Ganymede's orbital period, eccentricity and semimajor axis are respectively 172 h (about 7 days), 0.0013 and 15 Jupiter radii. These grooved regions are a clue that the moon experienced dramatic upheavals in the distan… How can Ganymede have an Earth-like gravity without us having realized it? It is the only known moon in the solar system which possess its own magnetic field. Its mass is 10% greater than Titan's, 38% greater than Callisto's, 66% greater than Io's and 2.02 times that of the Moon. I could happily go with an "ancient aliens seeded both Earth and Ganymede billions of years ago" theory if that makes things easier. The combined effect of those gravity generators should increase Ganymede's overall gravity and make it seem a bit more massive than it actually is. I think you were right the first time... To get the same gravitational acceleration (at the surface) as Earth (9.81$m/s^2$), but keep the same radius, Ganymede (1.5$m/s^2$) needs only to get about 7 times heavier ($a \propto m$), therefore 7 times more dense. for comparison, io is also about 1/6 g, mars is 1/3, and ceres is spun up to 1/3. If it had more gravity then it would distort the orbits of the other moons and we would know about it. The magnetic field is probably generated due to its molten core, just like earth. tr:Ganymede (uydu) The same thing happens (i.e. So yes. You'd have to do some elaborate hand-waving to make Ganymede appear to be its apparent mass while having a very different actual mass. But checking vs Iron by molar weight would probably be a useful comparison. I know you can't comment yet, and that's always a problem for new users, but there are a ton of questions that don't need any extra clarification. no:Ganymedes (måne) As the charged See note above - I made a mistake the first time, but I think this calculation is correct. Titan's lower gravity means that its atmosphere is far more extended than Earth… Why is Yehoshafat called the King of Yisrael in Divrei Hayamim? Ganymede size compared to the Moon and Earth. Suffice it to say, this is highly unlikely. And when space probes are put in orbit around Ganymede they may detect the effects of those gravity generators, just as the first lunar satellites detected mass concentrations (mascons) in the moon. It has the highest mass of all planetary satellites with 2.01 times the mass of the Earth's moon. (I'll upvote you as soon as I have enough rep to do so. Since Ganymede's true gravity field is unknown, we have also plotted two other possible gravity fields, obtained using Kaula's rule with A k values of 0.4 and 40, corresponding to a weak field and a strong field, respectively. Earth's acceleration due to gravity with respect to its radius can be examined in the Earth … Within the caves, gravity is unaffected and the inhabitants experience earth-normal conditions. th:แกนีมีด Beneath the caves there is a powerfull source of magnetism - ancient spaceship or natural phenomenon. but if we assume Aliens created an artificial planetoid out of stable super-heavy isotopes and coated it in more normal materials, that'd do it. Naturally, a real gravitational field would not act that way, but since you're inventing a gravity generator that generates artificial gravity, you're entirely free to make that artificial gravity behave in a non-standard manner. Gravity Field Magnitude of Jupiter compared to Earth. eo:Ganimedo (luno) One thing you probably shouldn't do is change Ganymede's mass. Ganymede participates in a 1:2:4 orbital resonance with the moons Europa and Io, respectively. They make this little moon the most actively volcanic world in the solar system. The Great Oxidation Event…Artificially Imposed on a Tharn-Like Alternate Earth. (it explains why they have so much iron to start with). mr:गॅनिमीड (उपग्रह) Thus, they are worlds in their own right. Ganymede is composed primarily of silicate rock and water ice. Any object at the radius of Ganymede would orbit Jupiter in the same period - regardless of its mass. Having gone away and looked up material densities, I realised that the required density in order for Ganymede to be literally 5000 times as massive as it appears is well beyond tungsten or uranium or even Osmium or Hassium. Except that people almost fly up if they are nude - but you can use that in your story too. Jupiter, on the other hand, has a mean radius of 69.911 km / 43.440 mi, and a diameter of around 142.984 km / 88.846 mi at the equator, and a diameter of about 133.708 km / 83.082 mi at the poles. Its surface gravity is 0.146g or 14.6% of the earths. I'm pretty flexible on the ultimate origins of life there. Earth. Gravity is linked to mass, and both govern orbital characteristics, so unless there is some external force at play, gravity is set for Ganymede. And I'd be fine with suggesting those ancient aliens used some unknown advanced technology or "impossible" materials to intentionally craft an ideal environment there. In fact it is considered possible that there could be lifeforms in liquid oceans beneath the ice covered surfaces of Ganymede and other moons in the outer solar system. lv:Ganimēds (pavadonis) Other ways to say "His English has got rusty". The inhabitants inside there would believe there was gravity outward toward the surface. It is also about 1.19 times as massive as Earth's overall, or about 7.3 times more massive on a per surface area basis. Ganymede has areas on its surface as old as the solar system, up to 4.5 billion years old. Your answer is good, but you should remove the last sentence. However, if Ganymede is mostly made of some very dense elements like Tungsten or Uranium (as mentioned by @Ruadhan) it would work. et:Ganymedes (kuu) But scientists aren’t yet sure how big each one might be, if they exist at all. So technically speaking it's somewhere between 2 and 3 times as dense. The centrifuge was left there by a previous, more advanced civilization that also left all their other life-support systems. Connect and share knowledge within a single location that is structured and easy to search. Moons › Jupiter Moons › Ganymede Ganymede In Depth. Here, the gravity of Jupiter and large moon Ganymede (with help from moons Europa and Callisto) play tug-o'-war, with Io playing the part of the rope! Let's back track and figure out how we know the mass/gravity on Ganymede. Iron is 7850kg/m^3, while Tungsten is 19600kg/m^3. (Longer read here). How to temporarily save and restore the IFS variable properly? Io bulges on two sides like a football. ur:گانیمید How can I undo it? The amount of ozone is small as compared to Earth. Similarly, you'll need to handwave a material to compose Ganymede's mantle that is extremely light and somehow looks to our telescopes like a salty ocean. Opaque haze layers block most visible light from the Sun and other sources and obscure Titan's surface features. It has a radius of 696.340 km / 432.685 mi and a diameter of 1.39 million km / 864.000 mi. Replace gravity with magnetizm. So...probably the best soft-sci-fi solution (without invoking artificial gravity generators) is that Ganymede's core contains degenerate matter which for some reason can't decompress. Welcome to Worldbuilding! Regarding the Ganymede orbital phase, 3GM will collect most of the data during the GCO-500. Actually, Earth has solid ground tides too, but they amount to less than 20 centimeters (about 8 inches). A really strange coincidence in Lagrangian Mechanics, Drawing lines on both sides with mdframed and TikZ (or tcolorbox). What is Ganymedes gravity compared to earth? Ganymede is the largest moon in the solar system, and is larger than the planet Mercury. You need a material with a density of 779,634,464,751.96 kg/m^3 to do it. Differences in the number and speed of cometary impacts onto Jupiter's large moons Ganymede and Callisto some 3.8 billion years ago can explain … Asking for help, clarification, or responding to other answers. Its diameter of 5,268 km is 0.41 times that of Earth, 0.77 times that of Mars, 1.02 times that of Saturn's Titan (Solar System's second largest moon), 1.08 times Mercury's, 1.09 times Callisto's, 1.45 times Io's and 1.51 times the Moon's. has no known atmosphere, but recently the Hubble Space Telescope detected ozone at its surface. Unless it's determined by perturbations of other moons' orbits, but that's hardly trivial. needed for their survival. Only Jupiter's satellite Ganymede is larger in diameter. DISCOVERED BY. It only takes a minute to sign up. You'd need something 5 times more dense than tungsten to achieve earthlike mass with Ganymede. Good luck manufacturing one that isn't a ridiculously short-lived radioactive element. @EricDuminil Well that illuminates the other half of the problem. Why? Gravity is generated by mass and has an infinite range. Juno scientists now think Mars may be the source of the dust. Ganymede has large, bright regions of ridges and grooves that slice across older, darker terrains. fi:Ganymedes (See https://en.wikipedia.org/wiki/Ganymede_(moon)#Composition ) Which bring us to our next point... We will need to handwave some of our observations of Ganymede's physical appearance and its moment of inertia factor ( https://en.wikipedia.org/wiki/Moment_of_inertia_factor ). The spaceship has of course artificial gravity and is built around a reactor in the core, but the reactor is on stand-by mode, only supplying the people living there with oxygen, water, etc. Is there scriptural basis for spiritual 'growth'? So you can't get Ganymede's mass simply from observing the radius and period of its orbit around Jupiter (it's a pretty good way to get Jupiter's mass - but that's not the point). ganymede vs earth. eu:Ganimede How can you circumvent this from a scientific point of view? Ganymede compared to other moons of the solar system With an immense diameter of about 5,2682 km or 3,273.5 miles, Ganymede is the most massive and largest moon in the solar system. Did something I feel guilty about at work. Why are the later revisions of the Motorola 68060 heavily sought after by Amiga fans? hu:Ganümédész (hold) Titan is the second-largest satellite in the solar system. he:גנימד Ganymede was one of the four moons of Jupiter discovered by Galileo in 1610. Ganymede itself is packed with high-density materials such as tungsten and uranium deposits resulting in an earth-like overall mass easily 50 times as huge as it should be. If you have a question for the OP, it should be asked in a comment. And possibly analysis of the strange gravity readings may prove that they can't be the result of Ganymedean mascons but must be caused by generated gravity. pt:Ganímedes (satélite) By comparison to the other Galilean moons, it is 9% bigger than Callisto, 40% bigger than Io and 68% larger than Europa. You need to come up with a way to achieve your goals that does not involve gravity as we know it. It is larger in diameter than the planet Mercury but has only about half its mass. nds:Ganymed (Maand) For one, as Jupiter’s largest moon, Ganymede has a gravitational force of 1.428 m/s 2 (the equivalent of 0.146 g) which is comparable to Earth’s Moon. ro:Ganymede (satelit) Earth’s gravity is 9.807 m/s², compared to the moon’s gravity of 1.62 m/s² or just 17 percent of Earth’s gravity. It does not orbit the sun directly, though it … Inkscape: Adding an item to a distribution. Ganymede compared to Earth and Mercury Planet Though the average density of this moon is 1.93 gm/cm 3 , whereas the average density of Mercury is 5.43 g/cm 3 . And why wouldn't Earth's astronomers have discovered that before now? First off, we need to calculate the radius of the Earth. Artificial Superheavy elements beyond anything ever manufactured in a lab. To have a solution from changing the density will still require some hand-waving, but maybe it's allowable in a "cotton-candy-scifi" universe...you can be the judge of that! Possibility of alien life is greatest mad star life in the solar system europa jupiter s ocean world nasa just how hot is io s volcanic surface. Moon’s radius is 1,737.1 km (1079 mi). It was discovered, along with Europa, Ganymede and Callisto by Galileo Galilei in 1610. you'd probably need an artificial super-dense element. https://en.wikipedia.org/wiki/Ganymede_(moon)#Composition, https://en.wikipedia.org/wiki/Moment_of_inertia_factor, https://en.wikipedia.org/wiki/Mass_concentration_(astronomy), Stack Overflow for Teams is now free for up to 50 users, forever. We can assume there's enough light that filters through the crystalline surface to support life, and that there's enough air trapped in these caves for them to breathe. Taking Earth's surface gravity as 1 gravity for other planets are given below. For a sphere of given size, the gravitational field at the surface is depends on the density so that: So if you want Earth-gravity on a planet the size of Ganymede, you'd need to make it out of material with a density of about $15\space g/cm^3$. wuu:木卫三 I made some quick calculations on this. And they had plenty of these two substances stored away in one form or another within their stony bodies. zh-classical:木衛三 To subscribe to this RSS feed, copy and paste this URL into your RSS reader. da:Ganymedes (måne) Ganymede is the largest moon in the solar system, one of the four main moons of Jupiter. Osmium is 22590kg/m^3, still not viable for this, and Hassium (the densest material ever made in a lab) is a little denser at 22610kg/m^3. zh-yue:木衛三, Individual and political action on climate change, Articles with dead external links since March 2009, Articles with invalid date parameter in template, Pages using duplicate arguments in template calls, File:Galilean moon Laplace resonance animation.gif, File:PIA00081 Ganymede Voyager 2 mosaic.jpg, Solar System's largest moon likely has a hidden ocean, http://www.lpl.arizona.edu/~showman/publications/showman-malhotra-1999.pdf, The Permanent and Inductive Magnetic Moments of Ganymede, http://www.igpp.ucla.edu/people/mkivelson/Publications/ICRUS1572507.pdf, The Far-Ultraviolet Oxygen Airglow of Europa and Ganymede, http://adsabs.harvard.edu/abs/1998ApJ...499..475H, SPS 1020 (Introduction to Space Sciences), Numerical Simulations of the Orbits of the Galilean Satellites, http://adsabs.harvard.edu/abs/2002Icar..159..500M, Free and forced obliquities of the Galilean satellites of Jupiter, http://adsabs.harvard.edu/abs/2005Icar..175..233B, Tidal Evolution into the Laplace Resonance and the Resurfacing of Ganymede, http://www.lpl.arizona.edu/~showman/publications/showman-malhotra-1997.pdf, A Primordial Origin of the Laplace Relation Among the Galilean Satellites, http://adsabs.harvard.edu/abs/2002Sci...298..593P, Internal structure of Europa and Callisto, http://adsabs.harvard.edu/abs/2005Icar..177..550K. It might be quite unlikely, but normal metals are plenty dense (as you said in your first answer!). For comparison with Earth, Miami, Florida lies at 26 degrees north latitude, and Berlin, Germany is located at 52 degrees north." Meaning you can walk around as normal, but throw a ball high into the air and it won't be coming down again.