# Tag Info

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Perigee is the Earth-specific name for periapsis. People use longitude (which is a composite angle rather than an angle) because this solves the problems of circular and equatorial orbits. The reason you need to use an epoch time to specify the Moon's argument of perigee and longitude of ascending node is because the Moon's orbit about the Earth precesses. ...

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For bodies small enough to be non-spherical, the mass is relatively low (as an example, Rosetta's bounces took a long time - it touched the surface at 15:34, 17:25 and 17:32 GMT comet time) but the centre of mass is still the point the lander will orbit. So a chaotic orbit is not a problem here What will be problems are: trying to arrange for the ...

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I know of two groups working on counting the number of long period Jupiter's in Kepler data (based on finding one transit only), but I haven't seen any results yet. Radial Velocities are the best way to answer your question because of the much longer timebase of observations.

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There are many planets known which have orbits longer than the longest exoplanet orbital periods found by Kepler. These planets were discovered using the "doppler wobble" or radial velocity technique. The plot below (a few months out of date now) shows many planets orbiting with similar periods to Mars and Jupiter. The red points we discovered by transits ...

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A simple argument why the gas cloud orbiting the Protosun formed a disc is as follows. There are two characteristic properties of this gas cloud: its total energy and its total angular momentum. While the angular momentum is conserved, the energy it not: radiation reduces the fluid temperature and hence the energy. So eventually, the cloud settles to a ...

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Is it possible to create the proposed system of satellites? Yes (in theorey). Hierarchical multiple systems (like the one proposed in the OP) tend to be stable if the periods differ by $\sim 5$ or more and the orbits are near-circular. So, such a system could be stable. A slight problem may be the commensurability of the periods (the fact that their ratios ...

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Oh my im not sure i think its by the gravity of the star pulling multiple bianry and trianry systems together to form a 7 star system it works just like a quadinary system it has 2 systems and the systems orbit each other like that continue that and it can go up to 100's of stars so the star is basicly a quadinary system orbiting a trianry or bianry with ...

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Yes. Two bodies in orbit around each other will inevitably collide. The reason for this is that the system will give off energy in the form of gravitational waves. This effect is commonly cited in binary neutron star systems, where the two stars are isolated and close together. One of the most famous of these systems is the Hulse-Taylor binary. The time it ...

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Even 100 meter NEOs could cause significant damage, and there are far more of them. LSST will be able to detect objects as faint as 24.5 in magnitude in a 30s visit, enabling it to detect 140m NEOs as far away as the Main Belt asteroids. [...] During its survey of the sky, LSST can find 90% of the PHAs over 140 meters in diameter. Earth is 1 ...

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