... Spacecraft . ... To space by cannon? Finally, the deep space explorers --spacecraft which break away from the Earth's gravity . ... The "Luna" series of the USSR conducted 7 soft landing of unmanned probes, two of them with wheeled robotic "Lunokhods," and two of those missions returned samples to Earth. Others spacecraft have visited the major planets of the Solar system. ... The Mariner series have explored Venus and Mars--and Mariner 10 even reached Mercury, for three separate encounters! ...

... 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. ...

... 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...

... The discovery of giant Jupiter-type planets in a close proximity to 51 Peg, Boo, and And has prompted the question of where the planets could be formed in the circumstellar disks of solar-type stars. ... Planet formation, at distance of ~0.05 AU from the star, requires that the temperature of the circumstellar protoplanetary disk is low enough for the condensation of rocky materials, and the surface density is sufficiently high. ...

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 . ...

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 | ...

home education > activities . SEARCH ASP SITE: Match ALL words Match ANY word . ... Astronomy . ... This classic activity by Dennis Schatz asks students to invent a more-or-less plausible life form that could survive on one of the moons and planets in our solar system. [a] . ... Good as far as it goes, but fails to point out a crucial difference with the real world: on the planets, the impacting bodies explode making craters much bigger and rounder than the ones the students will obtain. [m,h] . ...

... What is a planet? ... When they finally came up with an answer it had big consequences: The number of planets in our Solar System went from nine to eight! ... Then, in 2005, astronomers found an object in the outer Solar System, called Eris, which they thought was bigger than Pluto. ... However, recently astronomers were able to measure the size of the dwarf planet Eris more accurately and they have discovered that it isn t bigger than Pluto after all they re actually about the same size. ...

... 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 . ...

The Moon orbits around the Earth. ... To keep the Moon moving in that circle--rather than wandering off--the Earth must exert a pull on the Moon, and Newton named that pulling force gravity . ... If it was the same force, then a connection would exist between the way objects fell and the motion of the Moon around Earth, that is, its distance and orbital period. ... Newton went further and proposed that gravity was a "universal" force, and that the Sun's gravity was what held planets in their orbits. ...

... How much brighter is the Sun as viewed from the planet Mercury as compared to Earth ? ... Actually, all of these questions can be answered through a very simple mathematical relationship known as the inverse square law. ... As the distance from the Sun increases the surface area of the sphere grows by the square of the distance. ... Common sense tells us that the Sun will be brighter and the inverse square law tells us how much brighter. ... gr = 0.912 G or 91.2% gravity felt at Earth's surface. ...

... 8, ``Celestial Mechanics'', 2002 Precession and free core nutation of neutron stars A. Gusev, I. Kitiashvili Kazan University, Russia In 1992 Wolszczan and Frail discovered a planetary system around the pulsar PSR 1257+12 [1]. ... Third case: the most likely possibility is the free precession of the pulsar with a rigid 81 neutron star. ... It is known that rotation of the terrestrial planets having rigid mantle and elliptical liquid core is characterized by Free Core Nutation (FCN). ...

... Great oppositions. ... Proxima Centauri. ... Scientists proved that the problem of preserving the Earth's climate and the annual change of seasons can be solved by a small star, negligible mass, but similar to a main-sequence star, moving in a circular orbit around the Sun. ... Sombrero Galaxy. The Sombrero Galaxy, M104, is known as a holder of one of supermassive black holes. ... Roughly estimate the approximate mass of the supermassive black hole in the center of M104 (answer in solar masses m). ...

... Bad Astronomy . ... Every few months, one of a series of questions comes up on the USENET group sci.astro involving tides, or the rotation of the Moon, or the recession of the Moon from the Earth. ... Why the Moon's rotation period is the same as the length of time it takes to orbit the Earth (same as number 1, but phrased differently). ... But when this happens, the time it takes for the Earth to rotate once will be slowed to exactly the same time it takes for the Moon to go around the Earth once! ...

The solar system probably formed about 4.5 billion years ago from a giant disk of gas, dust and ice in space. ... All forms of life on Earth require liquid water to survive, so the presence of liquid water is a good criterion for deciding whether other planets in the universe could be habitable. Earth is the only habitable planet in the solar system. Venus, closer to the Sun, is too hot to have liquid water. Planets and moons in the outer solar system are too cold for liquid water. ...

Uranus: around the Sun, "lying in the side". Uranus . ... Mass . ... The period of rotation . ... The average distance from the Sun . ... Excentricity of the orbit . ... Uranus is the seventh from the Sun great planet of the Solar system. ... The theoretical model of Uranus structure is following its upper layer is a gasoliquid shell under which is an icy cloak (the water and ammonia ice) then comes the core of the solid soils. The cloak and the core mass is about 85-90% of all Uranus mass. ...

... What do we know? ... The peak radio emission is around 7(10-16Wm-2, and we are viewing it from a distance of half a light year. ... Radio Power. ... So the total power striking both is around 1017W. So the radio power coming out at 1420 MHz is comparable to all the Twinky light falling on both objects combined! ... If both planets had the same mass, they would orbit around a point mid-way between them, so the radius of motion of the radio source would be around 14,000 km. ... Reflected Twinky light...

I'm glad you're interested in collaborating on the ConcepTests for Astronomy WWW database project! ... I'm looking forward to your contributions! ... a) high luminosity, high temperature to low luminosity, low temperature . b) high luminosity, low temperature to low luminosity, low temperature . c) high luminosity, low temperature to low luminosity, high temperature . d) high luminosity, high temperature to low luminosity high temperature. ... Back to Paul Green's Peer Instruction page. ...

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 . ...

... 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? ...