... 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 . ...

Astronomy Picture of the Day . ... Advised by Alexandrian astronomer Sosigenes , Roman dictator Julius Caesar , pictured above in a self-decreed minted coin, created a calender system in 46 BC that contained one leap day every four years. ... This "Julian" calender system was used until the year 1582 when Pope Gregory XIII added that leap days should not occur in years ending in "00" except if divisible by 400, providing a further fine tuning. ... Publications with words: Julius Caesar - Leap Days . ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2000 February 29 . Julius Caesar and Leap Days . ... In 46 BC, Julius Caesar , pictured above in a self-decreed minted coin, created a calendar system that added one leap day every four years. ... That makes today the first leap day for a centurial year since year 1600 and the second such leap day of the Gregorian Calendar. ... About APOD | ...

... 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! ...

... 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? ...

... Main . ... April 2016 . ... December 2015 . November 2015 . October 2015 . September 2015 . August 2015 . July 2015 . June 2015 . May 2015 . April 2015 . March 2015 . February 2015 . January 2015 . December 2014 . November 2014 . October 2014 . September 2014 . August 2014 . July 2014 . June 2014 . May 2014 . April 2014 . March 2014 . ... December 2013 . ... April 2013 . ... December 2012 . ... April 2012 . ...

... Transits do not happen every time Mercury passes between the Earth and Sun because their orbits are not in exactly the same plane, as we will see in this activity. ... Transits of Mercury occur at only two times during the year (but not every year). ... Can you tell which two months the orbits of Earth and Mercury are in line with the Sun? _____________________ and ________________________ [pic] ----------------------- ( Transits of Mercury occur at only two times during the year (but not every year...

... For a timeline of the exploration of the magnetic environment of the Earth, Sun and Planets, see here . ... Galileo Galilei (1564-1642) builds the first astronomical telescope and observes for the first time craters on the Moon, satellites around Jupiter, and the way Venus goes through phases like the Moon (crescent, etc.) ... 17 December--First successful flight by the Wright brothers at Kitty Hawk, North Carolina. ... 16 March--Goddard launches his first liquid-fuel rocket. ...

... 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. ...

... The Round Earth . ... Aristarchus around 270 BC derived the Moon's distance from the duration of a lunar eclipse (Hipparchus later found an independent method). ... Let R be the radius of that circle and T the time it takes the Moon to go around once, about one month. ... Viewed from Earth, a "new Moon" (occuring between the time a thin crescent is last seen before sunrise and the time one is seen shortly after sunset) happens when the Moon in its apparent motion around the sky overtakes the Sun. ...

... 2000 July 1 . Ultraviolet Earth from the Moon . ... Far UV Camera , Apollo 16 , NASA . Explanation: Here's a switch: the above picture is of the Earth taken from a lunar observatory! This false color picture shows how the Earth glows in ultraviolet (UV) light. UV light is so blue humans can't see it. ... The part of the Earth facing the Sun reflects much UV light, but perhaps more interesting is the side facing away from the Sun. ... Tomorrow's picture: July GRB . ... About APOD | ...

Lectures . ... Home Lectures Lecture Series 2010-2011 Lecture Series 2010-2011 ? Greening the Earth Using Space Resources? by Greg Matloff . ... Lecture Series 2010-2011 . ... Beyond New York City . ... Observing Resources for Amateur Astronomers - Part 1: Beginning Observers . ... A History of the First Forty Years of the Amateur Astronomers Association . ... Amateur Astronomers Medal . ... 2016 Amateur Astronomers Association of New York Designed by Press Customizr Powered by . ...

... 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 . ...

NATIONAL ASTRONOMY AND IONOSPHERE CENTER . ... Astronomy . ... During the last 48 hours, solar activity of moderate-to-large intensity was registered with two class X events (one was a maximum X5), and also events of class M and C. Two Coronal Mass Ejections (CME) occurred in March 4 and 5 reached the Earth this (Thursday) morning, March 8 at 11 UT (7 AST), and large variations in the Earth's magnetic field and energetic particle precipitation into the poles are expected. ... Arecibo Observatory €а . ...

... The JSC History Portal offers access to the JSC History Collection , other JSC history materials, and hundreds of NASA history web pages. ... Johnson Space Center was established in 1961, and from the early Gemini, Apollo and Skylab projects to today's Space Shuttle and International Space Station Programs, the Center continues to lead NASA's efforts in human space exploration. ... JSC Space Shuttle Program . ... This link provides access to the NASA JSC History Portal Document Search page. ...

... Articles | ... Forums . ... 230 deg . 49 deg . ... 130 deg . ... More Info . ... 210 deg . ... 168 deg . ... 249 deg . ... 195 deg . ... 271 deg . ... 110 deg . ... 338 deg . ... July 15 . 247 deg . ... 224 deg . ... 340 deg . ... July Phoenicids (PHE) . ... August 10 . 341 deg . ... 339 deg . ... 307 deg . ... 334 deg . ... 335 deg . ... 286 deg . ... 327 deg . ... 262 deg . ... 102 deg . ... 153 deg . ... 117 deg . ... December 2 . ... 123 deg . ... 100 deg . ... www.astronomy.net . ...

... The Irkutsk IS radar has the opportinuty to measure several ionospheric plasma parameters such as electron density N e , electron and ion temperatures T e , T i , and drift plasma velocity along the sounding direction. ... To the 1999-2001 data we have added the E-layer ionosphere model to electron concentration profile, which has been constructed by integral concentration from the ionosphere beginning from 160 km obtained from experiment. ... Capabilities and samples | ...

... Supernova showered Earth with radioactive debris . ... If the Sun suddenly disappeared, it would take about eight minutes for Earth to become dark (due to the speed of light). How long would it take to feel the absence of the Sunт??s gravity? ... According to Albert Einsteinт??s general theory of relativity, if the Sun were to suddenly disappear, Earth would feel the absence of the Sunт??s gravity in the same time it would take for it to т??feelт?? the absence of the Sunт??s light. ...

... Р?С?С?С?Р?Р?Р?Р?РеС?Р?С?Р?РеР? ... Launched on February 17, 1996, the Near Earth Asteroid Rendezvous (NEAR) mission is to be the first of NASA's Discovery missions, a series of small-scale spacecraft designed to proceed from development to flight in under three years for a cost of less than $150 million. ... The ultimate goal of the mission is to rendezvous with and achieve orbit around the near Earth asteroid 433 Eros in February, 1999, and study the asteroid for approximately one year. ...

... Pre-university education . ... Samara region . ... A small spacecraft Aist-2D , developed by the scientists of Samara State Aerospace University (SSAU) and the experts of the Rocket and Space Centre Progress will see from outer space what is hidden under the thick top of trees and below the Earth's surface. The radar equipment was installed on Aist-2D , which was delivered to the space launcher complex Vostochniy on January 22. ... Tomography of the Earth's ionosphere will also be carried out. ...