This system appears to have formed from a disk of dust and gas, drawn together by gravity. Earth and the moon, sun, and planets have predictable patterns of movement. These patterns, which are explainable by gravitational forces and conservation laws, in turn explain many large-scale phenomena observed on Earth.
These orbits may also change somewhat due to the gravitational effects from, or collisions with, other bodies. These phenomena cause cycles of climate change, including the relatively recent cycles of ice ages. Gravity holds Earth in orbit around the sun, and it holds the moon in orbit around Earth. The pulls of gravity from the sun and the moon cause the patterns of ocean tides. Seasonal variations in that intensity are greatest at the poles. Next Generation Science Standards is a registered trademark of Achieve.
Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it. Visit the official NGSS website. B: Earth and the Solar System What are the predictable patterns caused by Earth's movement in the solar system?
K-2 Patterns of movement of the sun, moon, and stars as seen from Earth can be observed, described, and predicted. The solar system contains many varied objects held together by gravity. Solar system models explain and predict eclipses, lunar phases, and seasons. Observations from astronomy and space probes provide evidence for explanations of solar system formation.
Introduction to ESS1. B from A Framework for K Science Education: Practices, Crosscutting Concepts, and Core Ideas pages The solar system consists of the sun and a collection of objects of varying sizes and conditions—including planets and their moons—that are held in orbit around the sun by its gravitational pull on them.
The significance of this is that if a test particle comes within the radius R H of a planetesimal of mass M , it can become gravitationally bound and the planetesimal continues to grow. Rather than working with mass, it is possible to convert this to a ratio of densities.
This radius is generally much bigger than the radius R of the planetesimal, meaning that the planetesimal has access to a large volume of space.
Consider that the planetesimal will orbit and eventually come into contact with anything within that radius around the entire orbit, which makes a considerable volume of the nebula available. Thus, planetesimals can grow surprisingly fast of order 10 6 yr. A large planet like Jupiter, beyond the snow line, would have grown a core by the accretion method until it was perhaps M earth. At that point, it becomes massive enough to attract and hang onto gases such as helium and hydrogen, and could then grow much more rapidly.
Jupiter would grow until the gas was depleted, again taking perhaps 10 6 yr. More distant planets Saturn, Uranus, Neptune are progressively smaller mainly because the solar nebula's density would decrease outward.
In the inner solar system, the last stages of accretion would have involved collisions between very large bodies. The Earth's Moon is thought to be the remnant of a body the size of Mars hitting the proto-Earth, stripping off mainly the outer crust of Earth which then collected into the Moon.
It was during these very large collisions that rotation axes could get knocked helter-skelter. This could explain the upside-down Venus and sideways Uranus. After 10 7 yr, the planets would have largely stopped growing, and the terrestrial planets would have been completely molten and devoid of any volatiles no water. The above scenario is probably about right, but it was developed before we had observations of other solar systems.
With the tremendous number of examples we have now, we can ask how they agree with our solar system, and how they differ. A major surprise is the number of "hot Jupiters," which are found very close to their host star in a region well inside the snow line, where they could not have formed by the scenario just described.
The best guess for what is happening is that these giant planets can actually move inward or outward in orbital radius, so the "hot Jupiters" are formed initially in one location, and migrate inward to where we see them now. There are two migration mechanisms that have been proposed and confirmed with numerical simulations.
So-called Type I migration involves density waves set up in the nebula due to gravitational interaction see similar density waves in Saturn's rings. Even stranger things can happen: Hot Jupiters. There is also a slower Type II migration that occurs within gaps of the nebula where density waves are no longer relevant.
And finally, interactions with planetesimals just inside the orbit of a planet can cause the planet to give up angular momentum and scatter the planetesimals and itself therefore migrate outward. Simulations suggest that Jupiter formed about 0. During these migrations, the two gas giants would have moved through a critical orbital resonance.
Such a resonance would have meant that Jupiter's and Saturn's gravitational influence would have combined in the same way periodically on every other Jupiter orbit, causing significant perturbations in the surrounding sea of planetesimals. It is interesting that the simulations suggest that this would occur about Myr after the formation of the inner planets and the Moon, so that this orbital resonance could have caused the bombardment that led to the craters seen on Mercury, Mars and the Moon.
This same bombardment would have brought large amounts of water to the now cooling Earth and apparently also Mars , accounting for our present-day oceans. A similar migration of Neptune outward would have scattered the Kuiper Belt objects and forced some of them in the resonance we see today including Pluto. A huge number of them perhaps trillions would have been ejected from the solar system into a vast cloud of objects as many as 50, AU from the Sun, from which the long-period comets are seen to come from today.
This reservoir of comets is called the Oort Cloud, and we will discuss it more later. We conclude that our earlier picture of a static, well-behaved solar system, where the planets are formed as we see them today, is no longer tenable. Instead, planets can migrate inward and outward, causing all manner of havoc to the remaining unaccreted planetesimals. This ends our discussion of the formation of the solar system. We will now go on to discuss the individual components of our solar system in some detail, getting to know these strange worlds that are our neighbors in space.
Density waves in a ring of Saturn caused by an interaction of prometheus with the ring. Prometheus itself can be seen in the right-center of the photo.
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