What is a Lunar Eclipse?

The earth casts a long shadow into space, and when this shadow passes over the moon it causes an Eclipse. A Lunar Eclipse can only happen during a full moon, when the sun is directly behind the earth. It happens only occasionally, because the orbit of the moon is slightly tilted and so the shadow misses it. Lunar eclipses can last for over 1 hour, but they do not completely black out the shadowed part of the moon. Some sunlight always filters through, making the shadow look a reddish-brown colour.

Why does the moon seem to change shape each month?

The shape of the moon alters depending on the position of the sun in relation to the moon. The sun lights up only one side of the moon. As the moon orbits the earth, we see this lit up area from different angles. When the sun is almost behind the earth, it lights up the whole of the moon (this is called a full moon). When the sun is off to one side, part of the moon is in deep shadow and all we can see is a thin slice, or crescent, of the moon's lit surface.

What is the moon?

The moon is earth's only satelite, and it hes been orbiting our planet for at least 4000 million years. It is a rocky sphere about 3476 km in diameter, which is about a quarter size of the earth. scientists believe that the moon was formed when another planet about the size of Mars collided with the earth. The collision splashed a huge mass of molten rock into space. This molten rock quickly formed into a sphere, and the moon rapidly cooled into its solid form. The moon's surface is heavily pitted by collisions with debris, such as asteroids.

Why is Europa especially interesting?

Europa is one of Jupiter's moons. In 1979 the Voyager spacecraft passed by Europa and found that it had a very smooth surface covered with ice. It has very few craters, which has led astronamers to suspect that there may be liquid water beneath the surface. In theory, there might even be a form of primitive life hidden beneath the ice, where water remains as a liquid.

What are meteorites made of?

Meteorites are made of rock or metal. They enter the earth's atmosphere at speeds of at least 11 km per second, which makes them glow brightly. Several thousand meteorites enter the earth atmosphere every year, but very few of them reach the ground. The largest known meteorite is made of iron and weighed 66 tonnes. It probably fell to the earth in prehistoric times in what is now Nambia, Southwest Africa. In general, it is hard to find meteorites. Recently, researchers have been locating them on the ice sheets in the Artic and the Antartic, where they are easier to find.

What happens when a meteorite hits the ground?

When a large meteorite hits the ground it can produce a crater. Meteorite craters are rare on earth, because the atmosphere slows the meteorite and also usually burns it up. Many ancient meteorite craters have been worn away by water and by weather over thousands of years. On planets and moons with no atmosphere, huge numbers of meteorites strike with enormous power. Our own moon is estimated to have 3000000 million meteorite craters measuring 1m or more in diameter. Some of the large geographical features on the moon and other planets and moons throughout the Solar System are probably the result of strikes by large meteors hitting their surfaces.

What is an Asteroid?

Asteroids are small rocky or ice bodies that orbit the sun. They are sometimes called minor planets. Most asteroids are found in an orbit between Mars and Jupiter, and more than 7000 of them have been identified. Asteroids are smaller than any of the planets, and only a few have a diameter of over 30 km. The term asteroid is usually applied to objects larger than 1.6 km in diamter. One asteroid, called Ida, has a tiny moon of its own; this is the smallest known satelite in the Solar System. Asteroids were probably formed at the same time as the planets

What is the tail of a Comet?

You cannot see the nucleus of a comet with the naked eye, but you can sometimes see its tail. It appears as a smear of light that moves very gradually across the night sky. As a comet moves closer to the sun, the ice and other frozen gases in its nucleus begin to boil off, producing a long tail of gas and dust. The tail always points away from the sun because light and other forms of radiation from the sun push against the minute particles that are present within the tail.

What is a comet?

Comets are often described as 'dirty snowballs'. The solid centre, or nucleus, of a comet consists mostly of ice mixed with sooty material. The nucleus is quite small and is usually only a few kilometres across. Comets travel around the sun in and elongated orbit. They plunge out into deep space beyond the farthest planet before diving back into the Solar System and passing close to the sun. As the comet's nucleus comes closer to the sun it becomes smaller and may eventually break up into small fragments. Comets are thought to be as old as the Solar Sytem itself.

What are shooting stars?

Shooting stars, or meteors, are streaks of light across the night sky, but they can be seen for only 1 or 2 seconds. They are caused when a solid piece of rock called a meteroid, plunges through the earth's atmosphere, burning up due to air friction. When the rock enters the atmosphere it is known as a meteor. If, as rarely happens, a small fragment reaches the earth, it is called a meteorite. The earth regularly passes through clouds of meteors orbiting the sun. The best known cloud, called the Perseids, reappears each year on August 12-13, sometimes producing spectacular meteor showers. There is also a regular meteor shower in December called the Geminids.

Do other planets have Moons?

Apart from the earth, most of the other planets have Moons although these are usually quite small. Saturn has the most Moons, it has at least 18 Moons. Some of these are very strange. Enceladus has a smooth surface covered with shiny beads of ice that make it shine and glitter. Lapetus is black on one side and white on the other. Jupiter has 16 moons, four of which are very large. One of Jupiter's moons is larger than Mercury and the other 3 are larger than our moon.. Charon, which orbits Pluto, is either a large moon or a small companion planet.

What makes Neptune blue?

Neptune is covered with a blue ocean of liquid methane gas. It is a very cold place, its surface temperature drops to -210 degrees celcius. Neptune is made of Hydrogen, Helium and Methane, and probably has a rocky core. It takes an amazing 164.8 years to travel just once around the sun. Neptune was first identified in 1846 when astronamers found that an unidentified planet was disturbing the orbit of Uranus. Neptune has huge storms and one of these, the Great Dark Spot, was larger than the earth.

Which are the outer planets?

Uranus, Neptune and Pluto are the outer planets. They are so far away that they were discovered only when powerful telescopes were developed. Pluto, the smallest of the planets, is on the edge of deep space. It was only discovered in 1930, as a result of mathematical calculations to find out why Neptune's orbit was being disturbed by an unknown body. Pluto has an oval orbit that occasionally takes it inside the orbit of Neptune. As recently as 1978 scientists found that Pluto, which is only 2284km across, has an even smaller companion planet or moon, called Charon.

What are the rings of Saturn?

Shining rings of billions of tiny chips of ice, rock and dust surround saturn. The rings reflect light strongly and can be clearly seen through a telescope from the earth. It was first thought that Saturn had three wide rings, but it is now known that the rings are actually made of thousands of narrow ringlets. The rings are only 100m thick, but they extend into space for 76000km. The material in the rings was probably captured by saturns gravity when the Solar System was forming, or it might be the remains of a moon that has broken up. Recently space probes discovered that some of the rings are braided, or twisted, but so far there is no explanation for this strange effect.

Where is the largest known canyon?

It is on Mars of course. There is no running water to wear away the rock landscape on Mars, so huge valleys can survive for millions of years. A system of enormous canyons called the Valles Marineris (Mariner Valleys) was discovered by the space probe Mariner 9. The canyon is more than 4000 km long and 4 times as deep as the Grand Canyon in USA. Scientists think that these valleys were caused by erosion (wearing away). During storms, the gritty martian dust is blasted by winds reaching up to 450 km/h, wearing away softer rock.

Could we live on Venus?

Science fiction writers thought that life might exist beneath the thick clouds covering Venus. We now know that conditions there are too extreme for life as we know it. Robot spacecraft have landed on Venus and studied its atmosphere, which is mostly poisonous Carbon Dioxide and Sulphuric acid. We cannot see the planet's surface through its thick atmosphere, but enough sunlight gets through to raise the surface temperature to 480 degrees celcius. This atmosphere reflects sunlight, making Venus very bright when viewed from earth.

What are Sunspots?

Groups of black blotches appear on the sun every 11 years. These blotches are called Sunspots. They are areas that are about 1000 degrees celcius cooler than the rest of the sun's surface. Sunspots are caused by changes in the sun's magnetic field. When they appear, Sunspots cause radiation that often interferes with the radio and television signals on the earth. Some groups of Sunspots can be as much as 10 times the size of the earth.

What are the inner planets?

The four planets that are nearest to the sun are called the inner planets. In order from the sun, they are Mercury, Venus, Earth and Mars. The inner planets are different from the outer planets, which are farther away from the sun, because they are made from rock. The outer planets are mostly composed of gas. Each of the inner planets has an atmosphere. However, apart from the earth's atmosphere, the atmosphere's of the inner planets are very thin and would be poisonous to humans.

Which planet is closest to the sun?

Mercury is the closest planet to the sun. The temperature on the side of the planet facing the sun is as high as 430 degrees celcius. The shaded side of Mercury which faces away from the sun is bitterly cold at -180 degrees celcius. Mercury has almost no atmosphere because it has been burned off by the sun. The planet consists of bare rock, pitted and scarred by the impact of meteorites. It has extremely steep cliffs that are hundreds of kilometres long. These were formes when the planet cooled from its original molten (liquid) state, millions of years ago.

Why do stars twinkle?

Most stars burn steadily, and if we could see them from space they would not be twinkling at all. This is because as the light from a star passes through the earth's atmosphere, it is bent by changes in the air temperature. This makes the light appear to flicker. Because of this effect, astronomical observatories are situated on mountain tops. Higher up, the air is thinner and it is therefore less likely to cause this twinkling effect.

How far away are stars?

The nearest star to the earth is our own sun, which is 152 million km away. After the sun, the closest stars are Proxima Centauri and Barnard's star. The farthest stars in our galaxy are 80000 light years away. Other galaxies, each one containing millions of stars, are much more distant.

What is a Black Hole?

A Black Hole ia an area in space where the force of gravity is so strong that even light cannot escape from it. Black Holes are created when a burned-out star collapses. Eventually it shrinks into a tiny sphere of material. The gravity of this material is so powerful that it pulls in everything around it. It is said that nothing that goes into a Black Hole ever comes out. We cannot see Black Holes. We can sometimes recognize them from the radio waves given off as a star is drawn into it.

How does a Star die?

Stars die when they eventually use up all their fuel and burn out, but this process takes many millions of years. Towards the end of its life, a star starts to run out of hydrogen to power its nuclear fusion. It starts to cool, becoming a red giant. The red giant swells, and the pressure at its centre becomes so great that the star begins absorb energy instead of emitting it. In a matter of seconds the star collapses, then explodes into a supernova. This is a huge explosion of light and energy that can be seen right across the galaxy.

How big are Stars?

Our sun is quite a small star, even though is measures 1392530 km across, which is 109 more than the earth's diameter. If the sun were the size of a football, The earth would only be 2mm across. Some stars are known as Superiants. The star Antares, for example, is 700 times bigger than the sun. There is a star in the constellation of Auriga that may be 3000 million km in diameter, which is also known as 4000 times bigger than our sun. The neutron star that remains after the eplosion of a supernova may only be 20 km in diameter, but of enormous mass. If it weighs more than 2 or 3 times that of our sun, it begins to collapse into a black hole.

What is a star?

Stars are huge balls of burning gas that are scattered throughout the universe. They burn for millions of years, giving off both light and heat. Stars produce energy by a process called Nuclear fusion. The coldest stars are coloured red and are dim, while the hottest stars give off blue-white light. The temperatures on the surface range from 3500 degrees celcius for the coldest star to over 40000 degrees celcius for the hottest star. A new star is born when gas and dust are drawn together by gravity, forming a huge clump. It heats up until Nuclear Fusion begins, and the new star appears.

How does Gravity Work?

The force of gravity is the attraction between every piece of matter, even the smallest particles. The more matter there is in something, and the closer its particles are packed together, the stronger the attraction. Stars are large and very dense bodies, and so they have a strong field of gravity. It is our sun's force of gravity that holds the planets in their orbits. The earth's gravity keeps the moon in its orbit. Small bodies such as the moon have a very weak gravitational pull. This explains why astronauts on the moon's surface were able to jump up very high with little effort.

What is the Milky Way?

The Milky Way is a huge mass of gas and stars that can be clearly seen as a band of light across the night sky. The earth, and everything else in the Solar System, is part of the Milky Way. It is known as our galaxy. It is so huge that light takes nearly 100000 years to travel from one side to the other. Where stars are packed close together, the Milky Way is bright in that particular spot, but huge clouds of gas and dust block the light from the other parts ofthe galaxy. These clouds prevent astronamers from observing the whole Milky Way.

How old is the Universe?

It is possible to calculate the approximate age of the universe by looking at how fast dist galaxies are moving away from us. However, it is not possible for us to make this calculation accurately. Scientists have estimated that the universe is between 13000-18000 million years old.

What is the Universe made of?

The universe is made up almost entirely of hydrogen and helium. These are the two lightest elements. All the rest of the matter in the universe is very rare. Elements such as silicon, carbon and others are concentrated into clouds, stars and planets. The universe is held together by four invisible forces. Gravity and Electromagnetism are the two familiar forces. The other two kinds are strong and weak Nuclear forces. These operate only inside the incredibly tiny nucleus of atoms, holding the tiny particles together

What is the Big Bang?

The Big Bang is the most popular theory about the creation of the universe. According to it, the whole universe was created in a split-second in one huge explosion. All matter was squeezed together into a tiny, super hot, dense ball that was smaller than an atom. The ball gradually expanded as it cooled, then exploded, releasing energy and matter in all directions. We cannot see the Big Bang because it would have happened billions of years ago, but we can see that the universe is growing steadily bigger. All the galaxies are speeding away from each other as the universe expands.

Do insects have a Skeleton?

Insects, such as this bettle, have their skeleton on the outside of their body. It acts as a shell, covering and protecting the softer parts underneath. It also protects the insect from any preying animals.

What is a Skeleton?

The Skeleton is our Framework of bones. Our bones bones provide a firm surface for muscles to attach to, helping us to move. The skeleton also protects our body's organs. The skull protects the brain. Our heart and lungs are protected by the rib cage. The body's bones vary in shape and size. The places where twobones meet is called a joint, which is where muscles move bones.

What is the Cell Wall?

All plant cells are surrounded by a Cell Wall made mainly of Cellulose. Paper, which is made from Cell Walls, is also made of Cellulose. Cellulose belongs to a group of substances called Polysaccharides. Cellulose forms fibres that criss-cross over one another to form a very strong covering to the cell. This helps to protect and support the cell. Because of the spaces between the fibres, even very large molecules are able to go through the Cellulose Cell Wall. It is therefore said to be Fully-Permeable. Animal cells never have Cell Walls.

What is a Parasite?

A Parasite is an organism which lives in or on another organism and feeds from it. An example of a parasite is the tapeworm.

What is the Nucleus?

The Nucleus is where the information is stored which help the Ribosomes make the right sort of proteins. The information is kept in the Chromosomes, which are inherited for that organisms parents. Chromosomes are very long, but so thin that even Electron Microscopes can't see them properly. However, when the cell is dividing, they become short and thick, and can be seen by a good Light Microscope.

What is the Mitochondria (mitochondrion)?

Every cell has Mitochondria, because it is here that the cell releases energy from food. The energy is needed to help it move and grow. Mitochondria are sometimes called the 'powerhouses' of the cell. The energy is released by combining food with oxygen, in a process called Respiration. The moreactive a cell, the more Mitochondria it has. Mitochondria is plural for Mitochondrion

What are Ribosomes?

Ribosomes are very tiny, round objects, often attached to the Endoplasmic Reticulum. It is here that Proteins are made, by joining together smaller molecules called Amino Acids. To et Amino Acids inthe right order, the Ribosomes follow the instructions from the Nucleus.

What are Organelles?

All the structures within a cell are called Organelles. The Nucleus, Mitochondria (singular form Mitochondrion) and Ribosomes are all Organelles. Oranelles are structures in the cell that have special functions. Organeles are discrete.

What are Chloroplasts?

Chloroplasts will never be found in an animal cell. Most of the cells in the green parts of any plant will have them. Chloroplasts contain a green pigment called Chlorophyll. Chlorophyll absorbs sunlight, and the energy of the sunlight is then used for making food by means of Photosynthesis. Chloroplasts often contain Starch Grains, which have been made by means of Photosythesis. Animal cells never contain Starch Grains either.

What is the Endoplasmic Reticulum?

Endoplasmic Reticulum is a maze of membranes which runs all through the cytoplasm of any cell. They are assembly lines for making Fats and Proteins out of smaller molecules in the cell. Endoplasmic Reticulum is found in all cells.

What is a Vacuole?

A Vacuole is a space in a cell that contain a solution, it is also surrounded by its own membrane. Plant cells have very large Vacuoles, which contain a solution of sugars and other substances called cell sap. Animal cells have much smaller Vacuoles and may either contain food or water.

What is Cytoplasm?

Cytoplasm is a clear jelly. It is 70% water in most cells. It contains many substance dissolved in it, especially Proteins. It supports everything inside a cell, like the Nucleus and Mitochondria

What is the Cell Membrane?

All cells have a Cell Membrane on the outside, it is also called the plasma membrane. In a plant cell it is very hard to see because it is right up against a Cell Wall. The plasma membrane is a very thin layer made upof Proteins and Fats. It is very important because the it determines what goes in and come out of the cell. It is said to be Partially Permeable, which means that it will let some substances through but not others.

What is a Cell?

Every living thing is made up of cells. Cells are extremely small, so large organisms (animals or plants) can contain billions of cells. Some organisms are Unicellular, these are the Bacteria, Protozoa and some types of Algae. Unicellular means that the oraginsm has no Nucleus, Mitochondria, Chloroplasts or Endoplasmic Reticulum, but they have a cell wall.

As you should know by now, Cells are very small, so to see them clearly you need a special tool called a light microscope. It is named this because it shines light through the substance that you are looking at. Then it uses glass lenses to magnify and focus the image. To see even smaller things in the substance, you will need an Electron Microscope. This uses a beam of Electrons instead of light. The light microscope can only magnify about 400-1500 times, but the Electron Microscope can magnify from 40000-500000 times. This obviously mean that more detail will be shown inside the substance that you are exmining.

Firth of Fifth

This is a piano piece from a band named Genesis that i have learnt

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