| 单词 | planetesimal |
| 例句 | Eventually the clumps grew large enough to be called planetesimals. A Short History of Nearly Everything 2003-05-06T00:00:00Z "If the mounds are indeed representative of the building blocks of ancient planetesimals like Arrokoth, then planetesimal formation models will need to explain the preferred size for these building blocks." Large mound structures on Kuiper belt object Arrokoth may have common origin 2023-10-03T04:00:00Z While rocky planets like our Earth form from accretion and clash of dust, rocks and planetesimals. Stranger Things in a Stranger World 2023-06-26T04:00:00Z "In this model, 'Oumuamua began as an icy planetesimal that was irradiated at low temperatures by cosmic rays during its interstellar journey, and experienced warming during its passage through the Solar System." A new paper says 'Oumuamua was a comet, not an alien spacecraft. Not everyone agrees 2023-03-26T04:00:00Z “This provides further support that Oumuamua originated as a planetesimal relic broadly similar to solar system comets.” Oumuamua Was a Comet After All, a Study Suggests 2023-03-22T04:00:00Z Within the solar nebula, material first coalesced into planetesimals; many of these gathered together to make the planets and moons. Astronomy 2016-10-13T00:00:00Z "It will be important to search for mound-like structures on the planetesimals these missions observe to see how common this phenomenon is, as a further guide to planetesimal formation theories," Stern said. Large mound structures on Kuiper belt object Arrokoth may have common origin 2023-10-03T04:00:00Z The classic theory of planet formation starts with dust grains sticking together, gradually building up to become “planetesimals,” which are kilometers across in size. Jupiter-size exoplanet caught in the act of being born 2022-04-03T04:00:00Z The dense iron in the planetesimals would have sunk to the core of the molten proto-Earth, while lighter silicate rocks rose like oil on water to form the mantle. Scientists are probing the secrets of Earth’s inner core—and how it saved life on our planet 2022-03-30T04:00:00Z If the Trojans are similarly lumpy, that would be an indication that cloud collapse is the standard way to assemble planetesimals, says Jessica Sunshine, a planetary scientist at the University of Maryland, College Park. Tour of Jupiter’s Trojans could reveal Solar System’s chaotic origin 2021-10-07T04:00:00Z Gradually, as the planets swept up or ejected the remaining debris, most of the planetesimals disappeared. Astronomy 2016-10-13T00:00:00Z Psyche, launching in August 2022, will orbit a rare iron and nickel asteroid of the same name, believed to be the stripped-bare core of an ancient planetesimal. Venus can’t wait—NASA plans blockbuster return to hothouse neighbor 2021-06-02T04:00:00Z Those planetesimals grow by colliding with others until they become protoplanets, hundreds or thousands of kilometers across. Jupiter-size exoplanet caught in the act of being born 2022-04-03T04:00:00Z Other ideas include radiative heating, a relatively new idea that suggests planetesimals flying low over molten bodies could have been roasted and then cooled to produce chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Arrokoth’s lobed shape fits a model suggesting planetesimals formed when clouds of pebbles in the gassy disk collapsed to form city-size lumps; those might then have merged with others into progressively larger structures. Tour of Jupiter’s Trojans could reveal Solar System’s chaotic origin 2021-10-07T04:00:00Z In two regions, however, stable orbits are possible where leftover planetesimals could avoid impacting the planets or being ejected from the system. Astronomy 2016-10-13T00:00:00Z Their results suggest a crowded landscape in the early inner solar system, with a nascent sun surrounded by thousands of planetesimals, the rocky building blocks of planets, each tens of miles or so in size. Small Worlds With Lava Oceans Might Have Given Us Meteorites 2020-06-22T04:00:00Z The idea suggests planetesimals in the outer disk could grow faster, not through collisions, but by grabbing pebble-size material that has been made sluggish and easier to catch by thick gases. Jupiter-size exoplanet caught in the act of being born 2022-04-03T04:00:00Z Chondrules concern the opening chapters of the story, the leap from dust to planetesimals. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z The most massive objects in the disk are called planetesimals, and their locations are shaped by interactions with other planets in the system. Astronomers Watch as Planets Are Born 2020-06-01T04:00:00Z Describe the solar nebula, and outline the sequence of events within the nebula that gave rise to the planetesimals. Astronomy 2016-10-13T00:00:00Z They would tell us more about the nature of planetesimals in the early solar system, with chondrites being the scorched leftovers of the process that formed worlds such as Earth. Small Worlds With Lava Oceans Might Have Given Us Meteorites 2020-06-22T04:00:00Z “This might be common for the asteroids and even for planetesimals in the early solar system,” Okada says. Asteroid Ryugu has texture like 'freeze-dried coffee' 2020-03-16T04:00:00Z “Now more and more people are talking about a planetesimal source,” says Myriam Telus, a planetary scientist from the University of California, Santa Cruz. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Except there seems to be a crucial bottleneck in this planetary assembly line: the jump from pebbles to kilometer-scale building blocks called planetesimals. New Horizons May Have Solved Planet Formation Cold Case 2020-02-20T05:00:00Z Once they survive to those sizes, the largest survivors will continue to grow by accreting smaller planetesimals; ultimately, this process results in a few large planets. Astronomy 2016-10-13T00:00:00Z “It’s teaching us how planetesimals formed, and we believe the result marks a significant advance in understanding overall planetesimal and planet formation.” NASA’s New Horizons mission sheds new light on how planets form 2020-02-14T05:00:00Z The spacecraft burned some fuel to adjust its trajectory, and on Jan. 1, 2019, passed by the planetesimal at a distance of 2,198 miles. New Horizons images of Arrokoth show building blocks for planets 2020-02-13T05:00:00Z Here, planetesimals would collide at high velocities, creating the necessary heat to produce chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z From there, a pebble cloud will collapse, popping out planetesimals—plural, because the conservation of angular momentum spins out two or more dense, kilometer-scale bodies from the infalling material. New Horizons May Have Solved Planet Formation Cold Case 2020-02-20T05:00:00Z The first step in the formation of a giant planet is to build up a solid core, which happens when planetesimals collide and stick. Astronomy 2016-10-13T00:00:00Z “This indicates Arrokoth formed during the gravity-driven collapse of a cloud of solid particles in the primordial solar nebula, rather than by the competing theory of planetesimal formation called hierarchical accretion,” the space agency explained. NASA’s New Horizons mission sheds new light on how planets form 2020-02-14T05:00:00Z The most distant object ever explored, since named Arrokoth, was a “planetesimal” lurking quietly in the outer solar system a billion miles past Pluto. New Horizons images of Arrokoth show building blocks for planets 2020-02-13T05:00:00Z This suggests that planetesimals formed in localized conditions in which collision speeds were slow rather than from a gradual assembly of widely dispersed objects growing by randomly colliding with each other at higher speeds. Oddly shaped celestial body Arrokoth sheds light on planet formation 2020-02-13T05:00:00Z “I’m confident in this being a major advance in our understanding of planetesimal formation, but someone will probably ask, ‘Well, this is just one object. New Horizons May Have Solved Planet Formation Cold Case 2020-02-20T05:00:00Z These models show that material begins to coalesce first by forming smaller objects, precursors of the planets, which we call planetesimals. Astronomy 2016-10-13T00:00:00Z “Unlike the high-speed collisions between planetesimals in hierarchical accretion, in particle-cloud collapse, particles merge gently, slowly growing larger.” NASA’s New Horizons mission sheds new light on how planets form 2020-02-14T05:00:00Z “There was a previous picture that planetesimals formed ‘bottom-up’ as larger and larger chunks of rock would collide to form increasingly massive bodies. New Horizons images of Arrokoth show building blocks for planets 2020-02-13T05:00:00Z Eventually those clumps form what we call planetesimals, the building blocks of rocky and giant planets. How Did Water Get On Earth? 2019-10-06T04:00:00Z Thus, if planetesimals form via collapse, most of them should begin as binary systems—some of which will then either slowly merge together or lose their companions through gravitational interactions. New Horizons May Have Solved Planet Formation Cold Case 2020-02-20T05:00:00Z The Kuiper belt is made up of ice-and rock planetesimals, a remnant of the building blocks of the planets. Astronomy 2016-10-13T00:00:00Z This requirement is at tension with the expected mass in planetesimals within the orbit of Mercury in the early solar system. 'Oumuamua's Cousin? 2019-05-06T04:00:00Z “So if the sun was positioned where the white dwarf is, the planetesimal would be orbiting within the sun,” said Dr. Manser. Apocalypse Next? Astronomers Find a Chunk of Planet Around a Distant, Dead Star 2019-04-04T04:00:00Z Finding the planetesimal, 400 light-years from Earth, wasn’t easy. Astronomers spy an iron planet stripped of its crust around a burned-out star 2019-04-04T04:00:00Z The leading alternative to the “bottom-up” assembly process of hierarchical accretion is a “local cloud collapse” mechanism that would build planetesimals from the “top-down.” New Horizons May Have Solved Planet Formation Cold Case 2020-02-20T05:00:00Z Away from the center, solid particles can condense as the nebula cools, giving rise to planetesimals, the building blocks of the planets and moons. Astronomy 2016-10-13T00:00:00Z That is a change from older ideas of planetary formation: that objects called planetesimals grew slowly and steadily in size. How Ultima Thule Is Like a Sticky, Pull-Apart Pastry 2019-03-19T04:00:00Z “We are confident that we will discover additional planetesimals orbiting white dwarfs, which will allow us to learn more about their general properties,” Dr. Manser said. Apocalypse Next? Astronomers Find a Chunk of Planet Around a Distant, Dead Star 2019-04-04T04:00:00Z But writing in Science today, they reject all but one: that this is the signature of a planetesimal orbiting the star. Astronomers spy an iron planet stripped of its crust around a burned-out star 2019-04-04T04:00:00Z This led to the formation of medium-sized planetesimals. Distant object 'like nothing seen before' 2019-03-19T04:00:00Z Some planetesimals still survive today as comets and asteroids. Astronomy 2016-10-13T00:00:00Z Scientists believe MU69’s two lobes, with their sparse impact craters and generally smooth features, are primordial planetary building blocks called planetesimals. The space ‘snowman’ at the edge of our solar system is actually two lumpy pancakes 2019-03-18T04:00:00Z The rings are likely made up of warm dust, made up of the near continuous breakup of other "small rocky planetesimals" orbiting the dwarf, the statement said. Searching for Planet Nine, scientist finds ancient star with mysterious rings 2019-02-20T05:00:00Z As that gas cloud follows the planetesimal in its orbit, it boosts one emission peak while moving toward Earth and, an hour later, the other peak while moving away. Astronomers spy an iron planet stripped of its crust around a burned-out star 2019-04-04T04:00:00Z The last stage of the process was the merger between Ultima and Thule, possibly after the gravitational ejection of other planetesimal companions. Distant object 'like nothing seen before' 2019-03-19T04:00:00Z A substantial step up in size is required, however, to go from planetesimal to planet. Astronomy 2016-10-13T00:00:00Z On January 1, the New Horizons spacecraft took photographs of Ultima Thule, a planetesimal 4 billion miles away from our Sun. Ultima Thule, the Cold War and Trump's Wall 2019-01-11T05:00:00Z A line at 4.47 billion years ago marked the hypothetical impact of the planetesimal that gave rise to an atmosphere favorable to organic molecules. How an ancient cataclysm may have jump-started life on Earth 2019-01-10T05:00:00Z The jammed-together lobes of Ultima provide the most direct evidence yet of the standard hierarchical theory of how planets form: First dust grains stick together into pebbles, which gather into planetesimals. Pluto Probe Encounters a Pristine World in the Solar System's Suburbs 2019-01-08T05:00:00Z If it is indeed a pristine planetesimal, a building block of the planets, studying it will offer clues to how Earth and its neighbors formed. Snowman-like Photo of Ultima Thule Sent Home by NASA’s New Horizons Spacecraft 2019-01-02T05:00:00Z Some planetesimals were large enough to attract their neighbors gravitationally and thus to grow by the process called accretion. Astronomy 2016-10-13T00:00:00Z Kuiper belt objects “are the first planetesimals,” he said. New Horizons reveals a ‘snowman’ at the edge of the solar system 2019-01-02T05:00:00Z Already-formed planetesimals swim among them, and then grow quickly by accumulating more pebbles, much as a snowball gets bigger as it rolls downhill. These dusty young stars are changing the rules of planet-building 2018-12-03T05:00:00Z In such a chemically and dynamically cold region two neighboring planetesimals should have aggregated from an essentially identical mix of raw materials. Pluto Probe Encounters a Pristine World in the Solar System's Suburbs 2019-01-08T05:00:00Z However, the next 2 million years saw the planet pick up larger, kilometer-size small bodies, which are called planetesimals. Why Was Jupiter's Rapid Growth Spurt Delayed for Millions of Years? 2018-08-29T04:00:00Z Each of these attracted surrounding planetesimals until it had acquired a mass similar to that of Mercury or Mars. Astronomy 2016-10-13T00:00:00Z A vast majority of the half-million bodies in the inner asteroid belt may in fact be shrapnel from as few as five parent bodies called "planetesimals," scientists say. Many asteroids might be remnants of five destroyed worlds, scientists say 2018-07-03T04:00:00Z Once planetesimals form, the rest of the process is straightforward: the planetesimals clump together to form protoplanets that are somewhere between the moon and Mars in size, and these in turn coalesce into full-sized planets. Astronomers Spy Planet-Spawning Vortex around Young Star 2017-10-31T04:00:00Z Piecing together the planetesimals, the earliest ancestors of the asteroids, hasn’t been easy because eons of collisions have broken them apart. Watch ‘dark asteroids’ reveal secrets of the early solar system 2017-08-03T04:00:00Z Since these planetesimals were larger, they crashed into the planet with greater energy and released more heat, slowing Jupiter’s formation. Why Was Jupiter's Rapid Growth Spurt Delayed for Millions of Years? 2018-08-29T04:00:00Z Each of these protoplanets continued to grow by the accretion of planetesimals. Astronomy 2016-10-13T00:00:00Z "If we can turn back the clock and see the asteroid belt was made by these big planetesimals, that really is telling us something quite definitive about the circumstances that formed our own planet." Many asteroids might be remnants of five destroyed worlds, scientists say 2018-07-03T04:00:00Z The largest of these planetesimals grow faster than the ones around them and swallow their neighbors to grow into proto-planets. A New Theory of How the Moon Formed 2017-06-09T04:00:00Z While putting together these planetary puzzle pieces, the scientists also determined that the dark family’s original planetesimals were no smaller than 35 kilometers across. Watch ‘dark asteroids’ reveal secrets of the early solar system 2017-08-03T04:00:00Z Last year, two astronomers proposed that planetesimals perhaps as big as the moon itself buzzing through the inner solar system tipped the moon’s orbit through repeated close passes. If a ‘Big Whack’ Made the Moon, Did it Also Knock the Earth on Its Side? 2016-11-04T04:00:00Z Every incoming planetesimal was accelerated by the gravity of the protoplanet, striking with enough energy to melt both the projectile and a part of the impact area. Astronomy 2016-10-13T00:00:00Z Over a few million years, the dust builds up into grains, pebbles, boulders, and, eventually, kilometer-wide planetesimals. Forbidden planets: Understanding alien worlds once thought impossible 2016-07-28T04:00:00Z It’s a remarkable little warrior world, one that got clobbered early in its lifetime by a passing planetesimal, unleashing an explosive energy equivalent to one trillion 1-megaton bombs. Why You Should Care About Mercury's Transit of the Sun 2016-05-09T04:00:00Z In order for the theory to work, planetesimals had to be huge, and this family was one of the biggest. Watch ‘dark asteroids’ reveal secrets of the early solar system 2017-08-03T04:00:00Z Alessandro Morbidelli, one of the astronomers who proposed the planetesimals hypothesis, said nothing is proven yet, and both models rely on assumptions. If a ‘Big Whack’ Made the Moon, Did it Also Knock the Earth on Its Side? 2016-11-04T04:00:00Z However, the story of the formation of the solar system was not complete at this stage; there were many planetesimals and other debris that did not initially accumulate to form the planets. Astronomy 2016-10-13T00:00:00Z And it explains how those heavy elements, which are plentiful in rocky planetesimals, get into the atmosphere of a white dwarf. Zombie Star Caught Feasting On Asteroids 2015-10-21T04:00:00Z A similar frequency problem exists in the planetesimal theory. Mysterious Star Likely Doesn't Signal Aliens 2015-10-15T04:00:00Z And beyond that is the putative Öpik-Oort cloud, the likely repository of ice-rich planetesimals from the early era of solar system formation. Goodbye Pluto, Thanks for Everything 2015-07-15T04:00:00Z The planets formed by agglomeration, with dust grains combining to form pebbles, pebbles uniting into boulders, boulders into “planetesimals”, and so on. Harvest festival 2015-02-26T05:00:00Z In the inner parts of the system, remnant planetesimals and perhaps several dozen protoplanets continued to whiz about. Astronomy 2016-10-13T00:00:00Z Carbonaceous chondrites are leftover from comets, never were in a planetesimal. Attention QVC Shoppers, The Moon Is A Planet 2015-01-21T05:00:00Z The sun's heat and radiation drove most of the gases and some of the dust outward; closer in, the dust congealed into pebbles, then boulders, then asteroid-size bodies known as planetesimals. Kuiper Belt Missions Could Reveal the Solar System’s Origins 2014-10-15T04:00:00Z Farther away from the star, however, the disk is cool enough to preserve ices that are much more abundant than iron and rock, and that accrete readily on the planetesimals. Astronomy: Planets in chaos 2014-07-01T04:00:00Z I found that the first-generation planetesimals formed within a few million years of the Solar System's birth. Turning point: Liping Qin 2014-04-02T17:20:47.541Z Because the gravity of the giant planets could “stir up” the orbits of the planetesimals, the material impacting on the inner protoplanets could have come from almost anywhere within the solar system. Astronomy 2016-10-13T00:00:00Z These bodies, called planetesimals, are the essential bricks of planet formation. 'Star Wars' Planets Migrate into Position around Stellar Pairs 2014-02-07T20:00:00Z The objects that did form, moreover, would have looked a lot like planetesimals—small proto-planets that later combined to form planets. Kuiper Belt Missions Could Reveal the Solar System’s Origins 2014-10-15T04:00:00Z About 4.5 billion years ago, a Mars-sized planetesimal careered through the solar system and collided with the infant Earth, sending up a massive cloud of molten and vaporous debris. Earth's Great Gift to the Moon: Water 2013-05-10T10:55:00Z Before this discovery, researchers believed that these planetesimals formed later, as the Solar System developed, but our work helped to confirm the earlier timing. Turning point: Liping Qin 2014-04-02T17:20:47.541Z Where would you look for some “original” planetesimals left over from the formation of our solar system? Astronomy 2016-10-13T00:00:00Z Double trouble One sticking point is the stage in which planetesimals collide. 'Star Wars' Planets Migrate into Position around Stellar Pairs 2014-02-07T20:00:00Z “The biggest uncertainty in how the existing planets formed,” says M.I.T. planetary scientist Hilke Schlichting, “is the formation of the planetesimals—how they came to exist and how big they were.” Kuiper Belt Missions Could Reveal the Solar System’s Origins 2014-10-15T04:00:00Z The Earth is an end product of the agglomeration of the equivalent of about a trillion kilometer-sized planetesimals that themselves coalesced from the sticky microscopic dust of a proto-planetary disk some 4.5 billion years ago. Cosmic Citizens 2012-10-28T20:17:30.693Z I worked on a special group of meteorites made up mostly of iron, which are thought to be remnants of the cores of planetesimals, small bodies that lead to the formation of planets. Turning point: Liping Qin 2014-04-02T17:20:47.541Z Today’s fast computers can simulate the way millions of planetesimals, probably no larger than 100 kilometers in diameter, might gather together under their mutual gravity to form the planets we see today. Astronomy 2016-10-13T00:00:00Z Their models found that at the current location of the planet, impacts between planetesimals would always be catastrophically destructive. 'Star Wars' Planets Migrate into Position around Stellar Pairs 2014-02-07T20:00:00Z The absence of a dominating nucleus beyond Mars accounts for the zone of the asteroids remaining in some sense in the original planetesimal condition. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z Instead of assembling them and migrating them towards the star, Murray’s model first migrates rocky planetesimals and then allows them to accrete. Super-Earths give theorists a super headache 2011-12-14T18:20:24.937Z The researchers' main conclusion is that Lutetia looks to be an ancient planetesimal of the type that merged to form the planets in the first millions of years of solar system history. Hard Rock: Asteroid Lutetia May Be an Intact Leftover from Planetary Formation 2011-10-28T21:45:05.277Z Condensation in the disk led to the formation of planetesimals, which became the building blocks of the planets. Astronomy 2016-10-13T00:00:00Z According to both the nebular and the planetesimal hypotheses, the earth's crust appears to be colder now than it was hundreds or thousands of millions of years ago. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z The orbits of the planetesimals and the planetary and satellite nuclei would be very eccentric, forming a confusion of ellipses with frequently crossing paths. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z That would be a surprise, given the traditional view that the gas giants grew by sweeping up smaller planetesimals. Double Impact: Did 2 Giant Collisions Turn Uranus on Its Side? 2011-10-07T10:45:05.563Z "One of the reasons why we're interested in dust is it gets incorporated in stars and planetesimals," or planetary building blocks, Barlow says. Supernovae Seed Galaxies with Massive Amounts of Dust 2011-07-07T20:15:02.380Z Solar systems form when clouds of gas and dust swirling around a star begin to coalesce — and later, when rocks and planetesimals that are the result of this process collide and fuse into larger bodies. A carbon-rich planet and the possibility of life 2010-12-08T18:05:00Z The gravitational interactions among moon-sized embryos near Earth and Venus stirred up and gravitationally scattered grains, or planetesimals, in the disk. Why Mars Is a Lightweight 2010-10-05T14:39:00Z Each planet, then, would clear up the planetesimals of its zone; and Moulton shows that this process would give rise to axial revolution of the planet in the same direction as its orbital revolution. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z Probably by the time it had engulfed all the stray planetesimals it could, it was anywhere from 200 to 400 times as large as it is now. Unexplored! Now and then alarm bells would suddenly ring a warning of the approach of a small planetesimal or some other vagrant wanderer of outer space, and the ship would change course to avoid a collision. The Golden Amazons of Venus Kriijorl's face was tilted upward, and in the faint glow of the planetesimal belt that girdled Thrayx, it seemed more than ever that of an heroic Viking king of ages gone. The Women-Stealers of Thrayx Whatever part of the primitive bolt escaped and scattered was drawn out into independent orbits round the sun, forming the "planetesimals" which behave like minute planets. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told There is a gradual gathering together of the planetesimals at points or nodes of intersection, and these become aggregations of matter, nuclei that will perhaps become planets, though more likely other stars. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z If the angle were 30 degrees or 50 degrees or 80 degrees, instead of 7 degrees, the case for the planetesimal hypothesis would be somewhat stronger. Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 Other hypotheses, having the same end in view, are the meteoritic hypothesis of Lockyer and the planetesimal hypothesis that has been largely developed in the United States. History of Astronomy These particles, or fragments, are the ``planetesimals'' of the theory. Curiosities of the Sky But it grew by drawing planetesimals into itself until it had a diameter of over 8,100 miles at the end of its growing period. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told As is apparent, these investigations lead to conclusions very different from those derived by Chamberlin and Moulton from the planetesimal hypothesis. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z THE most elaborate structure yet proposed to explain the origin of the solar system is the planetesimal hypothesis by Chamberlin and Moulton. Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 But the planetesimal hypothesis has no room for this enormous percentage of carbon-dioxide in the primitive atmosphere. The Story of Evolution In consequence of the inevitable intersection of the orbits of the planetesimals, nodes are formed where the flying particles meet, and at these nodes large masses are gradually accumulated. Curiosities of the Sky These planetesimals formed the food on which the knots subsequently fed. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told Possibly the planetesimal hypothesis of Chamberlin and Moulton affords the true explanation, as the result of a rupture due to excessive tidal strain. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z The point is not necessarily in opposition to the planetesimal hypothesis; but whatever the explanation, it ought to apply to the planet as well as to the Sun. Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 In deference to the opinion of a number of geologists we must glance once more at the alternative view of the planetesimal school. The Story of Evolution The inner satellite of Mars and the rings of Saturn make no special difficulty under the planetesimal hypothesis. Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 Hence the fundamental importance of the early atmosphere, heavy with planetesimal dust, in blanketing the earth against intensities of radiance from without, as Chamberlin says, and inequalities of radiance from within. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told They are formed by a slow ingathering of the scattered particles, which are called "planetesimals" round the larger or denser masses of stuff which were discharged by the exploding sun. The Story of Evolution The evidence, except as to the asteroids and Mercury, is not favorable to the planetesimal hypothesis, unless we make special assumptions as to the distribution of materials in the spiral nebulae. Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 On one point the new planetesimal theory differs from the other theories. The Story of Evolution |
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