Planets

//﻿﻿A Learning Wiki by Dana A-M, Danielle M, Alysha K and Alex T //

= __//**Our Solar System**//__ =

The Sun is at the centre of our solar system. 8 planets orbit the sun and several of these have moons. The solar system is comprised of these planets in addition to asteroids and comets. Check out this amazing simulation (click on 'Solar System') of how our planets move and look in relation to each other. Most of the solar system is empty space. Our solar system is part of something much bigger. We are at the edge of a very large cluster of stars called the spiral galaxy. Our galaxy is called the Milky Way. The Milky Way is made up of about 100 billion stars. Scientists have estimated that there are at least 100 billion galaxies in the Universe. The Universe comprises of everything - us, galaxies, space and anything contained within them.

Facts about our Planets

// __**The Sun**__ //


 * //[|Sun] is a bright star in the centre of our universe, its mass accounts for 99.86% of the mass of the Solar System.[[image:https://fbcdn-photos-a.akamaihd.net/hphotos-ak-snc7/317038_107917752650059_100002955034111_66004_2092487852_a.jpg width="219" height="143" align="right"]]//
 * //Consists of hot plasma interwoven with magnetic fields.//
 * //The sun is made up of 74% hydrogen, with 24% helium. The remaining 2% includes trace amounts of iron, nickel, oxygen, and all the other elements we have in the// //Solar System.//
 * //With a diameter of approximately 1,392,000km, it’s about 109 times the size the Earth, the Sun makes a really big sphere. You could fit 1.3 million Earths inside the// //Sun.//
 * //The sun was formed from the solar nebula (hydrogen molecular cloud collapsed) about 4.59billion years ago.//
 * //The Sun lies close to the inner rim of the Milky Way Galaxy's Orion Arm, hypothesized distance of 7.5–8.5 kpc (25,000–28,000 light years) from the Galactic Center.//
 * //Informally designated as a yellow dwarf, although its colour is white, from the surface of the Earth it may appear yellow because of atmospheric scattering of blue light.//
 * //The sun has a temperature of approximately 5778 K (5505 °C).//
 * //Light travels from the Sun to Earth in about 8 minutes and 19 seconds. The energy of this sunlight supports life on Earth.//
 * //The Sun's orbit around the Galaxy is expected to be roughly elliptical, in addition the Sun oscillates up and down relative to the galactic plane approximately 2.7 times per orbit.//
 * //Extra Fact: The biggest star that we know of would almost reach Saturn if it// //were placed inside the Solar System.//

media type="youtube" key="HEheh1BH34Q" width="425" height="350"

__**Mercury﻿**__

> once every 87.969 Earth days.
 * The smallest planet and nearest to the sun in the solar system, orbiting the Sun
 * Its equatorial radius is approximately 2,439.7 km.
 * It has the smallest axial tilt, it completes three rotations about its axis for every two orbits.
 * Mercury is similar in appearance to the Moon: it is heavily cratered with regions of smooth plains, has **no** natural satellites and no substantial atmosphere.
 * Mercury consists of approximately 70% metallic and 30% silicate material.
 * Mercury has a large molten iron core, which generates a magnetic field about 1% as strong as that of the Earth. It is an exceptionally dense planet due to the large relative size of its core.
 * Surface temperatures range from about −183 °C to 427 °C, with the subsolar point being the hottest and the bottoms of craters near the poles being the coldest.
 * Recorded observations of Mercury date back to at least the first millennium BC. Before the 4th century BC, Greek astronomers believed the planet to be two separate objects: one visible only at sunrise, which they called Apollo; the other visible only at sunset, which they called Hermes.
 * Mercury's core has a higher iron content than that of any other major planet in the Solar System. One theory for this is that Mercury may have been struck by a planetesimal of approximately 1/6 that mass and several hundred kilometers across. The impact would have stripped away much of the original crust and mantle, leaving the core behind as a relatively major component.

__ **Venus**: Named after the Roman goddess of love and beauty.__ > the remaining 3.5% being nitrogen.
 * Venus is the second planet from the Sun, orbiting it every 224.7 Earth days.
 * Venus is 41,840,000 km away from the Earth.
 * It has a diameter of 12,100 km. It is about 1040km smaller in diameter than Earth and a mass of 81.5% of the Earth's.
 * Rotates n its axis in 243 Earth days (1 Venusian Day)
 * It has no magnetic field.
 * Venus’s temperature ranges from 500°C +/- 32°C at the surface.
 * After the Moon, it is the brightest natural object in the night sky, bright enough to cast shadows.
 * It never appears to venture far from the Sun, because Venus is an inferior planet from Earth: its elongation reaches a maximum of 47.8°. Venus reaches its maximum brightness shortly before sunrise or shortly after sunset, for which reason it has been known as the Morning Star or Evening Star.
 * Venus is classified as a terrestrial planet and it is sometimes called Earth's "sister planet" due to the similar size, gravity, and bulk composition.
 * The mass of the atmosphere of Venus is 96.5% carbon dioxide, with most of
 * The atmospheric pressure at the planet's surface is 92 times that of the Earth.
 * Its surface is approximately 300-600 million years old.
 * Venus is covered with an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light.
 * Venus has the densest carbon dioxide atmosphere of all the terrestrial planets in the Solar System.
 * Venus is believed to have previously possessed Earth-like oceans, but these evaporated as the temperature rose.
 * Venus's surface is a dusty dry desertscape with many slab-like rocks, canyons, and plains, with a 200-mile river of hardened lava. It is periodically refreshed by volcanism (80% of the surface is by volcanic plains).
 * Like Earth it is made up of a cor, mantle and crust.

media type="youtube" key="Ehgs3qazcvw" width="425" height="350"

__Earth__
 * Earth is the 3rd planet from the Sun. It is 149 million km away from the Sun.
 * The Earth orbits the Sun in an anti-clockwise direction following an elliptical shape orbit.
 * Earth’s atmosphere and it’s distance from the Sun allows ideal conditions for life.
 * 30% of the Earth’s surface is covered in land whilst 70% is covered in water.
 * Earth is surrounded by a blanket of air called an atmosphere. The atmosphere is primarily comprised of Nitrogen (78%), Oxygen (21%) and Argon (1%).
 * Earth turns on it’s axis in an anti-clockwise direction. It takes 24 hours to complete one turn.
 * The Earth’s axis is tilted which is the cause of Earth’s seasons.
 * A year on Earth lasts 365.3 days.
 * The Earth is 12,800 Km in diameter.
 * The Earth has one Moon which is spherical in shape and orbits the Earth. The moon can appear to change shape when viewed from Earth. The information on the following wiki page provides an explanation for this illusion.

// The Moon //



//• The Moon orbits the Earth once every 27 days, 7 hours, 43 minutes and 11.6 seconds in an anti-clockwise direction.// //• The Moon’s orbit is elliptical in shape.// //• The Moon is 384,400 km from Earth.// //• The Moon is 3476 km in diameter.// //• The Moon is 4.5 billion years old.// //• The surface of the Moon is the same size area as the continent of Africa.// //• The features of the surface of the moon include craters, lava plains, mountains and valleys. Scientists think that the craters were formed by meteors striking the Moon’s surface.// //• The Moon has no atmosphere, wind or weather.// //• Water was discovered on the Moon in November 2009.//

media type="youtube" key="RMINSD7MmT4?version=3" height="360" width="640"

//The first human to step onto the Moon's surface was Neil Armstrong on 20th July 1969. The video above shows the iconic images and words spoken on that famous day.//

__**Mars**__
 * Mars is the 4th planet from the Sun. It is 229 million km away from the Sun.
 * Mars is known as the ‘Red Planet’ because the surface is covered in red rocks and dust. This colouration is caused by rusted particles of iron.
 * Mars has a canyon system which is deeper and longer than the Grand Canyon. It has the largest mountain in the Solar System which is 27 km high with a crater measuring 81 km wide. The video below shows a collection of photographs taken of the surface of Mars.
 * A year on Mars lasts for 686.98 days. A day lasts for 24 hours 37 minutes.
 * The temperature range on Mars is -123 to 36 degrees Celsius.
 * Mars is 6800 Km in diameter.
 * The Mars atmosphere is very thin. It contains 95% Carbon Dioxide.
 * Mars has 2 moons called Deimos and Phobos. They are small and long in shape and not round.
 * Scientists have found evidence that water once flowed on Mars. This is evidenced by the existence of valleys and gullies which could have been formed by water erosion.

media type="youtube" key="Pe8ECk73-98?version=3" height="360" width="640"

__Jupiter__
 * 5th Planet from the sun at a distance of around 778 million kilometres.
 * Jupiter orbits the sun once every 11.86 years and rotates on its axis every 9 hours and 48 minutes.
 * Jupiter is about 11.2 times the size of earth with a diameter of 142,980 kilometres. It is the largest planet in the solar system.
 * Jupiter is a gas giant dominated by cloud layers of hydrogen, helium and other gases. In the upper levels these appear colourful and strongly banded.
 * Cloud top temperatures reach as low as -110 degrees Celsius.
 * Jupiter’s most prominent feature is its great red spot, an anticylonic weather system reaching up to 40,000 kilometres across.
 * Jupiter has narrow and faint rings and has over 60 moons (the largest of these are Lo, Europa, Ganymede and Callisto.

__Satu﻿rn__


 * 6th Planet from the sun at a distance of around 1427 million kilometres.
 * Saturn orbits the sun once every 29.46 years and rotates on its axis once every 10 hours 15 minutes.[[image:https://fbcdn-photos-a.akamaihd.net/hphotos-ak-ash4/313492_107925969315904_100002955034111_66049_835194037_a.jpg width="221" height="162" align="right"]]Saturn is about 9.5 times the size of earth and has a diameter of 120,540 kilometres.
 * Saturn, like Jupiter, is dominated by cloud layers of hydrogen, helium and other gases. In the upper levels these appear pale and weakly banded.
 * Cloud top temperatures reach as low as -180 degrees Celsius.Saturn has a spectacular extensive ring system, which extends into space up to 1 million kilometres around the planet.
 * Saturn has over 40 moons the largest of which is Titan.

__Uranus__ media type="youtube" key="q5g-t9vsDps" width="425" height="350" align="right"
 * 7th planet from the sun. It is 2.8 billion km from the sun.
 * Takes 84 years to orbit the sun
 * It is the coldest planet in the solar system
 * Summer on Uranus lasts 42 years due to its unusual tilt
 * Uranus like Saturn has a set of rings, but these are very dark and also very narrow
 * It has 27 moons, the largest of which is called Titania
 * You can see Uranus without a telescope
 * Uranus has only been visited once in 1986

__Neptune__
 * 8th planet from the sun. It is 4.5 billion km from the sun.
 * Out of its 13 moons there is a moon called Triton that is gradually getting closer and closer to the planet, eventually it may even be torn apart by Neptune's gravity and become rings like those around Saturn
 * Neptune was discovered in 1846
 * It is 30,200 miles in diameter
 * It is a sea blue colour due to the methane in its atmosphere
 * It orbits the sun once every 165 years
 * Neptune has a rocky core but is a gaseous planet composed of helium, hydrogen and methane

media type="youtube" key="76xz74X4ivw" width="425" height="350"

__Pluto__ __﻿__ media type="youtube" key="u1RU6P-fUr4" width="425" height="350"


 * Pluto is no longer a planet, it is a 'dwarf planet'. This is because Pluto has not cleared out its orbit of material.
 * It is 5.9 billion km from the sun.
 * It was discovered in 1985
 * It has 4 moons, Charon, Hydra, Nix (only 46km across) and a recently discovered moon designated "P4".
 * Pluto is named after the Roman god of the underworld
 * It is 2390km across
 * Because Pluto is so small, you would be very light if you visited, if you weighed 70 pounds on earth you would only weigh 4 there!
 * Pluto is comprised of half rock and half ice, therefore if it was any closer to the sun it would start to melt and become a comet

The link below takes you to a BBC video which is very useful when trying to learn the names and orders of the planets! [|http://www.bbc.co.uk/science/space/solarsystem/sun_and_planets/neptune#p007qy9p]

__and finally.......ENJOY!!!__ []  <span style="color: #ff0000; font-family: Impact,Charcoal,sans-serif; font-size: 130%;"> <span style="color: #ff0000; font-family: Impact,Charcoal,sans-serif; font-size: 130%;"> <span style="color: #ff0000; font-family: Impact,Charcoal,sans-serif; font-size: 130%;"> __<span style="color: #ff0000; font-family: Impact,Charcoal,sans-serif; font-size: 130%;">//﻿// __ <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;">__﻿__ <span style="font-family: Arial,Helvetica,sans-serif;">__﻿__
 * <span style="color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 130%;">__References:__ **

Arnold, B, Kingston, H and Poole, E (2010) //KS3 Success: Science Revision Guide,// Letts Educational Ltd: London Cross A and Bowden A (2009) //Essential Primary Science//. London: Open University Press. Peacock, G, Sharp, J, Johnsey, R, and Wright, D (2011) //Primary Science: Knowledge and Understanding,// Learning Matters: Exeter University of Manchester, n.d. //Earth in Space: A Pre-Course Pack for PGCE (Primary) Students//. [Booklet] Department of Education: University of Manchester.

[] [|www.kidscosmos.org/kid-stuff/] http://www.primaryscience.ie/activities_planet_profiles.php @http://www.chiddingstone.kent.sch.uk/homework/revision/Science/space.htm @http://www.childrensuniversity.manchester.ac.uk/interactives/science/earthandbeyond/shadows.asp @http://www.nasa.gov/offices/education/about/index.html []