Originally posted by Tela<3sHaldir
Sonia, Fifth Year RavenclawMars is the fourth planet from the sun. The planet is one of Earth's "next-door neighbors" in space. Earth is the third planet from the sun, and Jupiter is the fifth. Like Earth, Jupiter, the sun, and the remainder of the solar system, Mars is about 4.6 billion years old.
Mars is named for the ancient Roman god of war. The Romans copied the Greeks in naming the planet for a war god; the Greeks called the planet Ares«AIR eez». The Romans and Greeks associated the planet with war because its color resembles the color of blood. Viewed from Earth, Mars is a bright reddish-orange. It owes its color to iron-rich minerals in its soil. This color is also similar to the color of rust, which is composed of iron and oxygen.
Ten points Sonia!
Originally posted by Trickster
Earth
Otherwise known as 'The third rock from the sun'. The infatuation muggles have with their own planet has led American comedians to make and star in a prgram named after the other name. 'The Third Rock From The Sun', which is about aliens landing on Earth and not knowing what to do.
3 points to Dale
Edward walked slowly up to the desk. He was unsure as to whether the Professor would accept his homework - after all, it was not on a proved planet of our solar system, but an unproved one...
PLANET X
Sometime between 1905 and 1908, Percival Lowell coined the term 'Planet X' when referring to any undiscovered planet beyond the orbit of Neptune. Based on William Herschel's discovery of Uranus
in 1781 and Johann Gottfried Galle's discovery of Neptune in 1846, Lowell conjectured that even more distant planets were awaiting discovery. Because Urbain Jean Joseph Leverrier had
successfully predicted Neptune's position by computing its gravitational pull on Uranus, Lowell turned to similar orbital calculations to predict the location of Planet X. In 1930 Clyde Tombaugh, while working at the Lowell Observatory near Flagstaff, Arizona, found Pluto at
celestial coordinates very near the location predicted by Lowell in 1914. At first some hailed this as another triumph for celestial mechanics, although Tombaugh himself was more circumspect.
However, as it became increasingly clear that Pluto was far too small to induce any observable orbital perturbations on either Uranus or Neptune, astronomers agreed that the 1930 coincidence of Pluto's position with Lowell's prediction was fortuitous.
Although several observers insisted that there were unexplained motions in the orbits of both Uranus and Neptune, James W. Christy's 1978 discovery of Pluto's satellite Charon at the US Naval
Observatory and the subsequent mass estimate for the Pluto/Charon system by the Naval Observatory's Robert S. Harrington, ruled out Pluto as the cause. Recently a team at the Jet Propulsion Laboratory (JPL), led by George W. Null, used images transmitted from the Hubble Space
Telescope to conclude that the individual masses of Pluto and Charon yielded mean densities of 2.1 and 1.4 g cm-3 respectively. Further, the mass of the system was only 1.46 x 1022 kg about 0.0024 the Earth's mass, more in the category of icy satellites than planets. But although Pluto was ruled out, some astronomers insisted that the unexplained orbital motions of Uranus and Neptune had not gone away. Planet X was still a possible source of gravitational perturbation.
A few investigators, including Dennis Rawlins, Conley Powell, P. Kenneth Seidelmann and Robert S. Harrington of the Naval Observatory, and Adrian Brunini, R.S. Gomes and S. Ferraz-Mello in South America, concluded that the evidence for PIanet X was suggestive, though far from conclusive. They agreed, some with more conviction than others, that unmodeled forces were acting on Uranus and Neptune, and most of them predicted the general location of Planet X if that were the cause, but they arrived at no consensus on either its location or its orbit. At JPL E. Myles Standish, Jr took exception to the conclusion that there were problems with the orbits of Uranus and Neptune.
He insisted that any failure to fit the astrometric data over the past two centuries could be explained by systematic errors in the observations, and, in some cases by faulty data reduction and interpretation.
The spinning spacecraft Pioneer 10 and 11 acted as sensitive probes of gravitational fields in the outer solar system as they receded from the solar system. Over an interval of 16 years, celestial mechanics investigators at JPL obtained good fits to the Pioneer orbital data
without invoking Planet X. On the other hand, in 1986, A.S. Guliev in Azerbaidzhan used orbits of long-period comets to derive the orbital elements of a single Planet X at a distance of 36.2 AU, and more recently the orbital planesówith inclination of about 30 arc degrees to the eclipticófor two Planets X at distances of 48.5-56.6 AU and 102-112 AU respectively. Unfortunately the Pioneer data could not rule out these planets, or for that matter other predictions based on the Uranus
and Neptune data. If the dynamical evidence points to at least one Planet X, why have optical surveys and the Infrared Astronomical Satellite (IRAS) failed to find it?
Tombaugh conducted the most extensive optical search from 1929 to 1943. He became convinced that besides Pluto no planets existed to limiting magnitude 16, at least within a wide band surrounding the ecliptic. Between 1977 and 1984 Charles T. Kowal conducted an optical survey with the 48-inch (122-cm) Schmidt telescope at Palomar Observatory. He surveyed a region extending 15 arc degrees north and south of the ecliptic, and included significantly fainter objects than Tombaugh. He found no Planet X. Yet even these dedicated observers were unable to observe all the sky. A large region near the
celestial south pole was inaccessible to Tombaugh. Other regions were at high ecliptic latitude where there was little motivation to survey the sky for planets. The possibility remains that Planet X was hiding in a region not photographed extensively, or that it was darker than magnitude 16 in one of Tombaugh's regions. The problem with using the 1983 IRAS data is that there are many objects on the sky that emulate a planetary infrared spectrum, at least at the four IRAS wavelength bands centered at 12, 25, 60 and 100 p.m.
An unambiguous detection of Planet X requires a determination of its proper motion. Unless Planet X were moving fast enough to be identified in two confirmed IRAS scans of thc same location (HCONs) separated by 1-2 weeks, it could easily go undetected. Otherwise, only 72% of the sky was covered with HCONs separated by 6 months or more. A
group at the University of Toronto (Hogg, Quinlan and Tremaine, 1991) concluded that it was unlikely that any Planet X large enough to exert significant perturbations on the known planets would have escaped detection by IRAS; but they admitted that a smaller planet could have been missed for a variety of reasons. Considering all the evidence, we must conclude that the possible existence of Planet X is still an open question.
~Edward Cooper, Hufflepuff
RACHEL RIDDLE SLYTHERIN
Mercury
Mercury is the closest planet to the Sun. It is a rocky planet, like Venus, Earth, and Mars. but no gas planet ,like Jupiter, Saturn, Uranus, and Neptune. The most conspicuous feature on the surface of mercury is Caloris Basin - a crater 1300 km wide. It is one one of the largest impact craters in the Solar System. The impact that created this crater was so strong that it created large rocky ridges even on the the other side of plane mercury.
It is named after Mercury, the Roman messenger of the gods.
Mercury is the eighth largest planet. Only Pluto is smaller in our solarsystem. Mercury is even smaller in diameter than Ganymede, the seventh and largest of Jupiter's known satellites, and Titan, the largest planet of saturn, but more massive.
When Mercury is closest to the Sun, it is 46 million km away from it. The farthest that Mercury can go from the Sun is 70 million km.
Mercury's path around the Sun is like a highly flattened circle. Also, its rotation is a bit erratic due to its proximity to the Sun. Hence, if one were on the surface of Mercury, one would see the Sun rise and expand gradually. When the Sun would reach the highest point in the sky, it would stop for some time, reverse direction and then resume its earlier path. And while this was happening, the other stars in the sky would be seen moving rapidly and steadily along the sky. On different points of Mercury's surface, the Sun's movement would be different!
Of all planets, Mercury has the most wildly varying temperature ranging from -180 degree to 426 degree Celsius.
Being so close to the Sun, the atmosphere of Mercury is constantly exposed to streams of particles erupting from the Sun. Hence, the elements in the atmosphere of Mercury are constantly blasted into space and more particles from the surface of mercury come up into its thin atmosphere.
The gravity of Mercury is about one-hundredth that of Earth ad has no moons.
some facts
Average distance from the Sun: 58 million km, i.e. about one third the distance between the Sun and Earth.
Length of a year: 88 days
Rotation period: 58.65 days
Average speed of travel in orbit: 48 km/s
Diameter: 4,878 km, about one third the size of earth.
Number of observed satellites: 0
Mass: 3.30 x 1023 kg, about 5% the mass of Earth
Orbit: 57,910,000 km (0.38) from Sun
actually i had something written about saturn, but when i wanted to post i saw, airangel, had the very same subject with probably the same source... 😉 so...mercury, nobody had that yet!
Originally posted by Rachel Riddle
RACHEL RIDDLE SLYTHERINMercury
Mercury is the closest planet to the Sun. It is a rocky planet, like Venus, Earth, and Mars. but no gas planet ,like Jupiter, Saturn, Uranus, and Neptune. The most conspicuous feature on the surface of mercury is Caloris Basin - a crater 1300 km wide. It is one one of the largest impact craters in the Solar System. The impact that created this crater was so strong that it created large rocky ridges even on the the other side of plane mercury.
It is named after Mercury, the Roman messenger of the gods.
Mercury is the eighth largest planet. Only Pluto is smaller in our solarsystem. Mercury is even smaller in diameter than Ganymede, the seventh and largest of Jupiter's known satellites, and Titan, the largest planet of saturn, but more massive.When Mercury is closest to the Sun, it is 46 million km away from it. The farthest that Mercury can go from the Sun is 70 million km.
Mercury's path around the Sun is like a highly flattened circle. Also, its rotation is a bit erratic due to its proximity to the Sun. Hence, if one were on the surface of Mercury, one would see the Sun rise and expand gradually. When the Sun would reach the highest point in the sky, it would stop for some time, reverse direction and then resume its earlier path. And while this was happening, the other stars in the sky would be seen moving rapidly and steadily along the sky. On different points of Mercury's surface, the Sun's movement would be different!
Of all planets, Mercury has the most wildly varying temperature ranging from -180 degree to 426 degree Celsius.
Being so close to the Sun, the atmosphere of Mercury is constantly exposed to streams of particles erupting from the Sun. Hence, the elements in the atmosphere of Mercury are constantly blasted into space and more particles from the surface of mercury come up into its thin atmosphere.
The gravity of Mercury is about one-hundredth that of Earth ad has no moons.
some facts
Average distance from the Sun: 58 million km, i.e. about one third the distance between the Sun and Earth.
Length of a year: 88 days
Rotation period: 58.65 days
Average speed of travel in orbit: 48 km/s
Diameter: 4,878 km, about one third the size of earth.
Number of observed satellites: 0
Mass: 3.30 x 1023 kg, about 5% the mass of Earth
Orbit: 57,910,000 km (0.38) from Sunactually i had something written about saturn, but when i wanted to post i saw, airangel, had the very same subject with probably the same source... 😉 so...mercury, nobody had that yet!
excellent! Ten points!