A smaller body orbiting a larger, primary body, where the primary body is not a star.

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Apollo and orbital mechanics: orbital decay if the Trans Earth Injection (TEI) burn had failed

I'm reading Jim Lovell (Apollo 8 and 13) and Jeffrey Kluger's book Apollo 13, which is a fantastic read about a long past era I only have kindergarten memories of. On page 54 there is a paragraph that ...
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396 views

Why don't we see solar and lunar eclipses often?

Since we see the new moon at least once in a month when the Moon gets in between of the Sun and the Moon at the night and as far as I know if this happens during the day, you'll get to see a solar ...
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1answer
2k views

Why don't we see solar and lunar eclipses often? [duplicate]

Since we see the new moon at least once in a month when the Moon gets in between of the Sun and the Moon at the night and as far as I know if this happens during the day, you'll get to see a solar ...
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2answers
104 views

What is this shadow of the Sun on the Moon?

I was reading the article Moon Phases on HowStuffWorks. In the picture, each moon has a dark green area which represents the shadow of the Sun. How is this shadow formed and why is this important?
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147 views

Io - Turned inside out

In a lot of the descriptions of the moon Io it frequently states that the moon, because of volcanic activity, has been literally "Turned inside out". What exactly is meant by "Turned inside out" and ...
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1answer
184 views

Impact location that created the moon

I was reading an article today about the 1000th orbit of the Lunar Reconnaissance Orbiter, and as many of you know NASA created an animation that simulates the history of the moon. It is speculated ...
2
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1answer
205 views

Function to determine Earth-Moon distance vs. time

I had no luck trying to find a function that determines the distance between Earth and Moon versus time. (Moon ground level to Earth sea level) Accuracy: the acceptable time range would be for ...
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82 views

Was Aristarchos' method to compute Earth-Sun distance ever rediscovered in medieval or modern times?

Ancient Greek astronomer Aristarchos who lived around 300 BC found a method to compute the Eart-Sun distance by applying geometry. In this video about the cosmic distance ladder, at 26:30, Terence ...
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1answer
190 views

Stability of moons around tidally locked exoplanets

Can someone send me pointers to work (either theoretical or simulations) showing (in)stability of satellite orbits around tidally locked exoplanets? I want to know firstly if satellite orbits can ...
4
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1answer
304 views

How to make a moondial?

A question came up on Outdoors StackExchange, How to tell time at night. I wrote an answer to that question, and in my answer I said that a standard sundial wouldn't work without some fiddling, but ...
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3answers
521 views

Why does the moon appear bigger close to the horizon, rising or setting? [duplicate]

Possible Duplicate: Why does the moon sometimes appear giant and a orange red color near the horizon? I made a little research about this and found this article ...
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2answers
634 views

Is it possible that I just saw Jupiter's moons?

Today at about 18:00 I was looking for Venus near the moon and I saw a short bright line. I thought that maybe I was seeing Venus' crescent but it was perpendicular to the crescent of the moon. I then ...
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5answers
348 views

sun-moon-earth anomaly

When one looks at the sun and the moon in the sky together, why is it that the illuminated crescent of the moon does NOT "point" at the sun? (More correctly the perpendicular bisector of the straight ...
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0answers
54 views

Does Celestia take the lunar orbit precession into account?

Does the lunar orbit plane rotate (8 year period precession)? Does Celestia take this into account while drawing the moon orbit?
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2answers
1k views

How can the date of lunar eclipses be calculated by hand?

How can the date of lunar eclipses be calculated? Especially without the aid of a computer.
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3answers
24k views

The Moon during the day

Why do we see the Moon during the day only on certain days and not every day?
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2answers
10k views

Is the moon a planet?

Can our moon qualify as a planet? With regard or without regard to the exact definition of the planet, can the moon be considered as planet as Mercury, Venus and Earth etc. not as the satellite of the ...
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133 views

Polar ice deposits on the Moon - dispersed in permafrost loose rubble, or also massive/layered?

Water has been discovered on the Moon with remote sensing methods. Read the press release Diviner results indicate presence of widespread ice on the Moon on the "Diviner" infrared instrument on the ...
5
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1answer
58 views

Best observing techniques for a Total Lunar Eclipse?

Is there any good tricks to observing a total lunar eclipse that I should be aware of? Just wanting to know what to do to be prepared for the upcoming one, but please post in general for future ...
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1answer
183 views

Why is the shadow of earth red?

Reading this article about the forthcoming eclipse on December 10th, I noticed mention that the moon passes through the red shadow of Earth; I'd always held the impression that a shadow is universally ...
8
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1answer
347 views

How to explain the Moon halo phenomenon?

Today, here in Brazil, I have observed (and is still observing) an interesting phenomenon. The Moon is near to a big star in the sky, but this is normal. The interesting part is what's around them. ...
5
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1answer
66 views

Shadow of a Jovian moon over the Great Red Spot

Where can I find pictures of the shadow of any of the Jovian moons partially covering the Great Red Spot? A series of such pictures over time would even be better. The idea is to learn more about the ...
9
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2answers
210 views

Where does the dust on the moon come from?

From the Apollo missions we know that the moon is covered with dust. Where does it come from? Is it from the erosion of the moon rock? By what? Or by accretion of dust from space? Which comes from ...
6
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1answer
479 views

Is there a simple yet accurate formula for where on Earth the Sun and Moon are directly overhead?

I'm trying to improve a site that shows the region of the Earth currently under daylight, and I need a formula that, given the current time, tells where (latitude/longitude) the sun and moon are ...
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3answers
2k views

Why is moonlight less colourful than yellow light?

Just what the title states; and this isn't an original question ... On full-moon, moonlight is almost as bright as mid-dawn ; yet there is hardly any colour visible. This is not the case with ...
3
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1answer
68 views

Phases of the moon video

I am an educator, and I am looking for a specific video. In the video, they ask some middle school students and some college graduates about why the moon has phases. Most of the students in both the ...
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3answers
188 views

On what planar regions are the Earth, Moon.. for that matter, all astronomical bodies, placed in the Universe?

When we are on Earth, we look UP in the Sky to see the Moon. How do we have to look at Earth from Moon.. Is it the way ? If so, how are these bodies actually placed in the space? Are all astronomical ...
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How did the radiative flux of each gas giant planet change with respect to time (since their formation)?

We know that each gas giant planet was warmest when it was young. This warmth came from internal heating from both radioactive decay and from gravitational potential energy. This warmth, in turn, ...
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5answers
4k views

Why do we always see the same side of the Moon? [duplicate]

I am puzzled why we always see the same side of the Moon even though it is rotating around its own axis apart from revolving around the earth. Shouldn't this only be possible if the Moon is not ...
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2answers
95 views

What distinguishes a moon from orbiting space debris? Or in other words, when is a satellite “too small” to be a moon?

The Wikipedia article on Natural Satellites doesn't really give an adequate distinction as to what distinguishes a moon from other orbiting bodies. What I am looking for is a classification that ...
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1answer
116 views

Does the Earth help stabilize changes in the moon's obliquity as well?

We know that the moon helps stabilize changes in Earth's obliquity. But what about Earth and the moon? Are some of the obliquity-stabilizing effects (of the moon on the Earth) communicated through ...
3
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1answer
161 views

How do the day/night temperature variations of moons compare to those of their planets?

Does the planet's eclipse have a significant impact on the flux of light hitting the moon? Does tidal locking have any effect on the day-night difference of the planet?
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1answer
245 views

Next crescent moon?

How do I find the date of next crescent moon on wolframalpha or any other site which tells the appearance date time of next crescent on a specific location? I am searching for it to look for 1st of ...
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How does the central peak in moon craters form?

The central peak in many of the moon's large craters are visible with a telescope and they seem a little odd to me. Can someone explain how they form.
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If there is no gravity on the moon why is the american flag waving?

If there is no gravity on the moon, how could this flag be flapping in the wind? http://www.stumbleupon.com/su/2wD6eg/hea-www.harvard.edu/~fine/images/desktops/Armstrong.jpg
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3answers
52 views

How can one predict the length of the Synodic month? Why is it irregular?

I'd like to write a program that uses the exact (down to the second) amount of time from one new moon (or full moon) to the next. Yet, I am told that this period is irregular. Yet, it seems to be ...
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2answers
152 views

What is a “Trojan Moon”?

Today I read an article about Saturn's moon Helene, and it was described as a "Trojan Moon" but no further explanation was given. It was difficult to even get any context about the term from the ...
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3answers
92 views

What was the apparent magnitude of the June 15th 2011 lunar eclipse?

My plan was to observe and estimate the apparent magnitude of the Moon during totality of the June 2011 lunar eclipse, but the clouds rolled in at the exact moment, so I couldn't make any useful ...
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1answer
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Why did the june 2011 lunar eclipse last so long?

It was kind of hard to miss the lunar eclipse this week, although I didn't see it in person (Sod's law means that on every relatively major astronomical event clouds cover where I am). From what I ...
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4answers
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Why is a new moon not the same as a solar eclipse?

Forgive the elementary nature of this question: Because a new moon occurs when the moon is positioned between the earth and sun, doesn't this also mean that somewhere on the Earth, a solar eclipse ...
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4answers
553 views

Can a moon have another large body as a satellite, and are there any examples of such?

In my mind, I'm comparing it to the Sun-Earth-Moon system. After all, the Earth is primarily a satellite of the Sun, but the Moon is still gravitationally bound to the Earth. Could something like this ...
8
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1answer
258 views

Could the earth have another moon?

First, to clarify: I'm not asking if perhaps there's a moon that we haven't found yet. The question is, theoretically, would the earth be able to have another stable moon in addition to the current ...
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2answers
41 views

Where to find Lunar Eclipse data

I am wondering whether there's a good resource to find data about upcoming Lunar Eclipses. For example, showing the percentage of the eclipse over time. Such as: 17:23 GMT - 0%, 17:40 GMT - 10%, etc. ...
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989 views

Does the Moon's core still contain significant heat?

On earth, using earth-sheltering techniques can significantly reduce the temperature fluctuations on a structure. Would the same statement be true as well on the Moon? Does the Moon's core still ...
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2answers
213 views

Why can't you see meteors, but you can see comets from the moon?

Why can't you see meteors from the moon and why can you see comets?
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2answers
155 views

In what ways can a lunar eclipse occur?

In what ways can a lunar eclipse occur? Also, on what percentage of the Earth are they usually viewable? I am aware that there are multiple configurations that constitute a lunar eclipse (umbral, ...
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3answers
2k views

Why are there more lunar maria on the near side than on the far side?

It is widely known that the side of the moon that faces us has a particularly large number of dark patches, which resemble seas of liquid, hence, "maria". It is strange, though, that the far side of ...
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1k views

Observing Jupiter's non-Galilean moons

What strength of telescope is required to observe some of the non-Galilean moons of Jupiter? My current telescope at 50 magnification resolves the Galilean moons well, but I'm guessing it's far ...
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Why does the moon sometimes appear giant and a orange red color near the horizon?

I've read various ideas about why the moon looks larger on the horizon. The most reasonable one in my opinion is that it is due to how our brain calculates (perceives) distance, with objects high ...
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1answer
1k views

When will the Moon reach escape velocity?

From what I know, the Moon is accelerating away from the Earth. Do we know when it will reach escape velocity? How do we calculate this?