- rate of change of position
- the combination of speed & direction of motion
- how fast you go from one place to another
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.
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
- 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)
- 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
- 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
- equals mass times velocity (mv)
- angular momentum (r times mv)(r is radius)
- r decreases = faster/increases = slower
- stored hidden energy (later converts into kinetic)
- gravitational is most important
- also chemical & nuclear
- an individual particle of light, characterized by wavelength & frequency
- packets of energy
-the complete spectrum of light
-includes: radio waves, infared, visable light, ultraviolet light, x rays, and gamma rays
- 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
- matter absorbs radiative energy
- absorb those photons whose colors match their electron energy levels
- has all colors minus those that were absorbed.
- all the colors of the rainbow
- continuous but not equal in intensity at all wavelengths.
- spans a broad range of wavelengths without interruption
the effect that shifts the wavelengths of spectral features in objects that are moving toward or away from the observer
- bending light by passing it from one medium to a second medium
- focuses light using lenses
- 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.
- different colors of light bend differently.
- focuses are all at different spots
- the bigger the lens the more serious problem.
- 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.
- smallest angle which can be seen
- the smallest angle at which you can distinguish two objects
- the ability to separate two objects
- Air turbulence in the atmosphere distorts light
- Angular resolution is degraded.
- biggest issue
- Two (or more) radio dishes observe the same object. (the angular resolution of a larger telescope)
- Mercury, Venus, Earth, Mars
- Rocky surfaces, metallic interiors.
- Few large moons
- Jupiter, Saturn, Uranus, Neptune
- Gas Giant Planets: Made up mostly of hydrogen, helium, and hydrogen compounds.
- Rings and many moons
- rocky bodies that orbit the sun much like planets, but are much smaller
- leftover rocky planetesimals which did not accrete onto a planet
the idea that our solar system was born from a cloud of gas that collapsed under its own gravity
- elements &amp; compounds began to condense (i.e. solidify) out of the nebula.... depending on temperature!
- solid particles form in a gas
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
"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)
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.
a disk of material surrounding a young star (or protostar) that may eventually form planets
conservation of energy
energy can be neither created or destroyed, but can only change from one form to another
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