# Astronomy Ch 4-6

### 76 terms by jamiejaworski

#### Study  only

Flashcards Flashcards

Scatter Scatter

Scatter Scatter

## Create a new folder

James Cooney UCF

### Velocity

- rate of change of position
- the combination of speed & direction of motion
- how fast you go from one place to another

### Speed

rate at which an object moves

### Acceleration

rate of change of velocity

### Force

anything that can cause change in momentum

### Newton's Laws

1. remains at rest, or moves with constant velocity unless acted upon by an outside force
2. force equals mass times acceleration (F=ma)
3. for every applied force, a force of equal size but opposite direction arises.

### Weight

- a force of gravity
- weight equals mass times acceleration of gravity (W=mg)

### Universal Law of Gravitation

- Newton created
- F= m1m2/d^2
- m1 is pulling on m2 as m2 is pulling on m1. forces are the same. In exact opposite directions
- doubling the mass of one object doubles the force of gravity between the two objects

### Inverse Square Law

any quantity that decreases with the square of the distance between two objects

### Tidal Force

- caused when the gravity pulling on one side of an object is larger than that on the other side, causing it to stretch
- stretches the entire Earth to create two tidal bulges
- two high tides (or bulges) a day
- sun's tidal force not as strong (due to distance)

### Spring Tide

- new and full moon
- high tide higher than normal
- they "spring up"

### Neap Tide

- 1st & 3rd quarter moon
- small tides (high tide lower than normal)

### Tidal Friction

- the moon's gravity tires to keep the tidal bulges on the earth-moon line, while earth's rotation tries to pull the bulge around with it
- earth's rotation slows down
- moon moves farther away

### Synchronous Rotation

- moon rotates on its axis in exactly the same time period that it takes to orbit earth
- we always see the same side of the moon

### Momentum

- equals mass times velocity (mv)
- angular momentum (r times mv)(r is radius)
- r decreases = faster/increases = slower

### Kinetic Energy

"motion" the energy of movement

### Potential Energy

- stored hidden energy (later converts into kinetic)
- gravitational is most important
- also chemical & nuclear

energy carried by light

### Temperature

measures the average kinetic energy of particles

### Kelvin Scale

starts at absolute zero (no negatives)
- equals -273C

### Photon

- an individual particle of light, characterized by wavelength & frequency
- packets of energy

### Electromagnetic Spectrum

-the complete spectrum of light
-includes: radio waves, infared, visable light, ultraviolet light, x rays, and gamma rays

### Wavelength

λ the distance between adjacent peaks

### Frequency

ƒ rate at which peaks of a wave pass by a point
- how many waves every second pass me

### Proton

positive electrical charge

### Neutron

no electrical charge

### Electron

- negative electrical charge
- they give the atom its size

### Nucleus

where protons and neutrons are found in the center of the atom

### Ion

- if electrons missing or added
- atoms with positive or negative electrical charge

### Isotope

versions of an element with same number of protons &different numbers of neutrons

### Atomic Number

the number of protons in its nucleus

### Atomic Mass Number

the combined number of protons and neutrons

### Solid

atoms or molecules are held tightly in place

### Liquid

atoms or molecules remain together but move relatively freely

### Gas

atoms or molecules move unconstrained

### Plasma

- is in the world the most
- free electrons move along positively charged ions
- atoms in plasma become increasingly ionized

### Electron Energy Levels

- Only allowed to have specific levels.
- Starts off at ground state then gets excited

### Ground State

- level one or energy of 9 eV
- lowest energy possible

### Excited State

higher energy levels (more)

### Emission Spectrum

- matter emits visible light
- each element emits its own pattern of colors

### Absorption Spectrum

- matter absorbs radiative energy
- absorb those photons whose colors match their electron energy levels
- has all colors minus those that were absorbed.

### Continuous Spectrum

- all the colors of the rainbow
- continuous but not equal in intensity at all wavelengths.
- spans a broad range of wavelengths without interruption

### Doppler Effect

the effect that shifts the wavelengths of spectral features in objects that are moving toward or away from the observer

### Redshift

Light emitted from an object moving away from you will have its wavelength lengthened.

### Blueshift

Light emitted from an object moving towards you will have its wavelength shortened.

### Refraction

- bending light by passing it from one medium to a second medium
- focuses light using lenses

### Reflection

- bends light by mirroring it.
- focuses light using mirrors
- used more today

### Spherical Aberration

- the shape of the mirrors and lens have to be exactly right (a parabola)
- A lack of focus because of shape if it's not built perfectly right.

### Chromatic Aberration

Refractors Only
- different colors of light bend differently.
- focuses are all at different spots
- the bigger the lens the more serious problem.

### Sagging

Refractors Only
- sagging of the telescope structure under its weight etc., and therefore result in a static stray light halo strewn with planet-like but spurious speckles.

### Inhomogeneities

Refractors Only
- not the same everywhere (imperfection)

### Angular Resolution

- smallest angle which can be seen
- the smallest angle at which you can distinguish two objects
- the ability to separate two objects

### Twinkling

- Air turbulence in the atmosphere distorts light
- Angular resolution is degraded.
- biggest issue

### Light Pollution

Man-made light is reflected by the atmosphere, thus making the night sky brighter.

- Angular resolution improves
- eliminates the blurring caused by the atmosphere

### Interferometry

- Two (or more) radio dishes observe the same object. (the angular resolution of a larger telescope)

### Terrestrial Planet

- Mercury, Venus, Earth, Mars
- Rocky surfaces, metallic interiors.
- Few large moons

### Jovian Planet

- Jupiter, Saturn, Uranus, Neptune
- Gas Giant Planets: Made up mostly of hydrogen, helium, and hydrogen compounds.
- Rings and many moons

### Asteroid

- rocky bodies that orbit the sun much like planets, but are much smaller
- leftover rocky planetesimals which did not accrete onto a planet

### Solar Nebula

the idea that our solar system was born from a cloud of gas that collapsed under its own gravity

### Condensation

- elements &amp; compounds began to condense (i.e. solidify) out of the nebula.... depending on temperature!
- solid particles form in a gas

### Accretion

small grains stick to one another via electromagnetic force until they are massive enough to attract via gravity to form.
- the process where small "seeds" grew into planets

### Planetesimal

"pieces of planets"
Make themselves into planets and the stuff left over are asteroids.
- combine near the Sun to form rocky planets
- combine beyond the frostline to form icy planetesimals which...
- capture H/He far from Sun to form gas planets

### Nebular Theory of Solar System Formation

- start with cold cloud of gas & dust
- push - so part of the nebula becomes denser than another part of the cloud
- Everything starts to fall towards the denser part. (collapses)
- Conservation of Energy (hotter) & Conservation of Angular Momentum (spins faster)

### Frost Line

the minimum distance at which it was cold enough for ice to condense
- lies between mars and jupiter
- only rocks & metals condensed on inside, Hydrogen compounds (ices) condensed beyond the frost line.

### Protoplanetary Disk

a disk of material surrounding a young star (or protostar) that may eventually form planets

the most reliable method for measuring the age of a rock

### Half-Life

The time it takes half the amount of a radioactive isotope to decay

### energy

what can make matter move

### conservation laws

handful of quantities that you can calculate in nature

### conservation of energy

energy can be neither created or destroyed, but can only change from one form to another

### different forms of energy

Kinetic, Potential, & Radiative

...

### light like a wave

ƒλ = c or ƒλ = s
s=speed
c=speed of light which is a constant

### light like a particle

-E = hƒ= hc/λ ["h" is called Planck's Constant]
-The energy carried by each photon depends on its frequency (color)
- blue=more energy

### kinds of information we can glean from these spectra

Composition, Temperature, Velocity

### How do telescopes help us in astronomy?

- Collects a lot of light.
- The bigger the telescope the more photons fall on it.

- It improves your angular resolution.
- Makes it sharper and have finer details

Example:

## Press Ctrl-0 to reset your zoom

### Please upgrade Flash or install Chrometo use Voice Recording.

For more help, see our troubleshooting page.

Create Set