The universe is expanding March 15, 2010

Scene from the past

A couple years ago I was taking a walk. All of a sudden I saw a paper on the ground. I picked it up and it was to a person called Neil Armstrong. The person that wrote this I thought was a scientist because they seemed to know a lot about space. This is what the letter said:

The milky way is just one of about 100 billion others. When you look far out into space we see galaxies by the light they gave off a long time ago. The Andromeda galaxy is the closest large galaxy. As astronomers look at galaxies farther away, they see how the universe looked at different times in the past. Astronomers can also see how the universe has developed over the past billions of years.

A doppler effect is a change in the observed wavelength or frequency of a wave that occurs when the source of the wave or the observer is moving. This also happens with light and sound. If a galaxy is moving toward earth, the light will look compressed to shorter wavelengths. This change is called a blue shift. It is called this because the light moves toward the blue end of the spectrum. By analyzing the spectra of galaxies, astronomers have found out that galaxies move faster when they are farther away from each other. This observation has made astronomers believe that the universe has been expanding throughout its history. As the universe expands the galaxies become farther away from each other. The universe does not expand into anything because there is nothing outside it.

The big bang is the period in time when the universe started to expand out of an extremely hot, dense state. This expansion was very rapid. In one second the universe expanded from a tiny speck of dust to the size of our solar system. Astonomers have calculated and they believe that the big bang happened about fourteen billion years ago. Right after the big bang the universe was extremely dense and hot. It was way hotter than the core of the sun. Some evidence shows that the first stars formed on a couple hundred years after the big bang.

At the end of the letter it said from the “Mystery Man”. I really wanted to know who wrote it because it really taught me a lot.

Galaxies have different sizes and shapes

Dialogue

Lucy: Hey Tina! I just got out of science class and we learned about galaxies. I understand some of the information, but not all of it. Can you please help me?

Tina: Sure! Galaxies are my favorite. First of all, our solar system is in the milky way galaxy. A galaxy is a huge grouping of stars, gas, and dust held together by gravity. The milky way is shaped like a disk and has a bulge in the center. Because earth is on the disk we have a view of the rest of the galaxy. But you cannot see the center of the galaxy because it is covered by dust. The disk of the milky way measures 100,000 light years in diameter. The bulge of densely packed stars is at the center.

Lucy: What are the different types of galaxies?

Tina: The different types of galaxies are spiral, elliptical, and irregular. The milky way is a spiral galaxy. This galaxy has arms of stars, gas and dust. Like the milky way other spiral galaxies are disk-shaped and have a bulge. Most of the stars in the bulge and disk are old. Elliptical galaxies are shaped like a spere or an egg. Elliptical galaxies have almost no dust or gas between stars. All the stars in this galaxy are old. Next are irregular galaxies. Irregular galaxies are faint with no certain shape. This type of galaxy is very small and has less stars. Sometimes galaxies collide with others which causes them to change shape. Most of the big galaxies seem to have extremely big black holes in teh center. Like all the other black holes a supermassive black hole is invisible. The gravity from a black hole is so strong it draws in huge amount of gas from other stars. A quasar is the very bright center of a star. The galaxy around a quasar is usually hard to see, because the quasar is so bright.

Lucy: Thank you so much for your help! You are a great teacher.

Tina: No problem!!

Stars change over their life cycles

Dialogue

Fred: Hey Tom, I just got out of science class. We learned about stars and their life cycles. I did not really understand much and I have a test tomorrow. Can you help me?

Tom: Sure I can help. First of all, we classify stars by five characteristics. Brightness, distance, color, size, and temperature. When you look up at the sky you probably see stars that are brighter than others. Right?

Fred: Yea.

Tom: Well, there could be a star that gives off a lot of light but seems faint because it is so far away. So to figure out its real brightness, astronomers have to measure its distance from  the earth. One of the ways astronomers measure them is by using parallax. Parallax is the apparent shift in the position of an object when viewed from different locations. This is the same as putting your finger up, and then shut one eye and keep the other open. When you switch eyes it seems as if you finger has moved.

Fred: What’s next? I can’t wait to hear what you have to say!!

Tom: Next is how we classify stars by size. It is very difficult to see the real size of a star in space. The reason for this is because they seem smaller as they are farther away. Some stars are much larger than the sun. For example, the giant and supergiant stars. The supergiant which is called Betelgeuse, is more than 600 times the suns diameter. These two stars are very bright because they have such huge surfaces. We can also classify stars by their color and temperature. If you see the color of a star you can estimate its temperature. Like if the star is blue or white it is extremely hot. But if its red or orange it is very cool.

Fred: Wow, thanks Tom you have been a great help.

Tom: O no! We are not done we still have the life cycles. Even though stars last for a long time, they do not live forever. Stars are formed inside a nebula. A nebula is a cloud of gas and dust. The nebula forms a hot dense sphere. This sphere becomes a star if its center becomes hot and dense enough for fusion to occur. There are lower mass stars and higher mass stars. The lower mass stars is the stage where stars produce energy through fusion of hydrogen into helium. This is called the main sequence. Because they use not a lot of fuel, they last for billions of years. But higher mass stars use their fuel quickly so they do not live as long.

Fred: I think I am going to ace this test! Thank you so much!

Tom: No problem, good luck!!!

The sun is our local star March 14, 2010

Teacher

Hello Children!!!!

My name is Galileo and today we are going to learn about the sun and solar winds.

The sun is the only star in our solar system. The sun is so large it takes up 99 percent of the solar system. The sun is like an elephant and the earth is like a sparrow. The sun is made mostly of hydrogen gas. The energy is produced when hydrogen in the sun’s interior turns into helium. This energy is a source of light and provides warmth to the earth. This also makes life possible on earth.

The sun’s interior gets cooler and less dense as you move away from the center. The core, which is the center of the sun, is very dense and hot.Some particles collide and combine to form helium. This process is called fusion. This process releases energy that travels through radiation. All the energy is first produced inside the core. Next is the radiative zone. Energy from the core moves to the radiative zone. It is a thick layer that is very hot and dense. Even though they are hot and dense this is not that extreme for fusion to occur. After that is the convection zone. In the convection zone energy moves by convection. Convection is the transfer of energy from place to place by the motion of heated gas or liquid. In this zone, the energy is carried outward. The fourth layer is the photosphere. The photosphere is the visible layer of the sun. Since you see it, it’s usually called the sun’s surface. the fifth layer is the chromosphere. It is the thin middle layer of the sun’s atmosphere. This layer gives off pinkish light. Last but not least is the corona. The corona is the outermost layer of the sun. It has very low density, and you can only see the corona during a solar eclipse.

There are many features on the sun. Sunspots are spots on the photosphere that are cooler than other areas. Even though they seem to be dark, they are actually bright. They only look darker because the photosphere is much brighter. There are also flares. Flares are eruptions of hot gas fro the sun’s surface. Prominences are huge loops of glowing gas that extend into the corona. Prominences can soar 100,000 km above the photosphere.

Material from the corona is always going out into space. Particles that flow out in all directions from  the corona are called solar winds. Most of the flowing solar wind is protected from our planet because of the earths magnetic field. When the solar winds do enter the upper atmosphere they create beautiful patterns of glowing light in the sky, that are called auroras. Auroras often occur near the two poles.

Small space objects are made of ice and rock

Teacher

Hey kids!!

My name is Galileo and I am here to teach you about Pluto, its moon, and other space objects.

 Pluto and many other objects in space are made of ice and rock. Pluto is the smallest of all the other nine planets. Its mass is less than 0.3 percent of the earths mass. Pluto probably has a crust, mantle,and a core but it is not for sure. There has not been a spacecraft that has passed close to pluto, so scientists do not have clear images of its surface. Pluto also has a very thin atmosphere. No spacecraft has landed on Pluto but they might in a couple of years.

Pluto has a moon called Charon. Charon is half the size of Pluto and is 15 percent of Pluto’s mass. Since Pluto and Charon orbit each other, they are sometimes called a double planet. Pluto and Charon also always keep the same sided facing each other. Pluto’s path around the sun is not the same as the other planets. Pluto sometimes gets closer to the sun than Neptune. The reason for this is because it crosses Neptune’s path. Now Pluto is called a dwarf planet.

You have probably heard of an asteroid but did not know what it was. Well, and asteroid is a small, solid, rocky body that orbits close to the sun.

An object that produces a coma is called a comet. Comas are fuzzy spots that appear in the sky. When a comet does not have its coma it is a small, icy object that is hard to see even with a powerful telescope. Sice comets were formed away from the sun they are made of ices as well as rock and metal. When a comet gets close to the sun, solar radiation warms the surface and turns some the ice into gas. The coma forms as the gas moves forward.

There is a huge difference between a meteor and a meteorite. Meteors are brief streaks of light. You may be able to see a couple meteors on a clear night. A meteor produced by a particle from a comet might last for less than a second. Parts of rock and metal from asteroids make longer lasting meteors. A meteorite is a space object that reaches the earth’s surface. The outside is usually warm from melting, but the inside is usually frozen. Most of the meteorites come from the asteroid belt.

The outer solar system has four giant planets

Report

Gas Giants  

By:Rita Ebeid

There are four gas giants. They are Jupiter, Saturn, Uranus, and Neptune. These four planets are mainly made of hydrogen, helium, and other gases. The gas giants are so big that they have very large amounts of these gases, which makes them have a lot of mass. Inside the gas giants, the gases become more dense than water. The outermost areas are less dense, almost like the earths atmosphere.

Jupiter is the largest planet in the solar system. If you weighed all the planets together, they would all come out to weigh less than half the weight of Jupiter. Although Jupiter is big, it takes less than 10 hours for it to turn once on its axis. This produces extremely fast wind and stormy weather. But Jupiter takes twelve earth years to go around the sun. Jupiters core is very dense and hot. It is made of hydrogen gas and liquid metal. Between Jupiter’s white bands of clouds you can see the next layer. because Jupiter has not land to slow down the storms, they can last for a long time.

Saturn is the sixth planet from the sun. It is only a little smaller than Jupiter, but its mass is much smaller. Saturn has much lower density than Jupiter. Saturn was the first planet to have rings. A ring is a wide, flat zone of small particles that orbit a planet. All of the gas giants have rings, but Saturn’s rings are made of chunks of water ice. The outermost ring is three times as wide as the planet. People use Saturn’s rings to figure out what the seasons are like there. Saturn takes almost thirty years to go around the sun once.

Like all the other gas giants, Uranus has rings and moons around its equator. Unlike the other planets, Uranus has a rotation axis that is almost in the plane of its orbit. Some scientists think that there was a big collision in its early history.

Neptune has about the same outside temperature as Uranus. Light and dark areas often appear on Neptune. Sometimes things can happen to make Neptune look white. Storm systems can appear in darker shades of blue.

 

 

 

The inner solar system has rocky planets March 13, 2010

Report

Terrestrial Planets

By:Rita Ebeid

There are four terrestrial planets. They are Mercury, Venus, Earth, and Mars. They are called terrestrial planets because they are the ones closest to the sun. They are the same because they all have rocky crusts and dense mantles and cores. Their insides, surface, and atmosphere were formed in similar ways. The term terrestrial comes from the latin word terra which means earth.

All the terrestrial planets have layers. They also all have processes that shapes features on the surface. The first process is tectonics. Tectonics is the process of change in a crust due to the motion of hot material underneath. As the planet cools down, the crust becomes stiffer and the mantle may stop moving. This causes the process to stop. Next is volcanism. Volcanism occurs when molten rock moves from a planet’s hot interior onto its surface. The molten rock is called lava when it goes out the volcano on the planet’s surface. These volcanoes are found on earth, venus, and mars. When the inside of the planet cools, no more molten rock reaches the surface. The third process is weathering and erosion. The weathering or small impacts break down rocks. The material is moved by a process called erosion. The material might form dunes or new layers of rock. Finally the fourth process is impact cratering. Sometimes a small object hots a planet’s surface so fast that it causes an explosion. The impact crater that results is very big. On earth most of them have been erased by other processes, but other planets have them.

The atmosphere of the terrestrial planets are mostly made of gases that poured out of volcanoes. Venus, Earth, and mars hold a gas called carbon dioxide.

Mercury is a lot like the moon because it has smooth plains and many craters. The crust of Mercury is wrinkled up, forming cliffs, as the planet got smaller. Long high cliffs stretch across the surface. Parts of the surface were covered with lava a long time ago. Small impacts and temperature broke down rocks. Craters cover most of the surface but they have not changed the planet.

The hot mantle has stretched, wrinkled, and twisted the surface of Venus. Most of the surface has been covered with lava for the last billion years. Venus is way too hot to have liquid water, and winds do not move much of the material. Erosion might be slower on Venus than on earth. Round craters cover a little bit of the surface, but old ones have been erased by other processes.

Valleys and raised areas were formed on mars as the mantle moved. A huge system of valleys covers mars. Most of the northern hemisphere is covered with cooled lava. The fast winds on mars carry sand that breaks down the rocks. Finally, round craters cover most of the southern hemisphere of mars. Most of the craters are extremely old and eroded. Most of mars is carbon dioxide. The air pressure is only about 1 percent the air pressure on earth. There is no liquid water on mars today, because any liquid would quickly evaporate or freeze.

Planets orbit the sun at different distances

New discovery Internet article

There has just been an amazing new discovery about planets!! No one has ever known this but now we do.

I am sure that you have seen a planet but did not know it. The planets are so far away that they seem like tiny dots from earth. If you see a very bright star in the western sky it is probably the planet Venus. You also probably already seen Mars, Jupiter, and Saturn. Mercury is really hard to see but you can see it with a telescope. The other planets you see with a telescope are Uranus, Neptune, and Pluto. Planets do not give off visible light of their own. They reflect sunlight. All the objects in the earth are very different sizes.

The distance between objects in space are huge. Since they are so big astronomers use something called astronomical unit (AU). It is the average distance of something from the sun. An AU is equal to about 93 million miles. The earth is 1 AU. Jupiter is about 5 AU from the sun, Mercury is less than 0.5 AU, and Pluto is nearly 50 AU from the sun. The planets are not arranged in a straight line. The first four planets are pretty close to each other and the sun. They make up the inner solar system. Farther from the sun is the outer solar system. In the outer solar system the planets are much more spread out.

Since the mass of the sun is extremely big, it cause the planets and other objects to orbit it. The planets do not orbit the sun in a perfect circle. They orbit it in an ellipse. An ellipse is like an oval or flattened circle. A circle is a special type of circle, like a rectangle is a special type of shape. Most of the planets’ orbits are near to a circle. All except one planet which is Pluto. Pluto’s orbit is more flattened than round.

The solar system started out as a huge cloud of different gases and specks of dust. This was called a nebula. After that the nebula collapsed and became a flattened disk. As all this was happening a star began to form in the middle. This star was the sun. Also tiny bits of dust and frozen gas began to form clumps. These clumps became bigger and bigger. At the end most of the material cleared and went away, but the planets, sun, and other objects remained making the solar system.

Positions of the sun and moon affect earth

New Discovery internet article

There has just been a new discovery!!

When you look up into the sky and see moonlight, it is really the sun reflected by the moon’s surface. Also when you look at the moon you see different kinds of shapes. These shapes of the moon that are the patterns are called lunar phases. the cycle of the lunar phases begins with a new moon. During a new moon you cannot see the moon. The reason for this is because the sun is not shining on it. This happens on the first week. Still in the first week there is a waxing crescent. Waxing is when the shining part is getting bigger.

The second week is when half of the near side is in sunlight.This is called the first quarter, even though it looks like a half-moon. You see more of the moon as it goes along in its orbit. Also in the second week there is a waxing gibbous. Next are waning moons. In the third week (halfway through its cycle) is a full moon. A full moon is when the whole near side is in the sunlight. After that is a waning gibbous. Waning is when the part that is lit is becoming smaller.

Finally, in the fourth week there is a third quarter. The third quarter is when half of the near side is lit but it is the opposite side then a first quarter. Another name for a third quarter is last quarter. After the third quarter there is a waning crescent.

An eclipse occurs when a shadow makes the sun or moon seem to grow dark. There are two different eclipses. A solar eclipse is when the sun seems to darken. A lunar eclipse is when the moon darkens. The reason the moon becomes dark in a lunar eclipse is because it passes through the earths shadow. The umbra is the darkest peart in a lunar eclipse, and the penumbra is the spreading cone of a lighter shadow. Just before a lunar eclipse there is full moon. A total lunar eclipse happens when the moon passes completely into the earths umbra. If the moon misses part of the umbra it is called a partial lunar eclipse. During a solar eclipse, first it is a normal day. Then you start to see part of the sun going away, as the moon goes in front of it. After a couple hours, the moon covers the sun completely. Then the sky becomes as dark as the night and you might be able to see constellations. Solar eclipses happen when the moon passes directly between the earth and the sun.

the gravity of the moon causes tides on earth. Usually on a beach you see a regular tide then you start to see the tides getting higher and higher. At this point the water goes up farther into the sand. The average water level rises for about 6 hours. The highest tide is called a high tide. Then it drops for another 6 hours. The lowest tide level is called a low tide. The reason tides occur is because the moon’s gravity changes the earths oceans.

                                                                                                          Rita Ebeid

The moon is Earth’s natural satellite March 12, 2010

Childrens Book

Chapter 1

When you look at the moon, you see dark and light areas. People have told many stories about what they think these things are. The pull of gravity keeps the earth’s natural satellite (The moon), in orbit around the earth. Only one side of the moon can be viewed from earth. This means that the moon turns once on its axis, each time it orbits the earth.

Chapter 2

the part of the moon that faces the earth, is called the near side. The other half is called the far side. Most of the dark-colored areas are at the near side of the moon, while most of the light-colored areas are at the far side. The dark area on the moon is called a lunar mare. Also called a Maria. All the features on the moon are made up of different types of solid or broken rock. There is no life, air, oceans, or clouds on the moon.

Chapter 3

Light colored areas are higher so they are called highlands. The highlands have many round features that are called impact craters. The impact craters were formed when small objects from space hit the moon’s surface. In the past, more of these collisions would happen then they do today. Also in the past, some of the large craters filled up with lava or molten rock, and soon became under the moon’s surface. After that it cooled, and formed large, flat plains called maria.

Chapter 4

Scientists have used information from lunar rocks and other things to figure out what is inside the moon. Beneath its thin coating of rock, there are three layers, the crust, mantle, and core. Like on earth, the crust is the outer most layer. Next is the mantle. The mantle is thick and it makes up most of the moons volume. The mantle is made of dense rocks that include iron and magnesium. In the center of the moon is the core. Even though it is dense, it only makes up a tiny bit of the moons mass. Scientists are not sure but they think that the core consists of iron and other metals. The formation of the moon was very interesting. First was the collision, which was when an early version of earth was struck by a slightly smaller space body. Next was the re- forming. This was when the many pieces pulled each other into orbits. Most of the material formed a new version of earth. Finally, the moon formed material that orbits the new version of earth.