Talk:Europa (moon)

Gigantothermy
"The heating by radioactive decay, which is almost the same as in Earth (per kg of rock), cannot provide necessary heating in Europa because the volume-to-surface ratio is much lower due to the moon's smaller size."

I just think the sentence above should be reworded. Asuming the Earth and Europa to both be nearly spherical the volume-to-surface ratio would be the same regardless of size. Also, Europa's smaller surface area means it radiates less heat than earth if radioactive decay where the only heat source. JTTyler (talk) 00:56, 23 October 2010 (UTC)
 * The Earth has a dense atmosphere which helps hold heat in - and is closer to the sun - Europa bleeds heat into space much more rapidly. — Preceding unsigned comment added by 50.111.3.150 (talk) 21:25, 24 August 2019 (UTC)

User:JTTyler: That is not correct Surface-area-to-volume ratio. Let's call them spheres for a moment to make things easier. Volume = 4*pi*(r^3)/3, area = 4*pi*(r^2). Earth's mean radius is 6371 km, therefore it's surface area is roughly 5.1×10^8 km^2, its volume is roughly 1×10^12 km^3, resulting in a ratio of 4.7×10^-4. Europa's mean radius is about 1561 km, its area is roughly 3×10^7 km^2, its volume is roughly 1.6×10^10 km^3, leaving a ratio of 0.0019. Area to volume ratio varies inversly, if the radius is double, the ratio is half. So, Europa blows off heat much more easily than the earth in that respect.Are1718 (talk) 03:18, 31 July 2021 (UTC)

"habitable" in the lede
" ... whether Europa could be habitable" - let's find another word here - whether or not there are sea salts has nothing to do with human "colonization" - the article cite is not referring to that, but whether native life might exist under the ice crust. Thanks. 50.111.44.55 (talk) 09:53, 17 June 2021 (UTC)
 * "Habitable" does not mean "habitable to humans."  Serendi pod ous  16:18, 17 June 2021 (UTC)
 * common English usage - late Middle English: via Old French from Latin habitabilis, from habitare ‘possess, inhabit’. - this clearly speaks about human activity — Preceding unsigned comment added by 50.111.40.110 (talk) 22:36, 7 January 2022 (UTC)
 * I would have to comment that "habitable" does not exclusively mean habitable by humans, we could just be more detailed in the article to avoid confusion. MaximusEditor (talk) 23:32, 30 April 2024 (UTC)

Regarding the Musk video
Since there has been a revert (which I just re-reverted):

First of all, yes, I agree completely that proposals to inhabit the surface of Europa, without a lot of radiation shielding, are fundamentally ridiculous.

But: Europa is clearly not the focus of Musk's video. The actual video is clearly mostly interested in Mars. The rest of the Solar System was mentioned in passing (around 63 minutes in) in the context of where his proposed Interplanetary Transport System can get you. He did not talk much about colonising Europa as opposed to Mars. All he said was a throwaway line "It would be really great to do a mission to Europa, particularly." That and a piece of concept art are it, pretty obviously showing that this was not the focus and main proposal Musk was making. And in fact, the paper Musk wrote in 2017 that is based on this presentation doesn't even have that sentence (it only mentions an example of having a propellant depot at Europa). I see no serious "proposal" for Europa here. Given the amount of time he devoted to that vs the much greater amount of time he devoted to Mars, I don't see fixating on such a throwaway remark as due weight.

Second: surely we can do better than citing a video from a self-published YouTube channel prominently featuring "The complete and ongoing MoonFaker series, proving that the Apollo landings were hoaxes. The Grandson Of The Apollo Hoax Theory Will Return" (direct quote). Seems that White still believed Apollo was a hoax in 2019.

Third: The Thunderf00t video is (1) also self-published and (2) the substantive new criticism (about solar panels) is addressed to the idea of going to Saturn with solar panels. Not Jupiter. So it is even irrelevant to what is being discussed here. Yes, the picture of the spaceship at Saturn with solar panels is in Musk's presentation (and again it does not seem to be treated as a serious proposal), but that's not what's being discussed here. Thunderf00t only addresses the radiation-belt issue at Jupiter, which is all fine and well and correct, except that it does not seem to be countering something that was ever a serious proposal. In fact, going to Jupiter with solar panels is not stupid. Proof: NASA already did it. Inverse-square law just means you need very large solar panel arrays, of course.

There have been actual, serious proposals in scholarly literature to do human exploration of the Jovian system. (Obviously in the future.) The ones that I am aware of all focus on Ganymede and/or Callisto where the radiation environment is saner. (Online: a paper, NASA study of Callisto. Ganymede has some radiation, but much less than Europa, and on the low latitudes is partially protected even further by its magnetosphere. Not to mention that the paper by Kerwick suggesting it suggests a "shielded underground base" on Ganymede, which solves the radiation problem.) Robert Zubrin's old Entering Space (1999) comes to the same conclusion (p. 167), that only Callisto and perhaps Ganymede are sensible for settlement among the Galilean moons. And indeed, there is serious discussion at Callisto (moon).

If you can find a serious study suggesting Europa, feel free to add it. But it should preferably be backed up by a source that actually focuses on that as its main point, and any supporting or criticising material should preferably be (1) serious and (2) actually supported by its own citations. Double sharp (talk) 14:19, 18 July 2021 (UTC)
 * P.S. Finally found a Europa proposal that actually got some notice. That said, it's old, and the question is simply assumed fixed: Providing material shielding against this radiation would add prohibitive amounts of mass to the manifest. For the purposes of our mission, we assume that it takes place in an era in which the engineering challenges of providing electromagnetic shielding have been mastered. Oh well. Double sharp (talk) 08:29, 31 July 2021 (UTC)

This article needs a true color picture at the top
All these images of Europa featuring red-orange-brown streaks are made using luminance data from near infrared, green and violet exposures. Some are further overly saturated and have their constrasts heavily increased. I was unable to find a decent image of this satellite made using calibrated red, green and blue exposures, but by all means, if you find it, replace the main picture. It's sad we don't have a realistic view of this world. Europa is a beige-streaked, bright, icy world.

The closest I found is Gordan Ugarković's recalibration on Flickr and I'll ask him for permission to use it here.

https://www.flickr.com/photos/ugordan/4932718561/ Lajoswinkler (talk) 20:03, 11 July 2022 (UTC)


 * The spacecraft that have thus far produced high resolution color images of Europa have all used filter sets that were not fully in the visible color range. For example, the color filters on Galileo’s SSI camera (the one used for the current top image and Gordon’s images) typically use Violet, Green, and some Near-IR filter (in Gordon’s case, 756 nm). Voyager’s filters topped out at Orange. So I think what you are wanting is an image stretched more to reflect how Europa would appear to the naked eye than one with a histogram stretched meant to make surface features appear more clearly.
 * In the case of visible-light color images you are in luck though. If you can wait just 5 more weeks, there is a close flyby of Europa by Juno that should produce a nice RGB image of Europa. It won’t be a full-disk image, more like a half-moon view, but JunoCAM does have RED, GREEN, and BLUE channels. —Volcanopele (talk) 23:01, 20 August 2022 (UTC)

https://europa.nasa.gov/resources/91/natural-and-false-color-views-of-europa/ According to this, the left image is true color. It looks very similar to the alledgedly false color image used at the top of the article, while the false color looks farther from the one the article uses. Are we sure that it isn't already true color? I can imagine it more likely that a wikipedia user made a mistake than NASA, but its not impossible for it to be the other way around. 63.231.197.105 (talk) 20:27, 20 August 2022 (UTC)


 * ✅ CactiStaccingCrane (talk) 04:00, 13 November 2022 (UTC)

Volunteer(s) to update Europa's article on James Webb's recent detection of carbon dioxide and carbon
Last September 21, 2023, James Webb released a NIR image of Europa that confirmed the presence of carbon dioxide and carbon crystallines on Europa's Tara Region. This is extra hint that Europa can support life (or even supporting life right this moment). I am not confident enough to interpret the data or convert it into readable wordings: so can someone write a section about it?

Reference: https://www.nasa.gov/solar-system/nasas-webb-finds-carbon-source-on-surface-of-jupiters-moon-europa IapetusCallistus (talk) 18:40, 5 February 2024 (UTC)