to look back in time before the big bang happened. |
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Term
| On the scale of the Voyager model (sun as grapefruit) how far would you have to walk in order to get to the nearest star? |
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Definition
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Term
| How do you divide powers of 10 |
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Definition
subtract their exponents i.e.
(5.95 * 10^5)/ 10^10
5.95 * 10^(5-10)
5.95 *10^-5 |
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Term
| How do you divide powers of 10 |
|
Definition
subtract their exponents i.e.
(5.95 * 10^5)/ 10^10
5.95 * 10^(5-10)
5.95 *10^-5 |
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|
Term
| How do you multiply powers of 10 |
|
Definition
|
|
Term
| How many stars are in the observable universe |
|
Definition
|
|
Term
| What are the two rules associated with the expanding Universe? |
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Definition
Almost every galaxy outside the local group is moving away from us
The more distant the galaxy, the faster it seems to be moving away |
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Term
| Explain the Earth's elliptic plane and axis tilt |
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Definition
| The elliptic plane is the plane of the earth's orbit around the sun and the axis tilt is about 23.5 degrees off from perpendicular to the elliptic plane |
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Term
| Can you walk east from the North Pole? |
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Definition
| No. All directions away from the North Pole are south |
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Term
| What kind of energy does light carry? |
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Definition
|
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Term
|
Definition
|
|
Term
| What are the four basic ways light interacts with matter? |
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Definition
| Emission, Absorption, Transmission and Reflection or scattering |
|
|
Term
| Is light a particle or a wave? |
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Definition
| It has characteristics of both |
|
|
Term
| What exactly are light waves |
|
Definition
Light waves are electromagnetic waves
Light waves are vibrations of both the electric and magnetic fields by the motions of charged particles
Electrons bob up and down when light passes |
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Term
| The longer the wavelength of light... |
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Definition
... the lower the frequency
therefore, because red has the longest wavelength, it has the shortest frequency. Blue has the shortest wavelength and the longest frequency |
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Term
| What is the particle part of light called |
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Definition
|
|
Term
| The higher the frequency of light... |
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Definition
| ... the higher its energy |
|
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Term
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Definition
| has to do with the way an electro-magnetic field is vibrating and how the photons interact with the field. Polarized sunglasses block glare by blocking polarized light which is reflected off horizontal surfaces (the surface absorbed all of the photons vibrating the opposite way) |
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Term
| What is the range for visible light |
|
Definition
| around 400nm (blue-violet) to 700nm (red) |
|
|
Term
| What is the longest light wavelength? |
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Definition
|
|
Term
| What are the shortest wavelength light waves? |
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Definition
|
|
Term
| Light waves from shortest wavelength to longest |
|
Definition
Gamma Rays
X-Rays
Ultra Violet Rays
Visible Spectrum
Infrared
Radio Waves |
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Term
| Does all light interact with matter the same way? |
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Definition
| No, different types of light interacts with matter in different ways. Radio waves are not stopped by bricks, but X-rays can be stopped by bones or teeth. Ultraviolet rays can be stopped with some types of glass and cannot travel through the Earth's atmosphere (ozone) |
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Term
| The electrical charge of an atom... |
|
Definition
| ... determines how strongly it will react with electromagnetic fields |
|
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Term
|
Definition
| Versions of the same atom with differing numbers of neutrons |
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|
Term
|
Definition
|
|
Term
| Gas in which atoms have become ionized |
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Definition
|
|
Term
| When does plasma become fully ionized |
|
Definition
| At millions of degrees Calvin. |
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|
Term
What is plasma at tens of thousands of degrees K
at thousands |
|
Definition
At tens of thousands, this is just a plasma phase in which free electrons move among positively charged ions
at thousands, the atoms experience molecular dissociation |
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|
Term
| What are the three types of energy atoms have? |
|
Definition
mass energy E=mc2
kinetic energy
electrical potential energy |
|
|
Term
| How does an electron change energy levels? |
|
Definition
| An energy level transition (1eV = 1.60x10^-19 J) |
|
|
Term
| Does the amount of energy separating electrons get smaller at higher levels? |
|
Definition
|
|
Term
| What is the greatest level an electron can reach? |
|
Definition
| The ionization level. At this level it will escape and ionize the atom. Any extra energy beyond what is needed for ionization becomes kinetic energy |
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|
Term
| Why are electron's energy said to be quanticized? |
|
Definition
| Because they suddenly jump energy levels with no transition in between. Quantum Physics |
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|
Term
| What is a broad range of wavelengths without interruption called? |
|
Definition
|
|
Term
| What kind of spectra does a low density or thin cloud of gas produce? Does temperature matter? |
|
Definition
Emission line Spectra -- warm gas emits light only at specific wavelengths
a cooler gas is likely to only absorb |
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Term
| If there is a cloud of gas between us and a light bulb -- what kind of spectra is produced? |
|
Definition
| Absorption line spectra -- because the light bulb emits a continuous spectra, but the gas absorbs most of it, only letting a little bit through |
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Term
| Why do emission and absorption lines form? |
|
Definition
| Because ions, atoms, and molecules posses distinct energy levels |
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Term
| When an electron falls down an energy level, what happens to the energy it releases? |
|
Definition
| It is emitted as a photon of light. These photons will have the same energy as the electron and will therefore have a specific wl and frequency which allows scientists to figure out the composition of far off bodies |
|
|
Term
| How are absorption lines formed? |
|
Definition
| the electron absorbs the energy from the photon and moves up a level, creating the dark line |
|
|
Term
| Because each element has its own energy levels... |
|
Definition
| ... it leaves a chemical finger print and scientists can figure out the composition of a far off body. Ionized atoms are also different than neutral atoms -- this helps to determine temperature |
|
|
Term
| Do molecules produce spectra? |
|
Definition
| Yes, but their energy levels tend to be closer together, so they produce molecular bands of spectra that are tightly packed together |
|
|
Term
| What is Thermal Radiation |
|
Definition
| The spectrum of radiation produced by an opaque object that depends only on the object’s temperature; sometimes called blackbody radiation. |
|
|
Term
| Why is a continuous spectrum so continuous? |
|
Definition
| The photons are bouncing around inside and their energy levels get randomized -- largely dependent on temperature |
|
|
Term
|
Definition
Each square meter of a hotter object emits more light at all wavelengths
i.e. hotter objects are brighter, even if they're smaller |
|
|
Term
|
Definition
| Hotter objects produce photons with higher levels of energy |
|
|
Term
| What color light does the sun emit most strongly? |
|
Definition
| Green light (500nm) but we see it as white or yellow because it is also emitting other spectral colors |
|
|
Term
| What type of light would an object heated to millions of degrees release? |
|
Definition
|
|
Term
|
Definition
| This is how light tells us the speed of an object. There are shifts in the wavelengths of light |
|
|
Term
| What are red shift and blue shift |
|
Definition
| These are the Doppler shifts of a moving object relative to another object. A blue shift is an object moving toward you and a red shift is an object moving away from you (color coded according to wavelengths -- red because an object moving away has longer wavelengths) |
|
|
Term
| How does the Doppler effect tell us the rotation rate of bodies? |
|
Definition
| width of spectral lines -- the fast it is moving the wider the line. The part of the rotating body moving towards us is blue shifted and vice versa |
|
|
Term
| What are three major problems with telescopes on the ground |
|
Definition
ambient human light
atmospheric motion blurs images
most forms of light cannot reach the ground |
|
|
Term
|
Definition
| It is things like the wind which disturb the atmosphere and can change the way the atmosphere scatters light. This makes it difficult to have telescopes on the ground |
|
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Term
|
Definition
| Produced by nuclear reactions. These telescopes are generally deep underground |
|
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Term
|
Definition
| linking telescopes together to get a better view of space |
|
|
Term
| What kind of technology overcomes turbulence? |
|
Definition
|
|
Term
| Gravitational equilibrium |
|
Definition
| the balance in the sun between pressure pushing out and gravity pushing in |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| How long will the sun last? |
|
Definition
| 10 billion years -- it is almost 5 billion years into this time line |
|
|
Term
| Does the entire Sun rotate at the same rate? |
|
Definition
| No the equator region rotates faster |
|
|
Term
| If we captured just a second of the Sun's luminosity at full power, how long could that energy power the earth? |
|
Definition
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