Our view of the solar system has ________________ as technology and scientific knowledge has __________________.
Geocentric Model:
Geocentric Model – the ancient ______________ believed that Earth was at the _________________ of the universe.
Geocentric means “Earth-centered”
The sky, or heavens, are a set of spheres _______________ on top of one another.
Worked well by explaining why all the _____________ appear to rotate around Earth once per day and why the planets move ______________________ from the stars and from each other.
One problem is that some planets seem to move backwards (in retrograde) instead of in their usual _________________ motion around Earth.
Heliocentric Model:
Heliocentric Model – that the _________________ and all the other planets orbit the _____________ (which is at the center).
Heliocentric means “Sun-centered”
Johannes Kepler refined this model so that the planets moved around the Sun in _____________________ (ovals) not circles.
The Modern Solar System:
We know our solar system is just a ____________ part of the universe as a whole.
Neither the _____________ or the _________ are at the center
The Sun is off center
The Sun is a the “center” with the planets moving in _________________ orbits around the Sun
The planets do not emit their own _____________, but instead reflect the light from the _________.
There are ________ planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune)
_________ dwarf planets (Ceres, Pluto, Makemake, Haumea, and Eris)
Although the ____________ is just an average star compared to other stars, it is by far the ________________ object in our solar system.
In general, the ________________ away from the Sun, the greater the distance from one planet’s orbit to the next.
The orbit of the planets are not _________________, but slightly elliptical with the Sun located at one of the foci (focal point).
IF the orbital period of a planet is known than it is possible to determine the planet’s __________________ from the Sun.
Astronomical Unit (AU) – how _______________________ in the solar system are often measured in
One AU is defined as the distance from ___________ to the _________
1 AU equals about 150 million km (93 million miles)
The greater the object’s ____________, the greater the force of attraction; in addition, the greater the ____________________ between the objects, the smaller the force of attraction.
________________ keeps each planet orbiting the Sun because the star and its planets are very large objects.
The force of gravity also holds _____________ in orbit around planets
Formation of the Solar System:
There are ________ additional key features of the solar system:
All the planets lie in nearly the same ______________, or flat like disk like region
All the planets orbit in the ____________ direction around the Sun.
These features are _____________ to how the solar system formed
The most widely accepted explanation of how the solar system formed is called the ______________ hypothesis.
A Giant Nebula:
As _______________ particles of dust and gas smashed _________________ to create larger ones, they released kinetic energy.
As the ________________ collapsed, the gravity at the center increased and the cloud started to spin because of its angular _______________.
As it ___________________ further, the spinning got faster
Much of the cloud’s mass migrated to its ___________________ but the rest of the material flattened out in an enormous _______________.
This disk contained hydrogen and ________________along with heavier elements and even simple organic molecules.
Formation of the Sun and Planets:
As __________________ pulled matter into the center of the ___________, the density and _____________________ at the center became intense.
When the pressure in the center of the disk was _____________ enough, nuclear ______________ began.
A star was born – the ________, this burning star ___________________ the disk from collapsing further.
Meanwhile, the _______________ parts of the disk were _______________ off. Matter condensed from the cloud and small pieces of _____________ started to clump together.
Gravity at the center of the disk _____________________ heavier particles (rock, metal) while ___________________ particles remained further out in the disk.
Separation of the Planets:
Inner Planets:
Because of the _____________________ sorting of material, the inner planets (Mercury, Venus, Earth, and Mars) formed from dense ____________ and metal.
Outer Planets:
The outer planet (Jupiter, Saturn, Uranus, and Neptune) condensed farther from the Sun, from _________________ materials as hydrogen, helium, water, ammonia, and methane.
Out this far these materials form _______________ particles.
Kepler’s Law of the Solar System:
Supports the nebular hypothesis and our understanding of the solar system.
The path of each planet is like an ________________, the Sun at the focus (center).
Each planet revolves in an imaginary line over ___________ areas.
The planet must go ______________ when farther from the Sun and _______________ when closer to the Sun.
The time it takes the planet to orbit the Sun (_______________ period) is proportional to the distance from the Sun.
Measured in _____________ years
Planets distance to the Sun is expressed in astronomical units (AU) – the average distance between the Earth and the Sun
Planet Earth
Earth’s Shape:
Earth is a ____________, an orbital spheroid, which is a sphere that is a bit squished down at the ____________ and bulges a bit at the ______________.
Half of the sphere is a _______________________.
Earth’s Magnetism:
Earth has a magnetic _____________ that behaves as if the planet had a gigantic bar _______________ inside of it.
The magnetic field arises from the __________________ of molten iron and nickel metal in Earth’s outer _____________ core.
The magnetic field shields the planet from harmful __________________ from the Sun.
Earth’s Motions:
Axis – an imaginary line passing through the __________ of the Earth that goes through both the _____________ pole and ______________ pole.
Rotation – the Earth spins around its ________________ creating day/night (24 hours for 1 rotation)
Revolution – the orbit of the Earth around the ____________ (365 days/1 year)
Earth’s Rotation:
An observer in space will see that the Earth requires 23 hours, 56 minutes, and 4 seconds to make _______ complete rotation on its axis.
Since the Earth moves around the __________ at the same time that it is rotating, the planet has to turn just a little bit more to reach the same place relative to the Sun
At the equator, the Earth rotates at a speed of about 1,700km per hour, but at the poles the movement speed is nearly nothing.
Earth’s Revolution:
One ________________ revolution around the Sun takes 365.24 days.
Earth’s orbital path is an ________________ which causes the planet to sometimes be farther away from the Sun (_____________________) than at other times. The closest the Earth is to the Sun is called __________________.
Earth’s elliptical orbit has ____________________ to do with Earth’s seasons.
Earth’s Seasons:
The reason Earth (or any other planet) has seasons is that Earth is tilted ____________ on its axis.
Northern Hemisphere
Southern Hemisphere
Summer (the North Pole points __________ the Sun)
Winter (the South Pole points _________ from the Sun)
Winter (the North Pole points _________ from the Sun)
Summer (the South Pole points _____________ the Sun)
Earth’s Moon:
Lunar Characteristics:
The Moon is the Earth’s only natural satellite (a body that moves around a _______________ body in space)
The Moon orbits the Earth for the same reason the Earth orbits the Sun - __________________!!!!!
Lunar – having to do with the ________________
Moon’s Movements:
The Moon makes one complete ___________________ around the Earth every 27.3 days
The Moon rotates on its ___________________ every 27.3 days
This means the same side of the Moon always faces the Earth which is what we see in the night sky
The Moon only reflects light from the ______________.
The Lunar Surface:
The _____________________ of the Moon is very different
With no plate tectonics, features are not _____________.
With no atmosphere, features are not _________________.
Maria – the __________ spots on the Moon mean “seas”, since this is what the ancients thought they were.
Terrae – the _______________ parts of the Moon, or highlands
Lunar Interior:
Like the Earth, the ____________ has a distinct crust, mantle, and a core
The Sun and the Earth-Moon System:
Introduction:
The ________________ of the Earth relative to the Sun, and the _____________ of the Moon and Sun relative to ________________ affect different phenomena on Earth including:
Earth ____________ once on its axis every 24 hours
The Sun appears to move across the sky from ______________ to _____________ each day.
HOWEVER the Sun is ____________ moving, the Earth is rotating
Shadows – areas where an object _____________________ a light source so that darkness takes on the form of that object.
Earth’s Seasons:
Caused by the _____________ tilt on its axis
At the ________________ Solstice, June 21st, Earth’s axis points ____________ the Sun and so the Sun is directly _________________ at its furthest north point of the year, the Tropic of Cancer.
During the summer, areas north of the ________________ experience longer days and shorter nights
The _________________ occurs on the Winter Solstice, December 21st
Solar Eclipse:
Occurs when the ________ moon passes directly _____________ the Earth and Sun.
This cast a _________________ on the Earth and blocks Earth’s view of the Sun.
Solar Eclipses are ___________ and usually only last a few minutes because the Moon casts only a small shadow.
Lunar Eclipse:
Occurs when the ___________ moon moves through Earth’s shadow.
This only happens when Earth is between the Moon and the ___________ and all three are lined up in the same plane (called the ecliptic).
A total lunar eclipse occurs when the Moon travels completely in Earth’s ______________ (shadow).
Phases of the Moon:
The Moon does _________ produce any light of its own – it only _______________ sunlight.
As the Moon moves around the Earth, different portions of the __________________ are illuminated which causes the phases of the Moon.
It takes 29.5 days for the Moon to make _______ cycle relative to the Sun and go through all the phases.
The difference of 29.5 and 27.3 is that while the Moon is orbiting the Earth, the Earth is moving along its orbit so it takes longer for the Moon to reach the same position relative to the ________.
The Tides:
Tides are the __________________ rising and falling of Earth’s ______________ water in response to the gravitational attraction of the Moon and Sun.
The Moon’s ________________ pulls ________________ on Earth’s water causing it to bulge out in the direction of the Moon.
On the other side of the Earth, a high tide is produced where the Moon’s pull is the ________________.
There are ________ high tides and _________ low tides in one tidal day.
Spring Tides:
The gravity of the Sun also pulls Earth’s water _______________ it and causes its own tides.
When the Sun and Moon are in __________, during the __________ moon and the ________ moon their high tides add up and create a _______________ tide.
During a spring tide, high tides are really _____________ and low tides are really __________.
Neap Tides:
When the Earth and Sun are in line but the the Moon is ___________________________ to the Earth a neap tide occurs.
In a neap tide the difference between high and low tides is not very ______________ since the pull of gravity from the Sun partially cancels out the pull of gravity form the Moon.
Types of Radiation Through Space:
Electromagnetic Radiation:
The Earth is ________________________ from the rest of the universe by very large expanses of space.
Very rarely matter from the outside of Earth’s ______________________ reaches us.
Example: When a meteorite makes it through the atmosphere from elsewhere in the Solar System.
HOWEVER _____________ can travel across ______________ space, and as it does, it carries both energy and _________________.
Electromagnetic Radiation – energy that is ______________________ through space as a wave (example: ______________)
