... Here is a brief outline of the current theory of the events in the early history of the solar system: . A cloud of interstellar gas and/or dust (the "solar nebula") is disturbed and collapses under its own gravity. ... The gas cools off enough for the metal, rock and (far enough from the forming star) ice to condense out into tiny particles. (i.e. some of the gas turns back into dust). ... Once the larger of these particles get big enough to have a nontrivial gravity, their growth accelerates. ...

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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. ...

... 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 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. ...

... Tonight's Sky . ... DISK т?? ... Sky this Month . ... Star Atlas . ... A planet is forming in an Earth-like orbit around a young star . New images reveal never-before-seen details in the planet-forming disk around a nearby Sun-like star, including a tantalizing gap at the same distance from the star as Earth is from the Sun. ... ALMA image of the planet-forming disk around the young Sun-like star TW Hydrae. ... Disks of dust and gas that surround young stars are the formation sites of planets. ...

Astronomy Picture of the Day . White Oval Clouds on Jupiter . ... Jupiter's clouds can swirl rapidly in raised high-pressure storm systems that circle the planet. The above pictured white ovals are located near the Great Red Spot, and have persisted on Jupiter since the 1930s. The Great Red Spot has persisted for at least 300 years. ... Why do many galaxies appear as spirals? ... The above pictures taken by Mars Pathfinder highlight how clouds vary during the end of a Martian day. ... April . ...

Astronotes Armagh Planetarium's Stellar Blog! ... Comets and Asteroids . ... Image credit:ESO/J.Emerson/VISTA. ... However others are less pessimistic and it has even been claimed that the mysterious ?Wow! signal? received in 1977 originated from the direction M55.б  Sadly, this still unexplained pulse of radio energy originated from a location rather to the northwest of M55 so I doubt if the source was this cluster (if indeed the signal was genuinely of extraterrestrial origin). ... Mysterious Wow! ...

... Indeed, one alteration of orbits can be the outright ejection of a planet. When several big planets are orbiting a star under each other's influence, the system is inherently unstable. ... We know of no good reason why the smallest objects with fusion should have the same mass as the smallest objects that can form by themselves. ... 6) Mission Definition . ... I don't think this mission is impossible, and will suggest a definition in a future article in Mercury. ... Good luck! . ...

How the rings were formed. ... Because of the velocity of mutual collisions increases at the approaching to the planet, there is a region near an every planet where the particles reaching the definite sizes begin to pull due to the mutual collisions. ... Any big particle passes the whole cycle from the destruction to the restoration. ... Why the rings are so flat? ... The gravitation compresses the system from all sides and the rotation axis, but it cannot prevent compression along the axis. ...

On the inclination of planetary orbits! Caroline Terquem! ... Planets on inclined orbits Higher inclinations for planets around stars with Teff>6250K? Planet formation, Hot Jupiters and misalignments 1. If planets form by the core accretion scenario and migrate in: Hot Jupiters But no eccentricity and no misalignment (if the disc is in the star's equatorial plane) With further planet/planet scattering and/or Kozai cycles: Eccentricity and misalignment But companions required.. ...

... Bad Astronomy . ... A tidbit of news on the brown dwarf front came in this week. Regular readers may remember that brown dwarfs are objects that are intermediate in mass between a planet and a star . ... So this is even better evidence that brown dwarfs form like stars and not planets. Brown dwarfs may not turn out to be the 'missing link' between planets and stars the way some astronomers thought a few years ago, but they are providing clues on just how stars and planets do form. ...

... Dept. for Astrometry & Space Geodynamics . ... Dept. for Physics of Stars&Galaxies . ... Dept. for Physics of Planetary Systems . ... Science . ... All Pages . ... Research of the stars with planets which pass apparent star disk (transiting exoplanets). The transit method based on a detection star brightness decrease during a passing of planet in front of its disk. Observed brightness system decries when planet pass star disk and its volume depend of the relative sizes star and planet. ...

... Files in red?history) . ... Trapped Motion . ... 10a. Particle Drift . ... Fast Particles . ... The fact charged particles circle around field lines was well known to J.J. Thomson when he experimented with electron and ion beams in a magnetic field. ... The notion of adiabatic invariance is tied with the early years of quantum theory. ... By about1910, physicists realized that these patterns indicated changes in the laws of physics as one approached atomic dimensions. ...

... 2001 June 4 . The T Tauri Star Forming System . ... A prototype laboratory for the formation of low mass stars like our Sun is the T Tauri system , one of the brighter star systems toward the constellation of Taurus . In young systems , gravity causes a gas cloud to condense. The situation then usually becomes quite complex, as some of the infalling gas is heated so much by collisions that it is immediately expelled as an outgoing wind . ... About APOD | ...

Hubble Finds Oxygen Atmosphere On Jupiter's Moon Europa . Astronomers using NASA's Hubble Space Telescope (HST) have identified the presence of an extremely tenuous atmosphere of molecular oxygen around Jupiter's second moon, Europa . ... Europa's oxygen atmosphere is so tenuous that its surface pressure is barely one hundred billionth that of the Earth," said Principal Investigator Doyle Hall, of Johns Hopkins. ... The oxygen gas slowly leaks into space and must be replenished continuously. ...

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. ...

... How How do molecular clouds collapse to form do very young stars evolve? do planets grow in circumstellar disks? ... Real-time protoplanetary/protostellar disk evolution - movies of disks in formation High sensitivity, 2 AU resolution cm-wave observations (100K, 0.2 mas, 8 GHz bandwidth, A/T 10,000) proper motions (Reid ­ Bryden et al 1999) dynamical timescales months-years How do very young stars evolve ? cm-waves probe inner few AU of accretion ...

... part 1 | ... The Basic Stages in Earth's Pre-geological Development . ... After fragments of the Vortex sleeves separated, whirlwinds of second and third orders ("NC" - new micro-vortex) were generated- future planet cores and their satellites - all of them developing independently, governed by the common laws of development of cosmogenic vortexes. ... Our planet's core today is comprised of considerably deteriorated cosmogenic vortex; consequently, the Earth has a moderated magnetic field. ...

... Intuitive model Step 1 Step 2 Step 3 Predictions This simple theory leads to a number of, potentially, observable predictions (1) The ejection speed of the flow increases as one approaches the star (2) Stellar rotation period may be a fundamental period of the flow (3) The flow starts at Rt and ends at Ro when the transfield current runs out Current balance equation Predictions Mass ejection is proportional to mass accretion ... Inner disk dust ~ 90% crystalline silicate. ...