Astropark Home . Solar System . ... Planets . ... A year is the time that it takes for a planet to go around the Sun. ... As a result, an Earth year is very different in length from a year on Saturn or any other planet. ... But on this scale, most of the planets are too small to see, so their size has been increased by 200 times. ... The Astropark's red gravel represents the asteroid belt – thousands of smaller bodies which range in size from pebbles up to small planets hundreds of miles across. ...

... For example, take this new picture of an object in space called a planetary nubula it actually has nothing at all to do with planets! A planetary nebula is an object that forms when a star like the Sun (our nearest star) runs out of fuel. ... The star also loses its outer shells of gas, which float off into space. ... Cool Fact: Some planetary nebulae (when you talk about more than one nebula, you call them nebulae ) have two symmetrical clouds of gas on either side of the central star. ...

In ancient times the solar system was thought to be the whole Universe, so the study of planetary motions was cosmology. ... The planets other than the Moon and Sun generally move West to East through the stars, but occasionally stop and move in the opposite direction ( retrograde motion). In order to explain the retrograde motion of the planets, the geocentric model of the Solar System shown above puts the planets on small circles called epicycles . ...

Astronotes Armagh Planetarium's Stellar Blog! ... Solar System . ... Moon . ... Comets and Asteroids . ... What changed our view of Chariklo is the discovery of a ring system around it, the first such feature found around a Solar System body smaller than a gas giant planet. ... Almost certainly the rings were born when a collision with a smaller asteroid blasted millions of tonnes of debris off CharikloтАЩs surface. ... A ring system detected around the Centaur (10199) Chariklo (Braga-Rigas et al.) ...

The apparent path of the Sun across the sky. ... The path of the Sun across the celestial sphere is very close to that of the planets and the moon. ... In one year, as the Earth completes a full circuit around the Sun (drawing above), the Earth-Sun line and its continuation past Earth sweep the entire plane. ... Since the Sun and Earth are in the plane of the ecliptic, the line is automatically in that plane too; if the moon is also on the same line, it must be in the plane of the ecliptic as well. ...

... Planets and Brown Dwarfs . ... Mission Definition . Ask anyone on the street to give an example of a planet, and they'll consider you a bit dim. ... Finally, if you ask "What is the exact scientific definition of 'planet'?", it turns out that nobody can answer it, because there really isn't one. ... The word itself means "wanderer" in Greek, and other cultures generally have words for "planet" with a similar meaning. So why isn't that good enough for us today? ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2011 August 9 . Juno Rockets Toward Jupiter . Video Credit: NASA . ... When the robotic Jun o spacecraft reaches Jupiter in 2016, it will spend just over a year circling the Solar System's largest planet , using its unique cadre of instruments to probe the planet, sending back clues of its structure and origin. ... About APOD | ...

The Discovery of the Galilean Satellites . ... Probably the most significent contribution that Galileo Galilei made to science was the discovery of the four satellites around Jupiter that are now named in his honor. Galileo first observed the moons of Jupiter on January 7, 1610 through a homemade telescope. He originally thought he saw three stars near Jupiter, strung out in a line through the planet. ... Galileo's Observations of Jupiter's Moons . ... Jupiter . ...

... More on 51 Peg: . The discovery of a Jupiter--mass planet in orbit around the solar--type star 51Peg has been reported by Michel Mayor and Didier Queloz (Geneva Observatory) on October 6th at the 9th Cambridge workshop on "cool stars, stellar systems, and the sun" held at Florence (Italy). ... Recall that the measurements of radial velocity only yield v sin i which in turn gives us M sin i. For most values of i, sin i will be greater than 0.5 and this gives a mass estimate of 0.5 Jupiter masses. ...

... 1998 Leonid Fireball . ... Mercury And The Moon . ... Mercury is the closest planet to the Sun and never moves far from our parent star in Earth's sky. ... Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart, creating tides of matter, sheets of shocked gas, lanes of dark dust, bursts of star formation, and streams of cast-away stars. ... This Hubble Space Telescope picture of the center of the nearby elliptical galaxy NGC 4261 tells one dramatic tale. ... 1997 1998 . ...

... The planets differ greatly in size and properties, and their fields differ too. ... In 1959, after the Earth's radiation belt had been discovered, Frank Drake observed Jupiter and concluded from the relative intensities in a range of wavelengths that the signal was probably emitted by electrons trapped in a strong magnetic field. Then in 1973 the space probe Pioneer 10 passed by Jupiter and found there, sure enough, an enormous planetary magnetic field and a very intense radiation belt. ...

... Bad Astronomy . Misconceptions . ... Bad Astronomy : The Moon only shows one face to us because it is not rotating. Better astronomy : The Moon only shows one face because it is rotating, once every time it revolves around the Earth. ... Place the Moon model on the table about 30 centimeters (one foot) away with the X facing the Earth model. ... You'll see that to keep the X facing the Earth model, you have to rotate the Moon model as it goes around the Earth model . ... 2008 Phil Plait. ...

HUBBLE SPACE TELESCOPE DAILY REPORT #931 PERIOD COVERED: 0800 EST Daily Status Report as of 198/1200Z. 1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED: 1.1 Completed FGS 5056 (High Speed Astrometry - A Search for Planetary Companions to Low Mass) The Fine Guidance Sensors were used to make astrometric observations of Bernard's star to look for the presence of a Jupiter sized planet in orbit around the target star from the position perturbations caused by the planet. ... Both observations were received. ...

Determination of mass of Jupiter and that of some minor planets from observations of minor planets moving in 2:1 commensurability with Jupiter Olga M. Ko chetova and Yulija A. Chernetenko Institute of Applied Astronomy, St. Petersburg, Russia September 19, 2000 Keywords: Jupiter 's mass , asteroid's masses , observations of minor planets Great numb er of observations of minor ... Hoffmann (1989) p ointed out the fruitfull of that approach. ... Table II. ...

... With the Moon's terminator moving almost 10 mph (16 km/h) across its equator, how long would it take for an observer using binoculars to notice a change in lunar features? ... The lunar terminator, the sunset/sunrise line that sweeps across the Moon s surface as the Moon orbits Earth, travels at a rate of 9.6 mph (15.4 km/h) along our satellite s equator. ... Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

... Up: Data Analysis and Processing Techniques . ... Also, a method for quality control of CCD observations is suggested. ... Everyone who observes a celestial object using a CCD detects moving celestial objects as a ``by product''. ... We hope that our investigations may be useful for near-Earth space control and also for searches of the moving celestial objects through analysis of old and new CCD frames obtained at any amateur or professional astronomical observatory. ...

Giant Jupiter. Jupiter . ... Jupiter has no solid surface that is why speaking about its dimensious point the radius of the upper border line of the clouds, where the presseru is about 10 KPa; radius of Jupiter on the equator is 71400 km. ... The Jupiter satellites. ... Nowadays 16 satellites of the Jupiter are known: Adrastea, Mitis, Amaltea , Phina,then 4 Galilei satellites: Io , Europe , Hanimed , Callisto , Leda, Aimalia, Zicitea, Elara, Ananke, Carme, Pasipe and Sinope. ... Jupiter's ring. ...

... Although each chapter has its own set of links, this page offers the complete collection, with additional sites for those interested in general astronomy, amateur astronomy, professional astronomical institutions, and astronomy news. General Astronomy Links . Sky Telescope 's vast collection of astronomy sites . ... Space Telescope Science Institute . ... A page dedicated to sundial links across the Web . ... A page dedicated to sundial links . ... Overview of the moon . About the moon . ...

... SATELLITE: An object that revolves around a planet. ... SIDEREAL DAY: The length of a planet's rotation period relative to the stars. SOLAR SYSTEM: The sun and all the objects that are held in its gravitational field and move around it. ... SUPERIOR CONJUNCTION: The position of a planet when it is on the opposite side of the Sun from Earth (thus making in invisible). ... TRANSIT: The movement of an object between the Earth and the Sun and showing on the surface of the sun as a black dot. ...

Next: The Scenario Machine: Operational Up: Evolution of Magnetic Rotators Previous: Ejector-propeller hysteresis . ... The length of this segment is determined by the eccentricity. ... In this case no hysteresis occurs and transitions E -- P and the reverse take place in symmetrical points of the orbit. ... Here EP means a mixed state of the rotator at which it is in the ejector state during one part of the orbit, and in the propeller state during the rest of the orbital cycle. ...