The New DefinitionThe definition of a Planet is that a Planet is a body that orbits the sun, is large enough for its own gravity to make it round, and it has cleared its neighborhood of smaller objects. That means that it has to be large enough that gravity shifts the shape to be round and it has to have cleared its neighborhood of any thing other then itself.
VulcanOn the day in question, March 26 1859, Dr Lescarbault entered the small observatory head built onto his house and trained his heliostatic-telescope at the sun. As he watched he saw a dot appear near the upper left-hand edge of the sun and move gradually downwards. He was fascinated since, as an experienced solar observer he knew this was no sunspot. Soon afterwards, he was called away to see to a patient but, when he returned, the object was still there moving steadily across the sun. Lescarbault watched the object for several hours until it disappeared.
MercuryThe planet Mercury is very difficult to study from the Earth because it is always so close to the Sun. Even at elongation, it is never more than 28 degrees from the Sun in our sky. It is the second smallest planet (it was believed to be the smallest until the discovery that Pluto is actually much smaller than originally thought), and also the fastest in its orbit since it is the innermost planet. In fact, the name Mercury derives from its speed in moving around its orbit. Until the 1960s, Venus was often considered a "twin sister" to the Earth because Venus is the nearest planet to us, and because superficially the two planets seem to share many characteristics (image source).
VenusThe Planet Venus In earlier times, there was considerable speculation concerning the possibility of life on Venus, sometimes with rather elaborate characteristics. In 1686 a French "man of letters", Bernard de Fontenelle, wrote that I can tell from here. what the inhabitants of Venus are like; they resemble the Moors of Granada; a small black people, burned by the sun, full of wit and fire, always in love, writing verse, fond of music, arranging festivals, dances, and tournaments every day.
(Mass In Multiples Of jupiter's Mass)
EarthThe Earth is certainly the most familiar planet, though it has only been a few hundred years since we fully realized it was a planet. We begin our study of objects in the Solar System with the Earth because it is interesting in its own right, and it provides a test of many observing techniques that we wish to use for other objects in the Solar System. The Earth is, at least by human standards, a beautiful planet, as the following images indicate.
MobiusMobius is a beautiful blue and white ball that orbits the sun along the same orbitational flow as we do but it is hidden behind the sun opposite us and that is why we have not unable to see Mobius. and it is the sister planet of our own planet Earth and could be called the third planet from the Sun As well, it is the largest of the inner planets As well. Mobius & Earth are the only planet known to support life and are the only planets to have liquid water upon the surface.
Marsthe "Red Planet", is named after the Roman god of war because it commonly appears with a reddish tinge when viewed in our sky. It has always held a fascination for those interested in the possibility of life on other planets. In 1895 a professor of astronomy, Samual Leland Phelps, wrote in a book called World Making that with a new 40 inch telescope being built by the University of Chicago,
JupiterJupiter is by far the largest of the planets. It is more than twice as massive as all other planets combined; if it had been only about 100 times more massive at birth (not so much by astronomical standards) it would have become a star instead of a planet. Then the Solar System might be a double star system instead of a single star with a planetary system. Jupiter has features very different from terrestrial planets. Its composition is more like that of stars, and if it has any solid surface it is hidden deep at its center: Jupiter is apparently almost entirely gas and liquid. It also has an internal energy source and enormous magnetic fields. Finally, the 4 largest moons of Jupiter (the Galilean Moons) are sufficiently interesting in their own right that they are among the most studied objects in the Solar System. We shall devote a separate section to studying their properties.
SaturnSaturn, the second most massive planet, and the most distant planet known to the ancients, is one of the most beautiful sites in the Solar System, as witnessed by the adjacent image. The most striking feature of Saturn is the spectacular ring system. Although this feature is no longer unique, since we now know that all the Gas Giant planets have rings, the rings of Saturn are much more elaborate than those of any of the other planets. Saturn shares many features with its even larger Gas Giant neighbor Jupiter, but has various unique features in its own right.
UranusUranus, the first planet discovered in modern times. It was found accidentally by William Herschel while he was searching the sky with a telescope in 1781. It had actually been seen many times before but dismissed as a star. Uranus is largely hydrogen and helium, but (like Neptune) contains higher proportions of heavy elements than Jupiter or Saturn, and is covered with clouds. Our only direct spacecraft observation of Uranus came from Voyager 2 in 1986.
NeptuneThe Planet Neptune is like Uranus in many ways, but has its own unique features. Because of Pluto's highly elliptical orbit, it is currently the most distant planet from the Sun, at a separation of about 30 Astronomical Units. The full disk of Neptune in shown in the adjacent image (Ref). Neptune has been particularly challenging to study from the ground because its disk is small and badly blurred by the Earth's atmosphere at that distance. In spite of this, ground-based astronomers had learned a great deal about this planet since its position was first predicted by Adams and Leverrier in 1845. However, our most detailed information about Neptune has come from the Voyager 2 flyby in 1989.
2004 DWThe Planet 2004 DW could even be larger than Pluto's moon, Charon which is 1,300km (810 miles) across. It has an orbit that is much larger than Pluto's, being, on average, 2.4 billion km (1.5 billion miles) further out. Astronomers believe that there are many more so-called "Kuiper Belt Objects" awaiting discovery in the cold, dark, outer reaches of the Solar System. The Kuiper Belt (KB) is a region inhabited by small worlds of rock and ice. It is similar in some ways to the Asteroid Belt - a region of rocky debris between Mars and Jupiter. However, the KB contains a hundred times more material than all the asteroids put together.
PlutoThe Planet Pluto, which was discovered in 1930, is but a dot of light in even the largest Earth-based telescopes. Pluto is 2/3 the size of Earth's moon but 1,200 times farther away, which makes viewing surface detail as difficult as trying to read the printing on a golf ball located thirty-three miles away (more info). The adjacent movie made from recent Hubble Space Telescope computer enhanced images (Ref) indicates that we are finally beginning to resolve some detail on the surface of this distant planet.
QuaoarThe planet Quaoar is the 11th planet in the meridian solar system . Its orbit is different than the other planets in our solar system. The surface of Quaoar is barren it consists mainly of hard rock and ice there is a light atmosphere around the planet Quaoar but it's not fit for humans. There are no life forms on the surface of Quaoar it is a dead planet and you could say the planet Quaoar is a large rock trapped in the darkness of the Kuiper belt in a orbit around our sun.
SednaThe planet Sedna is the second most reddish planetary body in the Solar System, after Mars. Although inclined by only around 11.9 degrees from the ecliptic where the eight major planets orbit, Sedna's distant orbit is extremely elliptical indicating that its formation and orbit may have been influenced by by a passing nearby star during the early years of the Solar System, when Sol formed out of a molecular cloud with many other closeby stars around 4.6 billion years ago. There is indirect evidence (an unexpectedly slow 40-day rotation) that Sedna has its own moon, which astronomers hope to confirm with the Hubble Space Telescope (more information and images from NASA. The icy object will move closer to the Sun over the next 72 years -- to 76 AUs of Sol -- before receding back towards the inner Oort Cloud.
Icy Worlds Beyond PlutoRoughly 1,000 Kuiper Belt objects have been discovered orbiting beyond Neptune since the first was found in 1992. Now researchers are suggesting that these icy objects -- considered to be leftover building blocks of the solar system -- are much smaller than was originally thought. The key is albedo, a measure of how much light an object reflects. Using a presumed albedo of four percent, which is the figure for comets, astronomers had calculated the size of the Kuiper Belt objects, and believed there were more than 10,000 KBOs with diameters greater than 100 kilometers (62 miles), compared to 200 asteroids known to be that large in the main asteroid belt between Mars and Jupiter.
2002 AW197Stansberry and colleagues found that a distant KBO designated 2002 AW197 reflects 18 percent of its incident light and is about 700 kilometers (435 miles) in diameter. 'That's considerably smaller and more reflective than expected, Stansberry said.' " " '2002 AW197 is believed to be one of the largest KBOs thus far discovered,' he said. 'These results indicate that this object is larger than all but one main-belt asteroid (Ceres), about half the size of Pluto's moon, Charon, and about 30 percent as large and a tenth as massive as Pluto. Astronomers operating under the assumption that 2002 AW197 reflects four percent of its incident light would calculate that it is 1500 kilometers (932 miles) in diameter, or two-thirds as large as Pluto,' Stansberry said."
The current study shows 2002 AW197, one of the largest KBOs known, to be about one third as large (in diameter) as Pluto. Using previous reflectivity assumptions, the estimate was for 2002 AW197 being two thirds as large (diameter) as Pluto. So the gap between Pluto's size and the size of the next largest KBOs has been widened quite a bit, if this study proves correct.
NibiruNibiru is the tenth planet in our solar system and orbit the sun once every 5 million years and has an elliptical orbit that crosses close to our own orbit from time to time.
ASA's Kepler Spacecraft Discovers Extraordinary New Planetary System
Kepler-11 is a sun-like star around which six planets orbit. At times, two or more planets pass in front of the star at once, as shown in this artist's conception of a simultaneous transit of three planets observed by NASA's Kepler spacecraft on Aug. 26, 2010.
Image credit: NASA/Tim Pyle
Click image for full-resolution.
This artist’s conception shows the Kepler-11 planetary system and our solar system from a tilted perspective to demonstrate that the orbits of each lie on similar planes.
Image credit: NASA/Tim Pyle Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth.
"The Kepler-11 planetary system is amazing," said Jack Lissauer, a planetary scientist and a Kepler science team member at NASA's Ames Research Center, Moffett Field, Calif. "It’s amazingly compact, it’s amazingly flat, there’s an amazingly large number of big planets orbiting close to their star - we didn’t know such systems could even exist."
In other words, Kepler-11 has the fullest, most compact planetary system yet discovered beyond our own.
"Few stars are known to have more than one transiting planet, and Kepler-11 is the first known star to have more than three," said Lissauer. "So we know that systems like this are not common. There’s certainly far fewer than one percent of stars that have systems like Kepler-11. But whether it’s one in a thousand, one in ten thousand or one in a million, that we don’t know, because we only have observed one of them."
All of the planets orbiting Kepler-11, a yellow dwarf star, are larger than Earth, with the largest ones being comparable in size to Uranus and Neptune. The innermost planet, Kepler-11b, is ten times closer to its star than Earth is to the sun. Moving outwards, the other planets are Kepler-11c, Kepler-11d, Kepler-11e, Kepler-11f, and the outermost planet, Kepler-11g, which is twice as close to its star than Earth is to the sun.
"The five inner planets are all closer to their star than any planet is to our sun and the sixth planet is still fairly close," said Lissauer.
If placed in our solar system, Kepler-11g would orbit between Mercury and Venus, and the other five planets would orbit between Mercury and our sun. The orbits of the five inner planets in the Kepler-11 planetary system are much closer together than any of the planets in our solar system. The inner five exoplanets have orbital periods between 10 and 47 days around the dwarf star, while Kepler-11g has a period of 118 days.
"By measuring the sizes and masses of the five inner planets, we have determined they are among the smallest confirmed exoplanets, or planets beyond our solar system," said Lissauer. "These planets are mixtures of rock and gases, possibly including water. The rocky material accounts for most of the planets' mass, while the gas takes up most of their volume."
According to Lissauer, Kepler-11 is a remarkable planetary system whose architecture and dynamics provide clues about its formation. The planets Kepler-11d, Kepler-11e and Kepler-11f have a significant amount of light gas, which Lissauer says indicates that at least these three planets formed early in the history of the planetary system, within a few million years.
A planetary system is born when a molecular cloud core collapses to form a star. At this time, disks of gas and dust in which planets form, called protoplanetary disks, surround the star. Protoplanetary disks can be seen around most stars that are less than a million years old, but few stars more than five million years old have them. This leads scientists to theorize that planets which contain significant amounts of gas form relatively quickly in order to obtain gases before the disk disperses.
The Kepler spacecraft will continue to return science data about the new Kepler-11 planetary system for the remainder of its mission. The more transits Kepler sees, the better scientists can estimate the sizes and masses of planets.
"These data will enable us to calculate more precise estimates of the planet sizes and masses, and could allow us to detect more planets orbiting the Kepler-11 star," said Lissauer. "Perhaps we could find a seventh planet in the system, either because of its transits or from the gravitational tugs it exerts on the six planets that we already see. We’re going to learn a fantastic amount about the diversity of planets out there, around stars within our galaxy."
A space observatory, Kepler looks for the data signatures of planets by measuring tiny decreases in the brightness of stars when planets cross in front of, or transit, them. The size of the planet can be derived from the change in the star's brightness. The temperature can be estimated from the characteristics of the star it orbits and the planet's orbital period.
The Kepler science team is using ground-based telescopes, as well as the Spitzer Space Telescope, to perform follow-up observations on planetary candidates and other objects of interest found by the spacecraft. The star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in spring through early fall. The data from these other observations help determine which of the candidates can be identified as planets.
Kepler will continue conducting science operations until at least November 2012, searching for planets as small as Earth, including those that orbit stars in the habitable zone, where liquid water could exist on the surface of the planet. Since transits of planets in the habitable zone of solar-like stars occur about once a year and require three transits for verification, it is predicted to take at least three years to locate and verify an Earth-size planet.
"Kepler can only see 1/400 of the sky," said William Borucki of NASA’s Ames Research Center, Moffett Field, Calif., and the mission’s science principal investigator. "Kepler can find only a small fraction of the planets around the stars it looks at because the orbits aren’t aligned properly. If you account for those two factors, our results indicate there must be millions of planets orbiting the stars that surround our sun."
Kepler is NASA's tenth Discovery mission. Ames is responsible for the ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory, Pasadena, Calif., managed the Kepler mission development. Ball Aerospace and Technologies Corp., Boulder, Colo., was responsible for developing the Kepler flight system, and along with the Laboratory for Atmospheric and Space Physics at the University of Colorado, is supporting mission operations. Ground observations necessary to confirm the discoveries were conducted at the Keck I in Hawaii; Hobby-Ebberly and Harlan J. Smith 2.7m in Texas; Hale and Shane in California; WIYN, MMT and Tillinghast in Arizona, and the Nordic Optical in the Canary Islands, Spain.