AST Pt. 2
Nodes
are the points where the Moon's orbit crosses the ecliptic plane
When does a full moon appear near the west horizon?
around the time of sunrise
When does a full moon appear near the western horizon?
around the time of sunrise
Where would you have to place a space probe between Mars and Earth, in order for the probe to experience a net (total) zero force?
Closer to Mars.
Consider the seasonal differences that occur as Earth orbits the Sun with the different axis tilts.
The greater the axis tilt, the more extreme the seasonal temperature differences.
Newton's Third Law
The moon must be pulling on Earth with a force that is the same type (gravitational), and it of an equal strength, but in the opposite direction to the force that Earth exerts on the Moon.
The Universal Law of Gravitation
The strength of gravitational attraction between the two objects.
what is the cause of the seasons?
The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year. Without axis tilt, we would not have seasons on Earth. Seasons on other planets occur for the same reason, which is why planets with axis tilts (such as Mars and Saturn) have seasons and planets with very little axis tilt (such Jupiter or the "upside-down" axis of Venus) do not.
how variation in the Earth-Sun distance affects the seasons?
The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons.
If, somehow, the number of daylight hours did not change throughout the year, but Earth was still titled at 23.5 degrees, would there still be seasons in the northern and southern hemispheres of earth?
There would still be seasons, because the intensity of light would still change throughout the year, due to the earth's tilt. The temperature difference would not be as great because the Earth would not be heated for a longer time in summer.
If the moon is a full moon tonight, will the moon be waxing or waning one week later? Which side of the moon (right or left) will appear illuminated at this time?
Waning; left After full phase, the Moon's phases wanes for about 2 weeks. With the Moon high in the southern sky, the Sun would be in the East (sunrise) producing a third-quarter moon with the lit side facing east (left).
What do we mean by waxing and waning phases?
Waxing means phases that we see as the moon approaches full moon, and waning means phases that we see after full moon.
Which of the following correctly describes what we mean by "waxing" and "waning" phases of the Moon?
Waxing means phases that we see as the moon approaches full moon, and waning means phases that we see after full moon.
How often does a new moon occur?
once a month
If Earth were twice as far from the Sun, the force of gravity attracting Earth to the Sun would be
one-quarter as strong
If Earth were twice as far from the sun, the force of gravity attracting Earth to the sun would be
one-quarter as strong.
We see a full moon in our sky only when ____
the Moon and sun are on opposite sides of Earth
Consider Earth and the Moon. As you should now realize, the gravitational force that Earth exerts on the Moon is equal and opposite to that which the Moon exerts on Earth. Therefore, according to Newton's second law of motion __________.
the Moon has a larger acceleration than Earth, because it has a smaller mass Newton's second law of motion, F=ma, means that for a particular force F, the product mass x acceleration must always be the same. Therefore if mass is larger, acceleration must be smaller, and vice versa.
A solar eclipse occurs when
the Moon's shadow falls on Earth.
In winter, Earth's axis points toward the star Polaris. In spring:
the axis also points towards polaris
According to Newton's third law __________.
the strength of the force that the object on the left exerts on the object on the right has to be exactly the same (but in an opposite direction) as the force the object on the right exerts on the object on the left
We cannot see a new moon in our sky because _________.
A new moon is quite near the Sun in the sky
What is a solar eclipse?
A solar eclipse occurs when the moon's shadows falls on earth.
2 pieces of evidence why the varying distance between the Sun and Earth cannot account for the seasons
- The Northern and Southern Hemispheres do not experience the same season at the same time. -Eath is closest to the sun when the Northern Hemisphere is experiencing winter. So the varying distance between earth and the sun cannot account for the seaons.
What conditions must exist for a solar eclipse to occur?
- The phase of the Moon must be new and the Moon must be passing through Earth's orbital plane. -The two points at which the Moon's orbit crosses the Earth's orbital plane are called the nodes of the Moon's orbit. So another way to state the conditions for a solar eclipse is that (1) it must be new moon, and (2) the Moon must be at or quite near one of the nodes of its orbit.
why is it generally hotter in summer than in winter?
-The Sun is higher in the sky in summer. -We have more hours of daylight in summer. Both factors are a result of Earth's axis tilt relative to the Sun, which is why we say that axis tilt is the cause of the seasons.
What conditions must exist for a lunar eclipse to occur?
-The phase of the Moon must be full and the Moon must be passing through Earth's orbital plane. -The two points at which the Moon's orbit crosses the Earth's orbital plane are called the nodes of the Moon's orbit. So another way to state the conditions for a lunar eclipse is that (1) it must be full moon, and (2) the Moon must be at or quite near one of the nodes of its orbit.
2 things directly responsbile for the cause of seasons on Earth
-change in the number of daylight hours -change in the intensity of this daylight.
full moon
-occurs 14 days after the new moon -rises about the same time the sin sets -visible due south at midnight
waning crescent moon
-occurs about 3 days before new moon -visible near eastern horizon just before sunrise
waxing crescent moon
-sets 2-3 hours after the Sun sets -visible near western horizon about an hour after sunset
Provide two pieces of evidence that either supports of contradict that the varying distance between the Sun and Earth accounts for the seasons:
1. Earth is closest to the sun in summer (in the northern hemisphere) 2. Summer in the northern hemisphere occurs at the same time as winter in the southern hemisphere
According to Newton's second law, the greater the force exerted on an object, the greater the object's _____.
Acceleration According to Newton's second law, the asteroid with the largest acceleration will be the one that has the strongest gravitational force exerted on it by the object on the right.
If the Northern Hemisphere were tilted 90 degrees toward the sun, which location would be warmer in summer>
Arctic Circle
If you could change the layout of the solar system, which of the following would cause a lunar eclipse to occur at least once every month in this hypothetical situation?
Change the Moon's orbital plane so it is in the same plane as Earth's orbit around the Sun.
We say that Earth's axis has a tilt of 23.5 degrees, which means
Earth's axis is tilted at an angle of 23.5 degrees compared to a line perpendicular (straight up and down) to its orbit
Where (in the southern sky, on the eastern horizon, or the western horizon, high in the sky ect.) would you look to see the full moon when it starts to rise? What time would this happen?
Eastern horizon 6 pm
Newton's 3rd Law
For every action, there is an eqaul and opposite reaction.
It is ______ when we see all of the Moon's daylight side and none of its night side.
Full moon
Lunar eclipses can occur only during a _________.
Full moon
Velocity
How fact and in what direction position changes
Acceleration
How fact and in what direction velocity changes
Circular motion
If a planet is moving on a circular orbit, it must be accelerating. a = v^2/r
If we have a new moon today, when we will have the next full moon?
In about 2 weeks
Newton's 1st Law
In the absence of a net force, an object will move with constant velocity.
Newton's Second Law
Net force equals mass times acceleration -- the spaceprob would exerpience the greatest acceleration where it would exerpience the greatest net force which is at the surface of Earth.
Lunar Eclipse
Sometimes, the earth blocks the sunlight reaching the moon
Solar Eclipse
Sometimes, the moon blocks our view of the sun
Newton's 2nd Law
The acceleration experienced by an object is proportional to the force acting on it: Force = Mass X Acceleration
If the Northern Hemipshere were tilted 90 toward the Sun, which location would be warmer in summer: the Arctic Circle or Florida?
The artic circle would be warmer in the summer because it would be tilted directly at the Sun. This would cause the light to be directly overhead for 24 hours a day. While in Florida, even though the Sun be still be up for 24 hours, it would be low on the horizon because Florida is much closer to the equator. This would cause Floria to be much cool than the article circle during summer.
What conditions must exist for a lunar eclipse to occur?
The phase if the moon must be full and the moon must be passing through Earth's orbital plane.
What conditions must exist for a solar eclipse to occur?
The phase of the moon must be new and the Moon must be passing through Earth's orbital plane.
Suppose you lived on the Moon. Which of the following would be true?
Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth.
Suppose you lived on the moon. Which of the following would be true?
Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth.
We see about 3/4 of the Moon's face illuminated at waxing gibbous phase. What do we see about three to four days later?
a full moon
What do we see a few days after a waxing gibbous moon?
a full moon. we see 3/4th of the moon at a waxing gibbous
According to Newton's second law, the greater the force exerted on an object, the greater the object's ____
acceleration
The moon's phase is _____ when we see half of the moon's daylight side and half of its night side.
first quarter or third quarter moon.
Lunar eclipses can occur only during a
full moon
A car is accelerating when it is
going around a circular track at a steady 100 miles per hour.
If the Sun rises precisely due east:
it must be either the spring or fall equinox
When it is summer in Australia, the season in the United States is
winter