How The Life Begin

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Formation of the planets (part-2)

- July 13, 2019

The giantplanets ( Jupiter , Saturn , Uranus , and Neptune ) formed further out, beyond the frost line , which is the point between the orbits of Mars and Jupiter where the material is cool enough for volatile icy compounds to remain solid. The ices that formed the Jovian planets were more abundant than the metals and silicates that formed the terrestrial planets, allowing the giant planets to grow massive enough to capture hydrogen and helium, the lightest and most abundant elements. Planetesimals beyond the frost line accumulated up to 4 M ⊕ within about 3 million years. Today, the four giant planets comprise just under 99% of all the mass orbiting the Sun. heorists believe it is no accident that Jupiter lies just beyond the frost line. Because the frost line accumulated large amounts of water via evaporation from infalling icy material, it created a region of lower pressure that increased the speed of orbiting dust particles and halted their motion toward the Sun. In effec

Formation of the planets

- July 11, 2019

Formation of the planets See also: Protoplanetary disk The various planets are thought to have formed from the solar nebula, the disc-shaped cloud of gas and dust left over from the Sun's formation. The currently accepted method by which the planets formed is accretion , in which the planets began as dust grains in orbit around the central protostar. Through direct contact, these grains formed into clumps up to 200 metres in diameter, which in turn collided to form larger bodies ( planetesimals ) of ~10 kilometres (km) in size. These gradually increased through further collisions, growing at the rate of centimetres per year over the course of the next few million years. The inner Solar System , the region of the Solar System inside 4 AU, was too warm for volatile molecules like water and methane to condense, so the planetesimals that formed there could only form from compounds with high melting points, such as metals (like iron , nickel , and aluminium ) and rocky si

Formation and evolution of the Solar System | Pre-solar nebula

- July 09, 2019

Pre-solar nebula The nebular hypothesis says that the Solar System formed from the gravitational collapse of a fragment of a giant molecular cloud . The cloud was about 20 parsec (65 light years) across, while the fragments were roughly 1 parsec (three and a quarter light-years ) across. The further collapse of the fragments led to the formation of dense cores 0.01–0.1 pc (2,000–20,000 AU ) in size. One of these collapsing fragments (known as the pre-solar nebula ) formed what became the Solar System. The composition of this region with a mass just over that of the Sun 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. Late in the life of these stars, they ejected heavier elements into the interstellar medium .

Formation and evolution of the Solar System | new chapter begin

- July 03, 2019

Formation and evolution of the Solar System Jump to navigation Jump to search Artist's conception of a protoplanetary disk The formation and evolution of the Solar System began 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud . [1] Most of the collapsing mass collected in the center, forming the Sun , while the rest flattened into a protoplanetary disk out of which the planets , moons , asteroids , and other small Solar System bodies formed. 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 , physics , geology , and planetary science . Since the dawn of the space age in the 1950s and the discovery of extrasolar planets in the 1990s, the model has been both challenged and refined to account

What If the Big Bang Wasn't the Beginning? New Study Proposes Alternative

- July 01, 2019

What If the Big Bang Wasn't the Beginning? Was the universe created with a Big Bang 13.7 billion years ago, or has it been expanding and contracting for eternity? A new paper, inspired by alternative explanations of the physics of black holes, explores the latter possibility and rejects a core tenet of the Big Bang hypothesis. The universal origin story known as the Big Bang postulates that, 13.7 billion years ago, our universe emerged from a singularity — a point of infinite density and gravity — and that before this event, space and time did not exist (which means the Big Bang took place at no place and no time). There is ample evidence to show that the universe did undergo an early period of rapid expansion — in a trillionth of a trillionth of a second, the universe is thought to have expanded by a factor of 10 78 in volume. For one, the universe is still expanding in every direction. The farther away an object is, the faster it appears to move away from an observ

Grand unification epoch

- May 22, 2019

Grand unification epoch Between 10 −43 seconds and 10 −36 seconds after the Big Bang Main article: Grand unification epoch As the universe expanded and cooled, it crossed transition temperatures at which forces separated from each other. These phase transitions can be visualised as similar to condensation and freezing phase transitions of ordinary matter. At certain temperatures/energies, water molecules change their behaviour and structure, and they will behave completely differently. Like steam turning to water, the fields which define our universe's fundamental forces and particles also completely change their behaviors and structures when the temperature/energy falls below a certain point. This is not apparent in everyday life, because it only happens at far higher temperatures than we usually see in our present universe. These phase transitions in the universe's fundamental forces are believed to be caused by a phenomenon of quantum fields called " sy

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