<p><strong>update:</strong> I still haven't been able to get my hands on the <em>Icarus</em> paper linked below (I'll try other libraries) but these are newer and <em>quite interesting!</em>:</p>
<ul>
<li><a href="http://www.planetary.brown.edu/pdfs/5256.pdf" rel="nofollow noreferrer">Constraining the thickness of polar ice deposits on Mercury using the
Mercury Laser Altimeter and small craters in permanently shadowed
regions</a></li>
<li><a href="https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/2017JE005500" rel="nofollow noreferrer">nvestigating Mercury’s South Polar Deposits: Arecibo RadarObservations and High-Resolution Deter minationof Illumination Conditions</a></li>
</ul>
<hr />
<p>How did Arecibo make radar images of ice on Mercury's poles?</p>
<ol>
<li>How were observations of the poles of Mercury geometrically possible from Earth?</li>
<li>How was &quot;<a href="https://www.sciencedirect.com/science/article/abs/pii/S0019103510003131" rel="nofollow noreferrer">high-resolution (1.5-km) imaging</a>&quot; possible from Earth?</li>
<li>How was ice identified and imaged?</li>
</ol>
<hr />
<p>From <a href="https://www.nap.edu/read/21729/chapter/8#136" rel="nofollow noreferrer">Chapter 6; Planetary Radar Astronomy</a> in <em>A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum (2015):</em></p>
<blockquote>
<p>Radar observations from Earth continue to provide new information about the terrestrial planets and the Moon despite the many spacecraft flybys, orbiters, and landers. The unique radar back-scattering properties of water ice led to the discovery by ground-based radar of ice deposits in the permanently shadowed portions of impact craters at Mercury’s poles. High-resolution (1.5 km) radar imaging of these deposits has mapped out their distribution with high precision<sup>9</sup> (Figure 6.9).</p>
<p><sup>9</sup><a href="https://www.sciencedirect.com/science/article/abs/pii/S0019103510003131" rel="nofollow noreferrer">Radar imagery of Mercury’s putative polar ice: 1999–2005 Arecibo results</a> Icarus, 211, (1) January 2011, pp 37-50</p>
</blockquote>
<p><a href="https://i.sstatic.net/DzReN.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/DzReN.jpg" alt="FIGURE 6.9 Arecibo radar image of the distribution of ice deposits at the north pole of Mercury..." /></a></p>
<blockquote>
<p>FIGURE 6.9 Arecibo radar image of the distribution of ice deposits at the north pole of Mercury (yellow), superimposed on a mosaic of Messenger orbiter images showing the coincidence of the ice deposits with the shadowed portions of impact craters. SOURCE: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.</p>
</blockquote>

CC BY-SA 4.0
2020-07-13T13:03:53.920Z
I really don't understand your main question. Are you asking how the radiotelescope works, or which method is used for radar-imaging ?
Cornelis
CC BY-SA 4.0
2020-07-13T13:53:54.143Z
From Earth we see the side of Mercury, but these images look like they are taken "top-down". I'm trying to figure out geometrically how such detailed images can be made of the polar areas which are really viewed from the side, especially how details *at the bottoms of craters at the poles* can be investigate from Earth.
uhoh
CC BY-SA 4.0
2020-07-13T14:15:55.157Z
I think *details at the bottoms of the craters at the poles* are *not from Arecibo*, but it's  amazing for me too that the distribution is that detailed. Could the inclination of Mercury's orbit help in explaining ?
Cornelis
CC BY-SA 4.0
2020-07-13T14:54:40.997Z
@Cornelisinspace Oh, I see what you mean; I think that you have solved my problem! I think you can just write up the explanation as an answer. I totally missed that.
uhoh
<radio-astronomy><radio-telescope><mercury><water>
How did Arecibo make radar images of ice on Mercury's poles?
uhoh
# How did Arecibo make radar images of ice on Mercury's poles?

(Asked by: username_0 on 2019-05-21)

**update:** I still haven't been able to get my hands on the *Icarus* paper linked below (I'll try other libraries) but these are newer and *quite interesting!*:

* [Constraining the thickness of polar ice deposits on Mercury using the
  Mercury Laser Altimeter and small craters in permanently shadowed
  regions](http://www.planetary.brown.edu/pdfs/5256.pdf)
* [nvestigating Mercury’s South Polar Deposits: Arecibo RadarObservations and High-Resolution Deter minationof Illumination Conditions](https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/2017JE005500)

---

How did Arecibo make radar images of ice on Mercury's poles?

1. How were observations of the poles of Mercury geometrically possible from Earth?
2. How was "[high-resolution (1.5-km) imaging](https://www.sciencedirect.com/science/article/abs/pii/S0019103510003131)" possible from Earth?
3. How was ice identified and imaged?

---

From [Chapter 6; Planetary Radar Astronomy](https://www.nap.edu/read/21729/chapter/8#136) in *A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum (2015):*

> Radar observations from Earth continue to provide new information about the terrestrial planets and the Moon despite the many spacecraft flybys, orbiters, and landers. The unique radar back-scattering properties of water ice led to the discovery by ground-based radar of ice deposits in the permanently shadowed portions of impact craters at Mercury’s poles. High-resolution (1.5 km) radar imaging of these deposits has mapped out their distribution with high precision9 (Figure 6.9).
>
> 9[Radar imagery of Mercury’s putative polar ice: 1999–2005 Arecibo results](https://www.sciencedirect.com/science/article/abs/pii/S0019103510003131) Icarus, 211, (1) January 2011, pp 37-50

[![FIGURE 6.9 Arecibo radar image of the distribution of ice deposits at the north pole of Mercury...](https://i.sstatic.net/DzReN.jpg)](https://i.sstatic.net/DzReN.jpg)

> FIGURE 6.9 Arecibo radar image of the distribution of ice deposits at the north pole of Mercury (yellow), superimposed on a mosaic of Messenger orbiter images showing the coincidence of the ice deposits with the shadowed portions of impact craters. SOURCE: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

**Tags:** radio-astronomy, radio-telescope, mercury, water
> **Comments:**
> **username_1**: I really don't understand your main question. Are you asking how the radiotelescope works, or which method is used for radar-imaging ?  
> **username_0**: From Earth we see the side of Mercury, but these images look like they are taken "top-down". I'm trying to figure out geometrically how such detailed images can be made of the polar areas which are really viewed from the side, especially how details *at the bottoms of craters at the poles* can be investigate from Earth.  
> **username_1**: I think *details at the bottoms of the craters at the poles* are *not from Arecibo*, but it's  amazing for me too that the distribution is that detailed. Could the inclination of Mercury's orbit help in explaining ?  
> **username_0**: @Cornelisinspace Oh, I see what you mean; I think that you have solved my problem! I think you can just write up the explanation as an answer. I totally missed that.  

---

## 0 answers

