James K
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Is there a relation with the noun planet and to be in a plane?
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There is no close connection. Planet is from Greek asteres planetai meaning wandering stars (via Latin and French). Plane is from Latin planus meaning "level or flat". It is possible that both words ...

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How did they decide the length of one year even though it wasn't known that earth revolves around the sun?
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Originally a year would be noticed as the time between two winters (or two harvests, two annual floods etc), although the exact number of days might not be known with any accuracy. As people start ...

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Which star did Uranus occult in 1977 when the planet's rings were discovered?
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From wikipedia, the rings of uranus The definitive discovery of the Uranian Rings [...] use[d] the occultation of the star SAO 158687[...] The star SAO 158687, also cataloged as HD 128598 is a ...

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What point does Earth actually orbit?
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13 votes

Short answer is "The Sun". As Conrad notes, since when you include the effects of Jupiter, the Earth orbit is non-keplerian, notions of centre are not really defined. But you can ask, in Newtonian ...

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Do bigger telescopes equal better results?
13 votes

Magnification is not the main purpose of a telescope. A very small telescope will have a lower resolution than a larger one, but for larger ones, the atmosphere limits the amount of detail visible. ...

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What is the most accurate measurement of the Astronomical Unit?
12 votes

As mentioned in a comment, the AU is no longer measured, it is defined, as 149 597 870 700 metres, or exactly the distance that light travels in a vacuum in $499 \frac{9823}{2053373}$seconds. But I ...

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Logically, how can the universe be infinite in size?
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Something infinite can expand. Consider an infinite length of elastic. There are (infinitely) beads attached to it at 1m gaps. You might label one of the beads "0", then the next one is &...

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Orbits of Trojan Asteroids
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As an example, look at Earth's only confirmed Trojan By Phoenix7777 - Own work Data source: HORIZONS System, JPL, NASA, CC BY-SA 4.0, source Now, to understand what is happening here. The yellow dot ...

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How much mass per year may the black hole at the center of the Milky Way gain by capturing neutrinos?
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12 votes

Not enough to worry about. Most neutrinos we detect on Earth come from the sun. The black hole at the centre of the galaxy is not so close to a star as the Earth is so you would expect the neutrino ...

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What do the words "p-type" and "s-type" mean?
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"Satellite type" and "Planet type". The terms seem to have been coined by Rudolf Dvorak in 1982 paper "Planetenbahnen in Doppelsternsystemen" Due to the fact that ...

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Does a merging massive binary black hole ‘emits’ more than one gravitational wave?
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We can currently only detect gravitational radiation when it is extremely intense: in the last fraction of a second. For example the first gravitational wave detection lasted less 0.15 seconds. The ...

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Visible Stars in Andromeda Galaxy
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You are right that most of the dots of light that you see in the at image of Andromeda are stars in our galaxy that happen to be on the same alignment. However we can resolve stars in the Andromeda ...

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Has radio astronomy ever been done on objects that appear very close to the Moon? Is this avoided?
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Occulations of artificial probes has been used to investigate the ionosphere of the moon. See, for example http://adsabs.harvard.edu/full/2008MSAIS..12...53P In this technique, radio signals from the ...

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Why the Milky Way appears to be arching across the sky?
12 votes

The Earth is a sphere (or is nearly a sphere). So to make a map of the whole Earth you would need to project it onto a flat surface. When you do this you create distortions. For example, on many maps, ...

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Are these parallel lines I'm seeing in this image a real pattern on the Moon?
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12 votes

They are not real. The images used in the animation use a mosaic of photographs taken by an orbiting satellite, the Clementine orbiter. This satellite has a polar orbit, and so returns images in ...

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Can planetary rings form as a result of solidifed lava thrown up by volcanoes on the surface of small rocky moons/planets?
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11 votes

This doesn't seem to occur in our solar system. The most volcanic body, Io, does create a trail of gas around its orbit of Jupiter, but has no ringlike structure of its own. As uhoh notes, orbital ...

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Are satellites of trans-Neptunian objects classified as trans-Neptunian objects?
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11 votes

Yes/No as needed. The MPC, which is fairly authoritative, lists only (134340) Pluto, and doesn't include Charon and the other satellites of Pluto. Formally, binary asteroids are given a single ...

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How long was the HST initially supposed to work?
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11 votes

15 years. Hubble was designed with an anticipated 15-year lifetime based on the expected integrity of the main mirror. It was believed that over HST’s 15-year life the space environment in low Earth ...

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Is it possible to observe strong gravitational lensing with amateur telescopes?
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11 votes

The cosmic horseshoe is beyond amateur instruments. It is a magnitude 20 object. In a large (2.5 m) professional telescope it looks like: This image taken from the SDSS III data. It is small (10'', ...

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What is the longest natural bound orbit chain observed?
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11 votes

Certainly 4 (perhaps 5): The longest certainly-known chain is "3": Sun-Earth-Moon. Rhea (a moon of Saturn) has been observed to have a ring of orbiting material: That gives Sun-Saturn-Rhea-...

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Calculating the Angular Momentum of a planet
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The big essential fact about momentum is that it is conserved (in the presence of a central force, as is the case here). So the Angular momentum of Pluto today is the same as it was yesterday, and the ...

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Why don't we use amateur astronomers' telescopes to create a huge interferometer?
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11 votes

You can't make an interferometer by combining photographs. You need to combine the light sources so that the light waves can "interfere", which means you need to have not only the intensity ...

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Where are Moon's Apogee and Perigee? Do they rotate too?
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11 votes

The full moon and the new moon occur when the moon is in line with the sun. Since the Earth is orbiting the sun, the position of new moon in the moon's orbit moves. The moon takes about 27.3 days to ...

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What happens if the Moon moves twice as fast?
11 votes

No. The orbital speed is related to the distance of the moon by the equation $$v=\sqrt{\frac{GM}{r}}$$ Where G is a constant, M is the mass of the Earth (adjusted for the mass of the moon) and r is ...

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How far should the source be, for the gravitation waves to be visible on Earth?
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11 votes

The waves pass by at the speed of light. So you you would'nt see ripples, they would pass too fast, and remember the waves would be passing through you too. The wavelength was (relativly) long about ...

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Where is the Perseids meteor shower coming from?
11 votes

The comet releases lots of dust particles. The sunlight pushes these particles into orbits not quite the same as the comet Some particles will be pushed into faster orbits, some will be pushed into ...

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Why do years become shorter with time?
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11 votes

First we need to decide what you mean by "year" The first time period you mention "365.256" is the Orbital period of the Earth. It is equal 365 days, 6 hours, 8 minutes, 38 seconds. The second ...

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Temporary family member 2020-CD3
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11 votes

There is no chance of a collision in the short term. 2020 CD3 is in a rather chaotic orbit of the Earth that extends well beyond the moon and doesn't come very close to Earth Each orbit is different, ...

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Can I see Harvest moon in India?
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"Harvest moon" just means the full moon at around the time of the equinox on September 21. The full moon is low in the sky during summer (June and July in the Northern Hemisphere) and high during the ...

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Why different specifications for telescopes and binoculars?
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Binoculars tend to be mostly used for daytime observing (of birds, ships etc) Telescopes are mostly used for astronomical observing. The users of the two types of equipment want different information. ...

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