Exam 2 Flashcards
Light waves and photons carry ________, and the strength of ________ is often given as a power.
Energy; light
Why are some people color blind?
Color is a perception.
List the three primary light colors.
Red, blue, green
Note: The 3 primary art colors are cyan, magenta, and yellow.
Color that contains every other color.
White
Color representing absence of light.
Black
Light/Matter Interactions: light leaves matter.
Emission
Light/Matter Interactions: light enters matter.
Absorption
Light/Matter Interactions: light travels through matter.
Transmission
Light/Matter Interactions: light bounces off of matter.
Reflection
Light/Matter Interactions: random motions as light bounces off matter; during reflection/transmission.
Scattering
A mirror is an example of ________ reflection.
Secular
The color we see as an object’s color is ________, and all other colors are ________.
Reflected; absorbed
What color(s) does an orange shirt reflect? What color(s) does it absorb?
Orange; all other colors
Properties of Light: The distance from one peak to the next (or one trough to the next) in a light pattern.
Wavelength
In order to start, wavelengths require a:
Disturbance
Property of medium; propagate waves.
Wave speed
How often a light pattern will repeat.
Frequency
Require a physical medium to propagate through. (Hint: no one in space can hear you.)
Mechanical waves
Self-sustaining waves propagating through the electromagnetic field.
Electromagnetic waves
When a wavelength becomes longer, the frequency is ________.
Lower
Light is carried by ________.
Photons
List the electromagnetic spectrum from longest to shortest wavelength.
Radio, microwave, infrared, visible, ultraviolet, x-ray, and gamma ray.
Higher frequency waves have ________ energy.
Higher
Positively charged particle in the nucleus.
Proton
Neutral charged particle in nucleus.
Neutron
Negatively charged particle surrounding nucleus.
Electron
Atoms are held together by ________ force.
Electromagnetic
Classifying atoms: depends on protons.
Element
Classifying atoms: depends on total number of nucleons.
Isotopes
Classifying atoms: excess or depletion of electrons compared to ordinary state.
Ion
Number of protons
Atomic number
Number of protons and neutrons
Atomic mass number
States of matter: defined shape, defined volume.
Solid
States of matter: undefined shape, defined volume.
Liquid
States of matter: undefined shape, undefined volume, compressible.
Gas
States of matter: ionized gas, most common state of matter in the universe. (Hint: example: stars.)
Plasma
A spectrum of all colors. Can be produced by reflecting or emitting light.
Continuous spectrum
Colored lines produced by quantized energy released from storage in an atom or molecule. Used to identify elements and compounds.
Emission lines
Lines of absorption in a continuous spectrum that result from the light going through a semi-opaque object.
Absorption lines
Each element has a different ________.
Spectrum
Emission and absorption lines are produced in molecules by ________ and ________.
Rotation; vibration
Continuous spectrum of light emitted by an object as a result of the temperature of the object.
Blackbody/Thermal radiation
Stefan-Boltzmann Law
Hotter objects emit more light.
Wien’s Law
Hotter objects change colors.
Change in frequency of a wave caused by the relative motion of the wave source and absorber with respect to each other.
Doppler shift
When the wavelength of the light is longer, the light is:
Redshifted
When the wavelength of light is shorter, the light is:
Blueshifted
The Doppler shift can tell us how fast an object is:
Rotating
Acts as a shutter that controls the amount of light going into the optical system.
Pupil
Focuses the light entering the optical system, uses refraction to direct light.
Lens
Detects photons entering the optical system.
Retina
Transport photon information
Optical nerve
The process by which light can be bent or changed direction.
Refraction
A measure of how well a medium can bend.
Index of refraction
The point at which light rays focus and converge at a single point to form an angle.
Focal point
Not all sources produce parallel rays. The rays focus on this.
Focal plane
How are images created?
From the photons emitted or reflected from the source.
The length of time the shutter is open.
Exposure time
The amount of energy per unit time that is measured or produced.
Power
A detector is broken up into these multiple pieces.
Pixels
How much light a telescope can collect at one time.
Light-collecting area
The smallest angle two dots can be separated/distinguished from each other.
Angular separation
Actual angular separation depends on ________ and ________ _______.
Atmosphere
Process where light waves interact with each other.
Interference
Refracts light to a focal point. Limited by how much a material can refract/bend light.
Refracting telescope
Reflects light off of multiple mirrors to one focal point. More compact and easier to maneuver.
Reflecting telescopes
Reflecting telescope: two mirrors, focus at back.
Cassegrain
Reflecting telescope: two mirrors, focus at side.
Newtonian
Reflecting telescope: three mirrors, focus at side.
Nasmyth/Coude
Why do large mirrors need a lot of support?
They will break under their own weight.
What is a technique to lessen the weight of a telescope?
Segmented mirrors
How big (m) will the next generation of optical telescopes be?
30 meters
How are images created?
From a single wavelength or multiple wavelengths of light.
What limits the wavelengths of light received by a telescope?
Filters
How do we create images for invisible wavelengths? Explain this process.
False-color imaging; invisible wavelengths are translated and matched up with visible wavelengths of light.
The technique of analyzing light by looking at the intensity of light for each wavelength of color.
Spectroscopy
What does spectroscopy do?
Separate the various wavelengths, or colors, of light.
The amount of information that can be obtained from a spectrography depends on the:
Spectral resolution
When we decrease intensity for better spectral resolution, we must increase ________ to compensate.
Exposure
A plot of brightness versus time
Light curve
A dimming of the night sky due to artificial light (which lessens the sensibly of optical telescopes).
Light pollution
Does light follow a straight path through our atmosphere? Why?
No; it scatters off of the molecules in our atmosphere.
What causes the twinkling we see when we are viewing stars?
Atmosphere
Where could we place a telescope where we could prevent the most interference?
On top of a mountain, volcano, space.
Do most forms of light or electromagnetic waves penetrate the Earth’s atmosphere?
No; most do not.
What forms of light can make it to the surface of the Earth?
Visible, radio, near IR, and near UV.
Telescopes: huge dishes, too large to put in space, penetrate atmosphere easily, have radio wave pollution due to communication.
Radio telescopes
Telescopes: designed similar to optical telescope, must be placed high enough in atmosphere and space, pollution easily blocked by non-conducting shield around it.
Infrared telescopes
Telescopes: designed like IR and visible telescopes, must be placed in space because light is absorbed by the atmosphere, pollution not a concerned, excess waves blocked by shielding.
Ultraviolet telescopes
Telescopes: too energetic to be reflected or refracted like most forms of light, can only change direction a small amount when they interact with a surface, use grazing incidence mirrors to change direction of light photons a little with each reflection.
X-ray telescopes
Telescopes: so energetic they cannot be reflected, must be detected without any focusing, limiting its angular resolution.
Gamma ray telescopes
Large pools of water/ice under ground
Neutrino Detector
Very small, neutral subatomic particles produced by the sun
Neutrino
Both ground and space based little known about them
Cosmic Ray Detector
Very energetic subatomic particles
Cosmic rays
Large interferometers used to detect gravitational waves predicted by Einstein
Gravitational Waves Detectors
Technique of combining information from multiple telescopes to create a single image or spectrum
Interferometry
Which telescope would be better used and why: an extra telescope located in Antarctica, used to examine the sun’s Corona, or an x-ray telescope placed on a satellite in orbit around the earth, used to examine their sun’s Corona?
The x-ray on a satellite, because there are atmospheric interferences and though being in space would be more expensive, it would make more sense.
Which telescope would be better used and why: and ultraviolet telescope located at the summit of Mauna Kea, Hawaii, used to study galaxies, or an optical telescope located at the summit of Mauna Kea, Hawaii, used to study galaxies?
The optical telescope, because the ultraviolet telescope will not be of any use because it must be in space.
What telescope would be better used and why: an infrared telescope located at the summit of Mauna Kea, Hawaii, used to observe comets, or an infrared telescope placed on a satellite in orbit around Earth, used to observe comets?
The telescope located at the summit of Mauna Kea, because it can easily block pollution, and it is cheaper to place it on earth then in space.
What holds the solar system together?
The sun’s gravitational force
True or false: The sun’s mass is greater than the combined mass of the rest of the solar system.
True
The sun is normal except for this trait.
High metallicity
The sun is 98% ________ and ________.
Hydrogen; helium
Dark spots on the surface of the sun; they are cooler than the rest of the sun.
Sun spots
Why is the sun yellow in color?
Blackbody radiation
By what process does the sun create its energy by converting mass to energy?
Nuclear fusion
Bombard the objects in the solar system (not comets, asteroids, etc.)
Solar winds
Bursts of hot plasma from the surface of the sun
Solar flare
Type of planets that is closer to the sun, including Mercury, Venus, Earth, and Mars.
Terrestrial planets
Type of planet that is farther from the sun, including Jupiter, Saturn, Uranus, and Neptune.
Jovian planets
No atmosphere Heavily cratered Extreme temperature difference between night and day Smallest planet Closest to sun
Mercury
Hottest planet Has atmosphere Closest physical characteristics to Earth Spins backwards Second closest to sun
Venus
Densest planet Oxygen/nitrogen atmosphere Moon closest size to host planet Innermost planet with a moon Only habitable planet in solar system
Earth
Very little atmosphere
No magnetic field
Shows history of geological activity
Two moons, probably captured asteroids
Mars
Not a planet
Most likely a produce of an unformed planet
Largest asteroid, Ceres, is a dwarf planet
Asteroid Belt
Largest planet
Smallest axis tilt
Red spot-giant storm size of Earth
4 large moons (Galilean moons)
Jupiter
Which one of Jupiter’s moons is most likely to be a candidate for a potential colony? Also note: largest moon in solar system.
Ganymede
Less dense than water
Would float in an ocean
Has one moon Titan
Saturn
Coldest planet
Longest year
Only one visit from satellite (Voyager 2)
Neptune
Rotates nearly on its side
No solid surface
Closest planet with only one satellite visit (Voyager 2)
Uranus
Lost planet status, has not cleared its orbit, in the Kuiper belt, it’s largest moon, Charon, is locked and synchronous rotation with its host planet.
Pluto
Similar to the astroid belt, except that it’s objects are icy balls. Has a dwarf planet called Eris.
Kuiper belt
Leftover, cold material, distributed spherically around the sun. Likely source of comets
Oort Cloud
Dirty balls of ice. Tail created by radiation energy from the sun, points away from the sun.
Comets
Other than telescopes, what are other sources of information about planets?
Robotic missions
What are the four types of robotic missions?
Flybys, orbiters, landers, and sample return missions
Robotic missions: spacecraft passes by the object only once and then continues. Only type that can visit multiple planets. Cheapest. Only type of mission used for outer planets. Uses gravitational slingshot.
Flybys
Robotic missions: goes to planet and orbits it like a moon. Can gather information over a long period of time on one source. Provides most accurate measurement of the mass of orbited planet. More expensive than flybys, but information per cost is better.
Orbiters
Robotic missions: land on surface and explores surface of an object. Allows direct analysis of material. Costlier and more challenging. Due to harsh conditions, the robot has a shorter lifespan.
Landers
Robotic missions: what are the steps to getting a lander on the surface of an object?
- Friction slows spacecraft.
- Parachute slows spacecraft.
- Rockets slow spacecraft to halt; “Sky crane” lowers rover to surface.
- Tether releases, rocket heads off to crash a safe distance away.
Robotic missions: a sample is returned to Earth for analysis. Most difficult and most costly. Allows for more depth analysis. Other missions limited by payload size.
Sample return mission
What are some common characteristics between all the planets?
They all travel in the same direction around the sun, have nearly circular orbits, and are about in the same plane of space.
Explains major features of solar system. Being tested and adjusted as new planetary systems are discovered.
Nebular Theory
NASA panel; types of robotic missions: what robotic mission would best suit studying the atmosphere of the planet Neptune?
Orbiter
NASA panel; types of robotic missions: what robotic mission would best suit studying the composition of the Cerus dwarf planet in the asteroid belt?
Sample Return
NASA panel; types of robotic missions: what robotic mission would best suit studying several comets/asteroids in the Oort Cloud?
Flyby
NASA panel; types of robotic missions: what robotic mission would best suit studying the surface geology of Jupiter’s moon, Ganymede?
Landers
Bigger stars burner their fuel ________ than smaller stars.
Faster
Resulting from the conversion of potential energy into kinetic energy (note: higher temperature at center)
Heating
Nebula spins as energy is converted
Spinning
Caused by spinning, centripetal force holds material outwards
Flattening
Gathering of material increasing the size of an object
Accretion
How did the Terrestrial planets form?
Accretion (materials gathering), metal gathering until planetesimals form, becomes hard to grow. Only largest continue to grow. (Evidence: meteorites have same composition needed for solar nebula theory.)
How were the Jovian planets formed?
Similar to terrestrial planets, except that they use hydrogen compounds.
How does the sun “clear the nebula”?
The early sun rotated rapidly and had a stronger solar wind. Solar wind would push materials toward the edge of the solar system.
Pieces that were never accreted into larger objects, many hit planets in heavy bombardment period, many impact craters provide evidence.
Asteroids and comets
What are some exceptions to the rules?
The Earth’s moon is very large compared to its host planet, Mars has two moons, Venus’s rotation backwards, Uranus tilts on its side, Mercury has a large core.
What are captured moons?
Leftover planetesimals
Why is Earth’s moon so big?
Result of a giant impact: when Earth was molten, a Mars-sized planetesimal collided with the Earth. Resulted with a debris disk around the planet. The debris accreted into a moon.
What is a likely reason Uranus spins on its side?
Giant collision
Why does Venus spin backwards?
Giant collision or probably atmosphere
Mercury’s core?
Giant collision
How did the asteroid belt form?
It was an unformed planet, possibly caused by Jupiter’s gravity.
The age of rocks can be determined from when they ________.
Solidify
Uses radioactive elements and their decay rates to figure out life period of element
Radiometric dating
Amount of time required for half the element to decay
Half-life
Earth rocks have been dated to ___ billion years ago.
4
Moons rocks have been dated to ___ billion years ago.
4.5
Meteorites have been dated to ___ billion years ago.
4.55
Solar system is ___ billion years old.
4.5
New solar systems, reasonable or surprising: The solar system has four large Jovian planets and it’s in our solar system and six small terrestrial planets in its outer solar system.
Surprising due to frost line
New solar systems, reasonable or surprising: A solar system with 11 planets, all orbiting in the same plane and direction around the host star. The 17 largest moons in the solar system orbit their planet in nearly the same plane and direction. However, many small moons have highly inclined orbits around their planets.
Reasonable
New solar systems, reasonable or surprising: A solar system has four Earth-sized terrestrial planets, each with a single moon, identical in size to the Earth’s moon. There are no Jovian planets.
Surprising because the moons are the same size as their host and there are no Jovian planets.
New solar systems, reasonable or surprising: A solar system has several planets similar and composition to the Jovian planets, but similar in size to the terrestrial planets of our solar system.
Surprising and reasonable, depending on the size of the host star. If host star is dwarf, reasonable. If star is same size as Milky Way host, surprising.
