Boss, Alan (October 2006). "Is it a coincidence that most of the planets fall within the Titius-Bode law's boundaries?". Astronomy. Ask Astro. Vol.30, no.10. p.70. Archived from the original on 16 March 2022 . Retrieved 9 April 2022. The Sun is a population I star; it has a higher abundance of elements heavier than hydrogen and helium (" metals" in astronomical parlance) than the older population II stars. [85] Elements heavier than hydrogen and helium were formed in the cores of ancient and exploding stars, so the first generation of stars had to die before the universe could be enriched with these atoms. The oldest stars contain few metals, whereas stars born later have more. This higher metallicity is thought to have been crucial to the Sun's development of a planetary system because the planets form from the accretion of "metals". [86] Inner Solar System Overview of the Inner Solar System up to the Jovian System The Solar System's location in the Milky Way is a factor in the evolutionary history of life on Earth. Its orbit is close to circular, and orbits near the Sun are at roughly the same speed as that of the spiral arms. [232] [233] Therefore, the Sun passes through arms only rarely. Because spiral arms are home to a far larger concentration of supernovae, gravitational instabilities, and radiation that could disrupt the Solar System, this has given Earth long periods of stability for life to evolve. [232] However, the changing position of the Solar System relative to other parts of the Milky Way could explain periodic extinction events on Earth, according to the Shiva hypothesis or related theories, but this remains controversial. [234] [235]

Planetarium Software - The Nine Planets Planetarium Software - The Nine Planets

Experiment with the planets and objects in space, move the planets and see how this affects their orbit and put other objects in their paths such as asteroids and comets. Use your mouse to move around the universe and use all kinds of options to to see what happens enjoying the breathtaking sight. Have fun in Planetarium 2! A star is an immense glowing ball of extremely hot gases, mainly hydrogen and helium, where nuclear fusion releases a tremendous amount of energy. A few nearby stars are Sun, Proxima Centauri, Sirius, Polaris. G. Zotti gave a presentation about Stellarium (YouTube) for the China-VO (Virtual Observatory of the Chinese Academy of Sciences) on February 1st, 2021 Tours of Model Solar Systems". University of Illinois. Archived from the original on 12 April 2011 . Retrieved 10 May 2012. A dwarf planet is a body orbiting the Sun that is massive enough to be made near-spherical by its own gravity but that has not cleared planetesimals from its neighborhood and is also not a satellite. [4] Dwarf planets are considered planets by some planetologists but not by the IAU. [5] The IAU has recognized four other bodies in the Solar System as dwarf planets: Ceres, Haumea, Makemake, and Eris. [6] [7] Other objects commonly accepted as dwarf planets include Gonggong, Sedna, Orcus, and Quaoar. In a reference to Pluto, other dwarf planets orbiting in the trans-Neptunian region are sometimes called "plutoids", [8] though this term is seldom used.

Earth's Tilt

The next closest known fusors to the Sun are the red dwarfs Barnard's Star (at 5.9ly), Wolf 359 (7.8ly), and Lalande 21185 (8.3ly). [220] The nearest brown dwarfs belong to the binary Luhman 16 system (6.6ly), and the closest known rogue or free-floating planetary-mass object at less than 10 Jupiter masses is the sub-brown dwarf WISE 0855−0714 (7.4ly). [221]

Solar System and the Night Sky TheSkyLive - Your Guide to the Solar System and the Night Sky

The interplanetary medium is home to at least two disc-like regions of cosmic dust. The first, the zodiacal dust cloud, lies in the inner Solar System and causes the zodiacal light. It may have been formed by collisions within the asteroid belt brought on by gravitational interactions with the planets; a more recent proposed origin is the planet Mars. [66] The second dust cloud extends from about 10AU (1.5billionkm; 930millionmi) to about 40AU (6.0billionkm; 3.7billionmi), and was probably created by collisions within the Kuiper belt. [67] [68] Makemake (45.79AU average from the Sun), although smaller than Pluto, is the largest known object in the classical Kuiper belt (that is, a Kuiper belt object not in a confirmed resonance with Neptune). Makemake is the brightest object in the Kuiper belt after Pluto. Discovered in 2005, it was officially named in 2009. [166] Its orbit is far more inclined than Pluto's, at 29°. [167] It has one known moon. [168] Earth (0.983–1.017AU (147.1–152.1millionkm; 91.4–94.5millionmi) from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and the only place in the universe where life is known to exist. [101] Its liquid hydrosphere is unique among the terrestrial planets, and it is the only planet where plate tectonics has been observed. [102] Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen. [103] [104] The planetary magnetosphere shields the surface from solar and cosmic radiation, limiting atmospheric stripping and maintaining habitability. [105] It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System. Main article: Discovery and exploration of the Solar System The motion of 'lights' moving across the sky is the basis of the classical definition of planets: wandering stars. a b Lakdawalla, Emily; etal. (21 April 2020). "What Is A Planet?". The Planetary Society. Archived from the original on 22 January 2022 . Retrieved 3 April 2022.Kallenrode, May-Britt (2004). Space Physics: An introduction to plasmas and particles in the heliosphere and magnetospheres (3rded.). Berlin: Springer. p.150. ISBN 978-3-540-20617-0. OCLC 53443301. Archived from the original on 20 April 2022 . Retrieved 1 April 2022. Piccirillo, Lucio (2020). Introduction to the Maths and Physics of the Solar System. CRC Press. p.210. ISBN 978-0429682803. Archived from the original on 30 July 2022 . Retrieved 10 May 2022.

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Noever, David (2004). "Modern Martian Marvels: Volcanoes?". NASA Astrobiology Magazine. Archived from the original on 14 March 2020 . Retrieved 23 July 2006. {{ cite web}}: CS1 maint: unfit URL ( link) Greaves, Jane S. (7 January 2005). "Disks Around Stars and the Growth of Planetary Systems". Science. 307 (5706): 68–71. Bibcode: 2005Sci...307...68G. doi: 10.1126/science.1101979. PMID 15637266. S2CID 27720602. The outermost layer of the Solar atmosphere is the heliosphere, which permeates much of the Solar planetary system. Along with light, the Sun radiates a continuous stream of charged particles (a plasma) called the solar wind. This stream of particles spreads outwards at speeds from 900,000 kilometres per hour (560,000mph) to 2,880,000 kilometres per hour (1,790,000mph), [64] filling the vacuum between the bodies of the Solar System. The result is a thin, dusty atmosphere, called the interplanetary medium, which extends to at least 100AU (15billionkm; 9.3billionmi). Beyond the heliosphere, large objects remain gravitationally bound to the sun, but the flow of matter in the interstellar medium homogenizes the distribution of micro-scale objects (see §Farthest regions). [65] Just beyond at 8.6ly lies Sirius, the brightest star in Earth's night sky, with roughly twice the Sun's mass, orbited by the closest white dwarf to Earth, Sirius B. Other stars within ten light-years are the binary red-dwarf system Gliese 65 (8.7ly) and the solitary red dwarf Ross 154 (9.7ly). [222] [223] The closest solitary Sun-like star to the Solar System is Tau Ceti at 11.9 light-years. It has roughly 80% of the Sun's mass but only about half of its luminosity. [224] Cameron, A.G.W. (1985). "The partial volatilization of Mercury". Icarus. 64 (2): 285–294. Bibcode: 1985Icar...64..285C. doi: 10.1016/0019-1035(85)90091-0.

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Besides Pluto, astronomers generally agree that at least four other Kuiper belt objects are dwarf planets, [157] though there is some doubt for Orcus, [164] and additional bodies have also been proposed: [165] In the 17th century, Galileo publicized the use of the telescope in astronomy; he and Simon Marius independently discovered that Jupiter had four satellites in orbit around it. [242] Christiaan Huygens followed on from these observations by discovering Saturn's moon Titan and the shape of the rings of Saturn. [243] In 1677, Edmond Halley observed a transit of Mercury across the Sun, leading him to realize that observations of the solar parallax of a planet (more ideally using the transit of Venus) could be used to trigonometrically determine the distances between Earth, Venus, and the Sun. [244] Halley's friend Isaac Newton, in his magisterial Principia Mathematica of 1687, demonstrated that celestial bodies are not quintessentially different from Earthly ones: the same laws of motion and of gravity apply on Earth and in the skies. [34] :142 Pallas (2.77AU from the Sun) and Vesta (2.36AU from the Sun) are the largest asteroids in the asteroid belt, after Ceres. They are the other two protoplanets that survive more or less intact. At about 520km (320mi) in diameter, they were large enough to have developed planetary geology in the past, but both have suffered large impacts and been battered out of being round. [121] [122] [123] Fragments from impacts upon these two bodies survive elsewhere in the asteroid belt, as the Pallas family and Vesta family. Both were considered planets upon their discoveries in 1802 and 1807 respectively, and like Ceres, eventually considered minor planets with the discovery of more asteroids. Some authors today have begun to consider Pallas and Vesta as planets again, along with Ceres, under geophysical definitions of the term. [5] Asteroid groups Animations of the Solar System's inner planets and outer planets orbiting; the latter animation is 100 times faster than the former. Jupiter is three times as far from the Sun as Mars.