Solar Systems Exam Review 2

electromagnetic radiation / light

transport of energy, the amount of energy (E) is related to the wavelength or frequency

• E = h ∗ f = h∗(c / λ)

Interactions of Light and Matter

1. Emission 

2. Absorption

3. Transmission

4. Reflection or scattering

Emission

an object gives off light, a light source.

• ex: the Sun or a lamp.

Absorption

an object takes in light.

• ex: the green tree leaves absorb other colors besides green.

Transmission

light goes thro an object

• ex: I can see the tree outside because the window transmits visible light

Reflection or scattering

light bounces off an object.

• ex: there is a tree visible outside because sunlight bounces off of the tree

photons

“packets" of electromagnetic energy. Some are visible to our eyes (visible or optical light) and other are not (ultraviolet photons)

• All electromagnetic radiation is made of this

Crest

highest point in a wave

Trough

lwst pt on a wave

Amplitudes

height of wave ( middle to crest or middle to trough)

Wavelength

distance between successive crests (or successive troughs, or just one complete cycle of the wave)

• lambda: λ

Frequency

the number of crests that pass a certain point in a certain amount of time

Speed of light

the speed of the wave is the speed of light (c), no matter what type of photons

• v = λ∗f

• speed of wave/light = wavelength X frequency

Transparency of Earth’s atmosphere

we determine whether we can measure electromagnetic radiation by whether it passes thro Earth’s atmosphere as Earth’s is opaque at many wavelengths 

• Only the near-UV, visible, near-IR, and radio waves

Energy of electromagnetic radiation

is directly proportional to frequency

• As frequency increases, energy increases.

Energy is inversely proportional to wavelength

• as wavelength increases, energy decreases.

Spectrum (spectra)

spreading light out to diff wavelengths by prism or grating 

• rainbow is the spectrum of colors present in white light

Properties of thermal radiation

1. Hotter objects emit more light at all wavelengths (per unit area): higher temp curves never dip or cross below lower temp curves.

2. Hotter objects emit photons with a higher average energy.

The graph shows intensities across many wavelengths, but the peaks for higher temperature objects are at shorter wavelengths. This means that the average energy of those photons is also higher.

Wien’s Law: relationship between temperature and wavelength

peak of a thermal emission curve depends on the temp of the object

λ max = (constant)/ Temperature

• inverse relationship: peak wavelength decreases for higher temp objects & peak wavelength increases as you go to lower temp objects

Intensity

how bright is a particular wavelength

Relationship between wavelength and frequency 

Wavelength and frequency are inversely related for photons

• increase the frequency -> the speed stays the same, so the wavelength must decrease. And vice versa.

Kelvin

an absolute scale, 0 K (zero Kelvin) is absolute zero: nothing can be colder and there is a complete lack of motion on the atomic level.

Spectral line

sharp peak in intensity at a particular wavelength

• There is less or no emission between these spectral lines.

Continuous 

spectrum that is a smooth curve with no spikes or dips 

• solid or very dense object emits at all wavelengths depending on its temperature

• ex: visible light like a bulb shows all colors violet thro red

Emission

series of bright spectral lines

• produced by low-density, hot

• each element pattern is diff w/ distinct pattern of colors

Absorption

dark spectral lines among the colors of the rainbow, gaps in the continuous spectrum

• produced by low-density, cooler gas in front of a hotter continuous source 

• unique pattern

• ex: planet atmospheres, suns photospheres

Planet spectra and why they look like the Sun’s spectrum

They look like the Sun’s b/c the light from the Sun is being reflected onto the planet

Structure of atoms

• Nucleus

• Protons

• Neutrons 

• Electrons 

Model of hydrogen

has one proton and one electron

• commonly has no neutrons

Nucleus

neutrons, protons, electrons orbit around it 

Protons

positively charged

Neutrons

no charge

Electrons 

only have certain amounts of energy, they're restricted to certain energy levels

• can’t be at or move to energies between energy levels.

• negatively charged 

Energy levels in atoms

electrons in atoms only r restricted to certain lvls

structure of energy lvl depends on the atom as each atom has a unique set of energy lvl & series of gaps between energy lvl r specific 

Transitions between energy levels of electrons

Each transition between energy levels corresponds to a unique photon wavelength

• the photon must have the EXACT amount of energy for the electron to move between levels

Emission and absorption lines

to change energy lvls, electrons must lose or gain energy

• to go from high to low energy = photons r absorbed: electrons need to take in energy

• to go from low to high energy = photons r emitted: energy must go somewhere

Doppler effect 

Motion affects how sound waves behave differently as it approaches you than when it moves away

• blueshift

• redshift

Telescope

collect and focus light, usually using mirrors and/or lenses

• detect visible or non-visible light

• the bigger the telescope, the more light can be collected.

Light sorting instruments

sort the collected light before sending it to a detector which is either a

1. filter: to only look at certain wavelengths

2. spectrograph: to create a spectrum

Detector

record the light, usually by counting photons & wrks like a camera to sense radiation and record measurements

Refract telescope

light passes thro lens, the change in material (air →glass→air) & curvature of lens bends the light

• bend light to converge at a pt

Reflect

light bounces off of curved mirror

• reflects light to converge 

Light collection & light gathering power

primary mirror/len acts like a bucket to collect light.

• a larger "bucket" allows the telescope to collect more light and see fainter targets.

Focus point

pt where light converges is where the image appears

primary lens or mirror

largest lens or mirror which first collects the light

focal length

distance away from lens or mirror 

CCDs

made up of arrays of pixels but only count pixels & dont record wavelength/color info

• record white & black images

• count incoming photons 

  • high count → more light so brighter pixels, low counts → drker pixels 

• placed between the telescope

Resolution

high res = more details pictures 

• to get high res

  • telescope should have lrgr pirmary mirror

  • Interferometry (multiple telescopes wrking 2gether),

  • adaptive optics (make adjustments based on simultaneously measuring the atmosphere turbulence)

How a telescope forms an image

The objective (a large lens or mirror) gathers light from a distant object and forms a real, inverted image in its focal plane. The eyepiece, acting as a magnifier, then takes this intermediate image and magnifies it for your eye, producing a final, enlarged virtual image

How telescopes are funded

• publicly funded

• privately by a group or consortium

Natural color

an image displaying a combo of the visible red, green and blue bands to the corresponding red, green and blue channels on the computer display

• limited to color that r shown thro visible light 

False color

assign a color to a filter image that is not the true color

• color in the image does not match the wavelengths of the photons recorded, but we are able to see where certain types of light are located

Pseudo color

uses color to represent relative amounts of something (instead of light)

• ex: map population density: colors used to represent where ppl live

Imaging with filters

used to record color info for a regular image

• only transmits certain wavelengths, diff filters used & combines to male color image 

  • ex: red filter only allows red to go thro & others r absorbed

Recording a spectrum

spreads out wavelengths of light similar to a prism or grating. By bending the light, different wavelengths bend by different amounts and we can separate out the various wavelengths from the target.

• emission or absorption lines recorded determine the composition, color, temperature, and one dimension of motion

How are color images created?

between telescope (which collects and focuses the light) and CCD(which counts the incoming photons) another device is placed, color images use filters 

Why some telescopes must be in space

1. Earth's atmosphere blocks a lot of non-visible radiation.

2. Earth has lot of turbulence which distorts images (when you see 'twinkling' stars, that's usually due to air moving in the Earth's atmosphere)

Nancy Grace Roman

first woman to hold executive position at NASA, worked on the Hubble Space Telescope

Terrestrial planets

relatively small & have high densities → higher ratio of mass per volume as a whole

• made of rock, metal & of rare heavier elements due to hydrogen being the most common element in solar system

• solid surfaces w/ features of craters, mountains, volcanoes

Giant or Jovian planets

• lrg planets w/ lower densities

• made up of hydrogen-based ices, liquids, gases.

planetary differentiation

• densities inside terrestrial planets vary b/c of interior being layered w/ most dense material in the core & lighter material at the surface

• happened during formation of planets, planets were so hot that everything melted down. gravity sinked heavier material to the center & lighter materials floated to the surface

  • ex: Earth has dense iron core, less dense mantle & crust w/ the lowest density 

Dwarf planets

similar to other planets in the way they orbit sun & roughly spherical but share their orbit w/ other planets

Moons

natural satellites that orbit other objects

• planets, dwarf planets, even asteroids have them

• some have active volcanoes or subsurface water oceans 

Rings

made of smaller pieces of dust and/or ice & orbit above the equators.

• all 4 giants have rings w/ saturn’s being most reflective & distincitve

Asteroids

rocky debris leftover from solar system formation 

• orbit in asteroid belt between Mars & jupiter, others w/ Jupiter, or may be slightly more eccentric orbits that cross Earth’s path 

Comets

icy debris w/ highly eccentric orbits

• in the outer part of solar system beyond Neptune but form a coma & tail when closer to Sun

Cosmic dust

rock fragments scattered in solar system

• formed from collisonns 

• interact w/ Earth’s atmosphere to become a “shooting star“ or meteor 

Where is the mass in the solar system?

Most → Least

• sun w/ 99.8%,

• Jupiter,

• comets, icy debris w/ many spending most of their time in the farthest reaches of the solar system.

• all other planets and dwarf planets', which is mostly Saturn.

• Moons & rings

• asteroids

• cosmic 

Temperatures in the solar system

1. sun is the pwrhosue, creates energy & shines outward

2. distance from sun as well as the planet’s atmosphere affect planet’s temp

• depending on composition & density of the layer of gas surrounding a planet

Interior layers

crust, mantle, core

crust

outermost layer of Earth, divided in 12 tectonic plates (oceanic & continental)

• move relative to each other to form landforms such as mountains, volcanoes, earthquakes 

mantle

middle layer, lrgst prt of interior & is more or less solid

• semi-solid layer deforms & flows very slowly due to high temps

  • higher density than crust, plates of crust float on top of it & move around as the mantle flows

core

high density, outer core is liquid while inner is solid

• lrger than mercury 

Seismic waves

caused by earthquakes, the waves travel thro the interior of Earth 

• uses to study Earth’s interior: measure waves at stations at diff locations around the wrld, we study the changes & differences

Magnetosphere

magnetic field surrounding Earth, nearly aligned w/geographic poles

• caused due to earth’s core being prt liquid, the metals move & generate electric currents 

• extends outwards into space & behaves like a giant bar magnet inside earth 

Magnetic field and its cause

• solar wind: charged or trapped particles expelled at high speed at every direction by the sun

  • charge → earth’s megnetosphere is stretched 

  • trap → redirect towards poles → move inwards & collide w/ earth’s atmosphere → excites particles → gives us light such as the northern & southern light

Convection

Earth's mantle slowly flows even as a semi-solid, since hotter material is less dense than its surroundings it rises, and the more dense cooler material sinks.

• cycle repeats: material near high temps core heats up → then rises → cools near the surface → then sinks.

• this causes for plates to move around → mountains, volcanoes, earthquakes, and more

Plate tectonics

Earth's outer shell divided into lg moving pieces, float on a softer layer

Ozone

absorbs damaging uv radiation from sun,

• UV photons r absorbed by breaking apart the ozone molecules, those molecules r reform & continue to absorb incoming UV

• UV-c: highest energy

• UV-b

• UV-a: lowest energy

Composition

the greenhouse effect

Earth’s insulation, molecules in Earth’s atmosphere trap energy & keep the Earth warm

• sun heats earth’s surface → land & oceans radiate energy in the infrared → some infrared radiation escapes into space & some trapped by greenhouse in atmosphere 

Why Earth’s atmosphere is unique

• moderate greenhouse effect:

• temperature: just right to have liquid water oceans

• habitable

• protects earth from meteors as it dissolves it before it can make impact

Hotspot (shield) volcanoes

found above "hot spots" (regions where the mantle is hotter in a specific location), pushes material upwards thro to surface. 

• Volcanos occur where lava rises to the surface through the crust. erupt repeatedly that builds layer after layer of the broad volcano cone

Motion in the Earth’s mantle and its role in plate tectonics

tectonic plates move around due to the mantle’s convection, running into each other, moving apart, moving alongside, or even sliding beneath another plate → earth’s crust is recycled as old surface features are erased and new surface is formed

• only planet that is geologically active

Sister theory

Earth & moon formed side by side 

• Moon’s composition is similar but not the same as Earth, it’s missing some elements 

Capture theory

moon formed elsewhere & was captured when it passed by Earth

• physics to that doesn’t make sense as moon is too big to capture in a close encounter

Fission theory

as earth was forming, it was molten & a blob split it off to form Moon

• violates convo of angular momentum 

Giant impact theory

lrg object impacted the early earth as it was orbiting sun, the impact flung debris out into earth’s orbit & came/collected 2gether to form Moon

explains y:

• moon has little iron since its made from crust material flung from the impact 

• a slightly diff sompostion since impactor had its own composition

• earth’s titled roation axis & seasons

• y moon orbit is closer to the eliptic than the celestial equator 

Moon’s general properties (e.g. location in the solar system, type of planet, orbit, temperature compared to other planets)

• a dead world, no plate tectonics, no volcanic activity, & no air

• temp: extreme temperature changes from day to night w/o insulation

• orbit: rotates and revolves at the same rate, so 1"day" on the Moon (sunrise to sunrise) is about 1 month (one cycle of phases).

• interior study similarly to Earth as it has moonquakes caused by tidal forces, similar density to Earth's crust

• lack of activity: cooled off faster after formation 

Moon’s lack of atmosphere

likely related to the lack of volcanic activity, which would supply gas, and the weaker gravity, which is needed to hold on to the atmosphere once it forms.

• there’s no clouds, haze, or wind.

Margaret Hamilton

developed computer software that landed the first astronauts on the Moon

• Apollo 11 mission

craters

circular features have a raised rim and are formed through impacts with the surface

• Most of the Moon's craters formed in the early solar system, where a lot more debris was flying around

• larger impacts may also have a central rebound forming a mountain in the middle of the crater

rays

bright streaks radiating outward from a central crater

• formed from debris flying outwards from the destroyed impactor

rilles

long narrow depressions, meandering curves, and lines

• Cut thro some craters,

• caused by collapsed lava tubes beneath the surface or sunken sections of crust between parallel fault line

highlands

rugged areas pitted w/ many craters of varying sizes

• best seen during waxing and waning phases.

maria

large, smooth, dark areas composed of congealed lava

• Formed when molten lava flooded a large crater, smoothing away other details

• Best seen during full Moon

Moon’s 2 sides

1, hemisphere we see: bright higlands, dark maria

2. hemisphere facing away: dominated by highlands, lack of maria may be due to Earth's gravitational influence

scarps

cliffs are found on the surface, look like wrinkles

• likely formed as planet cooled and shrank.

Caloris Basin

lrgst crater, lack of mantle due to impact that formed carloris or the high temps

• on mercury

mercurys general properties

• smallest terrestrial planet

• temp: close proximity to sun & minimal atmosphere → extreme temps however there’s water ice present in craters near the poles due to it being permanently shielded from sunlight

• no moons

• weak magnetic field: prt of core must be liquid

mercurys atmosphere

• very minimal atmosphere due to its lower mass and proximity to the Sun

• no volcanos, it's possible it never had a significant atmosphere