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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Why can I see the whole moon during various non-full-moon phases?

Here's an image that describes the phenomenon I'm asking about. The very thin sliver to the left is of course the surface of the moon as lighted by the sun. But the rest of the moon is also faintly ...
TwoMice's user avatar
  • 203
10 votes
3 answers
2k views

Can Earth host another natural satellite than the Moon?

Are there orbits with long-term stability (astronomical time scales) around Earth? Low altitude orbits will decay due to friction with Earth's atmosphere. Inside Earth's Roche limit, a Moon could not ...
Anthony X's user avatar
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9 votes
2 answers
3k views

Can I measure the moon's gravity?

Since I learned about Newton's gravity law, I wonder if I can measure the moon's gravity using (almost) no special equipment. The best I could come up with is a pendulum, which is in a resting ...
agtoever's user avatar
  • 279
8 votes
2 answers
3k 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. ...
Treplef's user avatar
  • 81
8 votes
3 answers
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Implementation of formulae for Meeus for the Moon

With Astronomical Algorithms by J. Meeus (1998) I have obtained the relevant illuminated fraction of the disk and position angle. But they're numbers (all Greek to me!) I know, Meeus explains that ...
Danny F's user avatar
  • 192
6 votes
1 answer
729 views

How fast was the Earth spinning directly after the Moon formed?

I understand the Moon was perhaps five Earth radii away when it first formed (assuming it was formed by a giant impact of a Mars-sized body), and Earth has since transferred its rotational energy into ...
Ags1's user avatar
  • 394
5 votes
1 answer
275 views

How long does lunar opposition surge last? Are there measurements of the full Moon getting suddenly brighter?

Wikipedia's opposition surge is a short article and forwards shadow hiding and coherent backscattering as proposed mechanisms, but it doesn't really explain how much the brightness of the Moon ...
uhoh's user avatar
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4 votes
3 answers
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The RA and Dec of lunar poles

The moon faces the earth with one fixed side. However there is a small vibration. So I am not sure the south and north poles of the moon is fixed. Even if they are fixed points on the moon, the pole ...
questionhang's user avatar
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4 votes
1 answer
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How do times of lunar standstills vary over time? If we folded them back into a lunar month plot, would they have "prograde and retrograde motion"?

The recent question Are lunar phases and lunar standstills in sync with each other? brought me to a standstill because I don't fully know what a lunar standstill is. It's one of those words like "...
uhoh's user avatar
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4 votes
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Could an asteroid knock the moon out of its orbit?

As describe in this CNN article, an asteroid is going to pass near the Earth on Halloween. The article says that As it misses Earth by about 300,000 miles (slightly farther away than the moon), ...
DCShannon's user avatar
  • 143
4 votes
3 answers
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lunar calendar accuracy for predicting new moons

I wonder, how accurate the lunar calendar is? Can we predict the new moons precisely for tens of years in future? If we know all factors that affects the movement of the moon, then why it is not ...
M.M's user avatar
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4 votes
4 answers
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Is the full moon full everywhere on the planet?

When the moon is full, fully lit by the sun, will it appear full everywhere on the planet? E.g. if I where to set the date for the next three full moons for say: Sweden, Bali and Seattle how ...
u123's user avatar
  • 141
3 votes
1 answer
618 views

How can the next supermoon be analytically predicted?

The lunar motion can be predicted with basic celestial mechanics, but the perigee and apogee are not always the same, basically because the attraction of the Sun makes some oscilations in the semi-...
Carlos Vázquez Monzón's user avatar
3 votes
1 answer
105 views

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 ...
Ubi.B's user avatar
  • 221
3 votes
1 answer
397 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. ...
lowercasename's user avatar
3 votes
1 answer
2k views

Why does the moon not leave its orbit around the earth due to the gravitational force from the sun? [duplicate]

See additional information below added after the answer to the question. When the moon is between the earth and the sun, the gravitational force on the moon from the sun is greater than the ...
John Bentsey's user avatar
2 votes
2 answers
1k views

why hasn't Nasa gone back to our Moon? [closed]

why has not Nasa gone back to our Moon since the first landing on the moon
Alessandri Kevoogle Kev's user avatar
2 votes
2 answers
211 views

How does one go about submitting a name for a newly-discovered lunar crater?

Suppose I discover an uncatalogued crater on the lunar surface, and decide to name it. How would I submit my proposed name to the IAU?
jw01's user avatar
  • 23
2 votes
1 answer
734 views

Lunar terminator illusion

Sometimes, you can see the Moon high in the night sky, which is illuminated from the side where Sun goes down but slightly from above. It is paradoxical when Sun hangs at the lower level above the ...
valentin's user avatar
2 votes
1 answer
437 views

What makes the moon, a super moon

Caught a sight of moon tonight (by chance) and came in surprise that moon looks thrice in size to its usual size. Mostly called as Blue moon. Didn't succeed in getting the details and explanations ...
kaka's user avatar
  • 497
1 vote
1 answer
3k views

How to calculate declination of Moon?

Is there any way to calculate declination of Moon for any day?I'll subtract inclination of Earth on the ecliptic from the result. I'll get Moon's the shortest angular distance from Sun. Thanks for all ...
User123's user avatar
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0 votes
3 answers
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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”."...
Matt Jameson's user avatar
81 votes
6 answers
11k views

Is the Moon only 60x60 pixels?

In doing research on vision, I have learned that "20/20" vision corresponds to a visual acuity of being able to resolve details 1 arcminute in size, that most people have around 20/15 vision,...
Phrogz's user avatar
  • 937
54 votes
5 answers
20k views

Why is moon light not the same color as sunlight?

The light from the moon is light being reflected from the sun. The sun, in space, is white. But on Earth, when the light is filtered through an atmosphere, the light appears yellow. So then, why is ...
Andrew Johnson's user avatar
50 votes
3 answers
22k views

Is it possible to achieve a stable "selenostationary" orbit around the Moon?

Is there a stable geostationary orbit around the Moon? My feeling is, that the orbit would collide with Earth, because of the Moon's slow rotation.
Christian's user avatar
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41 votes
4 answers
20k views

Can the moon appear to be in any position in the sky?

It seems to me that the Moon has appeared in many locations - apparent locations - in the 'dome of the sky'. I know that the Sun follows an arc from east to west and that the arc is smaller in winter ...
Donagh McCarthy's user avatar
39 votes
3 answers
7k views

Is it a coincidence that on the far side of the moon almost no seas are visible?

Sorry for the maybe too large pictures. They do make the surface structures of both sides of the moon visible though. Is it just a coincidence that on the side facing us is so much sea is visible? It ...
Deschele Schilder's user avatar
29 votes
3 answers
9k views

If months are based on the moon, then why are the months longer in the Gregorian calendar than lunation?

What I have always thought / known is that: Days are based on the period of rotation of the earth. Months are based on the moon. Year is the time taken by the earth to make one revolution around the ...
lunisolar's user avatar
  • 391
26 votes
7 answers
13k views

If the Moon were impacted by a suitably sized meteor, how long would it take to impact the Earth?

An answer to the question of How well would the Moon protect the Earth from a Meteor? mentions as a possibility that the Moon could get knocked into the Earth. What is the smallest change to the ...
gilliduck's user avatar
  • 404
24 votes
2 answers
5k views

Can the Moon eclipse Venus?

The title basically says it all. As seen from the Earth, is it possible for the Moon to eclipse Venus (or any other planet) or are the orbits inclined such that this never happens? If such an eclipse ...
CatchAsCatchCan's user avatar
22 votes
6 answers
8k views

Puzzling quotes from astronauts about earth size

I have no doubt that we have been to the moon. This question has nothing to do with a moon landing hoax. But, there are two quotes from two different astronauts regarding the size of the earth as ...
Lambda's user avatar
  • 514
19 votes
2 answers
3k views

Do other planets in our solar system experience eclipses or is this unique to Earth?

Here on Earth we get to experience lunar and solar eclipses. Is this pure coincidence that everything happens to line up? Do other planets in the solar system experience this phenomenon or is this ...
user avatar
18 votes
3 answers
4k 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 ...
r.e.s.'s user avatar
  • 323
18 votes
2 answers
21k views

Does the Moon have any oxygen in its atmosphere?

Since the moon has gravity, it's almost impossible that there aren't some gasses trapped on the surface by the moon's gravity. Has any free-floating oxygen been found on the Moon? If so, in what ...
user avatar
18 votes
1 answer
5k views

Is there any telescope on Earth that can see the lunar rovers on the Moon?

If I have the right numbers, it seems to me that even the Hubble telescope might barely be able to make out a carcass of a blue whale on the surface of the Moon, which puts objects as small as the ...
Mark Bailey's user avatar
  • 1,013
17 votes
7 answers
6k views

Why would the side of the moon that faces earth be as dark as the far side of the moon?

Somebody suggested that the side of the moon that always faces the earth is as dark as the far side of the moon, but is that really the case? Doesn’t earth-shine make the earth-facing side of the moon ...
Constantthin's user avatar
17 votes
3 answers
6k views

Can large scientific telescopes observe the Moon without being damaged?

When I look at the full Moon through my 10cm telescope, it is so bright that it hurts. Can large scientific telescopes observe the moon at all? Does that require special protection equipment? Or ...
j6t's user avatar
  • 321
16 votes
2 answers
7k 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 ...
chowder's user avatar
  • 492
16 votes
5 answers
30k views

Why can I see sometimes a horizontal half moon instead of a vertical one?

Why do I sometimes see a horizontal half moon, instead of the more usual vertical one? I keep getting answers for crescent moons, but this is a half moon with its curve closer to the horizon, like a ...
Evilin Garnett's user avatar
16 votes
3 answers
5k views

Why is the Earth-Moon distance not the same at each perigee/apogee?

I wonder why the Earth-Moon distance is not the same at each perigee/apogee. Isn't the Moon's orbit a fixed ellipse with Earth at one of the foci? If it is so, shouldn't the distance at perigee/apogee ...
Michael Teoh's user avatar
15 votes
1 answer
2k views

Why does the Moon seem larger when it is close to the horizon? [duplicate]

I've noticed that when I look into the sky at night, sometimes the moon appears very large near the horizon. Sometimes it also looks like it has a yellow tint. Is this the light rays bouncing off ...
Timtech's user avatar
  • 1,685
15 votes
3 answers
10k views

How does moonrise/moonset azimuth vary with time?

In my tenacious attempts to observe moonrise (surprisingly difficult in a poor weather heavily urbanized hilly area with frequent bad smog, with busy work schedule and a bicycle) I was frequently ...
SF.'s user avatar
  • 6,259
14 votes
1 answer
5k views

Why does the darkening of the Moon go from left-to-right during an eclipse?

In anticipation of the upcoming April 2014 lunar eclipse, I decided to use the 3D virtual planetarium software Stellarium to simulate what it is supposed look like where I live, since I've never ...
David H's user avatar
  • 844
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
12 votes
3 answers
6k views

Why does the Moon never set in Svalbard, Norway?

I heard in a documentary that, in Svalbard (Spitsberg), Norwegian archipelago in the Arctic Ocean, the Moon never sets. Why? A drawing would certainly help.
Nicolas Barbulesco's user avatar
10 votes
3 answers
31k views

What is the angular diameter of Earth as seen from the Moon?

...today I must have left my brain home. I know it's a simple calculation but I keep failing simplest calculations today. What is the angular diameter of Earth as seen from the surface of the Moon?
SF.'s user avatar
  • 6,259
10 votes
3 answers
5k views

How well would the Moon protect the Earth from an Asteroid?

Would the Earth fare better if the Moon blocked the meteor, comet, rogue planet, or otherwise rather than a direct impact? At what point would the Moon's debris would be an extinction event? The ...
Muze's user avatar
  • 1
9 votes
1 answer
15k views

From which country or area is the new moon visible first?

Being able to see the Moon is dependant on various factors like sunset timing etc. Considering all these factors, which country or area of the world sees the new moon first? I am asking about the new ...
Gulshan's user avatar
  • 193
9 votes
2 answers
3k views

Is it possible for a person to not see the new moon at different places on earth?

It is known that theoretically we see the same moon phase everywhere on the earth, but practically I see that people are unable to observe the 0.8% waxing crescent at different places on earth. This ...
astro's user avatar
  • 191
8 votes
1 answer
279 views

How to send information from the far side of the Moon to the Earth?

Chang-E has just sent a shot after landing on the far side of the moon. It looks tricky, how can a device send information from a place that is oriented opposed to Earth?
nightcod3r's user avatar