I decided to then look into Planets as this is a huge part of what we know about space, i decided to generated research into when the planets where discovered and also the exploration missions that where send to explore the planet. I found this a very interesting part of my research learning about what missions investigated different planets and what they where sent for. However i also found out that many of the planets do not have a know discovery date as they have always been visible to the human eye.
We actually only know the exact date of when a few of the planets were discovered. Five of the planets, not including Earth, have been known to exist for thousands of years – Mercury, Mars, Venus, Jupiter, and Saturn. The Ancient Greeks and Romans wrote about the planets many centuries ago. Because the planets look like stars to the naked eye, that is where the term planets comes from. Because the planets move in the sky, they were termed wandering stars. The term planet comes from the Greek word for wanderer, “planetes.” Many ancient people thought that the planets were gods, so they gave them the names of their gods. All of the planets, except Earth have names of Roman deities.
The other three planets – Uranus, Neptune, and Pluto – were not discovered until at least the 1700′s. Pluto is no longer a planet since it was reclassified as a dwarf planet in 2006. It was known as the ninth planet for 70 years though, so its discovery will be included here. Uranus was discovered in 1781 by the famous astronomer Sir William Herschel, although that was not the first sighting of it. The planet had been sighted as early as 1690 by the English astronomer John Flamsteed. It was also sighted by Pierre Lemonier in the mid 1700′s. Sir Herschel at first thought that Uranus was a comet, but he noticed the irregularities early on and compared it to a planet in his notes.
Because Neptune cannot be seen without the help of a telescope, it was not discovered until after 1610, when Galileo created the telescope. Alexis Bouvard, a mathematician, saw that another planet had to be affecting Uranus’ orbit, so astronomers started looking for it. Two astronomers, John Couch Adams and Urbain Le Verrier, discovered Neptune independently or rather made the calculations and determined where Neptune could be found. The planet turned out to be 1° from Verrier’s calculations and 12° from Adams’. There was a dispute between France and England over who discovered the new planet because Adams and Verrier are from England and France respectively.
Pluto was the last planet discovered, although that distinction returned to Neptune when Pluto was reclassified as a dwarf planet. Pluto was discovered in 1930 by the astronomer Clyde Tombaugh. Many people had been searching for a ninth planet – the elusive planet X – for quite a while. Since Pluto was discovered near the calculated location of planet X, they thought the two planets were one and the same. Later, astronomers realized that there was no such planet X.
Read more: http://www.universetoday.com/34360/discovery-of-the-planets/#ixzz24JM7k04W
The sun is a star, a hot ball of glowing gases at the heart of our solar system. Its influence extends far beyond the orbits of distant Neptune and Pluto. Without the sun's intense energy and heat, there would be no life on Earth. And though it is special to us, there are billions of stars like our sun scattered across the Milky Way galaxy.
Featured Mission: Solar Dynamics Observatory
SDO will study the sun's influence by observing the solar atmosphere simultaneously in several wavelengths. The orbiting observatory will help determine if it is possible to make reliable space weather forecasts.
Sun-scorched Mercury is only slightly larger than Earth's Moon. Like the Moon, Mercury has very little atmosphere to stop impacts, and it is covered with craters. Mercury's dayside is super-heated by the sun, but at night temperatures drop hundreds of degrees below freezing. Ice may even exist in craters. Mercury's egg-shaped orbit takes it around the sun every 88 days.
Featured Mission: MESSENGER
NASA's MESSENGER orbiter is the second spacecraft to visit Mercury. It made three flybys before working its way into orbit about Mercury in March 2011. MESSENGER is the first spacecraft to orbit Mercury.
Venus is a dim world of intense heat and volcanic activity. Similar in structure and size to Earth, Venus' thick, toxic atmosphere traps heat in a runaway "greenhouse effect." The scorched world has temperatures hot enough to melt lead. Glimpses below the clouds reveal volcanoes and deformed mountains. Venus spins slowly in the opposite direction of most planets.
Featured Mission: Akatsuki
Japan's Akatsuki is the next planned mission to Venus. The orbiter will follow Venus' thick cloud layers as they are whipped around the planet by hurricane-force winds
Japan's Akatsuki is the next planned mission to Venus. The orbiter will follow Venus' thick cloud layers as they are whipped around the planet by hurricane-force winds
Earth is an ocean planet. Our home world's abundance of water -- and life -- makes it unique in our solar system. Other planets, plus a few moons, have ice, atmospheres, seasons and even weather, but only on Earth does the whole complicated mix come together in a way that encourages life -- and lots of it.
Featured Mission: Earth Science Missions
Orbiting spacecraft study our home world from above as a whole system and aid in our understanding how the planet is changing.
Orbiting spacecraft study our home world from above as a whole system and aid in our understanding how the planet is changing.
Our Moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate, and creating a rhythm that has guided humans for thousands of years. The Moon was likely formed after a Mars-sized body collided with Earth and the debris formed into the most prominent feature in our night sky.
Featured Mission: GRAIL
The Gravity Recovery And Interior Laboratory (GRAIL) mission will create the most accurate gravitational map of the Moon to date, improving our knowledge of near-side gravity by 100 times and of far-side gravity by 1000 times.
The Gravity Recovery And Interior Laboratory (GRAIL) mission will create the most accurate gravitational map of the Moon to date, improving our knowledge of near-side gravity by 100 times and of far-side gravity by 1000 times.
Mars is a cold desert world. It is half the diameter of Earth and has the same amount of dry land. Like Earth, Mars has seasons, polar ice caps, volcanoes, canyons and weather, but its atmosphere is too thin for liquid water to exist for long on the surface. There are signs of ancient floods on Mars, but evidence for water now exists mainly in icy soil and thin clouds.
Featured Mission: Mars Science Laboratory/Curiosity
Curiosity, a robotic rover about the size of a small SUV, is designed to find whether the Red Planet ever was -- or is still today -- an environment suitable for life. The rover will land on Mars on 5-6 August 2012.
Curiosity, a robotic rover about the size of a small SUV, is designed to find whether the Red Planet ever was -- or is still today -- an environment suitable for life. The rover will land on Mars on 5-6 August 2012.
Jupiter, the most massive planet in our solar system -- with dozens of moons and an enormous magnetic field -- forms a kind of miniature solar system. Jupiter does resemble a star in composition, but it did not grow big enough to ignite. The planet's swirling cloud stripes are punctuated by massive storms such as the Great Red Spot, which has raged for hundreds of years.
Featured Mission: Juno
NASA's Juno polar orbiter will study how Jupiter formed and became the dynamic world we see today. Juno will also help us to better understand the formation of our solar system and other planetary systems.
NASA's Juno polar orbiter will study how Jupiter formed and became the dynamic world we see today. Juno will also help us to better understand the formation of our solar system and other planetary systems.
Adorned with thousands of beautiful ringlets, Saturn is unique among the planets. All four gas giant planets have rings -- made of chunks of ice and rock -- but none are as spectacular or as complicated as Saturn's. Like the other gas giants, Saturn is mostly a massive ball of hydrogen and helium.
Featured Mission: Cassini
NASA's Cassini orbiter is on an extended mission to explore Saturn and its rings, its magnetosphere and its moons. Cassini also delivered Europe's Huygens probe to its historic landing on Titan in 2005
NASA's Cassini orbiter is on an extended mission to explore Saturn and its rings, its magnetosphere and its moons. Cassini also delivered Europe's Huygens probe to its historic landing on Titan in 2005
Uranus is the only giant planet whose equator is nearly at right angles to its orbit. A collision with an Earth-sized object may explain Uranus' unique tilt. Nearly a twin in size to Neptune, Uranus has more methane in its mainly hydrogen and helium atmosphere than Jupiter or Saturn. Methane gives Uranus its blue tint.
Featured Mission: Voyager 2
Most of what we know about Uranus came from Voyager 2's flyby in 1986. The spacecraft discovered 10 additional moons and several rings before heading on to Neptune.
Most of what we know about Uranus came from Voyager 2's flyby in 1986. The spacecraft discovered 10 additional moons and several rings before heading on to Neptune.
Dark, cold and whipped by supersonic winds, Neptune is the last of the hydrogen and helium gas giants in our solar system. More than 30 times as far from the sun as Earth, the planet takes almost 165 Earth years to orbit our sun. In 2011 Neptune completed its first orbit since its discovery in 1846.
Featured Mission: Voyager 2
Most of what we know about Neptune is thanks to Voyager 2's 1989 flyby. The spacecraft also discovered six of Neptune's moons.
Most of what we know about Neptune is thanks to Voyager 2's 1989 flyby. The spacecraft also discovered six of Neptune's moons.
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