# Tag Info

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The materials that made up the solar system can be studied through the analysis of pre-solar grains and the abundances of various isotopes in primitive meteoritic material. Pre-solar grains were formed in the photospheres of stars pre-dating the Sun. These grains were then expelled into the interstellar medium (ISM) in stellar winds and also in supernova ...

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This is a complicated problem but if we make several assumptions, we can an order of magnitude estimate that should address your question. Power Source First, the sun is the source of power/energy, and we know its luminosity is ~ $3.846 \times 10^{26}$ W. Therefore, the power per unit area at various distances can be determined by dividing this result by ...

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It all depends on the closest approach of any stars to the Sun. When galaxies collide it is not that their stars crash into each other, because their individual cross-sections are extremely small when compared to the space between them. This is dealt with in qualitative terms on the wikipedia page on the likely collision. The Milky Way disk at the ...

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I was wondering that if they were orbiting in same orbit then will they both have same time period? If yes, then why because as they both have different angular momentum and both have so much of differences. I'll break this down into two parts, first looking at the period of individual objects orbiting the Sun at a distance of one astronomical unit (but ...

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The rotation period $T$ is given by $$T=2\pi \sqrt{\dfrac{a^3}{G(M_\text{Sun}+M_\text{planet})}}$$ where $a$ is the sum of the half axes of the ellipse. Routhly: $M_\text{Sun}=2\times 10^{30}$ kg $M_\text{Earth}=6\times 10^{24}$ kg $M_\text{Jupiter}=2\times 10^{27}$ kg If you assume both Earth and Jupiter are orbiting around the Sun (and neglect the ...

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A collapsing gas cloud is an open system. It loses mass, energy and angular momentum as it collapses. Even if the net angular momentum of the cloud is zero, after the collapse the final planetary disk can have a significant net angular momentum, and the ejected material will have the opposite angular momentum. What can not happen, and that's where your ...

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So basically, You not at much risk piloting through an Established asteroid Field/Belt, Unless you trying to pilot something Huge like a Planet through it. But in star Wars, In the case of the destruction of Alderan, It is in that one case, a risky proposition as it is a newly created debris field which hasn't had time to Stabilize. In the Asteroid Field ...

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Approximations are made: Earth's orbital velocity remains the same: Angle between the Earth and the Earth's perihelion $\theta$ is increasing constantly. Eccentricity is small enough, that ellipse can be approximated to be $r=a(1-e \cos\theta)$. Earth is at its perihelion on 4th of January, and its eccentricity is 0.0167, so the given formula can be ...

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$$1- 0.01672*\cos(0.9856*(\text{day}-4))$$ This is an approximate expression. Term by term, $1$ The mean distance between the Earth and the Sun is about one astronomical unit. $0.01672$ This is the eccentricity of the Earth's about about the Sun. $\cos$ This is of course the cosine function, but with argument in degrees rather than radians. $0.9856$ This ...

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There is plenty of evidence for planets around evolved stars (giants) and there is also plenty of evidence for planetary material around white dwarfs and planets around neutron stars. Planets around red giants are primarily found using the Doppler technique (the planets are too small compared with the star to produce a significant transit signal). See for ...

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For your first question, a requirement for a solar system is that there must be at least one star contained within it. Without a star or some other intense gravity field holding the planets in orbit, the planets would drift away. It is possible for any class of star- from dwarf to supergiant- to hold planets in orbit and therefore have a solar system. ...

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If I understand the question right, we suppose we want to prove to someone that the earth orbits the sun. I'm not quite sure that' the case from a scientific point of view. Literally speaking, we can choose any reference frame we like and thus prove a heliocentric system or a or a geocentric. Quoting Einstein:" The struggle, so violent in the early days ...

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The latter idea you talk about is the Giant Impact Hypothesis. It turns out that you can make a moon in a few easy steps (given the correct conditions): Have a bunch of protoplanets whiz about on semi-chaotic trajectories. Smack two of them together at a 45° angle. Let the bits of the protoplanets that don't merge together be ejected from the resulting ...

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Why is angular momentum conserved when a planet revolves about sun in an elliptical orbit? Why is linear momentum not conserved in this case? $$\rm \text{no external }\color{red}{torque}\to\color{red}{angular}\text{ momentum conserved}\\ \text{no external }\color{red}{force}\to\color{red}{linear} \text{ momentum conserved}\\$$ There is no external ...

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Both are conserved if you consider the whole system: If the earth looses linear momentum, the sun will gain it and vice versa. Subsystems may violate conservation laws (e.g by transfering energy/momentum). This is called local violation. But globally conservation laws will always hold. The question why they hold globally in the first place, can be answered ...

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