# 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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### What evidence would there be that the Moon is migrating away from Earth?

I know Neil Armstrong placed a mirror on the Moon and people shoot lasers there which get reflected, by this, measuring the time the light is needing, they can conclude the current distance of the ...
2answers
82 views

### How can the Earth and the Moon be in synchronous rotation if the Moon won't be in geostationary orbit?

It is said that the Moon moves away from Earth and that during the Sun's red giant or white dwarf phase the Moon will be about 40% farther than now and in a synchronous rotation ("hantle rotation&...
1answer
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### How did DSCOVR capture the Moon's shadow on Earth during the August 21 2017 solar eclipse without the Moon itself also being visible?

In this gif you can clearly see the Moon's shadow moving from the West Coast of the U.S. towards the East Coast during the August 21 2017 eclipse. DSCOVR (the satellite that imaged this) is located at ...
2answers
2k views

### How to explain this trajectory of the moon taken from the same spot on Earth over 28 days?

Found this picture online, was wondering why the trajectory has taken such a beautiful shape ?
1answer
105 views

### Isn't it absurdly unlikely that our Moon would constantly be “facing” us? [duplicate]

I never thought about this until recently, but our Moon is constantly rotating in such a way that it happens to perfectly be "looking at us" at all times. That sounds incredibly unlikely to ...
1answer
40 views

### What are the Kinematics / Dynamics behind the motion?

https://www.timeanddate.com/eclipse/in/@8133395?iso=20200621 The link I have attached is a predicted model for the eclipse in my area! I am very much confused about the movement of the moon analogous ...
0answers
36 views

### Keplerian Elements for the Moon and Earth around their Barycenter

So I'm looking to replicate the inner Solar System to a decent degree of accuracy. So far I've been utilizing the Keplerian Elements and Equations for the planets, as shown here. There is one issue ...
3answers
5k views

### Why is the Moon's orbit so complicated?

I like to think I have a good enough understanding of astrophysics but there's still one thing that I just can't explain. Why does the Moon orbit the Earth the way it does? Many other moons in the ...
0answers
83 views

### Best response to shut down the fake Moon landing conspiracy [closed]

This Question was closed for various reasons. For people looking for the answer to similar question, please see this link. I believe this is a solid answer to my question. As the designated Space ...
3answers
938 views

### Why doesn't the moon always follow the same path? Or why aren't the moon's apoapsis and periapsis fixed?

I have seen many times that the moon doesn't follow the same path. Sometimes the moon gets very close to earth which is shown in the news. If the periapsis of the moon is soo close then why doesn't a ...
1answer
127 views

### Historical lunar occultation of Venus seen from Sicily in the winter?

I am looking for dates in history, from 400 years ago or older, when there was an occultation of Venus by the Moon during Winter as seen from Sicily. Venus was rising, and according to the text that ...
0answers
32 views

### Ladakh India where the moon (Ramadan moon) is sighted but not in rest of India [duplicate]

Today 22 May 2020 around 3 p.m Ladakh India sighted new moon(Ramadan moon) but not in rest of India.I read many articles acc. To them it is not visible today, then how it was seen from Ladakh... .
5answers
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### Why does Io cast a hard shadow on Jupiter, but the Moon casts a soft shadow on Earth?

Io (source): The Moon (source):
2answers
71 views

### First visibility of the moon

I am new here, and hope to state the question well. In Islam, it's known that the Lunar Month starts if the Moon is sighted after the sunset of the 29th day of that month. If someone claimed that ...
0answers
48 views

### How will the Solar tides affect the Earth's rotation once it is tidally locked to the Moon?

It is my understanding that the tidal forces of the Moon acting on Earth cause it to slow down its rotation and, because angular momentum is conserved, the Moon's orbit subsequently expands. This ...
1answer
95 views

### Where is the Moon?

I live in Western Australia and I have not seen the moon for almost a solid week. Last I saw it it was almost full, and the sky has been clearer than ever with all the stars bright and visible yet the ...
1answer
71 views

### How to calculate moon overhead and underfoot time?

For hunting purposes, some hunters follow the moon phases to hunt accordingly. To give some context, here's some links: Lunar cycle's effects on hunting: https://www.acurite.com/blog/weather-stations-...
1answer
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### What symbol is used for the moon when doing calculations?

When doing calculations the mass and radius of the Earth can be represented by $M_{\oplus}$ and $R_{\oplus}$ respectively. The planets all have their own symbols which can easily be found online. ...
1answer
44 views

### Determining moonset time from Nautical Almanac

I have recently learnt to determine moonrise and moonset times using the Nautical Almanac, as part of my maritime navigation course. I have a query regarding the determination of moonset times. I will ...
1answer
61 views

### Can lunar occultation of Venus occur during solar eclipse?

Moon can occult Venus. Venus can transit across the solar disc. Moon can elipse Sun. Can all three celestial events occur at the same time - Moon is at front of Sun (partial eclipse is fine) and Venus ...
1answer
90 views

### Do Astronomers really never call Lagrangian points “libration points”?

In this answer to Who called the Lagrangian points as “Libration” points and and why was the terminology “Libration” used? I described my feeling that Lagrangian points were also sometimes called &...
2answers
70 views

### Where is the sun relative to my lunar rover?

I'm a robotics researcher writing orienteering code for a solar-powered lunar rover. I have two similar problems: Given the position of a robot on the moon in lunar latitude/longitude, where is the ...
0answers
28 views

### Lunar surface illumination

I am trying to determine the lunar surface near or far side daytime illumination levels in Lux or foot-candles but there seems to be no directly measured values available. I did find this information ...
2answers
275 views

### Is it possible to explain the difference between synodic month and sidereal month by degrees?

Is it possible to explain the difference between synodic and sidereal month by degrees - in the following way? Just recently I learnt about these two types of months, and I want to see if I can ...
1answer
76 views

### Why the time that the moon orbits the earth is becoming shorter and shorter?

I read in past that the time that the moon orbits the earth is becoming shorter constantly? (0.3 seconds per 1000 years) and what is the simple astronomical explanation?
1answer
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### Implementing the VSOP-2000 Ephemeris

For a project I'm doing, I need to implement the VSOP-2000 ephemeris for the Moon. However, unlike VSOP-87, there is little to no documentation online on how to use the data. For example, here is the ...
2answers
94 views

### Moon’s orbit shift

Has our moon’s orbit shifted since its formation? Has there been eclipses on the Earth since last ~4 billion years? In other words, was there a time when Moon's orbit was at an inclination to Earth's ...
1answer
47 views

### Simple question about the phases of the Moon

If on March 20 the Moon were located at the position of the sun, how can I determine the phase in September 22, June 22, and December 20? I drew the orbit and calculated by dividing sidereal days to ...
1answer
132 views

### Sun, Moon: Relative Distance from Crescent?

This is more a question about the history of astronomy. It recently occurred to me that you can estimate the ratio of earth-moon and earth-sun distance in the following way: We can look at the ...
1answer
63 views

### How accurate should sun\moon ephemeris be for calculating eclipses?

I am writing a program to simulate eclipses for about -2000 to 6000. My question is, how accurate does my ephemeris for the sun and moon have to be to get a decent accuracy for eclipses? I currently ...
2answers
73 views

### Right Ascension to Zodiac House

At the moment (01-04-2020 09:36) the Moon is situated in Gemini: "The Moon is currently in the constellation of Gemini. The current Right Ascension is 06h 37m 56s and the Declination is +23° 42' 09”."...
3answers
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### During an eclipse, how big is the shadow of the moon on the earth?

This picture was taken from the ISS during a solar eclipse. You can see the shadow of the Moon on the surface of the Earth. But how big is this shadow? How many kilometers is its diameter?
2answers
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### Has radio astronomy ever been done on objects that appear very close to the Moon? Is this avoided?

This answer to Which kinds of astronomical observations most need to avoid the Moon being up? mentions For completeness - radio, mid-infrared and mm-wave observations are unaffected (unless the ...
0answers
182 views

### Telescope question [closed]

During the daylight, you hold a ruler in a distance of 60 cm away from your eyes, and you find the size of the Moon to be 0.55 cm (try it yourself!). At night, you use a telescope to observe rock ...
2answers
134 views

### Which kinds of astronomical observations most need to avoid the Moon being up?

This comment to Did nobody in the Astronomy community think 12,000 new satellites in LEO might be a problem? links to Phys.org's New ESO study evaluates impact of satellite constellations on ...
3answers
105 views

### What are some dark features on (or qualities to) the moon?

I know there are mare, oceani, and lacunae, but anything else that I'm overlooking from lists of lunar features? Does the "dark"/far side have a particular, maybe Latin scientific name (tho it gets ...
0answers
104 views

### Calculating the position angle of the moon (the rolling back and forth)

I have been watching the the NASA Moon Phases Video of the year 2020. Pretty much everything makes sense and I know how to calculate it including the moon phases, declination, azimuth, apogee and ...
1answer
40 views

### What is the last day a waning moon is visible in daytime (the afternoon)?

From the fourth quarter onward, can we see the moon in the afternoon sky?
4answers
347 views

### Why is there no concavity in the orbit of the moon around the Sun?

Such questions have been asked here and I have read the answers some of which are quite informative. However, I want an answer that's straightforward. I have gone through the following paper by A B ...
1answer
56 views

### Moon Images from Earth

Is there a resource online of images of the moon (taken from the Earth) suitable for processing with a computer: I.e. taken with the same camera, optics, location, etc, over months/years? Purpose: ...
1answer
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### Temporary family member 2020-CD3

So, recently I came to know that this asteroid is orbiting Earth from past 3 years and still it is orbiting. It is kind of a mini Moon to the Earth know to have come from asteroid-belt. Is there ...
1answer
105 views

### Why does moon moves to side if I change my position directly into it?

I've setup this scenario on Stellarium where the moon is aligned with East direction. I wanted to see the change of altitude of the moon if I move straight into its direction (time of observation is ...
0answers
27 views

### Moon rotation tidal braking

Do we know if the moon had an initial rotation or did it coalesce tidally locked. If it had an initial rotation how long would it take to become tidally locked?
1answer
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### Given this report, you can see why people may think the moon landings were fake? [closed]

I was reading today that, in research published in The Astrophysical Journal, molecular oxygen has been discovered in the Markarian 231 galaxy, 561 million light-years from Earth. A light-year, which ...
0answers
51 views

### Field rotation and observing the moon

For stars, field rotation can be accounted for with an equatorial mount aligned with the Earth's axis and turning at the correct rate. Since the Moon's orbit is on a different axis then the Earth's ...
1answer
42 views

### How to understand the meaning of this International Occultation Timing Association (IOTA) lunar occultation of Mars map?

Earthsky.org's Watch Mars disappear behind the moon on February 18 as well as Moon occults Mars morning of February 18 include the image below and credit it to The International Occultation Timing ...
0answers
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### What's the first written record of the moon being tidally locked to the earth?

I couldn't find references as to who first noticed (wrote down) that the moon was tidally locked to the Earth. This, to me, doesn't seem obvious from first glance, and looks like something only found ...
1answer
139 views

### If the earth lost 1/81th of its mass how would it orbit change? [closed]

If a planet becomes lighter, then I believe its orbit will change. For example, the moon is 1/81 of the mass of the earth. So, if the moon disappeared, then the earth-moon system would lose 1/81th of ...
1answer
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### Is Earth's moon the only one where a total eclipse of the sun covers the entire sun?

Is Earth's moon the only one where a total eclipse of the sun covers the entire sun? Are any other moons the same size as the sun as viewed from their planet like Earth's moon?
0answers
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### How do I calculate moon phase orientation at any Coordinates given all the necessary data?

I'm having a problem for a couple of days where I'm trying to accurately calculate the phase angle of the moon at any given Coordinates (lon,lat).If I know my current Coordinates, Moon and sun ...