Talk:Gravity of Mars

Feedback from Tamjwh

Feedback on "Gravity of Mars":

1. Many abstract concepts were found and it is observed that analogies were sometimes used for illustration. However, adding images would further aid in the explanation of the ideas. An example is using a gravity anomaly diagram to explain why different structures in Mars e.g. polar ice caps, impact basins can be inferred based on measured gravity anomalies.
2. Long-wavelength and short-wavelength gravity anomalies were mentioned, however little was done in explaining their nature and characteristics. It is suggested that elaboration can be made on long-wavelength and short-wavelength gravity fields, e.g. how they are generated, why anomalies of these waves are useful, what are their differences in applications etc.
3. Background is briefly described. It is suggested that more can be done on illustrating the evolution of gravity measurement methods, as to give a clearer message delivery of the technological development. A summary table can be constructed to show the important findings from past to present.

Tamjwh (talk) 10:23, 18 October 2017 (UTC)

Review from Graeme Bartlett

I would like to see some more numbers. What is the mass of Mars? moment of inertia? How offset is the centre of mass compared to the surface? What is the value of core flattening? For the mass of ice caps, are your numbers the amount of change each season? Also I suggest that you do not need to use that math markup, just use unicode characters. For example when I copy your text I get this: "275 k m ≤ D ≤ 1000 k m {\displaystyle 275\ km\leq D\leq 1000\ km} {\displaystyle 275\ km\leq D\leq 1000\ km}" whereas "275 km ≤ D ≤100 km" would do the job just fine. As well as for copying it also works better for searching, and screen readers.

Some paragraphs or sections have no reference footnotes yet. eg "Identification of Bouguer anomaly". You could use a textbook page to support your writing. For the areoid section, you could also give the mean radius at poles.

I second Tamjwh's idea that pictures should be added! Graeme Bartlett (talk) 10:55, 18 October 2017 (UTC)

Feedback from kakitc

I think the concepts in your page are quite difficult to understand. Here are some suggestions:

• Some of your sentences are difficult for laymen to understand, for instance in the introduction: Gravitational field is controlled by the mass of the attracting object and distance from the test point towards it, while the density of gravity field lines over a unit area with certain distance above the center of mass reflects the strength of gravity field of that cubic unit. This sentence is too complicated and abstract. It is hard to understand gravitational field using the concept of field lines. I also agree with Tamjwh's idea that you can use figures to explain these difficult concepts. You can also add links to some related articles so that the readers can read the page with some understandings to the background concepts.

• You have mentioned different ways and model to estimate the gravity on Mars in the page, but the result is not shown. The readers may not know what are the difference between these models. I agree with karaclc's idea that you can use a table to summarise the advancement of these gravitational models, the results, such as a contour map showing the surface gravity and perhaps the error/accuracy and difficulties can be included that so the readers know what have been improved and what method do the scientists used to overcome the problems.

• There are some equations in your page, for the equation in section Earth-based observation, it is a very complicated equation that the readers may not know what each components in the equation means and how the parameter affects the gravity at a point. Therefore, I think you can add a figure to show an example of how can the gravity at one point can be calculated by the equation. For the remaining equations, most of them are just the sum of several components, I think it is not necessary to use a equation and some of the subscript or parameters are long words, such as the atmosphere in the last equation, it maybe more useful to list them in bullet points. For instance, The measured potential of Mars from orbiters is the sum of
  • Gravity from the solid planet
  • Gravity from CO2 in the ice cap
  • Gravity from CO2 in the atmosphere

Kakitc (talk) 07:29, 22 October 2017 (UTC)

Feedback from dinohk

1. As others have pointed out, you should include some images in your page even though it is an abstract concept such as gravity. Even images just of Mars would make the page more attractive and help readers visualize what you are talking about.

2. I think that most readers would be interested in how gravity on Mars compare to Earth. It would help ground the topic in something everyone understands and can relate to. For example, you mentioned the surface gravity of Mars but by itself it is a meaningless abstract metric. If you include the surface gravity of Earth then at least people can immediately make a comparison they can understand.

3. You could provide a history of how the observational methods have advanced over the years before you go into how measurements are made.

— Preceding unsigned comment added by Dinohk (talk • contribs) 03:55, 23 October 2017 (UTC)

Review from Jupiter

Your page is explaining the concept of gravity of mars with description of the measurement. models, implications and applications. This topic quite complex, especially for readers without physics background.

Here are some suggestions:

1. For the equations, you may want check and define every parameters used. For example, in the gravitation potential equation in section "Earth-based observation", you put the explanation of "gravitational constant GM" at the beginning. But you do not "highlight" GM as what you did as other parameters. You may want to add that to the definition part or highlight/bold that in the text.

2. A diagram or animation to show the gravitation field or a Mars's surface gravity map will be a good tools to present the concept. On of page of Mars, there is a Video showing how three NASA orbiters mapped the gravity field of Mars. You may want to take it as reference.

3. Similarly, you can also add more picture or animation or diagrams on your page. For example, an image of Mariner 9 or Viking Orbiter mission, and examples of Mars (Giant impact basins Utopia, Hellas, Argyre and Isidis basins in the "Crust redistribution by impacting and viscous relaxation" section).

4. As mentioned by others, I think a short history of how the observational methods have developed over years before the measurement part will be a great idea. For example, any missions before the arrival of Mariner 9 and Viking Orbiter missions? Any development and improvement in data collection? A short and brief one will be good enough with links to other Mars mission wiki pages in the text.

Hope my comments will be useful to you! Jupmira104 (talk) —Preceding undated comment added 07:13, 24 October 2017 (UTC)

Feedback from celiayangyy

I think that the article is generally a very clear and easy to understand one. There are few things that i would like to talk about.

First is that i think the introduction can really introduce more the main content. It is quite brief and a bit hard to catch the main idea. Second is that i think more pictures included will be very nice especially on some hard concepts like areoid. Third is i think i sae some parts you haven't finished yet? there is a part called long wavelength anomaly with no content inside? I guess it would be really great if you can just add some more content on it!

— Preceding unsigned comment added by Celiayangyy (talk • contribs) 06:55, 28 October 2017 (UTC)

Feedback from kakitc

I think your page is good and comprehensive! Here are some suggestions:

• I think most of the figure are too small that some of the text in the figure cannot be read without enlarging the page. I think larger figure can catch the attention of reader when they scroll through the page. For instance, the Mars free-air gravity map can be larger or placed at the beginning of the page.

• For the figure about how crust-mantle boundary variation, intrusion, volcanism and topography affect the orbit of spacecraft, I think it is better to exaggerate the features, like the change of topography is too subtle. I think you can divide the figure into several sections with very distinct structures.

• Some of the maps do not have legend, for example the Mars Bouguer gravity map. I think you can describe which color is positive or negative in the caption and suggest the interesting portion in the caption.

Kakitc (talk) 10:04, 20 November 2017 (UTC)

Feedback from Jupiter 20171120

I saw you have added some remote sensing maps and diagram to the page, which is good. However, they are a bit too little, especially for those with label and words on it. You may want to enlarge the images so people can read the words on your page without viewing the original image. Also, although some of the data set/images are public domain, you may want to add the source (USGS) in the capture of the images to inform the reader the source of data. In last, you have added the part about the history of Mars gravity remote sensing, which is helpful for readers to know about the development.

Comment from GeoJeremy

Thank you for your informative page. Many was learnt.

Here are some comments: 1)I see that you have mentioned the resolution of the latest model. I would also like to know how the uncertainty is. 2)Would there be any further development? Or would there be any necessary for further development? 3)I think the graphs and diagrams are a bit too small. Readers would need to click in for the graphs and diagrams. GeoJeremy (talk) 07:52, 21 November 2017 (UTC)

Review from Dinohk

I see that you have added quite a few more images, but you should make them a bit bigger so they are more view-able without having to open the actual image.

The formulas that you have listed aren't explained all that clearly, try to be a bit more explicit in defining everything. — Preceding unsigned comment added by Dinohk (talk • contribs) 17:10, 21 November 2017 (UTC)

Review from eunicecyl

I find it a bit too technical to include the first 2-3rd sentence in the introduction. I think its purely fine to just skip this two sentences and explain it a bit in the later paragraph. U might also consider enlarging the graphs as well :) Beside, I think its useful to add in the general equation for time-variable gravity field that contributes to the whole gravity anomalies. Eunicecyl (talk) 04:12, 22 November 2017 (UTC)

Human gait

There should be a section on how humans would walk on Mars if they landed. Since Mars has more than twice the Moon's gravity but about 3/8 of Earth's it would be interesting to know an ideal gait in that gravity, whether it would be more like on Earth or like on the Moon (rather a hopping), and from what altitude a fall could be lethal or safe. 212.186.0.174 (talk) 18:15, 17 August 2019 (UTC)