How far is the moon from Earth?

[Admin]

The average distance between Earth and the moon is about 238,855 miles (384,400 kilometers).

How far is the moon from Earth? : Read more

 

[rod]

The article reports at the end, "The moon was once much closer to Earth. During the infancy of the solar system just as planets were finalizing their formation, a protoplanetary Earth collided with a Mars-sized object that may have formed farther away from the sun. Known as Theia, its impact produced the material that would eventually coalesce to form the moon. The distance between the Earth and the moon grew as time passed. Currently the moon drifts away from our planet at a rate of approximately 1.5 inches (3.8 cm) a year, according to NASA."

However, others today feel the Moon is still very close to the Earth

Moon - The Flat Earth Wiki (tfes.org), "The Moon is a revolving sphere. It has a diameter of 32 miles and is located approximately 3000 miles above the surface of the earth."

 

[Helio]

Moon - The Flat Earth Wiki (tfes.org), "The Moon is a revolving sphere. It has a diameter of 32 miles and is located approximately 3000 miles above the surface of the earth."

Those values would make the Moon to have an easily measurable angular size of a little more than 36.6 arcmin, which it will never have.

The Moon varies in angular size from 29.2 to 34.6 arc mintues. Thus they would have to claim that this variation of a 32 m dia. Moon would be due to the Moon moving from as close as 3200 miles and as far away as 3765 miles.

These close distances would make the Moon very easy to measure using the parallax method. But this won't happen. I can't respect any group that only wants to use science to serve their own world view when it is obvious they could actually do science to improve their world view.

 

[billslugg]

The Moon raises a tidal bulge in the Earth's waters. The rotation of the Earth and the friction of the ocean basins moves that bulge slightly eastward. The gravitational force associated with that mass pulls on the Moon from ahead in its orbit thus making it go faster. This is what raises its orbit.

 

[Wolfshadw]

Moon - The Flat Earth Wiki (tfes.org), "The Moon is a revolving sphere. It has a diameter of 32 miles and is located approximately 3000 miles above the surface of the earth."

Soooo.... the Earth is flat, but the Moon is a sphere... not a flat disk, but an actual sphere....
My head hurts!

-Wolf sends

 

[Pogo]

Yah! So are the Sun and the other planets and moons spheres, just the Earth is flat.

 

[billslugg]

Flat Earthers are the reason alien species refuse to talk with us.

 

[Helio]

Flat Earthers are the reason alien species refuse to talk with us.

I suspect they’re looking for a yellow Sun and can’t seem to find us.

 

[rod]

Yah! So are the Sun and the other planets and moons spheres, just the Earth is flat.

Pogo, the FES does say Mars is round and told that to Elon Musk too. Telescope observations of Mars show it is round and spins too, close to a 24 hour day almost like Earth.

 

[rod]

Helio (post #3) is correct about the Moon's angular size about 34 arcminute if the Moon is 32 miles across and about 3,000 miles or so above the Earth. However, numerous telescope observations of the lunar parallax does not allow for this. The lunar parallax is well documented using telescopes and is about 57 arcminute or a bit more. This measurement supports lunar laser ranging reports and radar measurements of the Moon's distance too.

"The resulting value of the moon’s distance is : 384,410 international kilometers,", A new determination of the lunar parallax. - NASA/ADS (harvard.edu) , 1950

Parallax of the moon in terms of a world geodetic system - NASA/ADS (harvard.edu), August 1962.

 

[rod]

This is a current report on FE teaching, 24 slides to review Meet the Flat Earthers -a small but vocal movement, Meet the Flat Earthers -a small but vocal movement (msn.com)

 

[Helio]

Helio (post #3) is correct about the Moon's angular size about 34 arcminute if the Moon is 32 miles across and about 3,000 miles or so above the Earth. However, numerous telescope observations of the lunar parallax does not allow for this. The lunar parallax is well documented using telescopes and is about 57 arcminute or a bit more.

Absurd. The Moon can’t have two different apparent sizes for any given distance, once atmospheric corrections are made. But I know you know this, so please explain.

This measurement supports lunar laser ranging reports and radar measurements of the Moon's distance too.

Of course, we know the distance in centimeters, and we know it’s diameter, thus it has an easily observable angular size, roughly a thump at arms length, IIRC.

"The resulting value of the moon’s distance is : 384,410 international kilometers,", A new determination of the lunar parallax. - NASA/ADS (harvard.edu) , 1950

Nice find, Rod. I only can read the abstract. Nevertheless, it’s interesting that they use parallax for mountain shadows, after adjusting for air and libration. But I don’t see any angular size contradiction.

 

[Helio]

This is a current report on FE teaching, 24 slides to review Meet the Flat Earthers -a small but vocal movement, Meet the Flat Earthers -a small but vocal movement (msn.com)

I prefer not to waste my time on their views unless you offer something from them you think has scientific merit. I’m a lousy psychologist.

 

[billslugg]

He didn't say the Moon had two different sizes, he said he lunar diameter as viewed from Earth is 34 minutes. Then he said the lunar parallax is 57 minutes. The parallax is the amount the Moon shifts against the background stars when an observer moves from dawn to dusk.

I can confirm that watching the Flat Earther's report would be a waste of time. It simply states their view but offers no evidence.

 

[Helio]

He didn't say the Moon had two different sizes, he said he lunar diameter as viewed from Earth is 34 minutes. Then he said the lunar parallax is 57 minutes. The parallax is the amount the Moon shifts against the background stars when an observer moves from dawn to dusk.

Ahh, that makes sense, but that involves orbital speed, so it’s trickier to use that for distance. Is there a connection I’m missing?

I can confirm that watching the Flat Earther's report would be a waste of time. It simply states their view but offers no evidence.

Thanks. That’s why science has advanced beyond philosophy. The degree to which objective evidence counters a claim determines its degree of silliness. There is an entire city where these claims eventually go - Sillyville. But always remember that some could earn their way out.

 

[billslugg]

Yes, you would have to account for orbital movement of the Moon, it is about 13 degrees per day or 6-1/2 degrees from sunrise to sunset. The parallax is only about a degree. It would be best to have a second observer on the other side of the Earth and coordinate your observations.

 

[rod]

FYI, if you use trig with a Moon 4828.032 km distance from Earth or 3,000 miles away, the arcminute size in the sky could be 34.17 arcminute - if the Moon is 29.816 miles across. That is close to what the FES is using. You can get this arcminute size only if the Moon is much smaller than what astronomy accepts as its size and distance is thus much closer to Earth. You can check these figures using Earth radius and lunar parallax of 3422 arcsecond size (about 57 arcminute). Lunar distance is then about 60.28 earth radii and the angular size near 34 arcminute shows the Moon is much larger size in diameter vs. 30 or 32 miles across. However this check shows problems with a Moon 32 miles across and 3,000 miles away. The lunar parallax is much larger than currently observed values near 3422 arcsecond

I suspect for many folks, FES math is not well known. You can apply their approach to the entire solar system and shrink everything down in distance and sizes too Thus we are back to a much smaller solar system as originally taught in geocentric astronomy during the days of Tycho Brahe and Claudius Ptolemy.