... Bad Astronomy . ... Bitesize Astronomy . ... Bad Astro Store . ... Slacker Astronomy . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... Life Under the Moon . ... Seeing Jupiter's Moons . ... Time Zones and the Spherical Earth . A Companion to the Earth? ... December 19, 1999) . ... Big Moon, Little Moon . ... How Big is the Moon? ... 14, 2000) . ... 2008 Phil Plait. ... Subscribe to the Bad Astronomy Newsletter! Talk about Bad Astronomy on the BA Bulletin Board! ...

... 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 . ...

... Near its first quarter phase, the bright Moon was intentionally overexposed but Saturn , Jupiter , Mars , and Mercury (and, of course, planet Earth's horizon) are all clearly visible in the deepening twilight. ... NASA Web Site Statements, Warnings, and Disclaimers . ... Publications with keywords: Moon - Jupiter - Mars - Earth - planet - Venus - Saturn - Mercury - sky . Publications with words: Moon - Jupiter - Mars - Earth - planet - Venus - Saturn - Mercury - sky . ... Earth at Twilight . ...

... August 13, 1998 . The Moons Of Earth . Credit: STS-91 Crew , NASA . ... Thick storm clouds are visible in the lovely blue planet's nurturing atmosphere and its largest artificial moon, the spindly Russian Mir Space Station , can be seen above the planet's limb. The bright spot to the right of Mir is Earth's very large natural satellite , The Moon. The Mir orbits planet Earth once every 90 minutes about 200 miles above the planet's surface or about 4,000 miles from Earth's center. ...

... Armagh Planetarium . ... Our Galaxy . ... Universe . ... For those of you that are still bearing the psychological scars from PlutoтАЩs demotion from planet to dwarf planet a decade ago, here is news that may add salt to [ ] . ... In 2015 Armagh PlanetariumтАЩs website (including Astronotes) received well over 2.6 million page views (and over 75 million web hits*) from all over the world. ... Here you will find the latest news and views from the fascinating worlds of astronomy and space exploration....

For circular orbits around Earth, we found . ... The distance of a satellite from the center of Earth in meters is an inconveniently big number, even before we raise it to the 3rd power. ... SQRT (25 638 838) = 5063.5 From this . ... T= 5063.5 seconds SQRT(r') 3 = 5063 sec r'SQRT=(r') . This is the practical form of Kepler's 3rd law for Earth satellites. ... International communication satellites are in the equatorial plane of the Earth and have orbits with a 24-hour period. ...

... Not so long ago, Space Scoop explained that right this moment you re hurtling through space at hundreds of thousands of kilometres per hour! ... We call the time it takes Earth to complete one full rotation a day . ... But the length of one rotation and one orbit can be different on other planets. For example, one orbit (or year ) on Mercury takes just 87 Earth days. ... The length of day is also different on other planets. For example, one day on Jupiter lasts just 10 Earth hours. ...

... Historical Data . Orbital Data . Physical Data . ... Sun . ... Jupiter . ... Saturn . ... William Herschel . ... William Cranch Bond . ... William Henry Pickering . Uranus . ... 1986 . Voyager 2 . ... William Lassell . ... J. Christy Key: Name Name of the planet or satellite. Orbits Sun or planet about which it orbits. ...

... Comments, Opinions Publications Dnepr Program . Dnepr launch record 17 August 2011. Cluster Launch of Dnepr LV 22 August 2013 KOMPSAT-5 Launch 21 November 2013. Dnepr Cluster Mission 2013 19 June 2014. ... ISC Kosmotras announces signing of a launch contract with T B?TAK Space Technologies Research Institute (T B?TAK UZAY) for injection of RASAT spacecraft - the first Earth observation satellite designed and manufactured in Turkey by Dnepr LV in 2010. ... Dnepr LV Performance . ...

... Kepler's 3rd Law . 21a.Applying 3rd Law . 21b. Fly to Mars! (1) . 21c. Fly to Mars! (2) . ... For circular orbits around Earth, we found . ... The distance of a satellite from the center of Earth in meters is an inconveniently big number, even before we raise it to the 3rd power. ... The ratio r' = (r / R E ) is the orbital distance measured in units of the Earth's radius. ... 25 638 838) = 5063.5 From this . ... This is the practical form of Kepler's 3rd law for Earth satellites. ...

... ATNF Home . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Murchison Radio-astronomy Observatory . ... Parkes radio telescope . ... Parkes | ... Cosmic engine for senior students . ... The Sun . The Sun is vital for life on Earth. ... The Sun is a typical star, emitting electromagnetic radiation and particles that influence the Earth . ... In the meantime you can view material on the Sun and its influence on Earth written for the first version of the new syllabus here . ...

... JSC Oral History . NASA History . ... NASA Oral History Project: Earth System Science at 20 . This NASA Oral History Project features recollections from those who significantly contributed to the launch and evolution of Earth System Science. These interviews were gathered as part of the 20th anniversary of the Earth System Science Program. ... NASA Headquarters, Washington D.C. Program Manager , Stratospheric Theory and Data Analysis, Earth Science and Applications Division . ...

... The Magazine . ... Observing . ... Magazine . ... Star Atlas . ... An artificial comet holds secrets to Earths life . ... stars . ... Observing Podcasts . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . Springtime observing for small telescopes . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ... Click here to receive a FREE e-Guide exclusively from Astronomy magazine. ... Astronomy Magazine . ...

The Twentieth RF Ionospheric Interactions 2014 Workshop 27-30 April 2014, Arecibo Observatory, Arecibo, Puerto Rico. Program Chairman: Michael Sulzer, Arecibo Observatory . ... 2014 Program . ... Instructions for Special Issue Journal . ... Special Issue on Ionospheric Modification in the Earth, Moon, Planets Journal application instructions . ... Special Issue Journal please click here . Sponsored by National Science Foundation in cooperation with The Arecibo Observatory and SRI International ...

T he Siding Spring Survey (SSS) is a Near-Earth Object search program that utilises the 0.5-m Uppsala Schmidt Telescope at Siding Spring Observatory, N.S.W., Australia. ... The mission of the Siding Spring Survey is to contribute to the inventory of near-earth objects (NEOs), or more specifically, the potentially hazardous asteroids (PHAs) and comets (PHOs) that may pose a threat of impact and thus harm to civilization. ... Based on the CSS Mission page . ... Siding Spring Survey Main Page . ...

... 13th European VLBI Network Symposium . and Users Meeting . on September 20-23, 2016. ... 13th European VLBI Network Symposium and Users Meeting on September 20-23, 2016. ... Year book "Ephemerides of Minor Planets for 2016" on-line . ...

... 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? ...

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... Space Telescope Science Institute and Johns Hopkins University . ... University of Arizona . ... Johns Hopkins University, Dept. of Chemistry . ... Space Telescope Science Institute . ... Johns Hopkins University, Dept. of Biology . ... Johns Hopkins University, Dept. of Earth and Planetary Sciences . ... Space Telescope Science Institute and Johns Hopkins University Center for Astrophysical Sciences . ... Site contents ї Space Telescope Science Institute and Johns Hopkins University . ...

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 . ...