Solar Wind Solar Wind and How it Affects Earth

Aurora Borealis NASA The Mystery of the Aurora

Phases of the Moon The Moon is a cold, rocky body about 2,160 miles (3,476 km) in diameter. It has no light of its own but shines by sunlight reflected from its surface. The Moon orbits Earth about once every 29 and a half days.

Phases of the Moon As it circles our planet, the changing position of the Moon with respect to the Sun causes our natural satellite to cycle through a series of phases:

Phases of the Moon New Moon > New Crescent > First Quarter > Waxing Gibbous > Full Moon > Waning Gibbous > Last Quarter > Old Crescent > New Moon (again)

Phases of the Moon NASA 2013-moon-phases New 2013 Phases of the Moon Animation

Eclipses Eclipses occur when an apparently large celestial body (planet, moon etc.) moves between the observer (that's you!) and a more distant object - the more distant object being eclipsed by the nearer one.

Solar Eclipses Solar eclipses occur when our Moon moves between the Earth and the Sun. This happens when the inclined orbit of the Moon causes its path to cross our line of sight to the Sun. In essence it is the observer falling under the shadow of the moon.

Solar Eclipses

There are three types of solar eclipses: Partial The Moon only covers part of the Sun's surface. Total The Moon completely obscures the Sun's surface. Annular The Moon is at aphelion (furthest from Earth in its elliptic orbit) and its disc is too small to completely cover the Sun. In this case most of the Sun's disc is obscured - all except a thin ring around the edge.

Solar Eclipses

Solar Eclipses Solar Eclipse Schedule

Observing Solar Eclipses Observing Solar Eclipses Safely

Lunar Eclipses Lunar eclipses occur when the Earth moves between the Sun and the Moon, and the Moon is in the Earth's shadow. They occur under the same basic conditions as the solar eclipse but can occur more often because the Earth's shadow is so much larger than the Moon's.

Lunar Eclipses

Astronomers recognize three basic types of lunar eclipses: 1. Penumbral Lunar Eclipse The Moon passes through Earth's penumbral shadow. These events are of only academic interest because they are subtle and hard to observe. 2. Partial Lunar Eclipse A portion of the Moon passes through Earth's umbral shadow. These events are easy to see, even with the unaided eye. 3. Total Lunar Eclipse The entire Moon passes through Earth's umbral shadow. These events are quite striking due to the Moon's vibrant red color during the total phase (totality).

Lunar Eclipses NASA | Lunar Eclipse Essentials in 3D

Lunar Eclipses Lunar Eclipse Schedule

Comets A comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail. Comets whose orbit brings them close to the Sun more frequently than every 200 years are considered to be short period comets, the most famous of which is probably Comet Halley, named after the British astronomer Edmund Halley, which has an orbital period of roughly 76 years.

Tides Rising and falling of ocean waters as a result of the Moon’s and Earth’s gravity The force of attraction between all masses in the universe is called gravitational force Caused by the difference between the force of gravity on the side of Earth nearest the Moon and the force of gravity on the side of Earth farthest from the moon

Stretching Effect

Bay of Fundy

Comets Comets have a very eccentric orbit (very elliptical), and as such spend most of their time a very long way from the Sun. Comets are composed of rock, dust and ices. When they come close to the Sun, the heat evaporates the ices, causing a gaseous release. This gas, and loose material which comes away from the body of the comet is swept away from the Sun by the Solar wind, forming the tail.

Comets Comets whose orbit brings them close to the Sun more frequently than every 200 years are considered to be short period comets, the most famous of which is probably Comet Halley, named after the British astronomer Edmund Halley, which has an orbital period of roughly 76 years.

Asteroids Asteroids are celestial bodies orbiting the Sun in more or less regular orbits mostly between Mars and Jupiter. They are generally rocky bodies like the inner (terrestrial) planets, but of much smaller size. There are countless in number ranging in size from about ten meters to thousands of kilometres

Meteoroids These objects are small pieces of space debris left over from the early days of the solar system that orbit the Sun. They come in a variety of shapes, sizes an compositions, ranging from microscopic dust particles up to about ten meters across.

Meteoroids Meteoroids is the name given to such objects when they are floating in space. A Meteor is the name given to the visible atmospheric phenomenon. Meteorites is the name given to objects that penetrate the atmosphere and land on the surface