M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

... Tonight's Sky . ... The Magazine . ... Star Atlas . ... An artificial comet holds secrets to Earths life . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... The planet has extreme temperature swings and perhaps active lava flows. ... A digital supplement to Astronomy magazine. ... Join TravelQuest International with Astronomy and Discover magazines on one of three great tour options surrounding this celestial spectacle . ... Astronomy Magazine . ...

... 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 . ...

In 1950 Jan Oort noticed that . no comet has been observed with an orbit that indicates that it came from interstellar space, . ... From this he proposed that comets reside in a vast cloud at the outer reaches of the solar system. ... Unfortunately, since the individual comets are so small and at such large distances, we have no direct evidence about the Oort Cloud. ... Its orbit is intermediate between the Kuiper Belt and what was previously thought to be the inner part of the Oort Cloud. ...

. 66%) of the extreme AGB stars are variable and only smaller fractions of carbon-rich (6.1%) and oxygen-rich (2.0%) stars are detected as variable sources. We also detect a population of variable young stellar object candidates. [ ADS ] . ADS Citation Query . # citations = 41 . citations vs. year [year,citations] . [2009,6][2010,6][2011,8][2012,4][2013,4][2014,4][2015,9] . Copyright 2012 Karl D. Gordon All Rights Reserved

... VB 10: A Large Planet Orbiting a Small Star . ... Credit: JPL-Caltech , NASA Explanation: Can a planet be as large as the star that it orbits? Recent observations have discovered that nearby Van Biesbroeck's star might have just such a large planet. ... Since faint M-type stars like VB 10 are so common, planetary system s surrounding them, including planets larger than their parent star, might be more common than planetary systems like our own Solar System . ... NASA Official: Jay Norris. ...

Comets necessarily obey the same physical laws as every other object. ... If one considers only two bodies -- either the Sun and a planet, or the Sun and a comet -- the smaller body appears to follow an elliptical path or orbit about the Sun, which is at one focus of the ellipse. ... Another quantity that is conserved is called angular momentum. ... Comets simply are bodies which in general have more angular momentum per unit mass than do planets and therefore move in more elongated orbits. ...

3) Planets and Brown Dwarfs . ... By its nature, this method is most sensitive to massive planets orbiting close to their stars. ... That means that some of the more massive extrasolar planets could actually be brown dwarfs (although the statistics of the finds suggest that most of them are not). ... Another possible difference between brown dwarfs and massive planets is how they are born. ... They would base the fundamental definition on the mode of formation: a planet is built from planetesimals. ...

... In addition to the planets and their satellites the solar system contains a large number of smaller but interesting objects. T here are thousands of known asteroids and comets and undoubtedly many more unknown ones. ... There are also some asteroids whose orbits carry them closer to the Sun than the Earth (Aten, Icarus, Hephaistos). Most comets have highly elliptical orbits which spend most of their time in the outer reaches of the solar system with only brief passages close to the Sun. ...