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The Oort cloud is a theoretical object. Its existence is more or less accepted on the basis of "comets have to come from somewhere", but no Oort cloud object has ever been observed (except for some comets that pass near us that presumably came from the cloud). It is theorized that it has two components, one disky and one spherical, both centered on the Solar ...


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If the Oort cloud is included to the Solar System and the calculation, it has a potential to influence the barycenter significantly. The distance of the Oort cloud from the Sun is some 100,000 AU (plus minus a factor of two) and its total mass is around 5 times the Earth's mass. If there were a single orbiting object at the location of the Oort cloud, its ...


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Yes. This can be done (and is done typically) using systems of pulsars, especially in 'Pulsar Timing Arrays'. See for example https://en.wikibooks.org/wiki/Pulsars_and_neutron_stars/Using_pulsar_timing_to_study_(and_navigate)_the_solar_system. Pulsars (specifically millisecond pulsars, MSP) can be incredibly accurate clocks. Relative motion between the ...


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The Sun pulls on the Earth as well. So both Earth and Moon are "falling towards the Sun" all the time, just as they are moving in almost the same orbit. Earth causes the orbit of the Moon to "wobble" a little bit. If you were simply given the coordinates of the Moon as it moves around the Sun, you would notice there is a deviation from the expected ellipse ...


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The surface of the Sun, as you can see from the following picture, is not uniform: But it is impossible to see it with your naked eye. You will need a telescope and specialized solar filters (more information here). Notice also that the picture is not showing visible light, but extreme-ultraviolet light. You will need a special telescope for that. Or you ...


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Short answer, the sun isn't on fire. Flames can flicker with wind or with pockets of fuel that might collect and burn in spurts or bits of water that can steam when the flame touches them, causing movement, or due to small bits of turbulence as the heat expands away from the flame. The visible surface of the sun is much more like a hot iron that has a ...


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They both refer to the same thing. The habitable zone is also called the Goldilocks zone, a metaphor of the children's fairy tale of Goldilocks and the Three Bears, in which a little girl chooses from sets of three items, ignoring the ones that are too extreme (large or small, hot or cold, etc.), and settling on the one in the middle, which is ...


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P.S.2 - Done on Earth. One cannot watch the skies! If you insist on this, it cannot be done. Your condition is equivalent to us living on a permanently clouded world. In that case, we would experience alternating light and dark periods and would have no way of hypothesizing what was happening. Understanding the universe would have to wait for the ...


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There is! It corresponds just to the tides due to the Sun. Let us suppose that the Earth is not rotating around the Sun, that is, we are not in free fall towards the Sun. In this case the liquid from oceans would accumulate nearest the Sun. The effect would be only one daily tide. On the other hand when we fall towards the Sun there are accumulation of ...


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The most straightforward observation to show that the Earth moves is stellar parallax. If you take photographs of a groups of stars over a period of six months (half an orbit), some of the stars will seem to shift in position compared to the others. These stars are much closer to Earth and so seem to move more. This is similar to how, when you are riding in ...


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Now perfect balance between the centrifugal force of orbital rotation and sun's gravity is impossible so the earth's orbit should either be slowly decaying inwards or expanding outwards due to difference in magnitude of those opposing forces. This assumption is incorrect. We could make the same argument about a weight suspended from a spring. ...



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