(2) Universe and solar system

The IAU says a planet must do three things:

it must orbit a star, big enough to have enough gravity, big enough to clear an other object in its orbit

[Unnatural events] This theory says that the planets were formed from the substance that as torn out of the sun. As speeding massive star passed near the sun, it pulled off the materials due to gravitational attraction

jeans-jeffreys tidal theory

Characteristics of the outer planets: "____________" - They are made up mostly of gases (primarily hydrogen & helium) and ices. - They are very light for their size and move quickly in space. - They have rings and many moons - May have a solid core but no solid surface

jovian planets

- Largest and most massive planet - Oldest planet - Has a great red spot from a storm system that is more than 400 years old (it is larger than earth) - have 4 rings - 80 moons - Greek Zeus

jupiter

The ___________ lies beyond neptune and comprise numerous rocky or icy bodies a few meters to hundreds of kilometers in size.

kuiper belt

- is part of the co-called _____ group of galaxies, which in turn is part of the ________________ of galaxies

local, virgo supercluster

- The 7th largest planet - "Red planet" - iron oxide, or rust, in its soil. - It has the tallest mount of the planets (olympus mons) - 2 moons - Phobos and Deimos - Greek god Ares

mars

An amount of time that an object takes to rotate once. Time it takes an object to revolve around the sun once counter clockwise direction

period of rotation, period of revolution

Most planets rotate ________.

prograde

______________ Developed by aristotle and company. It is where the earth is the center of the solar system or universe.

geocentric theory

- Discovered in 1781 - Last planet to discover - The 3rd largest planet - Ice giant planet - It's axis of rotation is titled 90 degrees - 27 moons - 13 rings - It has the coldest temperature recorded - Greek God Ouranos/Caelus or Coelus

uranus

________ are large pieces of space rock with irregular shapes.

asteroids

Two general hypothesis of the origin of solar system:

catastrophic or unnatural events, natural and continuous processes

[Unnatural events] This theory says that the planets were formed by the collision of the sun and giant comet. Buffon proposed that the debris flung out from a comet's collision with the sun became planets Problem: - rare occurrence - stars are made up of gases and when collision happens, it will expand - failed to explain many characteristics of the solar system

collision theory or buffon's collision theory

A _____ is a small body made from dust, rock, gas & ice. They are kind of like a dirty snowball.

comet

______ Building of larger particles (atom or molecule) at a time ______ sticking together of larger particles _____ coming together of two star _______ Separation of melted materials

condensation, accretion, collision, differentiation

[Natural processes] This theory says that the solar system as formed into bodies with nearly circular orbits because of the whirlpool-like motion in the pre-solar materials

descartes' vortex theory

- Is the only planet known to support life - the 5th largest planet - Has a surface composed of 71% water - densest planet - The moon is earth's only natural satellite

earth

[Unnatural events] This theory says that when a star passes close to the sun, several materials from that star and the sun were removed Lumps were formed and became planets problems: - rare occurrence - stars are made up of gases and when this happens, the gases will expand, and not contract to form lumps

encounter hypothesis

[Unnatural events] This theory says that the planets and other objects in the solar system are products of the sun's explosion Moons or satellites came from the planets (e.g. the earth's moon emerged from the pacific ocean)

fission theory

The outer four planets- Jupiter, Saturn, Uranus and Neptune are called "__________" because of the dominance of gases and their larger size. They rotate faster, have thick atmosphere, lower densities, and fluid interiors rich in hydrogen, helium, and ices

gas giants

- Its spiral arms rotate around a _________, at the center of which lies a supermassive blackhole.

globular cluster

_________ A force that pulls all objects toward each other.

gravity

__________ Developed by Copernicus and company. It is where the sun is the center if the solar system or universe. According to this theory, the earth and everything else revolves around the sun in concentric spheres

heliocentric theory

_______ The tendency of an object to stay either at rest or in motion along a straight path

inertia

_________________ planets are made of materials with high melting points such as silicates, iron, and nickel. They rotate slower, have thin or no atmosphere, higher densities, and lower contents of volatiles- hydrogen, helium, and noble gases

inner terrestrial

- Planet nearest to the sun - smallest planet - fastest orbiting planet - second densest planet - no atmosphere - no moon - Greek God Hermes

mercury

_____________ are pieces of rocks or dust that are smaller than asteroids. They are thought of as remnants of a "failed planets" When small meteoroids enters earth's atmosphere, they usually burn up & make a fiery tail as it falls, it is then called a ________ or a "shooting star" Meteors that land on Earth are called ________.

meteoroids, meteor, meteorites

- A huge disc and spiral-shaped aggregation of about at least 100 billion stars and other bodies. - a ________ is huge collection of gas, dust, and billions of stars and their solar systems

milky way, galaxy

Called Luna b the Romans, Selene and Artemis by the Greeks, and many other mythologies. It is responsible for the tides and keeping earth stable on its axis _____________ - the moon orbits the earth in an elliptical orbit.

moon, lunar orbit

[Natural processes] This theory says that a great cloud of gas and dust began to collapse because of gravitational pull. As the cloud contracted, it spun more rapidly. The spinning cloud flattens with a bulge at the center.

nebular hypothesis or kant-laplace nebular theory

- 4th largest planet - The farthest planet - Ice giant planet - First planet to be discovered by mathematical predictions in 1846 - it has the coldest overall average temperature - 14 moons - 5 rings - Greek Poseidon

neptune

The _________ marks the outer boundary of the solar system and is composed mostly of icy objects.

oort cloud

[Natural processes] This theory says that a massive cloud of gas and dust rotated slowly in space, the cloud shrank under the pull of its own gravitation. Most materials gathered around its own center. Temperature became so high that fuel a powerful reaction (fusion of H giving birth to the sun) Remaining materials around it formed plate-like disc called "eddies", that shrank into compact masses called protoplanets later formed planets and sattelites

protoplanet hypothesis

[Unnatural events] This theory says that the sun's gravity "captures" flying or nearby planets that ere formed independently Problems: - It happens rarely - It cannot explain how asteroids, comets and other objects were formed

random capture hypothesis

- 2nd largest planet - "Ringed planet" - Largest planetary rings (8 rings) - lowest density planet - Has great white spot- comprised of many periodic storms large enough to be seen from earth through a telescope. - Greek Cronus - 83 moons

saturn

[Natural processes] This theory says that stars are formed after giant molecular clouds which resulted to the coalesce of clumps Planets were then formed as a product of star formation

solar nebular disc model

It is a gravitationally bound system of the sun and the objects that orbit it.

solar system

______ - "sun" _______ - heavenly bodies that are attracted to the gravitational pull of the sun.

solar, system

A glowing ball of gas held together by its own gravity and powered by nuclear fusion. It is personified in many mythologies: the Greeks called it _______ and the Romans called it ___. ____ earths or __ jupiter to fit across the diameter of it

sun, helios, sol, 110, 10

Characteristics of the inner planets: "____________" - They are very heavy and move slowly in space - They have no rings and few moons (if any) - Thin atmosphere

terrestrial planets

Much of the mass of the solar system is concentrated at __________ (sun) while angular momentum is held by the __________

the center, outer planets

_______________________ or (IAU) downgraded the status of Pluto to that of a dwarf planet because it did not meet the three criteria, the IAU uses to define a full-sized planet. Essentially Pluto meets al the criteria except one- it "as not cleared it's neighboring region of other objects."

the international astronomical union

- The 6th largest planet - Even though Mercury is closer to the sun, it is the hottest planet - Earth's twin planet - No moon - The morning & evening star - Greek Goddess Aphrodite

venus