Formation Of The Solar System
By analyzing the radioactive decay of radioactive elements in the meteorites, astronomers have said that the origin of the solar system can be traced back to 4.6 billion years ago. This was when a gravitational collapse of a small portion of a giant molecular cloud occurred. This is known as Nebular Hypothesis which was developed for the first time by Emanuel Swedenborg, Immanuel Kant and Pierre-Simon Laplace in the 18th century, and is a theory widely accepted across the globe. However, this theory has been challenged and refined after the dawn of the space age and the discovery of extra solar planets in the 1950s and 1990s respectively.
Our Solar System Formed In Less Than 200000 Years
This was a rapid process.
The oldest solids framed in the Solar System are calcium-aluminumrich inclusions , small metallic droplets later incorporated into meteorites. The ages of CAIs are considered the age of the Solar System, however which exact moment in star arrangement they correspond to has been unclear.
New research by a group of Lawrence Livermore National Laboratory scientists- looking at isotopes of the element molybdenum found on meteorites- suggests that our sun and solar system formed over the short period of 200,000 years.
LLNL cosmochemist Greg Brennecka, lead author of a paper, said, This work shows that this collapse, which led to the formation of the solar system, happened very quickly, in less than 200,000 years. If we scale this all to a human lifespan, the solar systems formation would compare to pregnancy lasting about 12 hours instead of nine months. This was a rapid process.
The micrometer-to-centimeter-sized inclusions of CAIs in a high-temperature environment , probably near the young sun. They were then transported outward to the region where carbonaceous chondrite meteorites formed, where they are found today. The majority of CAIs formed 4.567 billion years ago, over about 40,000 to 200,000 years.
Key Concepts And Summary
A viable theory of solar system formation must take into account motion constraints, chemical constraints, and age constraints. Meteorites, comets, and asteroids are survivors of the solar nebula out of which the solar system formed. This nebula was the result of the collapse of an interstellar cloud of gas and dust, which contracted to form our star, the Sun, surrounded by a thin, spinning disk of dust and vapor. Condensation in the disk led to the formation of planetesimals, which became the building blocks of the planets. Accretion of infalling materials heated the planets, leading to their differentiation. The giant planets were also able to attract and hold gas from the solar nebula. After a few million years of violent impacts, most of the debris was swept up or ejected, leaving only the asteroids and cometary remnants surviving to the present.
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The Solar System: Facts About Our Cosmic Neighborhood
BySarah Wild10 July 2020
From the scorching surface of Mercury to the frozen outer reaches of the Oort Cloud, this is our galactic neighborhood.
About 4.6 billion years ago, a giant cloud of dust and gas known as the solar nebula collapsed in on itself and began to form what would eventually become our solar system’s sun and planets. Our solar system hosts the sun at its center a star so large that its gravitational pull keeps numerous planets, dwarf planets , comets and meteoroids orbiting around it.
The Late Heavy Bombardment
Once the planets matured, however, all was not calm in the solar system. The inner rocky worlds had stabilized, and the sun had ignited nuclear fusion. But the outer giant planets were surrounded by swarms of hangers-on the leftover bits of debris from the chaotic planet-building process.
So they began to dance.
Astronomers suspect that the four giant planets of our solar system Jupiter, Saturn, Uranus and Neptune initially formed much closer together than they are today, and subtle interactions with the remaining debris surrounding them caused them to shift their orbits. It took hundreds of millions of years to resculpt our solar system, and we’re not exactly sure how it all went down.
In one scenario, Jupiter and Saturn migrate inward toward the sun, which caused Uranus and Neptune to drift outward. In another scenario, the worlds of our outer solar system play a game of gravitational hot potato with a bonus fifth giant planet that eventually got ejected altogether. In yet another, Jupiter wanders nearly to the orbit of Mars before jumping back out, disrupting the otherwise placid orbits of the remaining outer worlds.
Despite the violence, it wasn’t all bad: the procession of comets raining in toward the inner solar system delivered an abundance of water to the rocky worlds, potentially making life, including us, ultimately possible once the solar system settled down, of course.
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Further Evolution Of The System
All the processes we have just described, from the collapse of the solar nebula to the formation of protoplanets, took place within a few million years. 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. What was their fate?
The comets visible to us today are merely the tip of the cosmic iceberg . Most comets are believed to be in the Oort cloud, far from the region of the planets. Additional comets and icy dwarf planets are in the Kuiper belt, which stretches beyond the orbit of Neptune. These icy pieces probably formed near the present orbits of Uranus and Neptune but were ejected from their initial orbits by the gravitational influence of the giant planets.
In the inner parts of the system, remnant planetesimals and perhaps several dozen protoplanets continued to whiz about. Over the vast span of time we are discussing, collisions among these objects were inevitable. Giant impacts at this stage probably stripped Mercury of part of its mantle and crust, reversed the rotation of Venus, and broke off part of Earth to create the Moon .
Is There Life In The Solar System Aside From On Earth
Europa and Enceladus, moons of Jupiter and Saturn respectively, are ice-covered rocky objects that scientists think may harbour life in the water beneath the surface. Some geological evidence points to the possibility of microorganisms on .
Solar system, assemblage consisting of the Sunan average star in the Milky Way Galaxyand those bodies orbiting around it: 8 planets with about 210 known planetary satellites countless asteroids, some with their own satellites comets and other icy bodies and vast reaches of highly tenuous gas and dust known as the interplanetary medium.
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Formation Of The Terrestrial Planets
The grains that condensed in the solar nebula rather quickly joined into larger and larger chunks, until most of the solid material was in the form of planetesimals, chunks a few kilometers to a few tens of kilometers in diameter. Some planetesimals still survive today as comets and asteroids. Others have left their imprint on the cratered surfaces of many of the worlds we studied in earlier chapters. A substantial step up in size is required, however, to go from planetesimal to planet.
Some planetesimals were large enough to attract their neighbors gravitationally and thus to grow by the process called accretion. While the intermediate steps are not well understood, ultimately several dozen centers of accretion seem to have grown in the inner solar system. Each of these attracted surrounding planetesimals until it had acquired a mass similar to that of Mercury or Mars. At this stage, we may think of these objects as protoplanetsnot quite ready for prime time planets.
The Sun And Planetary Environments
Around 5.4 billion years from now, the core of the Sun will become hot enough to trigger hydrogen fusion in its surrounding shell. This will cause the outer layers of the star to expand greatly, and the star will enter a phase of its life in which it is called a red giant. Within 7.5 billion years, the Sun will have expanded to a radius of 1.2 AU256 times its current size. At the tip of the red-giant branch, as a result of the vastly increased surface area, the Sun’s surface will be much cooler than now and its luminosity much higherup to 2,700 current solar luminosities. For part of its red-giant life, the Sun will have a strong stellar wind that will carry away around 33% of its mass. During these times, it is possible that Saturn‘s moon Titan could achieve surface temperatures necessary to support life.
As the Sun expands, it will swallow the planets Mercury and Venus.Earth‘s fate is less clear although the Sun will envelop Earth’s current orbit, the star’s loss of mass will cause the planets’ orbits to move farther out. If it were only for this, Venus and Earth would probably escape incineration, but a 2008 study suggests that Earth will likely be swallowed up as a result of tidal interactions with the Sun’s weakly bound outer envelope.
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How Our Solar System Was Born
Discover how a giant interstellar cloud known as the solar nebula gave birth to our solar system and everything in it.
The solar system as we know it began life as a vast, swirling cloud of gas and dust, twisting through the universe without direction or form.
About 4.6 billion years ago, this gigantic cloud was transformed into our Sun. The processes that followed gave rise to the solar system, complete with eight planets, 181 moons, and countless asteroids.
Researcher Tim Gregory explains how it burst into being.
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In the 1940s, British astronomer Fred Hoyle proposed that the Sun once had a much larger companion star which had exploded as a supernova. Some of the resulting shrapnel was snared by the Suns gravity, later coming together to form the planets. But that didnt hold water either, partly because it struggled to explain the low masses of Mercury and Mars.
It wasnt until the 1970s that things started to make more sense, when astronomers returned to Laplaces nebula theory. The main problem with this theory that the observed rotation of the Sun was slower than expected could be eliminated if drag caused by dust grains in the surrounding cloud had helped put the brakes on.
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How Did Our Planet Form
It all started with a tremendous bang. Somewhere in our galaxy a star exploded, throwing out masses of gas and dust. This supernova, as these explosions are called, happened about 5bn years ago. The wreckage from the explosion then crashed into a nearby cloud of gas, bringing together the ingredients for our solar system to form.
Because the explosion was so energetic it made the dust mixture very hot and things began to cook. Little bits of dust began to cluster, making bigger and bigger lumps, and the mixture began to pull together under its own gravity.
Eventually the central lump became so hot and dense that it started to generate its own energy, igniting nuclear fires. This was the birth of our sun. The remaining dusty mixture swirled around the star, fanning out into a disc.
Gradually the sun grew in size and the dusty disc cooled. Over millions of years the dust clustered into grains, then lumps, boulders and eventually planetesimals – chunks of rock big enough to have their own gravitational field. Some of these planetesimals became the embryonic forms of the planets in our solar system today.
Slowly these rocky planets began to organise themselves, settling at a comfortable distance from the sun and finding their own orbit. Earth found its path as third planet from the sun. In the early days rocky pile-ups were still common, leaving craters on the surface of all of the planets.
The Solar System: How Do We Know How It Formed
Asking questions about where we come from is one of the traits that marks us out as distinctly human. Yet this inquisitive streak hasnt always led us in the right direction, particularly when we think we are more important than we ultimately are.
The story of our quest to discover how our Solar System formed is littered with false starts, and one that astronomers are still refining.
The worlds greatest thinkers originally had the Earth at the centre of creation, with the Sun, Moon, planets and stars circling around us. Its an idea that lasted for more than 1,000 years, dating back to the days of Aristotle and Ancient Greece.
It wasnt until the Polish astronomer and mathematician Nicolaus Copernicus challenged this idea in the 16th Century that the tide of opinion started to shift. He said that the planets including Earth orbit around the central Sun.
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Solar System Formed In Less Than 200000 Years
A long time ago roughly 4.5 billion years our sun and solar system formed over the short time span of 200,000 years. That is the conclusion of a group of Lawrence Livermore National Laboratory scientists after looking at isotopes of the element molybdenum found on meteorites.
The material that makes up the sun and the rest of the solar system came from the collapse of a large cloud of gas and dust about 4.5 billion years ago. By observing other stellar systems that formed similarly to ours, astronomers estimate that it probably takes about 1-2 million years for the collapse of a cloud and ignition of a star, but this is the first study that can provide numbers on our own solar system.
Previously, the timeframe of formation was not really known for our solar system, said LLNL cosmochemist Greg Brennecka, lead author of a paper appearing in Science. This work shows that this collapse, which led to the formation of the solar system, happened very quickly, in less than 200,000 years. If we scale this all to a human lifespan, formation of the solar system would compare to pregnancy lasting about 12 hours instead of nine months. This was a rapid process.
Since the observed time span of stellar accretion is much longer than CAIs took to form, the team was able to pinpoint which astronomical phase in the solar systems formation was recorded by the formation of CAIs, and ultimately, how quickly the material that makes up the solar system accreted.
But Exactly How Did This Proceed
New observations of young solar systems, complete with still-forming material around just-born planets, may give us a clue. And that clue has one name: dust.
According to new research, the material around the young Jupiter acted as a dust trap, collecting any wayward material drifting through the baby solar system. This allowed proto-moons to form one by one and then migrate inwards to find a home orbit around their parent planet. Without the dust, it’s a little unclear how exactly the moons of the gas giants could form in a short enough amount of time .
This new model is bolstered by the observation of a lot more dust than expected around young alien exoplanets if it is happening over there, right now, it might have happened here, long ago.
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Despite The Exteme Conditions Of The Bombardment Could Life Have Survived The Lhb
On Earth the end of the late heavy bombardment coincides with another important epoch for our planet the emergence of life.
When the LHB was first postulated it was thought that comet-like impactors may have brought the ingredients necessary for life, most notably water.
However, findings from missions such as Rosetta show that its unlikely comets brought any appreciable about of water to the Earth, though they may have brought other prebiotic compounds such as hydrocarbons.
Another theory is that life emerged long before the bombardment, but that all evidence was eradicated by the barrage.
If this was so, then only the hardiest of life would have survived. An impact large enough to affect the global environment would have struck every century or so.
And around every 10 million years there would have been an impact large enough to melt up to 10 per cent of the surface.
But even such colossal collisions would not have destroyed all havens for life across the planet.
While the top few kilometres of ocean might boil away, there could still be enough water left behind for life to survive.
Its quite possible that life started before, and found ways to protect itself, says Herbert Frey of NASAs Goddard Space Flight Center.
I think life is pretty hardy once it gets started, and it may have found a way to survive through that.