Term
| Define electromagnetic radiation. |
|
Definition
| an electric and magnetic disturbance that transports energy at the speed of light. |
|
|
Term
|
Definition
| light is the visible form of electromagnetic radiation |
|
|
Term
| What does the electromagnetic spectrum include? |
|
Definition
1. gamma rays
2. X-Rays
3. Ultraviolet radiation
4. visible light
5. infrared radiation
6. radio waves |
|
|
Term
|
Definition
|
|
Term
| the amount of energy a photon carries depends on what? |
|
Definition
|
|
Term
| what is the wavelength of visible light usually measured in? |
|
Definition
|
|
Term
| what does the wavelength of visible light range betweeN? |
|
Definition
|
|
Term
| Do radio/infrared radiation have longer or shorter wavelengths? less or more energy? |
|
Definition
| longer wavelengths/less energy |
|
|
Term
| XRay/gamma ray/ultraviolet radiation have longer or shorter wavelengths? more or less energy? |
|
Definition
| shorter wavelengths/more energy |
|
|
Term
|
Definition
| the number of waves that pass a point in one second |
|
|
Term
| what is wavelength related to? |
|
Definition
|
|
Term
| what two atmospheric windows is Earth's atmosphere transparent in? |
|
Definition
|
|
Term
|
Definition
| telescopes use a primary lens (mirror) or objective lens to gather light and bring it into prime focus where it is magnified by an eyepeice |
|
|
Term
| how are telescopes limited? |
|
Definition
| short-focal-lengths are more expensive and harder to make |
|
|
Term
| What does a refracting telescope do? |
|
Definition
| uses a lens to bend the light and focus in on an image. (common with chromatic aberrations--color fringing) |
|
|
Term
| What do reflecting telescopes do? |
|
Definition
| use a mirror to focus the light. Do not suffer from chromatic aberration (color fringement) |
|
|
Term
| where does light first come to focus? what do the secondary mirrors do? |
|
Definition
| first comes into focus in PRIME FOCUS. The secondary mirrors DIRECT LIGHT to other focus locations |
|
|
Term
| what is the difference between resolving power, magnifying power, and light gathering power? |
|
Definition
resolving power: the ability of a telescope to resolve fine detail
magnifying power: ability of a telescope to make an image larger
light-gathering power: ability of a telescope to produce bright images |
|
|
Term
| what does interferometry refer to? |
|
Definition
| to connecting two or more separate telescopes together to act as a single large telescope |
|
|
Term
| what has replaced photographic plates in most applications? |
|
Definition
| charge-coupled devices (CCD's) |
|
|
Term
| what does a comparision spectrum allow astronomers to measure? |
|
Definition
| the wave-lengths of spectral lines |
|
|
Term
| for what three reasons do astronomers use radio telescopes? |
|
Definition
1. they can detect cool hydrogen in space
2. they can see through dust clouds that block visible light
3. they can detect certain objects invisible at other wavelengths |
|
|
Term
|
Definition
| subatomic particles, such as electrons and protons, traveling at nearly half the speed of light |
|
|
Term
| if you had to choose between a refracter telescope and reflecting telescope, which would you choose and why? |
|
Definition
| a reflecting telescope, because they are less expensive and dont suffer from chromatic aberration |
|
|
Term
| why do astronomers do their studies outside of the city and on higher surfaces (like mountains)? |
|
Definition
| to avoid light pollution (artifical city lights that dims faint objects). |
|
|
Term
| what does a spectrograph do? |
|
Definition
| spreads the light out according to wavelength to form a spectrum |
|
|
Term
| what makes CCD's more useful than photographic plates? |
|
Definition
| CCDs can detect the faintest object and the brightest in a single exposure, more sensitive, and read directly into comp. memory. |
|
|
Term
| how do astronomers investigate the objects they study? |
|
Definition
| analyze the light and radiation |
|
|
Term
| Light waves are characterized by what two things? |
|
Definition
| wavelength and frequency (F= speed of light/wavelength) |
|
|
Term
| what is the speed of light? |
|
Definition
|
|
Term
| different colors of light correspond to what two different things? |
|
Definition
| wavelengths and frequencies |
|
|
Term
| True or False: the energy of a photon depends on the intensity or brightness of light |
|
Definition
|
|
Term
| What are the most energetic waves in the electromagnetic spectrum? |
|
Definition
|
|
Term
| What do astronomers use telescopes for? |
|
Definition
| to gather more light from astronomical objects (the larger the telescope, the more light it gathers) |
|
|
Term
| What are the two types of optical telescopes? |
|
Definition
1. refracting (uses lens)
2. reflecting (uses mirrors) |
|
|
Term
| What type are most modern telescopes? |
|
Definition
|
|
Term
|
Definition
| the minimum angle you can use to tell the whats between two objects |
|
|
Term
| What are the three powers of a telescope? |
|
Definition
1. light-gathering power
2. resolving power
3. magnifying power |
|
|
Term
| What are four types of telescopes? |
|
Definition
1. Prime focus
2. Cassegrain Focus
3. Newtonian Focus
4. Coude Focus |
|
|
Term
| how does adaptive optics use computers to compensate for distortions? |
|
Definition
| by atmospheric turbelance |
|
|
Term
| What is the proces of combining signals from smaller telescopes to create one larger mirror? |
|
Definition
|
|
Term
| What will spectral lines tell us about an object? |
|
Definition
| chemical composition and other properties |
|
|
Term
| name three factors that radio telescopes allow us to observe. |
|
Definition
1. Neutral Hydrogen clouds (contain 90% of all atoms of universe)
2. Molecules
3. regions where visible light is heavily absorbed |
|
|
Term
| What are the three types of radiation that can only be observed from space? |
|
Definition
1. Far-infrared
2. ultraviolet
3. xray radiation (gamma rays) |
|
|
Term
| if you have a shorter wavelength, do you have a lower or higher frequency? |
|
Definition
|
|
Term
| NOTE: Ultraviolet has shorter wavelengths, infrared has longer wavelengths |
|
Definition
| NOTE: The larger the wavelength, the lower the frequency |
|
|
