Welcome to Mr. Cameron's Y11 Cosmology Class WikiEdit
A wiki dedicated to Cosmology, defined as the the study of the physical universe considered as a totality of phenomena in time and space.
The Sun, Earth and Moon
THE PHASES OF THE MOON:
(Sofia Napolitano) New Moon: occurs when the Moon is positioned in between the Sun and the Earth. It is positioned so that the enlightened part is towards the sun and therefor it is hard to see it from the Earth.
Crescent Moon: a crescent Moon is part way between a half Moon and a new Moon, or between a new Moon and a half Moon. It is called this way because when the Moon is in this stage one can only slightly see it (from Earth). Half Moon: is both first quarter and third quarter moons. The half moon happens when the Moon is at a 90 degree angle with respect to the Earth and Sun. So we can see half of the Moon enlightened and the other half in shadow. Gibbous Moon: a gibbous moon is between a full moon and a half moon, or between a half moon and a full moon. Full Moon: the full moon is the opposite of the new moon. It occurs when the moon is on the opposite side of the Earth. This way the entire sunlit part of the Moon is facing the Earth.
Explanation of the Diagram:
This diagram shows the eight main phases of the moon. The Earth is in the center and the sunlight is coming from the left. The dotted line represents what we can see from the Earth. The bigger drawings of the moon next to the smaller ones are what we see of the moon during that phase.
An important aspect to notice is that the Moon is always half lit by the sun and what changes is the relative position of the Earth.
'T'HE DARK SIDE OF THE MOON (THE FAR SIDE OF THE MOON): (Sofia Napolitano) The same side of the Moon always faces Earth causing there to be a section of the Moon that one can never see from our
planet. This section is called “the dark side of the Moon”. Why does the Moon always face the Earth with the same side? This phenomeno
n is caused by the speed at which the Moon rotates. Millions of years ago, the Moon spun at a much faster pace than it does now. However, the Earth’s gravity has caused the Moon to slow down. This influence slowed the rotational period of the Moon to match that of its orbit – about 29.5 days – and it is now permanentily this way. The first time a picture was taken of the dark side of the Moon was in 1959 by the Soviet Luna 3. With these images it was possible to observe that the dark side of the Moon had restricted basaltic volcanoes and widespread battered highlands crust. The crust on the farside is thicker causing it to be more difficult for magmas to erupt on the surface.
LUNAR ECLIPSE: (Andrea Nordquist)
A lunar eclipse is when the moon is in the Earth’s shadow, or umbra. For this to be able to take place, the Sun, Earth and moon have to be aligned in a very straight line, with the Earth in the middle. It also has to be a night of a full moon in order for this to take place. A lunar eclipse lasts for a few hours, unlike the solar eclipse, which only lasts for a few minutes. It is also, unlike the solar eclipse, possible to observe a lunar eclipse without eye protection, since it is much dimmer brightness, due to the fact that lunar eclipses are much dimmer than an actual full moon. There are two types of lunar eclipses, partial and total. A partial lunar eclipse is when the moon only enters the umbra of the Earth partially. A total lunar eclipse is when the moon enters the umbra completely. Lunar eclipses usually occur twice a year (about ever six months) but they are rarely total lunar eclipses. There is a scale called the Danjon scale, which was introduced by André Danjon, which rates the overall darkness of a lunar eclipse. The last lunar eclipse that occurred, happened the 4th of June 2012, and the next one is predicted to appear the 28th of November 2012. The one that occurred the 4th of June, was a partial lunar eclipse.
(Frederique Steffens) • tides= The periodic variation in the surface level of water • Tides are created because the Earth and the moon are attracted to each other, just like magnets. The moon tries to pull at anything on the Earth to bring it closer. But, the Earth is able to hold onto everything except water. Since water is always moving, the Earth cannot hold onto it, and the moon is able to pull at it. • Each day, there are two high tides and two low tides. The ocean is constantly moving from high tide to low tide, and then back to high tide. There is about 12 hours and 25 minutes between the two high tides • Winds and currents move the surface water causing waves. The gravitational attraction of the moon causes the oceans to grow out in the direction of the moon. Another growth occurs on the opposite side, since the Earth is also being pulled toward the moon. Ocean levels fluctuate daily as the sun, moon and earth interact. As the moon travels around the earth and as they travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall. Since the earth is rotating while this is happening, two tides occur each day. • Spring Tides: When the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. • Neap Tides: During the moon's quarter phases the sun and moon work at right angles, causing the growths to cancel each other. The result is a smaller difference between high and low tides and is known as a neap tide. Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another.