Questions tagged [the-moon]

Questions regarding Earth's only natural satellite. For questions about the natural satellites of other planets, use the tag [natural-satellite].

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7 votes
1 answer
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Why are lunar craters preferentially north-south aligned?

Loading the dataset from Robbins 2018, A New Global Database of Lunar Impact Craters >1–2 km: 1. Crater Locations and Sizes, Comparisons With Published Databases, and Global Analysis which I ...
David McKee's user avatar
1 vote
0 answers
57 views

How to calculate the Topocentric Elongation of the Moon?

I was trying to calculate the Topocentric Crescent Width and I found this answer, How to calculate Topocentric Crescent Width and Moon Radius/Semi-Diameter? However, I am missing the Topocentric ...
Jari's user avatar
  • 11
3 votes
2 answers
132 views

Will the Moon recede far enough that the Earth-Moon barycenter lies outside of Earth's radius before the Sun becomes a red giant?

As most people know, the Moon is receding from Earth at a rate of a few centimeters per year. This rate is not constant; as the Moon gets farther away, the tides it raises will be weaker and thus will ...
user267545's user avatar
10 votes
3 answers
783 views

Proportion of Lunar Fraction in a Year

I grabbed a year of lunar fraction data from the USNO and binned the counts to find the shape of the curve as below My understanding of lunar fraction was that 0.5 does not distinguish between the ...
Zac Warham's user avatar
1 vote
1 answer
75 views

calculating apogee and perigee for moon and sun

The perigee does not necessarily happen when we have a full moon, using swevents we can easily determine the moon phases. Now can we use python to determine when ...
dimitri33's user avatar
  • 127
1 vote
0 answers
49 views

Looking for data and models for events of Sun and Moon apparent motion in distant past?

For the current Julian Era (from 1, 1, 4713 BCE to modern day), I am looking for a raw data tables or a model that allows to predict the following events related to apparent motion of Sun and Moon: ...
Suiinditor Impudens's user avatar
5 votes
2 answers
552 views

Sky illumination based on moon phase and altitude

Does anyone know if there has been any work in determining the impact of the moon on sky brightness based on phase, moon altitude (including below the horizon), location altitude, humidity, etc? This ...
tockpeas's user avatar
1 vote
0 answers
65 views

Is there a specific area on the far side of the moon, directly below the L2 Lagrange point in the Earth/Moon system?

It seems like there should be, and if so I wonder how large an area it is, if it changes size over time, and if it moves or wobbles in some way. On the latst point, I imagine it would certainly wobble ...
Nick Codignotto's user avatar
-2 votes
1 answer
133 views

Earth and the Moon Question [closed]

(For the purpose of this question, I will refer to Earth's Moon as Luna to keep it separate from the general term of 'moon') I know the IAU has been hedgey about giving an official definition of what ...
user53218's user avatar
-1 votes
3 answers
3k views

Is it possible to view the sun and moon in the sky at the same time?

I'm writing a story. I want my ending to have the sun and moon visible in the sky at the same time. It is symbolism for the larger story. Is this possible? I have tried searching and can't find ...
CJ Winters's user avatar
4 votes
4 answers
5k views

What is the ring of light around the moon and which star seen near it?

In this amatuer photograph, the following are to be noted: There is a faint ring of light around the moon. What is the distance we see this at. From the ground it looks like a hundred meters. There ...
Nick's user avatar
  • 239
3 votes
3 answers
1k views

Celestial "orbits"

I heard that we're losing our moon, its slipping away from us in such tiny imperceptible steps that we don't notice any significant change even over kiloyears. The same must apply to planets, inching ...
Agent Smith's user avatar
3 votes
0 answers
88 views

Confusion about the position of lunar perigee

I'm using python pkg named astronomy-engine.First,I find 2 consecutive perigee times of moon. ...
AInseven's user avatar
1 vote
1 answer
109 views

sideways crescent moon but also no moon somewhere else?

I live in Sumter, South Carolina and the moon looked like a crescent moon but sideways like a bowl. But when I told my friend to look at the moon they couldn't find it and they live in Buffalo, New ...
Cakebandit06's user avatar
11 votes
1 answer
5k views

Why did Theia create only one moon if it struck Earth?

If I dropped a heavy ball into some magma it would splash all over the place. So why would Theia create only one large drop of liquid (the moon) and if it impacted the Earths mantle (Bits of Theia ...
DaveTheWave's user avatar
4 votes
1 answer
153 views

Could a Martian observer witness the Moon's formation with naked eye?

Suppose a human observer was standing on Mars during the early Solar System, looking up into the night sky, in the approximate direction of the young Earth, as the Theia planet hypothesized in the ...
Ezra Bailey's user avatar
6 votes
1 answer
1k views

How can the new moon set before the sun, as will happen in some locales on November 13, 2023?

I have somewhat of an interest in sighting the new moon. I recently heard a lecture by someone who had written a program to provide the conditions for the first new moon sighting for any location for ...
Michael Appel's user avatar
1 vote
1 answer
56 views

Moon's libration from Mathematica data

Wolfram Mathematica provides "TransitTime" option (for the Moon in particular). Knowing this time moment, you can get the position of the moon at upper culmination (for example, for each day ...
lesobrod's user avatar
  • 123
5 votes
2 answers
334 views

What causes the variation in the length of the synodic month, BESIDES the eccentricity of the Moon's orbit? And how much do they contribute?

When explaining the reason for the variation in the length of the synodic lunar month, usually the only explanation given is that the Moon's orbit is elliptical, and the portion of its elliptical ...
George Lee's user avatar
3 votes
1 answer
124 views

How much does the eccentricity of EARTH'S orbit effect the length of the synodical lunar month?

Usually, only the eccentricity of Moon's orbit is used as an explanation for the varying length of the lunar month. But Earth's orbit's eccentricity should also contribute to that. How much does it ...
George Lee's user avatar
2 votes
0 answers
82 views

Which conditions / situations / place / moment is there a purple moon in the sky in?

According to this A purple moon? In March 12, 2017 there was a purple moon somewhere , "just risen, color altered red moon". I've seen yellowish, redish moons, but I've never seen a purple ...
Pablo's user avatar
  • 1,081
3 votes
1 answer
185 views

Will Lunar Months be the same length Millions of Years in the Future?

If I remember correctly, the amount of time it takes for the moon to rotate around Earth is getting longer over time. Is this true, and if so or the opposite is true and a lunar month is getting ...
Dromeoraptor pennato's user avatar
4 votes
1 answer
162 views

Get Moon libration data from JPL Horizons

I've been searching Horizons settings to find lunar librations but can't find. How can I get the libration data? So I have tested this Horizons Web Application and selected Moon as the target. Whether ...
user3202179's user avatar
0 votes
1 answer
102 views

North Node cross longitude?

It appears that that swetest can tell the exact longitude as long as you give it the date and time ...
dimitri33's user avatar
  • 127
1 vote
1 answer
116 views

Identify the bright object to the left of the moon

I'm seeing the sky at 23:00 on September 29, 2023, from the east of Algeria's point of view. To the left of the moon, there is something very bright. I need to confirm if it's Jupiter? (My camera ...
Mr Saw's user avatar
  • 13
1 vote
1 answer
166 views

Determining the position of the North Node using math?

I have to be honest. Been learning python for few months but when I saw this code I was blown away, mainly by its simplicity and secondly by not understanding it .. can someone help me understand ...
dimitri33's user avatar
  • 127
2 votes
0 answers
99 views

True node (NN) calculation .. off by 10 seconds

...
dimitri33's user avatar
  • 127
0 votes
2 answers
2k views

How do people of the opposite side see the Moon and the Sun?

I was looking in the StarTracker android application from Tehran, Iran; and this is the screenshot: As you can see the Moon covers a small portion of the Sun. The green line above them is the ...
Snack Exchange's user avatar
1 vote
2 answers
214 views

Sun or moon, finding the date and time of crossing a specific longitude

the Sun is currently in Virgo ♍, 13°7'9" or longitude 56.0762 degrees how does one calculate when exactly the Sun will reach this position again. Since the moon is doing a spin in 29.x days lets ...
dimitri33's user avatar
  • 127
2 votes
1 answer
71 views

What secondary and tertiary conclusions can be drawn from the temperature characteristics of lunar soil sent by ISRO Chandrayaan 3?

ISRO Chandrayaan 3 released the following data today about the temperature characteristics of lunar soil. What secondary and tertiary conclusions can be drawn it? More specifically, what may be the ...
Ritesh Singh's user avatar
1 vote
1 answer
69 views

What is the duration of a year on the Moon (Tropical/Sidereal period) for orbit about the Sun ? How/why does length of lunar days vary ? Soltices?

The inclination of the lunar equator to the ecliptic is 1.543°. Synodic period or Length of a day on the moon = 708.7344 hours Moon Fact Sheet 100 Lunar Days - Parts I and II
Viśvakarmā's user avatar
21 votes
4 answers
7k views

Why doesn't the Moon, like the Sun, turn bright red when it's close to the horizon?

Why does the Moon, being close to the horizon, turn red only slightly, or not at all? Aren't the causes that lead to the coloring of the Sun (atmospheric refraction) are also true for the Moon? In ...
Vladimir Orlov's user avatar
1 vote
2 answers
1k views

Why isn't a month 28 days?

1 days is a rotation of earth. 1 years is an orbit of the sun. I've always beleived that one month is 1 period of the moon orbiting earth but the inconsistent distribution of days throughout the ...
Ethan's user avatar
  • 147
1 vote
1 answer
49 views

How to compute Date and time to next Ascension / Descension of the Moon

Is there an easy way to calculate the next date and time for Ascension / Descension of the Moon? I work with swift language but a mock code will be ok for me.
Sebastien REMY's user avatar
9 votes
2 answers
221 views

What is the albedo of the far side of the Moon?

As is well known, and as you can see in the image below, the far side of the Moon is brighter than its near side. What is its overall albedo? And what would be the magnitude of a full moon if the (...
George Lee's user avatar
12 votes
3 answers
5k views

How do we know the Moon was much closer than it is now?

We know that right now, by measurement, the Moon is moving further away from the Earth. So I've heard the conclusion that the Moon was much closer to the earth in the past. How do we know that part? ...
scm's user avatar
  • 301
0 votes
1 answer
236 views

How old are the total solar eclipses as we see them today? [closed]

I've seen it referenced often that "total solar eclipses" (of the kind we see today where the corona of the Sun is visible as opposed to all of it being blocked) have become possible only ...
Rohit Pandey's user avatar
7 votes
2 answers
2k views

Position of the Moon viewed from same spot couple of months apart

In the below image, the position of the moon as viewed from the same spot is displayed. The drawing to the left is from today at local time of 2am. The drawing to the right is from a couple of months ...
Pika-Chu's user avatar
  • 103
9 votes
1 answer
3k views

Moon moving near horizon much faster than at zenith, reason? error?

I read that the apparent motion of the moon is approximately its diameter every hour. However, we just observed the moon appearing to rise through a stationary cloud in about 10 minutes, it definitely ...
Dov's user avatar
  • 201
0 votes
1 answer
285 views

Why does the moon move within the zodiacal circle if its orbit is at an angle to the plane of the ecliptic?

The moon moves along the zodiac circle along with other planets, this is a known fact. But at the same time, its orbit is inclined to the plane of the ecliptic. According to the above diagram, the ...
Vladimir Orlov's user avatar
1 vote
1 answer
66 views

Will the Earth tidally lock to the Moon (ignoring Sun's expansion)

At some point, won't the tidal forces from the Moon be less than the ones from the Sun? Would that mean that the Moon stops moving away, or would the process still continue. Would the Earth start ...
user138890's user avatar
2 votes
3 answers
208 views

What does the rate the Moon moves away from Earth depend on?

Is it based on the distance between the Earth and Moon? Would that make the Moon move away faster or slower as time goes on?
user138890's user avatar
12 votes
1 answer
2k views

Would the Earth and Moon still have tides after the Earth tidally locks to the Moon?

Ignore the Sun's expansion. From my understanding, tidal locking happens from torque as a result of tidal bulges being offset from the line between the two planets. So when the Earth and Moon tidally ...
user138890's user avatar
1 vote
1 answer
99 views

How far should we be from Earth to see a half Moon while it is seen as a crescent on the Earth?

When we see a crescent Moon that means it should be seen a half Moon from another position in the sky, because the terminator line (i.e. the line that separates the bright and dark areas of the Moon) ...
Snack Exchange's user avatar
1 vote
1 answer
165 views

How to calculate Topocentric Crescent Width and Moon Radius/Semi-Diameter?

I have the Topocentric Moon Altitude, T. Moon Azimuth, T. Sun Altitude, T. Sun Azimuth, T. Elongation, T. Phase Angle. How do I calculate the Topocentric Crescent Width and the Topocentric Moon Radius/...
orchid's user avatar
  • 31
5 votes
2 answers
141 views

Why does earthshine fade out when night comes and reappear on the next evening?

While watching the Moon in the thin-crescent phase (a few days after new Moon), I often noticed that the earthshine becomes noticeable near the end of civil twilight, and very noticeable during ...
Ruslan's user avatar
  • 897
1 vote
1 answer
146 views

If someone were to create a lunarcentric solar system model, what would have to change about the math and model besides swapping Earth and the Moon?

A story I wanted to think about has a society centred on the Moon in some colony, and for some reason didn´t have telescopes of their own. Why is not important. The Moon orbits the Sun in almost the ...
R-Obsessive's user avatar
4 votes
2 answers
353 views

What does the moon's phases look like from the Equator?

I recently found out that the moon's appearance changes based on one's latitude, and while googling for more information I found conflicting images about what the moon's phases look like from the ...
Wimateeka's user avatar
  • 141
4 votes
3 answers
575 views

Is this definition of tidal locking really satisfying?

We always are hearing this: "If a moon has equal rotational and orbital periods it's tidally locked to its host planet and always one side of it will face to the planet." But what if, for ...
Snack Exchange's user avatar
2 votes
0 answers
84 views

Moon position differences on JPL Horizons, GMAT, Skyfield (using DE421)

I found a relevant difference in the positions for the Moon when calculating its Geocentric position with GMAT and Skyfield (https://rhodesmill.org/skyfield/), in both cases with JPL DE421. ...
Thibault's user avatar

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