<p>The Moon landing sites <em>have</em> been photographed, but from orbit around the Moon. For example: <a href="https://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html" rel="nofollow noreferrer">https://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html</a> It is legitimate to ask why not from the Earth?</p>
<p>A lunar module has a diameter of about 4m. At a distance of 400,000 km, this subtends an angle of 0.002 arcseconds.</p>
<p>The absolute best angular resolution you can obtain from the surface of the Earth, using massive telescopes and adaptive optics imaging is about 0.1 arcsecond.</p>
<p>i.e. You cannot resolve anything on the Moon's surface, using a telescope on Earth, that is much smaller than about <strong>200 m</strong> in diameter.</p>
<p>The observations you refer to (see <a href="https://arxiv.org/abs/2001.11675" rel="nofollow noreferrer">Wang et al. 2020)</a> are of a <em>galaxy</em>, taken at microwave wavelengths (so hardly comparable). <strong>A galaxy is far away, but very big</strong>. The observations were able to resolve emission from the central 20 kpc (about 60 thousand light years) diameter region of this galaxy. The galaxy itself is at a distance of about 180 Mpc (about 600 million light years), so the angular resolution involved, using a bit of basic trigonometry, was about 22 arcseconds, which is set by the instrumentation they were using (i.e. the signature they found could be more concentrated than that). Thus this central region in Markarian 231 subtends an angle of 22 arcseconds at the Earth, which is roughly 10,000 times the apparent size of a lunar module on the surface of the Moon.</p>

CC BY-SA 4.0
2020-02-23T03:24:32.563Z
related to seeing things on the Moon: [Is seeing the apollo moon Landers via earth telescope that hard?](https://astronomy.stackexchange.com/q/33254/7982) and [Is there any telescope on Earth that can see the lunar rovers on the moon?](https://astronomy.stackexchange.com/q/1117/7982) and [Will the Magdalena Ridge Optical Interferometer be able to image extended objects like the surface of the Moon?](https://astronomy.stackexchange.com/q/33914/7982) and several other questions linked therein.
uhoh
CC BY-SA 4.0
2020-02-22T16:56:28.387Z
2023-08-06T09:45:01.117Z
2023-08-06T09:45:01.117Z
ProfRob
<p>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 measures distance in space, equals about 6 trillion miles.</p>
<p>And yet we can't photograph the Apollo landing equipment 243,000 miles away.</p>
<p>Why is it that we can better observe this far-away oxygen than stuff nearby on the surface of the Moon?</p>

CC BY-SA 4.0
2020-02-22T16:42:01.573Z
But the Moon landing stuff has been photographed.
ProfRob
CC BY-SA 4.0
2020-02-22T19:27:00.003Z
This appears to be an invitation to discuss, rather than a question to answer. Please take the [tour] to see how this differs from a discussion forum.
James K
CC BY-SA 4.0
2020-02-22T21:48:07.970Z
One has nothing to do with the other. The molecular oxygen was discovered by spectroscopy.
David Hammen
CC BY-SA 4.0
2020-02-23T00:10:49.330Z
We have absolutely nothing to image anything in that galaxy, not even a star system. The molecular oxygen was discovered by spectroscopy (we have seen photons what is given out exclusively by molcular oxygen).
peterh
CC BY-SA 4.0
2020-02-23T03:10:24.510Z
"Thoughts?" is not a proper Stack Exchange question, therefore voting to close because [answers to this question ("Thoughts?") will tend to be almost entirely based on opinions](https://astronomy.stackexchange.com/help/closed-questions). If you are curious how they are able to detect molecular oxygen so incredibly far from Earth, then please feel free to ask a new question! As long as your question is on-topic and can have a fact-based answer, it might be much better received. Thanks!
uhoh
CC BY-SA 4.0
2020-02-23T03:27:39.957Z
as for "Good luck getting Excel to calculate that!": https://i.sstatic.net/cc7My.png
uhoh
CC BY-SA 4.0
2021-05-22T00:13:44.993Z
False fact, followed by false fact, followed by rampant bad logic, followed by false fact, concluded with snide remark. Congratulations. YOu must be so proud of your achievement
PcMan
CC BY-SA 4.0
2023-08-09T12:36:44.643Z
I thought even the original version was a semi-reasonable question (or it is at least clear what an answer should look like).
ProfRob
<the-moon>
Given this report, you can see why people may think the moon landings were fake?
user31866
# Given this report, you can see why people may think the moon landings were fake?

(Asked by: username_0 on 2020-02-22)

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 measures distance in space, equals about 6 trillion miles.

And yet we can't photograph the Apollo landing equipment 243,000 miles away.

Why is it that we can better observe this far-away oxygen than stuff nearby on the surface of the Moon?

**Tags:** the-moon
> **Comments:**
> **username_1**: But the Moon landing stuff has been photographed.  
> **username_2**: This appears to be an invitation to discuss, rather than a question to answer. Please take the [tour] to see how this differs from a discussion forum.  
> **username_3**: One has nothing to do with the other. The molecular oxygen was discovered by spectroscopy.  
> **username_4**: We have absolutely nothing to image anything in that galaxy, not even a star system. The molecular oxygen was discovered by spectroscopy (we have seen photons what is given out exclusively by molcular oxygen).  
> **username_5**: "Thoughts?" is not a proper Stack Exchange question, therefore voting to close because [answers to this question ("Thoughts?") will tend to be almost entirely based on opinions](https://astronomy.stackexchange.com/help/closed-questions). If you are curious how they are able to detect molecular oxygen so incredibly far from Earth, then please feel free to ask a new question! As long as your question is on-topic and can have a fact-based answer, it might be much better received. Thanks!  
> **username_5**: as for "Good luck getting Excel to calculate that!": https://i.sstatic.net/cc7My.png  
> **username_6**: False fact, followed by false fact, followed by rampant bad logic, followed by false fact, concluded with snide remark. Congratulations. YOu must be so proud of your achievement  
> **username_1**: I thought even the original version was a semi-reasonable question (or it is at least clear what an answer should look like).  

---

## 1 answers

### Answer by username_1 on 2020-02-22. Score: 11 | Accepted answer

The Moon landing sites *have* been photographed, but from orbit around the Moon. For example: <https://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html> It is legitimate to ask why not from the Earth?

A lunar module has a diameter of about 4m. At a distance of 400,000 km, this subtends an angle of 0.002 arcseconds.

The absolute best angular resolution you can obtain from the surface of the Earth, using massive telescopes and adaptive optics imaging is about 0.1 arcsecond.

i.e. You cannot resolve anything on the Moon's surface, using a telescope on Earth, that is much smaller than about **200 m** in diameter.

The observations you refer to (see [Wang et al. 2020)](https://arxiv.org/abs/2001.11675) are of a *galaxy*, taken at microwave wavelengths (so hardly comparable). **A galaxy is far away, but very big**. The observations were able to resolve emission from the central 20 kpc (about 60 thousand light years) diameter region of this galaxy. The galaxy itself is at a distance of about 180 Mpc (about 600 million light years), so the angular resolution involved, using a bit of basic trigonometry, was about 22 arcseconds, which is set by the instrumentation they were using (i.e. the signature they found could be more concentrated than that). Thus this central region in Markarian 231 subtends an angle of 22 arcseconds at the Earth, which is roughly 10,000 times the apparent size of a lunar module on the surface of the Moon.

> **Comments:**
> **username_5**: related to seeing things on the Moon: [Is seeing the apollo moon Landers via earth telescope that hard?](https://astronomy.stackexchange.com/q/33254/7982) and [Is there any telescope on Earth that can see the lunar rovers on the moon?](https://astronomy.stackexchange.com/q/1117/7982) and [Will the Magdalena Ridge Optical Interferometer be able to image extended objects like the surface of the Moon?](https://astronomy.stackexchange.com/q/33914/7982) and several other questions linked therein.  

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