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].

Filter by
Sorted by
Tagged with
2 votes
0 answers
33 views

tool to calculate moonrise/moonset and moon phase for any date for any location

I have googled for such a solution but I have not found anything substantial: I found one website but it was someone's side hobby so my confidence in it is low. Thankfully, I have discovered ...
  • 183
2 votes
0 answers
37 views

How can I compute the shape and orientation of the crescent for a given time and geographic location using data from the JPL Horizons?

I can compute the following data for the Moon for a given time and geographic location using the JPL Horizons system: Apparent RA & DEC Apparent azimuth & elevation (AZ-EL) Target range & ...
-5 votes
1 answer
151 views

Help me better understand how the plane of Moon's orbit around Earth behaves

Is the plane in which Moon orbits around earth, inclined with respect to earth's equatorial plane? If yes, is it constant or does it change with time? If it changes, how much time does it take to make ...
  • 219
-2 votes
1 answer
57 views

Tidal locking of Moon [duplicate]

Since our Moon is tidally locked with earth, we always see only one side of the Moon. In such a case, how and when did mankind first realize that the Moon is also revolving around its own axis? or for ...
  • 219
3 votes
1 answer
262 views

Bolometric correction of the full moon

Now I am solving the problem about the transition from $V$ (= -13 in 400-700nm) to $m_{Bol}$. V is the full moon's apparent magnitude in 400-700mm(i.e., visible light), and $m_{bol}$ is the bolometric ...
  • 315
3 votes
0 answers
64 views

How to measure the latitude of the moon?

In the geocentric solar ecliptic (GSE) system of coordinates, the position of the Moon is described by its longitude and latitude. The former is, with great accuracy, the angular distance between the ...
  • 131
-6 votes
1 answer
168 views

Why is the moon tidally locked with the earth?

Why the moon is tidally locked with the earth? What is the reason for the tidal locking of the moon with the earth? What causes tidal locking?
  • 861
1 vote
1 answer
37 views

Lunar Librations and Subsolar Point in Matlab

So I have been trying to write a program to generate the latitude and longitude of the lunar subsolar point in Matlab. I have the ephemeris data from aero toolbox, but I can't seem to get values that ...
1 vote
2 answers
100 views

Waning gibbus moon tilt

Can anyone explain why on the 14 Oct 2022 at 7.00 UTC at location (Lat 52.339 Long 0.419)does the waning gibbous moon (Alt 39º) appear to be illuminated from a different direction, i.e. slightly ...
  • 11
2 votes
0 answers
64 views

Besides Luna, are there any models of how moons become spherical and round?

Question Given the theorized exceptional formation of Luna, (Giant-impact Hyphothesis, Wikipedia), are there any similar animated models of how the other, much smaller, moons in our solar system ...
10 votes
2 answers
198 views

How do we know the hydrocarbon lakes on Titan are actually liquid?

Cassini failed to detect any waves in the seas/lakes it observed, despite winds of 72 km/h (45 mph) being present on Titan which are able to create "sand" dunes from frozen particles, and ...
  • 345
16 votes
2 answers
4k views

How does the earth cast straight and reversed shadows on the moon?

When the Earth regularly casts a shadow on the moon, why does the shadow progress from circular to a straight line and then to a reversed circle? Since the earth is a sphere, shouldn't it cast round ...
  • 448
1 vote
1 answer
54 views

Sky viewer from the moon

Is there any app or website that is able to view the sky from the moon? It would be like https://www.timeanddate.com/astronomy/night/ except that it is viewed from ...
8 votes
3 answers
2k views

What is the difference between New Moon day and Lunar Eclipse?

A lunar eclipse occurs when the Earth is in between Sun and Moon. OK, I understand this (see diagram from Nasa). A new moon is also when the Earth is in between Sun and Moon. So, why are they not the ...
  • 181
1 vote
1 answer
76 views

Can the Celestron Powerseeker 127EQ observe the moon during day time?

I am able to find the moon with the finder scope during the day. However, when I use my 20mm lense, it seems like I am unable to focus the moon at all. Is there a fix to this?
1 vote
1 answer
96 views

The exact definition of lunar eclipse

I was finding the definition of the lunar eclipse (in which the earth blocks the sunlight that comes to the moon), and I have found that it could be defined differently. Definitions of lunar eclipse ...
15 votes
3 answers
6k views

What is the **actual** average distance of the Moon from Earth?

The Moon orbits Earth at a semi-major axis of 384400 km, with its periapsis being 363300 km and apoapsis being 405500 km. (All figures from this NASA fact sheet.) If the Moon orbited Earth at a ...
  • 2,222
1 vote
3 answers
491 views

Is there a Lagrange point between the earth and the moon?

Is there a Lagrange point between the earth and moon where a space station could sit forever without orbiting around either? Just curious, but it seems like a place like that would be perfect for ...
1 vote
1 answer
171 views

How much energy to shorten a synodic month by about 1.56%?

Suppose the moon underwent a single, massive, large-object bombardment event. About what number (or range) of about what mean mass of objects could shorten the synodic month by about 1.5633%? (Assume ...
1 vote
1 answer
73 views

Lunar sky brightness

Looking at the report "The Measurements of Sky Brightness on Lunokhod-2"1, I read that the day time visible light sky brightness was so large that it was off the scale. Unfortunately I have ...
  • 41
5 votes
1 answer
299 views

Is there a word or short phrase that denotes the apparently moving part of the lunar limb?

Between new moon and full moon, the moon's disc as viewed from the earth is bounded by a semicircular arc on its right and an arc on its left that moves to the right until at full moon it forms the ...
's user avatar
2 votes
1 answer
58 views

How to explain this elongation frequency diagram between the Sun and the Moon

Intrigued by my recent question about the average angular distance between the Sun and the Moon, I tried to inquire this little more in attempt to find the source of the asymmetry. Basically I have ...
  • 1,482
5 votes
1 answer
105 views

If the Earth became tidally locked with the moon, would that last forever?

If the Earth and the moon became tidally locked, would this last theoretically forever (assuming no external gravitational force modifies their orbits, for example, ignoring the effects caused by the ...
  • 151
3 votes
2 answers
2k views

Is it possible to block the surrounding light in a solar eclipse if we made the moon bigger or closer to the earth?

Is it possible to block the surrounding light in a solar eclipse if we made the moon bigger or closer to the earth? In an eclipse, you always see a ring of light surrounding the moon, but I am ...
  • 149
1 vote
2 answers
125 views

Earth’s rotation speed vs rate of lunar cycle

Hypothetical Question If the earth’s rotation slowed down to align to the lunar cycle so that the orbital period began and ended at the same lunar phase, what other things would result? For example, ...
5 votes
2 answers
205 views

What is the average angular distance between the Sun and the Moon?

Naturally we would expect the average angular distance(*), to be exactly 90°, for although the Moon is not running in uniform speed (or rather, to be more precise, the relative angular speed of the ...
  • 1,482
9 votes
3 answers
2k views

The moon in the first phase visible in the sky is tilted

I never noticed it before that moon I see in the sky is tilted. Does the tilt of the moon in the sky indicate the direction of the Earth's axis and direction of Earth's rotation around the sun?
18 votes
3 answers
3k views

What is this 877-year cycle in the orbits of Jupiter & Saturn, and this multimillion-year cycle in the lunar orbit?

The book The Theory That Would Not Die (by Sharon Bertsch McGrayne, 2011) states the following on page 28: He [Pierre-Simon Laplace] used other methods between 1785 and 1788 to determine that Jupiter ...
  • 323
7 votes
1 answer
253 views

Earth-Moon Barycenter Perihelion

I am trying to implement an algorithm I created to get the sun rise, transit and set accurately, but in order to do that I need to get the Earth-Moon barycenter (EMB) perihelion, and not the Earth ...
  • 173
17 votes
3 answers
3k views

Can the Earth be seen from the moon when we have a total lunar eclipse at the perigee?

We know that the Moon doesn't have an atmosphere; thus the sky is seen dark. Also, from this question, the angular diameter of the Earth viewed from the Moon is a bit bigger than $2^\omicron$ at the ...
15 votes
6 answers
8k views

How is this picture of the moon possible?

I need help understanding this images I personally took. If the phases of the moon are determined by the position of the earth, moon & sun. Then how is the moon a crescent while it is rising in ...
  • 151
6 votes
2 answers
459 views

The moon rises at a different time each day, but that difference changes. Why?

Let's say the moon rose at 5pm yesterday and 5:30pm today. The difference is 30 minutes – but that difference changes from day to day and can be anywhere between twenty-some to seventy-some minutes. ...
  • 61
1 vote
1 answer
138 views

Moon path diagram for a location

There are a lot of sun path diagrams online (i.e. https://www.gaisma.com/en/location/seattle-washington.html), but I'm struggle to find a moon path diagram. Is that called something different? I'm ...
  • 11
2 votes
1 answer
63 views

Earth-Mars-Moon or No Moon Barycenter Orbit Possible?

Could an object of sufficient mass deflect Mars so that it ends up stably orbiting an Earth-Mars-Moon barycenter? What would the distances eventually become between each orbiting body? What if the ...
-1 votes
2 answers
295 views

What if Earth’s moon started rotating?

Hypothetically speaking, what might happen to Earth if one day the moon became un-tidal locked and started to rotate?
5 votes
1 answer
52 views

When does DSCOVR see the Moon transit Earth?

In 2015, NASA published the first images of the Moon transiting the Earth as seen from DSCOVR. The text accompanying these images says such a transit would be captured on camera about twice a year. I ...
  • 153
2 votes
0 answers
51 views

How strong is the evidence or argument for the Moon as stabilizer of Earth's axial tilt? [duplicate]

It's thought that the Moon stabilizes Earth's axial tilt, and so without it, seasons as we know them could not exist i.e. there could be extremes during periods where the tilt approaches 90 degrees. ...
  • 713
22 votes
2 answers
3k views

What ground-based observational evidence is there that the Moon doesn't have an atmosphere?

The Moon doesn't have any significant atmosphere (surface pressure is $3\times10^{-15}$ bar). Can the absence of atmosphere on the Moon be determined with ground-based observations? When was it first ...
  • 16.8k
5 votes
2 answers
405 views

Tips of Crescent

Can it be shown mathematically that the line connecting tips of crescent is parallel to the North-South line and the line gives latitude of the plane ( When the Moon is sufficiently close to the ...
1 vote
1 answer
111 views

Can I use 75mm Plano convex lens to build telescope [closed]

I want to see Jupiter with moon. So am planning to build telescope. Can I use 75mm Plano convex lens with 1000mm focal length?
2 votes
1 answer
146 views

Sun Moon earth Angle

I want to do a theoretical prediction before trying out an experiment. I just noticed that the arc separating the illuminated side of moon and the shadowed side is an ellipse arc. So Is it possible to ...
7 votes
1 answer
107 views

Would anything be different on Earth if the rotation of the Moon wasn't synchronous?

The Moon is in synchronous rotation, meaning the same side of the Moon is always pointing towards the Earth. My intuition is that it wouldn't make any difference (other than the fact that the whole ...
  • 16.8k
3 votes
1 answer
113 views

Is the high-low tide difference greater, on average, at new moon, full moon, or neither?

The difference between high tide and low tide peaks when the moon is full and also when the moon is new. At both of these points in the lunar cycle, the tides are known as "spring" tides. On ...
  • 130
1 vote
1 answer
98 views

At what rate does the right ascension and declination of a planet, the sun and moon change per hour?

I'm currently building a web app and am getting the RA's and Dec's of solar system objects based on date and time chosen by the user. Then using the gmst for 0 hours of the date, the app calculates ...
20 votes
2 answers
4k views

Where in space would the Earth and Moon appear to be the same size?

If I'm directly in between the Earth and Moon, what distance from the Earth would I have to be so that the Earth and Moon have the same apparent size? How big would the moon appear compared to it's ...
16 votes
3 answers
2k views

Was lunar libration first observed or first predicted? In either case, who was the responsible party?

How old is the idea of the far side of the Moon? got me thinking that as soon as we see the moon librate we have to come to terms with there being even more of it we can't see. The Moon's libration is ...
  • 30.5k
3 votes
1 answer
276 views

How old is the idea of the far side of the Moon?

The far side of the Moon is the side which always faces away from the Earth, due to tidal locking. Due to libration, about 18% of this far side can be seen at one point or another through telescopes. ...
1 vote
0 answers
54 views

Which edge of the Moon was deeper submerged into the Earth's shadow?

I was trying to solve this little task: An Australian astronomer at the latitude of Melbourne (-38 °) observed a series of unusual events. First, he watched the setting of the sun and the rising of ...
  • 1,017
21 votes
4 answers
5k views

Where is it possible to observe the Moon for 24 hours?

I wrote an astronomy olympiad yesterday and there was one task I couldn't figure out an answer to: Estimate at what latitudes it is possible to observe the Moon for at least 24 hours. Under what ...
  • 1,017
11 votes
3 answers
4k views

Can you see the shadow of a spaceship on the Moon while looking towards the Earth?

It's a classic movie cliche. We see the surface of the Moon with the Earth in the distance and a dark shadow of an invading alien spaceship slowly covering the landscape. We see this in the opening ...

1
2 3 4 5
15