# Science: An Elementary Teacher’s Guide/Beyond the Earth
## A Brief History of Our Universe

* How old is our universe?
There is not an exact way to answer “how old is our universe?” According to research we can only get an approximate number. Based on the studies of many astronomers the universe is between 12 and 14 billion years old. Our universe consists of planets, natural satellites, minor planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy.
It all began with the Big Bang.
* How are planets formed?
Planets are thought to have formed the solar nebula. The solar nebula is a disc-shaped cloud of gas and dust left over from the Sun's formation. The currently accepted method by which the planets formed is accretion, in which the planets began as dust grains in orbit around the central protostar. As clouds collapsed they started rotating in the same direction. Then, they started through direct contact, material began to stick together creating larger and larger clumps, these clumps formed up to 200 meters in diameter, which in turn collided to form larger bodies’ planetesimals (the beginnings of a planet) of ~10 kilometers (km) in size. These gradually increased through further collisions, growing at the rate of centimeters per year over the course of the next few million years. After millions of year and many collisions, a planetary system begins to reach maturity.
The Sun is a star and the largest object in the Solar System, where it lies in the middle of the galaxy and is 92.95 million miles away from the earth. The sun is orbited by matter including: planets, comets, asteroids, meteoroids, and dust. The sun is a major and important source of energy for life on earth (giving a photosynthesis to plants and other life forms) and drives the earth's climate and weather.
Containing 99.8% more of the total mass of the Solar System (since Jupiter contains the rest). Currently, the mass of the sun is about 70% hydrogen, 28% helium by mass, and less than 2% of other metals. It slowly changes over time as the sun converts hydrogen to helium in its core. Producing around 3.86e33 megawatts by nuclear fusions reactions, it's considered to be the sun's energy output. Traveling out toward the surface, the energy is continuously absorbed and re-emitted lower temperatures, therefore by the time it reaches the surface, the light is primarily visible.
The Sun is roughly middle aged and has not changed dramatically for over four billion years, and will remain fairly stable for more than another five billion years. However, after hydrogen fusion in its core has stopped, the Sun will undergo severe changes and become a red giant.

### Harboring Energy

Solar energy is radiant light and heat from the Sun harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture and artificial photosynthesis.
It is an important source of renewable energy and its technologies are broadly characterized as either passive solar or active solar depending on the way they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

## The Star

A star is a brilliant sphere of plasma (mostly hydrogen and helium) held together by its own gravity. The sun is the nearest star to the earth. You can see other stars during the night from earth, many are fixed brilliant points in the sky due to their vast distance from the earth. Stars that are smaller than our sun are red, and stars that are larger than our sun appear blue. The most well-known stars were grouped into constellations and asteisms and proper naming of the brightest stars. Astronomers have put together an extensive catalogues of stars, which include standardized star designations. Stars create their own light by nuclear fusion. When nuclear fusion occurs, the star heats up and shines bright!

## The Milky Way Galaxy

The Milky Way galaxy is 1 out of 100 billion galaxies.
It is the galaxy that we live in! It is about 120,000 light years across with a central bulge that has a diameter of 12,000 light years.
It is really dusty and gassy making up 10-15% of visible matter. It is made up of other galaxies and is almost as old as the universe itself! (13.6 billion years old.) The Milky Way galaxy is one out of ten galaxies that support complex life. As with everything else in the universe, the Milky Way galaxy is moving through space.
Appearance
The "Milky Way" can be seen as a hazy band of white light some 30 degrees wide arcing across the sky. Although all the individual naked-eye stars in the entire sky are part of the Milky Way, the light in this band originates from the accumulation of unresolved stars and other material located in the direction of the galactic plane. Dark regions within the band, such as the Great Rift and the Coalsack, are areas where light from distant stars is blocked by interstellar dust. The area of the sky obscured by the Milky Way is called the Zone of Avoidance.
The Milky Way has a relatively low surface brightness. Its visibility can be greatly reduced by background light such as light pollution or stray light from the Moon. The sky needs to be darker than about 20.2 magnitude per square arcsecond in order for the Milky Way to be seen. It should be visible when the limiting magnitude is approximately +5.1 or better and shows a great deal of detail at +6.1. This makes the Milky Way difficult to see from any brightly lit urban or suburban location, but very prominent when viewed from a rural area when the Moon is below the horizon.
As viewed from Earth, the visible region of the Milky Way's Galactic plane occupies an area of the sky that includes 30 constellations. The center of the Galaxy lies in the direction of the constellation Sagittarius; it is here that the Milky Way is brightest. From Sagittarius, the hazy band of white light appears to pass around to the Galactic anticenter in Auriga. The band then continues the rest of the way around the sky, back to Sagittarius. The band divides the night sky into two roughly equal hemispheres.
The Galactic plane is inclined by about 60 degrees to the ecliptic (the plane of Earth's orbit). Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth’s equatorial plane and the plane of the ecliptic, relative to the Galactic plane. The north Galactic pole is situated at right ascension 12h 49m, declination +27.4° (B1950) near β Comae Berenices, and the south Galactic pole is near α Sculptoris. Because of this high inclination, depending on the time of night and year, the arc of Milky Way may appear relatively low or relatively high in the sky. For observers from approximately 65 degrees north to 65 degrees south on Earth's surface, the Milky Way passes directly overhead twice a day.

## Our Solar System

Our Solar System consists of all the planets that orbit the Sun. It also contains moons, asteroids, minor planets, comets, dust, and gas. Everything in our solar system revolves around our Sun.The Sun contains about 98% of all material found in the Solar System. The sun is so large it has a very powerful gravitational force. Gravity is relative to size of the object. The bigger it is, the greater its gravity is. The Sun's gravity is so powerful, it attracts all the objects in our solar system.

### Formation of planets

The formation of the Solar System began 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small Solar System bodies formed. The nebular hypothesis is the most accepted model of how planets form and describes gases and debris in a large disc around the sun slowly collecting into planets. The vast majority of the system's mass is in the Sun, with most of the remaining mass contained in Jupiter. The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. The four outer planets are giant planets, being substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called ices, such as water, ammonia and methane. All planets have almost circular orbits that lie within a nearly flat disc called the ecliptic.
The Solar System has evolved considerably since its initial formation. Many moons have formed from circling discs of gas and dust around their parent planets, while other moons are thought to have formed independently and later been captured by their planets. Still others, such as Earth's Moon, may be the result of giant collisions. Collisions between bodies have occurred continually up to the present day and have been central to the evolution of the Solar System. The positions of the planets often shifted due to gravitational interactions. This planetary migration is now thought to have been responsible for much of the Solar System's early evolution.
The Solar System is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the planets,[c] with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury.
Our Solar System has eight planets which orbit the sun. In order of distance from the sun they are; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto, which until recently was considered to be the farthest planet, is now classified as a dwarf planet. Additional dwarf planets have been discovered farther from the Sun than Pluto. Some asteroids are also dwarf planets.

## Our Moon

Our moon is our planet's natural satellite. It was most likely formed after a huge mass collided with Earth.The debris generated from that collected and formed the moon. This collision happened approximately 4.5 billion years ago. The moon is in synchronous rotation with the Earth. The same side is always facing the Earth.
The Moon's gravitational force effects ocean tides, body tides, and day lengthens. The moon's orbital distance is about thirty times more than the Earth's diameter, in the sky it appears that the moon and the sun are the same size that during a total solar eclipse the Moon covers the Sun nearly precisely. In the future the matching visual size will not continue. The Moon's linear distance from Earth is currently increasing at a rate of 3.82 ± 0.07 centimetres (1.504 ± 0.028 in) per year, but this rate is not constant.

## Quick Facts About the Moon

* Both sides of the moon get the same amount of sunlight from the sun.
* The cause of the rise and fall of the oceans' tides are due to the gravitational pull that the moon exerts on our planet.
* The moon is drifting away from the Earth
* A person will weigh much less on the moon due to the moon being of smaller mass and having less gravity than Earth.
* The moon has been walked on by 12 people- all American.
* The moon has no atmosphere
* The moon has quakes-just like Earth
* The moon is the fifth largest natural satellite in our Solar System.
* The moon may be visited by humans perhaps by 2019.

### Lunar Phases

The lunar phase or phase of the moon is the shape of the illuminated (sunlit) portion of the Moon as seen by an observer on Earth. The lunar phases change cyclically as the Moon orbits the Earth, according to the changing positions of the Moon and Sun relative to the Earth.
The Moon's shadow actually has two parts:
1. Penumbra The Moon's faint outer shadow. Partial solar eclipses are visible from within the penumbral shadow.
2. Umbra The Moon's dark inner shadow. Total solar eclipses are visible from within the umbral shadow.

## Lunar Eclipse

A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the sun, Earth and moon are aligned exactly, or very closely so, with the Earth in the middle. A lunar eclipse can occur only the night of a full moon. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes. Composed of two coned-shaped components by the shadow, which is nested inside the other. The outer shadow is a zone where the Earth blocks some part, but not all of the sun's rays from reaching the moon. While the inner shadow, in contrast, is a region where the Earth blocks all direct sunlight from reaching the moon. Therefore, only on a Full Moon can a lunar eclipse occur.
A total lunar eclipse has the direct sunlight completely blocked by the earth's shadow. The only light seen is refracted through the earth's shadow. This light looks red for the same reason that the sunset looks red, due to scattering of the more blue light. Because of its reddish color, a total lunar eclipse is sometimes called a blood moon.

## The Moon

The Moon, of course, has been known since prehistoric times. It is the second brightest object in the sky after the Sun. As the Moon orbits around the Earth once per month, the angle between the Earth, the Moon and the Sun changes; we see this as the cycle of the Moon's phases. The time between successive new moons is 29.5 days (709 hours), slightly different from the Moon's orbital period (measured against the stars) since the Earth moves a significant distance in its orbit around the Sun in that time.

### Lunar Month

A lunar month is the amount of time it takes for the Moon to pass through each of its phases (new moon, half, full moon), and then return back to its original position. It takes 29 days, 12 hours, 44 minutes and 3 seconds for the Moon to complete one lunar month.
A lunar month is the amount of time it takes for the Moon to get from a specific phase, like a new moon, back to the same phase. In other words, the Moon has to get back to the point in its orbit where the Sun is in the same position from our point of view. Since the Moon is going around the Sun with the Earth as part of its orbit, the Moon has to catch up a little bit on each orbit. It takes 2.2 additional days each orbit of the Moon to catch up.

### Changes Color

The moon appears to change colors sometimes due to the scattering of light through the atmosphere. Moonlight has to pass through more atmosphere when it is on the horizon than when it is higher in the sky. By the time the moonlight is visible, all of the fragments of light on the blue end of the color spectrum have been scattered away by the air molecules, leaving only red, yellow and orange pieces of light.
The moon tends to look more reddish when it is closer to the horizon because its light must pass through heavier atmosphere. Once it has risen directly overhead, it looks more yellow or white. The same process occurs with the sun when it rises. During the day, the moon must also compete with sunlight being scattered through the atmosphere, which causes it to appear to be white.

### Lunar Phases

* New Moon: The Moon's unilluminated side is facing the Earth.
* Waxing Crescent: The moon appears to be partly but less than one half-illuminated by direct sunlight.
* First Quarter: One half of the Moon appears to be illuminated by direct sunlight.
* Waxing Gibbous: The Moon appears to be more than one half but not fully illuminated by direct sunlight.
* Full Moon: The Moon's illuminated side is facing the Earth. The Moon appears to be completely illuminated by direct sunlight.
* Waning Gibbous: The Moon appears to be more than one half but not fully illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is decreasing.
* Last Quarter: One-half of the Moon appears to be illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is decreasing.
* Waning Crescent: The Moon appears to be partly but less than one-half illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is decreasing.

### Eclipse

An eclipse takes place when one heavenly body such as a moon or planet moves into the shadow of another heavenly body. There are two types of eclipses on Earth: an eclipse of the moon and an eclipse of the sun.
* Moon Eclipse:
Lunar eclipses occur when Earth's shadow blocks the sun's light, which otherwise reflects off the moon. There are three types — total, partial and penumbral — with the most dramatic being a total lunar eclipse, in which Earth's shadow completely covers the moon. A lunar eclipse can be seen from Earth at night. There are two types of lunar eclipses: total lunar eclipses and partial lunar eclipses.
* Solar Eclipse:
Sometimes when the moon orbits Earth, it moves between the sun and Earth. When this happens, the moon blocks the light of the sun from reaching Earth. This causes an eclipse of the sun or solar eclipse. During a solar eclipse, the moon casts a shadow onto Earth.
There are three types of solar eclipses.
The first is a total solar eclipse. A total solar eclipse is only visible from a small area on Earth. The people who see the total eclipse are in the center of the moon’s shadow when it hits Earth. The sky becomes very dark as if it were night. For a total eclipse to take place, the sun, moon, and Earth must be in a direct line.
The second type of solar eclipse is a partial solar eclipse. This happens when the sun, moon, and Earth are not exactly lined up. The sun appears to have a dark shadow on only a small part of its surface.
The third type is an annular (ANN you ler) solar eclipse. An annular eclipse happens when the moon is farthest from Earth. Because the moon is farther away from Earth, it seems smaller. It does not block the entire view of the sun. The moon in front of the sun looks like a dark disk on top of a larger sun-colored disk. This creates what looks like a ring around the moon.
Some facts about eclipses are: Each year there are between 2 and 5 solar eclipses, the total solar eclipse, when the Moon completely obscures the Sun and leaves only the faint solar corona, is known as a Totality, total solar eclipses are rare, happening only once every 18 months, there is another type of solar eclipse, known as a hybrid eclipse, which shifts between a total and annular eclipse depending on where you view it from on Earth, these are comparatively rare, the speed of the Moon as it moves across the Sun is approximately 2,250 km (1,398 miles) per hour, from either the North or South Pole, only a partial solar eclipse is able to be viewed, a total solar eclipse can last a maximum of 7 minutes and 30 seconds, 269 km is the maximum width of the path of totality.

## Solar Eclipse

As seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and Earth, and the Moon fully or partially blocks the Sun.
Permanent eye damage or blindness may occur when looking directly into the sun. It is important to wear special eye protection especially when viewing a solar eclipse during certain phases. A solar eclipse may last two hours, while the total phase only lasts about 7.5 minutes, trained people will know exactly when to protect their eyes during the eclipse.
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#### Types of Solar Eclipses

* Total Solar Eclipse A total eclipse occurs when the dark silhouette of the Moon completely obscures the intensely bright light of the Sun. When the moon's distance from the Earth is low, the moon appears significantly larger and can completely obscure the sun causing a total solar eclipse.
* Annular Solar Eclipse An annular solar eclipse occurs when the moon is furthest from the Earth. On these occasions the moon will appear to be smaller and not fully eclipse the sun. The Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun.
* Partial Solar Eclipse A partial eclipse occurs when the Sun and Moon are not exactly in line and the Moon only partially obscures the Sun. Some eclipses can only be seen as a partial eclipse, because the umbra passes above the Earth's polar regions and never intersects the Earth's surface.
* Hybrid Solar Eclipse A hybrid eclipse shifts between a total and annular eclipse. At certain points on the surface of Earth it appears as a total eclipse, whereas at other points it appears as annular. Hybrid eclipses are comparatively rare.

## Exploring Space

Our interest and desire to learn about what is outside our planet has driven us to be persistent and continue to make improvements to our technology, our learning, and to keep pushing boundaries. We have found answers to many of our questions but we have also found a lot more questions that still need to be answered.
One gallery "Exploring Space" at the Connecticut Science Center allows visitors to closely examine the moon's ancient craters and moon rocks. The first ever Mars flyover flight chair takes visitors into a black hole and through a supernova as they navigate through the galaxy.

## Sunspots

Sunspots are a spot or patch appearing from time to time on the sun's surface, appearing dark by contrast with its surroundings. These dark spots appear on the suns surface near its equator. They look dark mainly because they are cooler than the surrounding, glowing gases. The sunspots are associated with the magnetic storms within the sun that send out electrified particles that end up striking the Earth's ionosphere but sometimes they interfere with radio, TV, and long distance telephone communication. The particles also strike the lower atmosphere which produce a brilliant colored light show near both the northern and southern poles. The name for this colored lights are called the Northern Lights or the Aurora Borealis this is when your in the north pole. In the south pole the lights are called the Aurora Australis.

## Activities & Demonstrations

* The Scale of the Universe is a good tool for trying to wrap your head around the immense scale of the universe.
Another way elementary students can learn about the moon stages is using Oreo Cookies. Children love cookies. By using the cream in the cookie, the students can cut out the different stages of the moon. Not will they have a great time with the project, but also remember the stages when the moon is out.

## Stars

Stars are different. Some are brighter than others due to different distances. They also produce different amounts of light. Stars are different colors, some are white, red, blue, or orange due to temperature. A hot star will have a blue color. A cooler star will have a red color. Stars are mainly composed of hydrogen with helium as the second resource. The sun has a surface temperature of approximately 5500 degrees Celsius and is a G2 star. A hotter star would be a G1 and a cooler star would be a G3. Sirius is the brightest star; it is hotter than the sun and is categorized as A0. There are no green stars because of the way our eyes see colors. Our eyes mix other colors to form other colors other than green. The sun gives off more green light than any other color but our eyes see all of the mixed colors together as the color white. The luminosity of a star depends on it's size and temperature. For example, if there two stars that are the same in size but one is hotter, then the hotter star will be more luminous. Another example is if two stars are the same temperature but one is bigger than the other, then the bigger star will be more luminous. Most stars live on the "Main Sequence".
Here is a video that describes the "Main sequence" in more detail. https://www.youtube.com/watch?v=SvaXfFgrKg4
Facts about stars: every star you see in the night sky is bigger and brighter than our sun, you can’t see millions of stars on a dark night, our sun is a green star, our sun is a dwarf star, and stars don’t twinkle.

## Asteroids, Comets, and Meteors

Asteroids
Asteroids are relatively small, inactive, rocky body objects that revolve around the sun in a belt among the orbits of Mars and Jupiter. They happen to be smaller than any of the planets. Thousands of asteroids are several hundred miles in diameter and are also known as "minor planets". Some scientists have a theory that the craters on the moon and on Mars were caused by collisions with asteroids.
Comets
Comets in some cases are composed of ice, and rock they are often referred to as"dirty snowballs" which form part of our solar system. They have long, oval-shaped orbits that come close to the sun, and can stretch out far into out solar system. In fact when a comet comes near the sun some of ice is vaporized by the solar energy. Causing gas, and dust to be ejected from the tail of the comet. Some comets can take numerous years to make a single trip around the sun.An astronomer named Edmond Halley was the first person to accurately calculate a comet's cycle in 1758.
Meteors
Our solar system is composed of many things planets, stars, comets, and asteroids, they are billions of fast moving objects are called meteors. Meteors are a combination of rock, and iron they vary in shape, and size. Some meteors have different masses some can weigh less than a gram, and some thousands of kilograms. Most meteors that enter the Earths atmosphere are burned up by the friction of moving through the atmosphere; they are commonly known as "falling stars" in fact they are about the size of a grain of sand. Meteorites are they the few meteors that reach the Earths surface.