Neptune is approximately the same size as Uranus and is known for its supersonic strong winds. The planet is more than 30 times as far from the sun as Earth. Pessimism, Futility, and Extinction" Theory, Culture & Society interview with Thomas Dekeyser (17 March 2020). Moons have come to exist around most planets and many other Solar System bodies. These natural satellites originated by one of three possible mechanisms:

One unresolved issue with this model is that it cannot explain how the initial orbits of the proto-terrestrial planets, which would have needed to be highly eccentric to collide, produced the remarkably stable and nearly circular orbits they have today. [49] One hypothesis for this "eccentricity dumping" is that terrestrials formed in a disc of gas still not expelled by the Sun. The " gravitational drag" of this residual gas would have eventually lowered the planets' energy, smoothing out their orbits. [50] However, such gas, if it existed, would have prevented the terrestrial planets' orbits from becoming so eccentric in the first place. [35] Another hypothesis is that gravitational drag occurred not between the planets and residual gas but between the planets and the remaining small bodies. As the large bodies moved through the crowd of smaller objects, the smaller objects, attracted by the larger planets' gravity, formed a region of higher density, a "gravitational wake", in the larger objects' path. As they did so, the increased gravity of the wake slowed the larger objects down into more regular orbits. [52] Asteroid belt [ edit ] Uranus holds the record for the coldest temperature ever measured in the solar system — minus 371.56 degrees F (minus 224.2 degrees C). The average temperature of Uranus is minus 320 degrees Fahrenheit (-195 degrees Celsius). That is the 1 million Euro question. We are currently just exploring what processes drive the formation and evolution of other solar systems, and what we can learn from this about our own solar systems (and Earth’s!) history. We think that many other stars have exoplanets around them but probably not all of them. In average, studies found there to be about 1 to 2 exoplanet per star — but that is an average! Some stars may have 8, others may have none. What is (and isn't) a planet? Explore the solar system in greater detail with these interactive resources from NASA. Discover the wonders of the solar system with this educational material from ESA. See where the planets are in their current orbit of the sun with this interactive orrery from NASA. BibliographyThere have been five human-made objects so far, Voyager 1, Voyager 2, New Horizons, Pioneer 10 and Pioneer 11, that have crossed the threshold into interstellar space.

See the essays "Data Made Flesh: Biotechnology and the Discourse of the Posthuman," Cultural Critique no. 53 (2003), "Biohorror/Biotech," Paradoxa no. 17 (2002).Ultimately, the Solar System is stable in that none of the planets are likely to collide with each other or be ejected from the system in the next few billion years. [102] Beyond this, within fivebillion years or so, Mars's eccentricity may grow to around 0.2, such that it lies on an Earth-crossing orbit, leading to a potential collision. In the same timescale, Mercury's eccentricity may grow even further, and a close encounter with Venus could theoretically eject it from the Solar System altogether [99] or send it on a collision course with Venus or Earth. [104] This could happen within a billion years, according to numerical simulations in which Mercury's orbit is perturbed. [105] Moon–ring systems [ edit ] And They Were Two in One and One in Two, co-edited with Nicola Masciandaro. Schism Press, 2014. ISBN 978-1494701239. Astronomers believe an object twice the size of Earth collided with Uranus roughly 4 billion years ago, causing Uranus to tilt. That tilt causes extreme seasons that last 20-plus years, and the sun beats down on one pole or the other for 84 Earth-years at a time. Hubble image of protoplanetary discs in the Orion Nebula, a light-years-wide stellar nursery probably very similar to the primordial nebula from which the Sun formed Creative Biotechnology: A User's Manual, co-authored with Natalie Jeremijenko and Heath Bunting. Locus+, 2004. ISBN 978-1899377220.

Leper Creativity: The Cyclonopedia Symposium, co-edited with Ed Keller and Nicola Masciandaro. Punctum Books, 2012. ISBN 978-0615600468. But that restrictive definition helped isolate what should and should not be considered a planet — a problem that arose as astronomers discovered more and more planet-like objects in the solar system. Pluto was among the bodies that didn't make the cut and was re-classified as a dwarf planet. The Patron Saints of Pessimism - A Writer's Pantheon, excerpt from Infinite Resignation @ LitHub (2018) As Jupiter migrated inward following its formation (see Planetary migration below), resonances would have swept across the asteroid belt, dynamically exciting the region's population and increasing their velocities relative to each other. [55] The cumulative action of the resonances and the embryos either scattered the planetesimals away from the asteroid belt or excited their orbital inclinations and eccentricities. [53] [56] Some of those massive embryos too were ejected by Jupiter, while others may have migrated to the inner Solar System and played a role in the final accretion of the terrestrial planets. [53] [57] [58] During this primary depletion period, the effects of the giant planets and planetary embryos left the asteroid belt with a total mass equivalent to less than 1% that of the Earth, composed mainly of small planetesimals. [56]

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The nebular hypothesis says that the Solar System formed from the gravitational collapse of a fragment of a giant molecular cloud, [9] most likely at the edge of a Wolf-Rayet bubble. [10] The cloud was about 20 parsecs (65 light years) across, [9] while the fragments were roughly 1parsec (three and a quarter light-years) across. [11] The further collapse of the fragments led to the formation of dense cores 0.01–0.1parsec (2,000–20,000 AU) in size. [a] [9] [12] One of these collapsing fragments (known as the presolar nebula) formed what became the Solar System. [13] The composition of this region with a mass just over that of the Sun ( M ☉) was about the same as that of the Sun today, with hydrogen, along with helium and trace amounts of lithium produced by Big Bang nucleosynthesis, forming about 98% of its mass. The remaining 2% of the mass consisted of heavier elements that were created by nucleosynthesis in earlier generations of stars. [14] Late in the life of these stars, they ejected heavier elements into the interstellar medium. [15] Some scientists have given the name Coatlicue to a hypothetical star that went supernova and created the presolar nebula. The Solar System is chaotic over million- and billion-year timescales, [99] with the orbits of the planets open to long-term variations. One notable example of this chaos is the Neptune–Pluto system, which lies in a 3:2 orbital resonance. Although the resonance itself will remain stable, it becomes impossible to predict the position of Pluto with any degree of accuracy more than 10–20million years (the Lyapunov time) into the future. [100] Another example is Earth's axial tilt, which, due to friction raised within Earth's mantle by tidal interactions with the Moon ( see below), is incomputable from some point between 1.5 and 4.5 billion years from now. [101] The planets were originally thought to have formed in or near their current orbits. This has been questioned during the last 20 years. Currently, many planetary scientists think that the Solar System might have looked very different after its initial formation: several objects at least as massive as Mercury may have been present in the inner Solar System, the outer Solar System may have been much more compact than it is now, and the Kuiper belt may have been much closer to the Sun. [48] Terrestrial planets [ edit ] Gravitational disruption from the outer planets' migration would have sent large numbers of asteroids into the inner Solar System, severely depleting the original belt until it reached today's extremely low mass. [56] This event may have triggered the Late Heavy Bombardment that is hypothesised to have occurred approximately 4billion years ago, 500–600million years after the formation of the Solar System. [2] [75] However, a recent re-appraisal of the cosmo-chemical constraints indicates that there was likely no late spike (“terminal cataclysm”) in the bombardment rate. [76]

Radiolab - In The Dust Of This Planet", original broadcast Monday September 8, 2014. The story was also covered by NPR's On The Media. See the entry "Biomedia" in Critical Terms for Media Studies, eds. W.J.T. Mitchell & Mark Hansen (University of Chicago Press, 2010).Main article: Late Heavy Bombardment Meteor Crater in Arizona. Created 50,000 years ago by an impactor about 50 metres (160ft) across, it shows that the accretion of the Solar System is not over. This model, known as the nebular hypothesis, was first developed in the 18th century by Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace. Its subsequent development has interwoven a variety of scientific disciplines including astronomy, chemistry, geology, physics, and planetary science. Since the dawn of the Space Age in the 1950s and the discovery of exoplanets in the 1990s, the model has been both challenged and refined to account for new observations. It is smaller than Earth's moon; its orbit is highly elliptical, falling inside Neptune's orbit at some points and far beyond it at others; and Pluto's orbit doesn't fall on the same plane as all the other planets —instead, it orbits 17.1 degrees above or below.