Our Solar System: Facts & Information
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| Our Solar System |
✪ The solar system is a vast place, with lots of empty space between planets. But out there are comets, asteroids and more rocky, frozen objects (including dwarf planets) yet to be discovered in the Kuiper Belt and Oort Cloud. (Credit: Nasa)
✪ Apart from the Sun, the largest members of the Solar System are the eight major planets- Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
✪ Nearest the Sun are four terrestrial planets (also called telluric planets or rocky planets) - Mercury, Venus, Earth and Mars.
✪ Beyond Mars other four are gas giants, mostly made of hydrogen and helium sometimes also known as the 'Jovian planets' after the planet Jupiter, or giant planets - Jupiter, Saturn, Uranus and Neptune.
✪ A belt lies between Mars and Jupiter, called asteroid belt – a region populated by millions of rocky objects.
✪ Disk-shaped Kuiper belt can be found beyond the orbit of Neptune, in which dwarf planet Pluto resides, and far beyond that is the giant, spherical Oort Cloud and the teardrop-shaped heliopause.
✪ Five planets that can be seen without using a telescope are Mercury, Venus, Mars, Jupiter and Saturn. In the sky at night, the planets do not twinkle in the way that stars do.
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Universe Top to Bottom: The Scale of Our Solar System
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NASA's EYES ON THE SOLAR SYSTEM
(A Complete Visualization of Our Solar System - 30.5 MB)
(Solar System Infographics)
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NASA's EYES ON THE SOLAR SYSTEM
(A Complete Visualization of Our Solar System - 30.5 MB)
THE SUN
SUN FACT BOOK: FACTS ABOUT THE SUN
SUN FACT BOOK: FACTS ABOUT THE SUN
SUN PROFILE
Age: 4.6 Billion Years
Type: Yellow Dwarf (G2V)
Diameter: 13,92,684 km (8,65,374 mi)
Circumference at Equator: 43,70,005.6 km (109 × Earth) (27,15,395.5 mi)
Mass: 1,989,100,000,000,000,000,000 billion kg (333,060 x Earth)
Surface Temperature: 5500°C (9941° Fahrenheit)
Age: 4.6 Billion Years
Type: Yellow Dwarf (G2V)
Diameter: 13,92,684 km (8,65,374 mi)
Circumference at Equator: 43,70,005.6 km (109 × Earth) (27,15,395.5 mi)
Mass: 1,989,100,000,000,000,000,000 billion kg (333,060 x Earth)
Surface Temperature: 5500°C (9941° Fahrenheit)
✪ The Sun is our nearest star.
✪ This huge ball of superhot gas is 1.4 million kilometres across, 109 times wider than Earth, and is 3,30,000 times heavier. About 13,00,000 Earths would fit inside the Sun.
✪ Sun contains 99.86% of the mass in the Solar System.
✪ Around 74% of the Sun’s mass is made up of hydrogen. Helium makes up around 24% while heavier elements such as oxygen, carbon, iron and neon make up the remaining percentage.
✪ The distance from the Sun to Earth (149,600,000 km (92,960,000 miles) changes throughout the year as the Earth travels on an elliptical orbit around the Sun, the distance between the two bodies varies from 147 to 152 million kilometers.
✪ Mercury is the smallest and closest planet to the Sun.
✪ Because of it's proximity to the sun, it is hard to directly observe from Earth except during twilight.
✪ Unlike the Earth and most other planets Mercury only turns very slowly on its axis, taking 59 days to complete the turn from day to night.
✪ Mercury has no moons. Moons are satellites that travel with a planet as it orbits the sun.
✪ If we suppose the gravity of Earth = 1 than the gravity of Mercury will be 0.38.
✪ The atmosphere on Mercury is almost non-existent, so there is no weather on Mercury and because of it there is no possibility of life on Mercury. As it has no atmosphere around it to protect it from the Sun or to retain any heat when it rotates on its axis, the surface of Mercury is covered with craters and completely dry.
✪ Mercury’s sunny side has a temperature rising to 427° Celsius or 800.6° Fahrenheit. On other hand Mercury’s dark side, however, is very cold indeed, with the temperature going down to -173° Celsius or -279.4° Fahrenheit.
✪ Despite being the closest planet to the Sun, Mercury is not the warmest. Venus is warmer. In fact, Mercury can be one of the coldest planets in the Solar System
✪ Only one spacecraft has ever visited Mercury: Mariner 10, which imaged about 45 percent of the surface. The Mariner 10 spacecraft passed close to the planet in 1974 and 1975 and took very clear photographs.
✪ Mercury is the most cratered planet in the Solar System with a surface similar to Earth's Moon.
✪ NASA’s latest mission to Mercury is called Messenger. The Messenger spacecraft entered Mercury’s orbit in March 2011 and is sending back new pictures of the planet. Messenger is now moving with Mercury round the Sun.
✪ BepiColumbo (Europe, 2011) is the planned mission for Mercury.
✪ 2nd planet from the Sun, Venus is the brightest planet in the Solar System and the brightest object after Sun and Moon when seen from earth.
✪ Venus is called after the Roman Goddess of love and beauty.
✪ Venus is known as morning star because it rises just before the rise of sun, when it is west of sun and on the other hand when it is east of the sun, Venus is known as evening star as shines just after the sunset.
✪ Venus orbits round the sun in 262 days. So a year on Venus lasts for 262 days.
✪ Earth is the only planet in the Solar System to have water in its three states of matter: as a solid (ice), a liquid (sea, rain, etc.) and as a gas (clouds).
✪ Earth is the only planet that has an atmosphere containing 21 percent oxygen.
✪ Earth is the only planet in the Solar System not to be named after a mythical God.
✪ The Earth is the only inner planet (Mercury, Venus, Earth and Mars) after mars to have satellite, the Moon. Earth have the largest satellite (Moon) among these. Mars has tiny two - Phobos and Deimos.
✪ Earth is the only planet in the Solar System known to be geologically active, with Earthquakes and volcanoes forming the landscape, replenishing carbon dioxide into the atmosphere and erasing impact craters from meteors. The craters have sunk down or been worn away by wind and rain over millions of years.
✪ The Earth takes 365¼ days to complete its revolution round the Sun. The Earth’s year is therefore 365 days long but the ¼ days are added up and every fourth year has one extra day, on the 29th of February. This fourth year is called a Leap Year (366 days) and is always a year which can be divided exactly by 4 and 400 – 2000, 2004, 2008, 2012, 2016.
✪ As the Earth orbits round the Sun it rotates on its axis. It takes 24 hour to complete a rotation. The side of the Earth that faces the Sun has daytime and the side of the Earth that is turned away from the Sun has nighttime.
✪ As the Earth orbits round the Sun it tilts very slightly and so gives us the seasons.
✪ Hence formation of seasons is due to earth's revolution and formation of day-nights are because of it's rotation on its own axis.
✪ Distance of Earth from the Sun (about 150 million km = 1 AU): 1. Perihelion (closest): 147,098,291 km (91,402,640 miles); 2. Aphelion (farthest): 152,098,233 km (94,509,460 miles)
✪ The Earth’s diameter, the distance round its middle at the Equator, 12756 kilometers or 7926 miles.
✪ The Earth is not an exact sphere; the diameter going round the North and South Poles is slightly less than the diameter round the Equator.
✪ Mars, the Red Planet, is the fourth planet from the sun.
✪ Mars is home to an ever present red tint. This is due to a mineral called iron oxide that is very common on the planet’s surface.
✪ Mars has two moons Phobos and Deimos.
✪ Earth and Mars are similar in a lot of ways: (Credit: PlanetsforKids.org)
Polar Ice Caps – Mars has both North and South polar ice caps, much like Earth. Polar caps contain mostly frozen carbon dioxide instead of frozen water.
Though scientists think that life could have once existed there and the polar caps might be of water.
Length of a Year – Mars is not much farther from the Sun than Earth. As a result, a typical year on Mars is 1 year and 320 days.
Length of a Day – While a year on Mars might be almost twice as long as a year on Earth, the length of a day there is almost identical. A Martian day is 24 hours and 39 minutes long, less than an hour longer than a day on Earth.
Seasons – Mars has seasons like Earth too. These seasons are much longer than Earth seasons because Mars is so much farther from the sun.
✪ The largest volcanic mountain (largest volcano and largest mountain) in the Solar System is on Mars at more than 25 kilometers high (that’s three times higher than Mount Everest). It is called Olympus Mons.
✪ Valles Marineris is the largest canyon in the solar system, stretching 4,000 kilometers across the planet’s surface.
✪ The Borealis Basin makes up 40% of the planet’s surface, taking up almost the entire northern hemisphere.
✪ Mars doesn't have a protective layer of atmosphere like Earth, so it cannot store heat from the sun. As a result, the temperature on Mars regularly drops to -125°F (-82°C) in the winter and only rises to 23°F (-5°C) in the summer.
✪ The first true Mars mission success was Mariner 4 in 1965.
✪ Since the start of the twenty first century, NASA's Mars Odyssey 2001 was launched in 2001 and is currently orbiting the planet. It was joined in 2003 by Europe's Mars Express and in 2006 by NASA's Mars Reconnaissance Orbiter.
✪ Jupiter is the fifth planet in order from the Sun and is about 777 million km or 483 million miles from the Sun.
✪ Jupiter is called after the ancient Roman sky-god, Jupiter, known to the Greeks as Zeus.
✪ Jupiter is the third brightest object in the solar system – It is one of five planets that can be seen with the naked eye, the others are Mercury, Venus, Mars and Saturn.
✪ Jupiter's atmosphere resembles that of the sun, made up mostly of hydrogen and helium, and with a total of 67 known moons — including four large moons known as the Galilean satellites, orbit around it, Jupiter by itself forms a kind of miniature solar system.
✪ Four largest moons of Jupiter are: Io, Europa, Ganymede and Callisto.
✪ Jupiter has a mass 318 times greater than the Earth's and a diameter that is 11 times larger.
✪ The mass of Jupiter is 70% of the total mass of all the other planets in our Solar System.
✪ Jupiter has two rings, rings just like Saturn and Uranus. These are thought to be composed of material from it’s moons where they have been struck by meteorites.
✪ The most extraordinary feature on Jupiter is undoubtedly the Great Red Spot, three times the diameter of the Earth. Its a giant hurricane-like storm seen for more than 300 years. Its edge spins counterclockwise around its center at a speed of about 225 mph (360 kph).
✪ Jupiter has the biggest moon in the Solar System, Ganymede. It’s has a diameter of 5,268 km making it larger than the planet Mercury.
✪ Gravity at Jupiter is 2.4 times of Earth.
✪ Jupiter has the strongest magnetic field in the Solar System (14 times stronger than of Earth). Astronomers think the magnetic field is generated by the movements of metallic hydrogen deep inside Jupiter. This magnetic field traps ionized particles from the solar wind and accelerates them to nearly the speed of light. These particles create a dangerous belt of radiation around Jupiter that can cause damage to spacecraft, as to NASA's Galileo probe. (Source: Universe Today)
✪ Jupiter has nature of both star and planet. Star, as it has its own radio-energy.
✪ Seven missions have flown by Jupiter — Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Ulysses, Cassini and New Horizons — while another, NASA's Galileo, actually orbited the planet.
✪ Saturn is best known for its fascinating ring system, discovered by Galileo Galilei in 1610.
✪ Saturn's rings are composed primarily of billions of tiny ice particles, with traces of dust and other debris. These rings are visible to Earth-based telescopes because ice is very reflective of sunlight.`
✪ Saturn is sixth planet in order from the sun and the second largest planet in the solar system.
✪ Saturn is the most distant planet that can be seen with naked human eyes.
✪ Saturn is named after the Greek God Cronus, the lord of Titans.
✪ Saturn and Jupiter combined account for 92% of the entire solar planetary mass.
✪ Saturn is a gas giant made up mostly of hydrogen (96.3%) and helium (3.25%); and its least dense planet in the solar system, least dense than water means it’s a floating planet if put in a bathtub!
✪ Saturn’s mass is about 96 times Earth’s mass and it is big enough to hold more than 750 Earths.
✪ Saturn has a magnetic field about 578 times more powerful than Earth's.
✪ Saturn’s gravity is 1.1 times of Earth’s gravity means your weight will increase on Saturn if you go there!
✪ Saturn emits approximately 2.5 times more radiation than it receives from the Sun. This is due to the Kelvin-Helmholtz mechanism, which essentially creates energy through gravitational compression of the planet due to its enormous mass
✪ Saturn appears a pale yellow colour because its upper atmosphere contains ammonia crystals in ice forms.
✪ Saturn has 62 known moons, highest after Jupiter (67 Moons).
✪ Saturn's largest moon, Titan, is slightly larger than Mercury, and is the second-largest moon in the solar system behind Jupiter's moon Ganymede. (Earth's moon is the fifth largest.)
✪ Saturn spins so quickly on its axis (once every 10 hours and 34 minutes giving it the second-shortest day of any of the solar system’s planets) that the planet flattens itself out into an oblate spheroid. It’s because Saturn's polar diameter is 90% of its equatorial diameter.
✪ It is the flattest of the eight planets of our solar system.
✪ Saturn has oval shaped storms, similar to those of Jupiter.
✪ Saturn has been visited by four spacecraft: Pioneer 11, Voyager 1 and 2 and the Cassini-Huygen mission.
✪ Uranus, the ice giant, is seventh planet in order from the sun and the third largest planet in the Solar System.
✪ Uranus was the first planet to be discovered by scientists. It was first seen by William Herschel in 1781 during a survey of the sky using a telescope.
✪ Uranus was long mistaken as a star because of the planet’s dimness and slow orbit.
✪ Uranus is notable for its dramatic tilt, which causes its axis to point nearly directly at the sun.
✪ Though Neptune is farthest planet from Sun but Uranus is the coldest planet (with surface temperature of -224°C) in our Solar System. How strange!
✪ Uranus has rings like Saturn. We know of a total of 13 rings yet. Scientists do not yet understand exactly what causes these rings.
✪ Uranus is blue-green in colour because of the result of methane in its mostly hydrogen - helium atmosphere.
✪ Uranus is the second least dense planet in the solar system, after Saturn.
✪ Uranus' magnetic field is tilted, with its magnetic axis tipped over nearly 60 degrees from the planet's axis of rotation whereas the magnetic poles of most planets are typically lined up with the axis along which it rotates.
✪ Uranus rotates on its axis once every 17 hours and 14 minutes whereas Earth takes 24 hours.
✪ Uranus orbits the Sun lying on its side and takes 84 years to complete one orbit.
✪ Uranus has 27 known moons. The five major moons are called Titania, Oberon, Miranda, Ariel and Umbriel. Its first four discovered moons were named after magical spirits in English literature, such as William Shakespeare's ‘A Midsummer Night's Dream’ and Alexander Pope's ‘The Rape of the Lock.’
✪ The chemical element Uranium, discovered in 1789, was named after the newly discovered planet Uranus.
✪ NASA’s Voyager 2 is the only spacecraft in the history of spaceflight has ever made a close approach to Uranus in January, 1986.
✪ Neptune is the eighth planet in order from the Sun making it the most distant in the solar system.
✪ Neptune is the fourth largest planet in diameter and third largest in mass in the Solar System.
✪ Neptune's existence was predicted on mathematical calculations before it was actually seen through a telescope in 1846.
✪ Neptune is named after the Neptune, Roman God of the Sea.
✪ Neptune's vivid blue tint is result of the absorption of red light by methane (1%) in the planets mostly hydrogen (74%) – helium (25%) atmosphere.
✪ Neptune has an average surface temperature of -214°C, higher than of Uranus (-224 °C).
✪ Neptune's winds can reach up to 1500 mph (2400 km/h), the fastest detected yet in the solar system.
✪ Neptune has 14 known moons. Triton is firstly discovered (1846) moon of Neptune. It is a most unusual moon since it orbits Neptune in the opposite direction of Neptune’s own rotation on its axis. It’s also the only spherical moon of Neptune.
✪ Triton is probably the coolest moon in the solar system.
✪ Like the other outer planets, Neptune possesses a ring system, though its rings are very faint. These rings are not uniform, but possess bright thick clumps of dust called ‘arcs’.
✪ NASA's Voyager 2 satellite was the first and as yet only spacecraft to visit Neptune in 1989.
✪ The Sun generates huge amounts of energy by combining hydrogen nuclei into helium. This process is called nuclear fusion.
✪ Sun lies about 150 million km away from us.
✪ It takes about 8 minutes for sunlight to reach us – even when it is travelling at about 3,00,000 km/s. This means that we see the Sun set eight minutes after the event has actually taken place!
✪ The Sun is 24,000-26,000 light years from the galactic centre and it takes the Sun 225-250 million years to complete an orbit of the centre of the Milky Way. It means The Sun travels at 220 kilometres per second.
✪ The Sun is 24,000-26,000 light years from the galactic centre and it takes the Sun 225-250 million years to complete an orbit of the centre of the Milky Way. It means The Sun travels at 220 kilometres per second.
✪ The distance from the Sun to Earth (149,600,000 km (92,960,000 miles) changes throughout the year as the Earth travels on an elliptical orbit around the Sun, the distance between the two bodies varies from 147 to 152 million kilometers.
✪ The distance between the Earth and the Sun is called an Astronomical Unit (AU).
✪ The surface of the Sun, called the photosphere, is at a temperature of about 5526.85°C (5800 K). Sunspots are "cool" regions, only 3526.85°C (3800 K) (they look dark only by comparison with the surrounding regions). Sunspots can be very large, as much as 50,000 km in diameter. Sunspots are caused by complicated and not very well understood interactions with the Sun's magnetic field.
✪ Chromosphere lies above the photosphere.
✪ The highly rarefied region above the chromosphere, called the corona, extends millions of kilometers into space but is visible only during a total solar eclipse. Temperatures in the corona are over 1,000,000 K.
✪ In addition to heat and light, the Sun also emits a low density stream of charged particles (mostly electrons and protons) known as the solar wind which propagates throughout the solar system at about 450 km/sec. The solar wind and the much higher energy particles ejected by solar flares can have dramatic effects on the Earth ranging from power line surges to radio interference to the beautiful aurora borealis (The Northern Lights) and aurora australis (The Southern Lights).
✪ The solar wind causes Radio Interference and the characteristics of tails of comets. It can also alter the trajectory of spacecraft.
✪ Chromosphere lies above the photosphere.
✪ The highly rarefied region above the chromosphere, called the corona, extends millions of kilometers into space but is visible only during a total solar eclipse. Temperatures in the corona are over 1,000,000 K.
✪ In addition to heat and light, the Sun also emits a low density stream of charged particles (mostly electrons and protons) known as the solar wind which propagates throughout the solar system at about 450 km/sec. The solar wind and the much higher energy particles ejected by solar flares can have dramatic effects on the Earth ranging from power line surges to radio interference to the beautiful aurora borealis (The Northern Lights) and aurora australis (The Southern Lights).
✪ The solar wind causes Radio Interference and the characteristics of tails of comets. It can also alter the trajectory of spacecraft.
:: 8 PLANETS ::
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| "Distance of the Planets (Mercury, Venus, Earth, Mars, Jupiter) from the Sun in Astronomical Units (AU)" |
:: 8 PLANETS ::
1. MERCURY - FACTS ABOUT THE SMALLEST ONE
MERCURY PROFILE
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Mass
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330,104,000,000,000 billion kg (0.055 x Earth)
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Equatorial Diameter = Polar Diameter
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4,879 km
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Equatorial Circumference
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15,329 km
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Satellites
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none
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Orbit Distance
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57,909,227 km (0.39 AU)
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Orbit Period
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87.97 Earth days
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Surface Temperature
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-173 to 427°C
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✪ Because of it's proximity to the sun, it is hard to directly observe from Earth except during twilight.
✪ Unlike the Earth and most other planets Mercury only turns very slowly on its axis, taking 59 days to complete the turn from day to night.
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| Mercury's Size Compared to the Size of Earth |
✪ Mercury has no moons. Moons are satellites that travel with a planet as it orbits the sun.
✪ If we suppose the gravity of Earth = 1 than the gravity of Mercury will be 0.38.
✪ The atmosphere on Mercury is almost non-existent, so there is no weather on Mercury and because of it there is no possibility of life on Mercury. As it has no atmosphere around it to protect it from the Sun or to retain any heat when it rotates on its axis, the surface of Mercury is covered with craters and completely dry.
✪ Mercury’s sunny side has a temperature rising to 427° Celsius or 800.6° Fahrenheit. On other hand Mercury’s dark side, however, is very cold indeed, with the temperature going down to -173° Celsius or -279.4° Fahrenheit.
✪ Despite being the closest planet to the Sun, Mercury is not the warmest. Venus is warmer. In fact, Mercury can be one of the coldest planets in the Solar System
✪ Only one spacecraft has ever visited Mercury: Mariner 10, which imaged about 45 percent of the surface. The Mariner 10 spacecraft passed close to the planet in 1974 and 1975 and took very clear photographs.
✪ Mercury is the most cratered planet in the Solar System with a surface similar to Earth's Moon.
✪ NASA’s latest mission to Mercury is called Messenger. The Messenger spacecraft entered Mercury’s orbit in March 2011 and is sending back new pictures of the planet. Messenger is now moving with Mercury round the Sun.
✪ BepiColumbo (Europe, 2011) is the planned mission for Mercury.
2. VENUS: EARTH'S TWIN SISTER
✪ 2nd planet from the Sun, Venus is the brightest planet in the Solar System and the brightest object after Sun and Moon when seen from earth.
✪ Venus is called after the Roman Goddess of love and beauty.
VENUS PROFILE
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Mass
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4.87 x 1024 kg
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Diameter
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12104 km
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Mean density
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5250 kg/m3
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Average distance from Sun
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108,208,930 km (0.723 AU)
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Rotation period (length of day in Earth days)
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243.02 (retrograde)
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Revolution period (length of year in Earth days)
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224.7
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Mean surface temperature
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452.85°C (726 K)
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Atmospheric components
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96% carbon dioxide, 3% nitrogen, 0.1% water vapour
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✪ Venus is known as morning star because it rises just before the rise of sun, when it is west of sun and on the other hand when it is east of the sun, Venus is known as evening star as shines just after the sunset.
✪ Venus is the only planet in the Solar System to turn clockwise (East to West). All other planets turn anti-clockwise.
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| Venus' Size Compared to the Size of Earth |
✪ Venus has phases like the moon because the orbit of Venus is between the Earth and the Sun.
✪ Venus has no orbiting moons like mercury.
✪ Venus is the planet which is closest to the Earth and is a little smaller than the Earth but it looks bigger than the earth because of thick atmosphere (deep layers of gases that surrounds the planet).
✪ The diameter of the Earth (the distance right round the middle of the Earth at the equator) is 12,760 km (7926 miles). The diameter of Venus is 12,103 km (7520 miles).
✪ Venus is the hottest planet in the Solar System, even hotter than Mercury, which is closer to the Sun. The temperature on the surface of Venus is about 847.13° Fahrenheit or 452.85°C (726 K) because the surface is heated by radiation from the sun, but the heat cannot escape through the clouds and layer of carbon dioxide (called "Greenhouse Effect.").
✪ Spacecraft has ever visited Venus: 1. Russia: Venera 9 and Venera 10 (1975) and 2. United States of America: Pioneer Venus 2 (launched on 8th August 1978 ) and Magellan (sent full image of Venus in 1993)
3. EARTH: OUR MOTHER
✪ The Earth is the third planet from the Sun and comes between the planet Venus and the planet Mars.
✪ Earth is the only planet in the solar system that has life.
EARTH PROFILE
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Mass
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5.98 x 1024 kg
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Diameter
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12756 km
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Mean density
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5520 kg/m3
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Escape velocity
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11200 m/s (11.2 km/s)
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Rotation period (length of day in Earth days)
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1 (23.93 hours)
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Revolution period (length of year in Earth days)
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365.26
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Obliquity (tilt of axis degrees)
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23.4
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Mean surface temperature
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281 K (07.85°C)
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Mean maximum surface temperature
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310 K (36.85°C)
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Mean minimum surface temperature
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260 K (-13.15 °C)
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Visual geometric albedo (reflectivity)
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0.39
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Highest point on surface
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Mount Everest (over 8 km above sea-level)
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Atmospheric components
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78% nitrogen, 21% oxygen, 1% argon
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Surface materials
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Basaltic and granitic rock and altered materials
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Credits: NASA Planet Profiles
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✪ Earth is the only planet in the Solar System to have water in its three states of matter: as a solid (ice), a liquid (sea, rain, etc.) and as a gas (clouds).
✪ Earth is the only planet that has an atmosphere containing 21 percent oxygen.
✪ Earth is the only planet in the Solar System not to be named after a mythical God.
✪ The Earth is the only inner planet (Mercury, Venus, Earth and Mars) after mars to have satellite, the Moon. Earth have the largest satellite (Moon) among these. Mars has tiny two - Phobos and Deimos.
✪ Earth is the only planet in the Solar System known to be geologically active, with Earthquakes and volcanoes forming the landscape, replenishing carbon dioxide into the atmosphere and erasing impact craters from meteors. The craters have sunk down or been worn away by wind and rain over millions of years.
✪ The Earth takes 365¼ days to complete its revolution round the Sun. The Earth’s year is therefore 365 days long but the ¼ days are added up and every fourth year has one extra day, on the 29th of February. This fourth year is called a Leap Year (366 days) and is always a year which can be divided exactly by 4 and 400 – 2000, 2004, 2008, 2012, 2016.
✪ As the Earth orbits round the Sun it rotates on its axis. It takes 24 hour to complete a rotation. The side of the Earth that faces the Sun has daytime and the side of the Earth that is turned away from the Sun has nighttime.
✪ As the Earth orbits round the Sun it tilts very slightly and so gives us the seasons.
✪ Hence formation of seasons is due to earth's revolution and formation of day-nights are because of it's rotation on its own axis.
✪ Distance of Earth from the Sun (about 150 million km = 1 AU): 1. Perihelion (closest): 147,098,291 km (91,402,640 miles); 2. Aphelion (farthest): 152,098,233 km (94,509,460 miles)
✪ The Earth’s diameter, the distance round its middle at the Equator, 12756 kilometers or 7926 miles.
✪ The Earth is not an exact sphere; the diameter going round the North and South Poles is slightly less than the diameter round the Equator.
4. MARS: THE RED PLANET
MARS PROFILE
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Mass
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6.42 x 1023 kg
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Diameter
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6787 km
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Mean density
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3940 kg/m3
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Escape velocity
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5000 m/s (5 km/s)
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Average distance from Sun
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1.524 AU (227,936,640 km)
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Rotation period (length of day in Earth days)
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1.026
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Revolution period (length of year in Earth days)
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686.98
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Obliquity (tilt of axis degrees)
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25
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Maximum surface temperature
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310 K
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Minimum surface temperature
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150 K
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Visual geometric albedo (reflectivity)
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0.15
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Highest point on surface
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Olympus Mons
(about 24 km above surrounding lava plains) |
Atmospheric components
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95% carbon dioxide, 3% nitrogen and 1.6% argon
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Surface materials
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Basaltic rock and altered materials
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Credits: NASA Planet Profiles
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✪ Mars is home to an ever present red tint. This is due to a mineral called iron oxide that is very common on the planet’s surface.
✪ Mars has two moons Phobos and Deimos.
✪ Earth and Mars are similar in a lot of ways: (Credit: PlanetsforKids.org)
Polar Ice Caps – Mars has both North and South polar ice caps, much like Earth. Polar caps contain mostly frozen carbon dioxide instead of frozen water.
Though scientists think that life could have once existed there and the polar caps might be of water.
Length of a Year – Mars is not much farther from the Sun than Earth. As a result, a typical year on Mars is 1 year and 320 days.
Length of a Day – While a year on Mars might be almost twice as long as a year on Earth, the length of a day there is almost identical. A Martian day is 24 hours and 39 minutes long, less than an hour longer than a day on Earth.
Seasons – Mars has seasons like Earth too. These seasons are much longer than Earth seasons because Mars is so much farther from the sun.
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| Volcano: Olympus Mons, Canyon: Valles Marineris and Basin: Borealis |
✪ Valles Marineris is the largest canyon in the solar system, stretching 4,000 kilometers across the planet’s surface.
✪ The Borealis Basin makes up 40% of the planet’s surface, taking up almost the entire northern hemisphere.
✪ Mars doesn't have a protective layer of atmosphere like Earth, so it cannot store heat from the sun. As a result, the temperature on Mars regularly drops to -125°F (-82°C) in the winter and only rises to 23°F (-5°C) in the summer.
✪ The first true Mars mission success was Mariner 4 in 1965.
✪ Since the start of the twenty first century, NASA's Mars Odyssey 2001 was launched in 2001 and is currently orbiting the planet. It was joined in 2003 by Europe's Mars Express and in 2006 by NASA's Mars Reconnaissance Orbiter.
JUPITER: THE JOVIAN GAS GIANT
JUPITER PROFILE
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Mass
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1.90 x 1027 kg
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Diameter
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142,800 km
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Mean density
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1314 kg/m3
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Escape velocity
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59500 m/s (59.5 km/s)
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Average distance from Sun
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5.203 AU (778,412,020 km)
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Rotation period (length of day in Earth days)
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0.41 (9.8 Earth hours)
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Revolution period (length of year in Earth days)
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11.86
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Obliquity (tilt of axis degrees)
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3.08
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Mean surface temperature
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120 K (cloud tops)
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Visual geometric albedo (reflectivity)
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0.15
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Atmospheric components
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89.8% hydrogen, 10.2% helium and 0.07% methane
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Rings
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Faint ring. Infrared spectra imply dark rock fragments.
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Credits: NASA Planet Profiles
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✪ Jupiter is the giant of the Solar System, with a mass more than 300 times the mass of the Earth.
✪ Jupiter is called after the ancient Roman sky-god, Jupiter, known to the Greeks as Zeus.
✪ Jupiter is the third brightest object in the solar system – It is one of five planets that can be seen with the naked eye, the others are Mercury, Venus, Mars and Saturn.
✪ Jupiter's atmosphere resembles that of the sun, made up mostly of hydrogen and helium, and with a total of 67 known moons — including four large moons known as the Galilean satellites, orbit around it, Jupiter by itself forms a kind of miniature solar system.
✪ Four largest moons of Jupiter are: Io, Europa, Ganymede and Callisto.
✪ Jupiter has a mass 318 times greater than the Earth's and a diameter that is 11 times larger.
✪ The mass of Jupiter is 70% of the total mass of all the other planets in our Solar System.
✪ Jupiter has two rings, rings just like Saturn and Uranus. These are thought to be composed of material from it’s moons where they have been struck by meteorites.
✪ The most extraordinary feature on Jupiter is undoubtedly the Great Red Spot, three times the diameter of the Earth. Its a giant hurricane-like storm seen for more than 300 years. Its edge spins counterclockwise around its center at a speed of about 225 mph (360 kph).
✪ Jupiter has the biggest moon in the Solar System, Ganymede. It’s has a diameter of 5,268 km making it larger than the planet Mercury.
✪ Gravity at Jupiter is 2.4 times of Earth.
✪ Jupiter has the strongest magnetic field in the Solar System (14 times stronger than of Earth). Astronomers think the magnetic field is generated by the movements of metallic hydrogen deep inside Jupiter. This magnetic field traps ionized particles from the solar wind and accelerates them to nearly the speed of light. These particles create a dangerous belt of radiation around Jupiter that can cause damage to spacecraft, as to NASA's Galileo probe. (Source: Universe Today)
✪ Jupiter has nature of both star and planet. Star, as it has its own radio-energy.
✪ Seven missions have flown by Jupiter — Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Ulysses, Cassini and New Horizons — while another, NASA's Galileo, actually orbited the planet.
:: SATURN: GAS GIANT WITH BEAUTIFUL RINGS::
SATURN PROFILE
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Mass
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5.69 x 10^26 kg
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Diameter
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120660 km
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Mean density
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690 kg/m3
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Escape velocity
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35600 m/s
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Average distance from Sun
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9.537 AU (1,426,725,400 km)
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Rotation period (length of day)
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0.44 Earth days (10.2 Earth hours)
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Revolution period (length of year)
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29.46 years
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Obliquity (tilt of axis)
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26.7 degrees
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Orbit inclination
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2.49 degrees
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Mean temperature (K)
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88 K (1 bar level)
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Atmospheric components
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97% hydrogen, 3% helium, 0.05% methane
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Source: NASA Planet Profiles
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✪ Saturn is best known for its fascinating ring system, discovered by Galileo Galilei in 1610.
✪ Saturn's rings are composed primarily of billions of tiny ice particles, with traces of dust and other debris. These rings are visible to Earth-based telescopes because ice is very reflective of sunlight.`
✪ Saturn is sixth planet in order from the sun and the second largest planet in the solar system.
✪ Saturn is the most distant planet that can be seen with naked human eyes.
✪ Saturn is named after the Greek God Cronus, the lord of Titans.
✪ Saturn and Jupiter combined account for 92% of the entire solar planetary mass.
✪ Saturn is a gas giant made up mostly of hydrogen (96.3%) and helium (3.25%); and its least dense planet in the solar system, least dense than water means it’s a floating planet if put in a bathtub!
✪ Saturn’s mass is about 96 times Earth’s mass and it is big enough to hold more than 750 Earths.
✪ Saturn has a magnetic field about 578 times more powerful than Earth's.
✪ Saturn’s gravity is 1.1 times of Earth’s gravity means your weight will increase on Saturn if you go there!
✪ Saturn emits approximately 2.5 times more radiation than it receives from the Sun. This is due to the Kelvin-Helmholtz mechanism, which essentially creates energy through gravitational compression of the planet due to its enormous mass
✪ Saturn appears a pale yellow colour because its upper atmosphere contains ammonia crystals in ice forms.
✪ Saturn has 62 known moons, highest after Jupiter (67 Moons).
✪ Saturn's largest moon, Titan, is slightly larger than Mercury, and is the second-largest moon in the solar system behind Jupiter's moon Ganymede. (Earth's moon is the fifth largest.)
✪ Saturn spins so quickly on its axis (once every 10 hours and 34 minutes giving it the second-shortest day of any of the solar system’s planets) that the planet flattens itself out into an oblate spheroid. It’s because Saturn's polar diameter is 90% of its equatorial diameter.
✪ It is the flattest of the eight planets of our solar system.
✪ Saturn has oval shaped storms, similar to those of Jupiter.
✪ Saturn has been visited by four spacecraft: Pioneer 11, Voyager 1 and 2 and the Cassini-Huygen mission.
::URANUS: PLANET WITH DRAMATIC TILT::
URANUS PROFILE
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Mass
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8.68 x 10^25 kg
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Diameter
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51118 km
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Mean density
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1290 kg/m3
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Escape velocity
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21300 m/s
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Average distance from Sun
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19.19 AU (2,870,972,200 km)
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Rotation period (length of day)
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0.72 Earth days (17.9 Earth hours)
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Revolution period (length of year)
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84 years
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Obliquity (tilt of axis)
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97.9 degrees
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Orbit inclination
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0.77 degrees
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Mean temperature (K)
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59 K (1 bar level)
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Atmospheric components
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83% hydrogen, 15% helium, 2% methane
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Source: NASA Planet Profiles
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✪ Uranus, the ice giant, is seventh planet in order from the sun and the third largest planet in the Solar System.
✪ Uranus was the first planet to be discovered by scientists. It was first seen by William Herschel in 1781 during a survey of the sky using a telescope.
✪ Uranus was long mistaken as a star because of the planet’s dimness and slow orbit.
✪ Uranus is notable for its dramatic tilt, which causes its axis to point nearly directly at the sun.
✪ Though Neptune is farthest planet from Sun but Uranus is the coldest planet (with surface temperature of -224°C) in our Solar System. How strange!
✪ Uranus has rings like Saturn. We know of a total of 13 rings yet. Scientists do not yet understand exactly what causes these rings.
✪ Uranus is blue-green in colour because of the result of methane in its mostly hydrogen - helium atmosphere.
✪ Uranus is the second least dense planet in the solar system, after Saturn.
✪ Uranus' magnetic field is tilted, with its magnetic axis tipped over nearly 60 degrees from the planet's axis of rotation whereas the magnetic poles of most planets are typically lined up with the axis along which it rotates.
✪ Uranus rotates on its axis once every 17 hours and 14 minutes whereas Earth takes 24 hours.
✪ Uranus orbits the Sun lying on its side and takes 84 years to complete one orbit.
✪ Uranus has 27 known moons. The five major moons are called Titania, Oberon, Miranda, Ariel and Umbriel. Its first four discovered moons were named after magical spirits in English literature, such as William Shakespeare's ‘A Midsummer Night's Dream’ and Alexander Pope's ‘The Rape of the Lock.’
✪ The chemical element Uranium, discovered in 1789, was named after the newly discovered planet Uranus.
✪ NASA’s Voyager 2 is the only spacecraft in the history of spaceflight has ever made a close approach to Uranus in January, 1986.
::NEPTUNE: PLANET WITH THE COOLEST MOON::
NEPTUNE PROFILE
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Mass
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1.02 x 10^26 kg
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Diameter
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49528 km
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Mean density
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1640 kg/m3
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Escape velocity
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23300 m/s
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Average distance from Sun
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30.07 AU (4,498,252,900 km)
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Rotation period (length of day)
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0.67 Earth days (19.1 hours)
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Revolution period (length of year)
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164.8 years
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Obliquity (tilt of axis)
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29.6 degrees
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Orbit inclination
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1.77 degrees
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Mean temperature (K)
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48 K (1 bar level)
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Atmospheric components
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74% hydrogen, 25% helium, 1% methane
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Source: NASA Planet Profiles
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✪ Neptune is the eighth planet in order from the Sun making it the most distant in the solar system.
✪ Neptune is the fourth largest planet in diameter and third largest in mass in the Solar System.
✪ Neptune's existence was predicted on mathematical calculations before it was actually seen through a telescope in 1846.
✪ Neptune is named after the Neptune, Roman God of the Sea.
✪ Neptune's vivid blue tint is result of the absorption of red light by methane (1%) in the planets mostly hydrogen (74%) – helium (25%) atmosphere.
✪ Neptune has an average surface temperature of -214°C, higher than of Uranus (-224 °C).
✪ Neptune's winds can reach up to 1500 mph (2400 km/h), the fastest detected yet in the solar system.
✪ Neptune has 14 known moons. Triton is firstly discovered (1846) moon of Neptune. It is a most unusual moon since it orbits Neptune in the opposite direction of Neptune’s own rotation on its axis. It’s also the only spherical moon of Neptune.
✪ Triton is probably the coolest moon in the solar system.
✪ Like the other outer planets, Neptune possesses a ring system, though its rings are very faint. These rings are not uniform, but possess bright thick clumps of dust called ‘arcs’.
✪ NASA's Voyager 2 satellite was the first and as yet only spacecraft to visit Neptune in 1989.
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