Two astronomy questions:?

[eh]

Ok: I'm asking these questions to restore my faith in the human race, as apparently a lot of people don't know the right answer. I'll vote for the most thorough answer.1. How do the phases of the moon work--when is it a full moon and when is it a new moon, etc? What causes the 'shadow' of the moon?2. What causes the seasons on Earth? Please show me that you're all really smart!

[Mak4228]

1) Phases of the moon are caused when the shadow of the earth falls on it. You know that moon is revolving round the earth and earth is revolving round the sun. To, understand you'll need three balls of different sizes. take basket-ball as sun, a smaller volley ball as earth and a base-ball, ball as the moon. Put the 'sun' , 'earth' and 'moon' in a straight line in the same order. Now, you can see that the shadow of the earth is falling on the moon which makes it completely invisible or partially visible. Various phases of moon can be seen while it revolves round the earth. The time when shadow of the earth does not fall on the earth, the moon is completely visible.2) Seasons on the earth are caused due to various reasons.a) Revolution of earth round the sun : The earth revolves round the sun. Its distance is a little responsible for the change of season.b) Rotation of earth on its own axis : Rotation on of the earth on its own axis causes winds to blow.c) Tilted earth : Earth is tilted about 23.5 degrees. This cause the area near the equator to heat up more and the area near the poles remain cold throughout the year. This is the reason behind the causation of water currents.All the above three factors are majorly responsible for the change of seasons. There are many more local factors which affect the seasonal change.

[ErikR]

So the moon has it's phases because of it's Revolution around the earth. The moon is completely lit up when it is directly behind the Earth opposite of the Sun, which makes sense cause the sun is lit it up completely (the earth's shadow on the moon isn't a big factor in how much is lit up). The moon is a new moon when it is between us and the Sun. when it is super perfectly lined up they're called eclipses. The seasons are due to the tilt of the Earth's axis, because of this tilt the hemisphere that's tilted toward the sun (i.e. the sun is directly overhead) heats up more because more light is let in by the atmosphere and therefore heating the ground more.

[Level7]

"...How do the phases of the moon work..."Lunar phases result from the relative positions of the Earth, moon and sun."...when is it a full moon..."Earth is directly between the moon and the sun"...when is it a new moon..."The moon is directly between Earth and the sun"...What causes the 'shadow' of the moon..."If by 'shadow' you mean that portion of the moon in darkness, that's a result of where the moon is in its orbit around Earth which in turn determines which part of the moon is lit by the sun.See this animated graphics to better understand lunar phases =>http://www.astro.uiuc.edu/projects/data/Seasons/seasons.html"...What causes the seasons on Earth?..."Earth's seasons are caused by the ≈23° tilt of Earth on its rotational axis. Because of this tilt, as Earth orbits the sun its light strikes the surface at different angles. The most direct sunlight in the Northern Hemisphere occurs during summer, the opposite in winter. See this excellent animation =>http://www.astro.uiuc.edu/projects/data/Seasons/seasons.html

[Conradical8652]

To understand the phases of the moon, think of the earth and sun fixed in space. As the moon goes around the earth, sunlight hits it at a different angle. When the moon is between the earth and the sun, none of the sun's light shines on the side of the moon that we can see. That's the new moon. When the moon is on the other side two weeks later, so that the earth is between the sun and moon, then the sun's light is shining on the side of the moon we see. That's a full moon. When the moon is between those positions -- think of a right triangle with the earth as the point with the right angle and the sun and moon forming the other points -- we can only see half of the portion of the mkoon that the sun is shining on. That's what we call a quarter moon. In each case the sun is illuminating half of the moon. The phases result fromt he fact that we on earth can see different portions of that illumination, from none to all.The seasons are caused by the tilt of the earth on its axis. During summer in the northern hemisphere the tilt causes a larger portion of each day in that hemisphere to be spent in sunlight and the light to hit the surface more or less full-on, while the southern hemisphere is in darkness for most of the day and catches the light at an oblique angle, making it winter there. When the earth is on the other side of the sun the tilt causes the opposite effect -- the southern hemisphere leans toward the sun.

[mathgeek6894]

The phases of trhe moon are caused by the shadow of the earth passing over the moon. It is a new moon when the earth is directly between the sun and the moon, so we cannot see the moon at all. it is a full moon when the earth's shadow does not tough the moon at all and we can see the entire surface of the moon reflected in the sunlight. I'm not sure what you mean by the shadow of the moon. We see the moon's shadow whenever there is a solar eclipse, and the moon passes directly between the sun and the earth.The seasons on earth are caused by the slant of the earth. Think of the earth as a ball with a pole through it for its axis of rotation. This axis is not straight up and down, but is slanted at about 23.5 degrees. The portion of the earth that is closest to the sun gets summer, the part that is farther away gets winter. When the earth goes around the sun during the year, the slant does not change, so the parts switch, and the seasons change.

[pet_m0nster]

It's been 12 years since my last astronomy class, but lets see if I can get this right.1. (I'm going to try to use an analogy that even the most dim-witted individuals can understand.) Imagine an analog clock on the wall. Earth is the center of the clock, and the sun is at 12 o'clock. Now imagine the moon is between the two. This position represents the beginning of the month. In this position, the sun illuminates the "back" half (the side opposite Earth) of the moon. Since the side facing Earth is covered by shadow, it is invisible to us. This is what's known as a New Moon. As the moon revolves counter-clockwise, it eventually reaches the 9 on our clock (which would represent approximately 7 days time). People standing on Earth looking toward the 9 would see the sunlight along the right half of the moon. This is a Quarter Moon. (Get it? 15 minutes, or a "quarter" of an hour?)Still, the moon continues it's counter-clockwise journey until it reaches the 6 on our clock (the 14 day mark). At this position, still only half of the moon is illuminated by sunlight, but the people on Earth can see that "full" half. This is the Full Moon. (If the moon isn't careful and doesn't watch where it's going, it might occasionally wander into Earth's shadow, and become part of a lunar eclipse...oooh!)I'm sure you get the idea, so I won't beat my analogy further into the ground.2. Earth experiences seasons because it rotates around an axis that's tilted 23.5 degrees. This means that during it's revolution around the sun, there are times when the northern axis is pointed toward the sun, and times when it points away from the sun. When it's pointed toward the sun, the northern half of the globe spends more time in the sunlight and warms up to cause summer. At the same time, the southern axis is pointing away from the sun, so the southern half of the globe spends less time in the sun, which causes their simultaneous winter. Obviously, the opposite season occurs when the Earth is on the opposite side of the sun. Well, if you're still reading, I hope that was thorough enough for you.

[GeoffG5945]

The Moon's phases are caused by the angle from which the Sun is shining on the Moon, a sphere. It has absolutely nothing to do with the Earth's shadow, which only falls on the Moon a couple of times a year when there is a lunar eclipse.The seasons are caused by the tilt of the Earth's axis. The Earth's poles point in the smae direction in space all year around, which means the northern hemisphere is tilted away from the Sun for six months of the year (September to March) and towards the Sun for the other six months (March to September).