With this knowledge of orbits, we are ready to plan a trip to Mars. ... The spacecraft will already have the 107,000 kilometers per hour (66,500 miles per hour) speed of Earth, whereas Mars moves at only 86,900 kilometers per hour (53,900 miles per hour). ... A speed of about 42,000 kilometers per hour will be enough to escape the Earth's gravity and, when added to the Earth's orbital speed around the Sun, put the spacecraft on a Hohmann transfer orbit to the Red Planet. ... 1,570,000 . ... Earth . ...

Circling around magnetic field lines. ... The ring current . Because positive ions and negative electrons drift in opposite directions (see drawing), that motion will create an electric current that circulates clockwise around the Earth when viewed from north. ... How then can the radiation belt and ring current arise? ... Electric fields are able to push trapped particles earthward, and unlike the purely magnetic motion described earlier, an electric field can also energize them. ...

... Aurora from Space . ... Magnetic Storms . ... The "ring of fire" seen by satellite cameras around the polar caps (picture below) is probably created by electrons leaking from the tail's plasma sheet, whose magnetic field lines form a somewhat imperfect trap. ... One possible explanation involves the close association between auroral arcs and electric currents which flow along field lines between the ionosphere and distant space ( Birkeland currents ). ... Why no aurora at the magnetic poles? ...

... Bad Astronomy . ... Mad Science . ... The Nine Planets . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... Area of science: Astronomy . ... Yes, you can use a black hole to slingshot a rocket. The slingshot effect we use to accelerate space probes works by approaching a planet ``from behind''; that is, it approaches the planet in the same direction the planet is moving around the Sun. ... 2008 Phil Plait. ... Subscribe to the Bad Astronomy Newsletter! ...

... 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. ...

... Star Atlas . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... galaxies . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Dave's Universe . ... Everything around us is spinning: particles, planets, stars, galaxies. ... Planets rotate, as do stars and galaxies. ... Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

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... Planets . ... Earth Satellites . ... The newly discovered ?mega-Earth? ... Its sibling, the lava world Kepler-10b, is in the background (the two planets? proximity is grossly exaggerated) .€а Kepler-10c has a diameter of about 29 000 km, 2.3 times as large as Earth, and weighs 17 times as much. ... The first mega-earth to be discovered is Kepler-10c which orbits a star lying about 560 light years from the Sun in the constellation Draco. ... Astronomers Find a New Type of Planet: The ?Mega-Earth? ...

God Science Forum Message . ... God and Science | ... Pluto Is Not A Planet, But A Moon Of Neptune. ... Pluto Is Not a Planet, but a Moon of Neptune . 60 years ago, at 1947, the late Mohammed Ali Hassan Al-Hilly, said in his book: (The Universe and the Quran), that Pluto is not a planet but a moon of Neptune. ... He said: " Astronomers, however, think that Pluto is a planet, but I say it is merely a moon of Neptune, and actually it is not a planet. ... www.astronomy.net . About Astronomy Net | ...

My research efforts have focused on three areas which are: . More than 200 extrasolar planets have been discovered around relatively nearby stars, primarily through the Doppler line shifts owing to the reflex motions of their host stars, and more recently through transits of some planets across the face of the host stars. ... Gravitational microlensing provides a novel technique to look for planets around lens stars, and this is the only technique currently capable of detecting Earth-mass planets. ...

Astronomy Picture of the Day . ... 31.01.1996 . ... Credit: E. Williams, G. Marcy, and L.-A. McConnaughey, ( UC Berkeley ), ( SFSU ) Explanation: Do many Sun -like stars have planets? ... The above plot summarizes the four known cases of normal stars having planets. ... The later two cases were discovered by astronomers led by Geoff Marcy and Paul Butler as part of a greater project inspecting 120 stars for orbiting planets. ... January 1996 . ... 1995 1996 . ... Publications with keywords: planets . ...

... The study of extra solar planets will be one of the most important areas of research in astronomy in this century. ... The first planets outside the solar system were found in 1992 around the millisecond pulsar PSR B1257+12 by Alex Wolszczan at the Arecibo Observatory . ... Three space missions based on this principle (MOST, COROT and Kepler ) have already been launched or approved, and have the last one at least has the potential to find Earth-sized planets. ... SIM ( NASA ) is one of such missions...

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 . ...

... January 31, 1996 . Planets Around Sun-Like Stars . ... The above plot summarizes the four known cases of normal stars having planets. ... The later two cases were discovered by astronomers led by Geoff Marcy and Paul Butler as part of a greater project inspecting 120 stars for orbiting planets. Interestingly enough, the planets around the later two stars have temperatures in the right range to allow liquid water - and hence may have conditions ripe for the development of life . ...

Jupiter is the largest of the nine planets, more than 10 times the diameter of Earth and more than 300 times its mass. ... The mean density of Earth is 5.245 times that of water. The pull of gravity on Jupiter at the top of the clouds at the equator is 2.4 times as great as gravity's pull at the surface of Earth at the equator. ... It is tipped about 11њ to Jupiter's axis of rotation, similar to Earth's, but it is also offset from the center of Jupiter by about 10,000 kilometers (6,200 miles). ...

Subject of Astronomy. ... Celestial Sphere. ... Spherical Frames of Reference: Horisontal and Equatorial Coordinates, Ecliptical System. ... Transformation of Celestial Coordinates. ... Change of Object Coordinates as a Result of Diurnal Rotation of Celestial Sphere. Phenomenons, Which Lead to Celestial Coordinates Change. ... Motion of Equator, Ecliptic, and Their Poles. ... Diurnal Solar Motion on Different Latitudes. ... Time Equation. ... Apparent Motions and Configuration of Planets. ...

... ESO, the European Southern Observatory . ... Visits to ESO Sites . ... Survey Telescopes . ... Star Clusters . ... Stars@ESO . ... Educational Material . ... ESO 3.6-metre telescope . ... MPG/ESO 2.2-metre telescope . ... TRAnsiting Planets and PlanetesImals Small Telescope . ... Particles in the dust ring are kept inside the ring by gravitational interactions with planets. The faster-moving inner planet transfers energy to dust particles, moving them outward, deeper into the ring. ... Fomalhaut . ...

The radiation belts around the planets are the interrnal regions of planets' magnetospheres where the own magnetic field of a planet keeps the charged particles (protons and electrons) having the great kinetic energy. ... They usually distinguish the Earth's internal and external radiation belts. the internal radiation belt of the Earth has the maximum particles density (mainly protones) over the equator in the height of 22 thousand km. ... Jupiter and Saturn have the powerful radiation belts. ...

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... Many massive planets contrary to Jupiter have large eccentricities of orbits. ... Another problem is to study the conditions and boundaries of stable, regular motions of small mass planet in systems having `Jupiter' with large orbital eccentricity as well as properties of regular, stable, and irregular, chaotic motions. ... The regular eccentricity evolution described above demonstrates that stable quasi--circular orbits of small planet are unusual. ...