... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Risks Comparable to NEOs . ... The Increasing Rate of Discovery of Asteroids . ... Comet and Asteroid Collision Probabilities . ... Extreme albedo comets and the impact hazard (PDF Format) . ... Asteroid Impact Animations . ... Workshop on Scientific Requirements for Mitigation of Hazardous Comets and Asteroids - 2002 . ... The Spaceguard Survey Report, 1992 (PDF) . Tsunami from Asteroid/Comet Impacts . ...

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... GRACE Maps the Gravity of Earth . ... To help better understand the Earth's surface , slight distance changes between a pair of identically orbiting satellites named GRACE have been used to create the best ever map of Earth's gravitational field . ... Maps like this also help calibrate changes in the Earth's surface including variable ocean currents and the melting of glaciers . ... Publications with keywords: GRACE - Earth . ... Hurricane Paths on Planet Earth . ... All the Water on Planet Earth . ...

... Planets . ... The planets were found using the HARPS instrument on the 3.6m telescope at ESOтАЩs La Silla Observatory. ... A planet in orbit around a star causes the star to regularly move towards and away from observers on Earth. ... One newly discovered planet, HD 85512 b, is best hope found so far for a habitable exoplanet. ... The HARPS team so far have found that about 40% of stars similar to own Sun have at least one planet smaller than Saturn (which is 95 times more massive than Earth). ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2007 March 25 . Welcome to Planet Earth . Credit: Apollo 17 Crew , NASA . Explanation: Welcome to Planet Earth , the third planet from a star named the Sun . The Earth is shaped like a sphere and composed mostly of rock . ... The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen . ... About APOD | ...

... The remote planet Pluto and its moon Charon orbit the Sun at a mean distance of almost 6,000 million kilometres, or nearly fourty times farther out than the Earth. During a recent investigation by an international group of astronomers [1], the best picture ever of Pluto and Charon [2] was secured with the European Space Agency's Faint Object Camera at the Hubble Space Telescope (HST). ... The new HST image was taken when Charon was near its maximum elongation from Pluto (0.9 arcseconds). ...

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). ...

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The Earth. ... The middle raiding of the Earth is 6371,032 km, the pole 6356,777 km equatorial - 6378,160 km. The Earth surface area is 510,2 mln km^2, 70,8% of which is the World ocean. ... According to the modern cosmogonical views the Earth was formed 4,6 - 4,7 billions years ago from the protoplanet cloud captured by the Sun. ... The Earth is conditionally divided into 3 parts: a bark a cloak and a core (in the centre). The external layer - the bark is 35 km thick. ... Above the Earth. ...

... The forcing by the solar wind is able to modify this field, creating a cavity called the magnetosphere. ... The outer boundary of the magnetosphere is called the magnetopause . In front of the dayside magnetopause another boundary called the bow shock is formed because the solar wind is supersonic. ... Solar wind and the magnetic field it carries along ( IMF ) modify the form of the magnetosphere, by pushing it in in the dayside and creating a long magnetotail in the nightside. ...

... Bad Astronomy . Misconceptions . ... Bad Astronomy : "That's as remote as the dark side of the Moon!" ... As the tired, hackneyed refrains went on, one in particular caught my ear: " Fly me away to the bright side of the moon, and meet me on the other side." ... As the Moon orbits the Earth, different parts of it get illuminated by the Sun. ... Bad Addendum : At the end of the album "Dark Side of the Moon" by Pink Floyd, there is a voiceover that actually says "There is no dark side of the moon. ...

... Detection of Earth-like Planets with the COROT Space Mission . ... Staff Directory . ... Missions . ... Research . ... The french space mission COROT (COnvection & CORotation) originally devoted to asteroseismology, is also particularly well adapted for the detection of low-mass objects, using the method of stellar occultations. Due to its high photometric accuracy, a few tens of detections can be expected over the mission life time, assuming that about 50% of stars possess an Earth-like planet. ...

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 . ...

Class 1 Introduction, Background History of Modern Astronomy The Night Sky, Eclipses and the Seasons Kepler's Laws Newtonian Gravity General Relativity Matter and Light Telescopes Class 2 Solar System Characteristics Formation Exosolar Planets Class 3 Stars The Sun Stellar Evolution of Low and High Mass Stars Deaths of Stars Exotic Stars Class 4 Galaxies Galaxy Classification Formation of Galaxies Galactic Evolution ... So far, one planet has been studied by this method. ...

... Peter J.K. "Jeff" Wisoff (Ph.D) . NASA Astronaut (former) . ... A veteran of four space flights, STS-57 in 1993, STS-68 in 1994, STS-81 in 1997 and STS-92 in 2000, Dr. Wisoff has logged a total of 42 days, 56 hours, 1 minute and 48 seconds in space, including , 19 hours and 53 minutes of EVA time in three space walks. ... Following 183 orbits of the Earth in 269 hours and 46 minutes, the eleven-day mission ended with Space Shuttle Endeavour landing at Edwards Air Force Base, California. ...

... Asteroid . ... In case you didn't hear about it, which you probably didn't: On Jan. 7, an asteroid 1,000 feet across -- nearly three times the current diameter of Marlon Brando -- barely missed the Earth, which is most likely your planet of residence. ... What if this asteroid had hit the Earth? ... As it happens, the American Astronomical Society was holding a conference in Washington AT THE VERY SAME TIME as the asteroid nearly hit the Earth. ...

Internet Sites | Children's Books | ... Tilt of the Earth - Beautiful site explaning the tilt of the Earth. ... Nine Planets: Planet Data - It might be fun to discover how tilted the other planets are in the Solar System! ... Bill Nye the Science Guy-Episode: Climates - Learn a bit about the Earth's climates and make a model of a weather system. Weather Links for Teachers and Parents - Nick the Weather Dude's list of useful links about weather. ... Philomel Books, 1995. ... Tilt-A-World | ...

This is an illustration of the hypothetical appearance of the exoplanet GJ 1214b, which is known as a "super-Earth" type planet because it is slightly more than six Earth masses. Spectroscopic observations with NASA's Hubble Space Telescope provide evidence of high clouds blanketing the planet. These clouds hide any information about the composition and behavior of the world's lower atmosphere and surface. The composition of the clouds is unknown. ... NASA/ESA/G. Bacon (STScI) ...

... 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. ...

Microsymposium 38, MS015, 2003 (letter format) MARS: MOVEMENT OF GEOGRAPHICAL POLES AND DEFORMATION OF ITS SURFACE. ... The global analysis of the Earth linear structure elements has allowed to define the position of geographical poles in the different geochronological periods [3, 4]. ... It is the curves that unite sequences of geographical poles - poles of symmetry of faults in the global stress field fixed by faults on a surface of the mantle during its rotation around of the core. ...