# Tag Info

77

The same things that make houses expensive today First of all, while the wealthy generally live in bigger houses, the price does not scale linearly with square meters of living space. A five million dollar house isn't necessarily ten times bigger than a 500k house. Instead, it's of higher quality with better features, materials, and design. In a planet, this ...

65

The problem your going to have in any open sky area however, is the familiarity of the moon and constellations - a dead giveaway that your still on earth. To that end, I'd suggest the best place for this scenario would be a large underground cave system, like Reed Flute cave in China:

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A simple answer is that the planet is on an orbit with a high inclination relative to our line of sight. The other planets in the system may appear, from our perspective, to be in line with us and the star; we could then discover them through transits. This new planet, on the other hand, would never produce a transit as seen from our vantage point on Earth. ...

64

Make your portals (to borrow a term from physics) 'magnetic'. In other words, two magic portals that are too close to each other in space will attract each other and merge into a single portal, and because portals between planets require tremendous amounts of magical energy, they have tremendous 'magnetic' attraction. Two portals that have their origins and ...

61

If the creatures can be mistaken for planets, then by duck typing, they must have the following properties: They orbit stars, They have sufficient mass to assume hydrostatic equilibrium (a nearly round shape) They have "cleared the neighborhood" around their respective orbits. This means that they cannot copulate by physical contact. The ...

60

Mount Kilimanjaro, despite being close to the Equator, has permanent glaciers on its top. This hints toward the solution to your problem: orography! While one hemisphere is mostly flat, with limited elevation and can enjoy the benefit of a warm climate, the other hemisphere is much more mountainous with most of its peaks above the snow line. The ...

59

This place cannot have any obvious life forms. Nothing too complex (Small microbial creatures are fine) No humans for at least a few hundred miles, and no signs of their presence. Must be somewhat hostile to human life Cannot be underwater Inland Antarctica seems to satisfy all the above: Doesn't have obvious life form, not animal nor vegetal,...

57

On Space Exploration Stack Exchange, Russell Borogove addressed a very similar question and made some reasonable estimates about the required mass of a Saturn V-like rocket (arguing it's impractical to consider all possible rocket designs, given the variation in performance) to escape a planet of various surface gravities (see also Hippke 2018). Above $10g$, ...

49

Combine an significant axial tilt with a elliptical orbit. Axial tilt allows one hemisphere to be in winter while the other is in summer. Earth has approximately 23.44 degrees of tilt. Even in mid-summer the temperature at the south pole is far from tropical because the sun never rises above 23 degrees and sunlight is correspondingly dim. 45 degrees is too ...

48

A different take on Daron's answer: They play god--guided evolution. All that junk in our DNA? Some of it is actually the genetic material of the planet-beings. The sentient star travelers are the gametes.

44

The ultimate sign of wealth is being able to command other humans' services. Most people are only served by robots. The really wealthy will have human butlers, secretaries, cooks, tutors for their children, stewards to organize the other servants, etc. The human servants will be people with only a house but who would like a planet, or with planets that need ...

43

Two places come to mind immediately; The soda lakes of Tanzania The soda lakes of Tanzania are quite uncomfortable places for humans to be, and ultimately they fill the brief of 'somewhat' hostile to human life. But, they also look the part when you think of an alien landscape. These lakes of soda ash are pink in colour and extremely alkaline, meaning that ...

42

It's very much a matter of what information they want to display in their primary 3d to 2d projection. The Mercator projection that everyone is so familiar with is simply designed so that lines of latitude are straight horizontal and any simple compass bearing is a straight line. This makes ocean navigation easier as the important factor was knowing how ...

41

I asked this same question, on the physics stack. The answer is that a body can have only one axis of rotation. Below pasted is the link to the question and the answer I picked. https://physics.stackexchange.com/questions/322200/how-many-different-axes-of-rotation-can-coexist Q: I have questions about rotation. There is a sphere in space. I can ...

41

Religion Some book considered holy and written long ago claims some deity created that specific planet, and then all sorts of creatures and finally humans on it. So the inhabitants of Eden think they have been expelled from the Garden of Earth, without ever realising that Earth is another planet.

40

why invade at all? Most structures of a civilisation are probably going to be on a surface. It is, after all, more difficult to build underground than on a surface. That means that most items of value can be simply blasted from above. But you might not want to blast them from orbit because these items might also be of value to you. You might want to avoid ...

39

Bizarre real maps In our real world of the planet Earth, some traditional cultures created maps that for most people would look absolutely like alien objects and will not be recognized as being actually maps, still the are maps, and they are of practical use. Inuit wooden maps The Inuit people of Greenland used carved pieces of floatwood to depict the ...

36

The Earth had life without multicellular animals for roughly three billion years, so it should be pretty obvious that such a planet is possible. There were certainly plants for some of that very long period — the amount of time depends on your exact definition of a plant. But there has been photosynthesis for nearly as long as there has been life.

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Time This is normally done with the application of a few hundred years, technological collapse and a migration of the population away from any physical artifacts of interplanetary travel. Technological collapse takes away all their records, even if they reinvent computers later they probably won't be able to read the old records. The technological collapse ...

29

Photosynthesizing plants will have serious troubles and are already well covered by the other answers. But what about other kinds of plants? Life is not limited to using the sun as a power source (it just happens to be most abundant one on earth, so most organisms using it easily outcompete others in ecological niches where sunlight is available) - many ...

29

would it be feasible for there to be a unique but similar civilisation on each 'Plane'? Define "similar". Given how thoroughly you've cut off each face, there's no guarantee that inhabitants of different faces would have the same set of amino acids, let alone anything more complex in common. You'd need to set up some means for information (cultural or ...

29

Add Danakil in Ethiopia .. Volcanic activity and solved salts give multicolored water that's borderline acid and thus dead - and the colors give a nice flavor even combined with a natural azure sky Edit: Not even microbes were found in the ponds ... thus they not only appear foreign and dead .. they are deadly, poisonous, acidic

29

Minerals of biological origin. Chalk, various types of limestone, marble, coal, fossils, petrified wood, amber, guano. It is surprisingly hard to find examples of non-biological minerals that are unique to planets. Early solar system conditions allow of the formation of minerals we would not think would be able ot form at a casual look at space conditions. ...

28

It only takes a generation or two before that which may once have seemed foreign may then be seen as something that was always there. For example, in our daily lives, we don't think about how certain food items aren't native to our current homes, yet mere centuries ago, pineapples were a luxury. We take things for granted, and that's something that can ...

28

That really depends on what you consider 'negligible'. Is it 'Sterilization of all life, but planet is still there in one piece in the same orbit'? Or is it 'Everyone in the direct impact zone gets squashed and the rest of the planet suffers earthquakes, but after a decades-long volcanic winter we only have a mass extinction event'? The second case might be ...

28

Hitch a ride on Spaceships. Renan mentioneed these creatures cannot possibly make physical contact and live to tell the tale. The answer suggests spores, meaning much smaller particles that get shot off the surface to find other spores in the depths of space. Problem: Space. Is big.[citation needed] Solution: The reproduction strategy relies upon sentient ...

27

Maps don't have to be geographical, they can also be diagrammatical, like the London Tube map. For instance, ancient Roman maps, the itinerarium, were graphs showing points of interest along a road rather than geographical relations. A branch in the road was a branch in the graph line. Another approach is symbolic maps, like the medieval T-O maps and mappa ...

27

Hydrogen and Helium Light elements are abundant in universe, but are hard to remain in small gravity bodies. However, gas giants Saturn and Jupiter are the obvious sources in Solar System.

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Ideas: The target of a portal is somehow related to its location. If you want to create a portal on A that leads to B, there is exactly one place on A that such a portal can be created. (Create a portal anywhere else, and it will lead somewhere else.) There is some fudge factor here, but the fudge factor is less than the size of the portal. Similarly, when ...

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Assuming by "planet" you mean a roughly spherical body - encompassing both dwarf planets and "true" planets - then the smallest naturally occurring body is somewhere between 1 Ceres (dwarf planet) and 4 Vesta (not a dwarf planet because it's insufficiently round). Ceres is about 900-950 km across; Vesta more like 450-600 km. An object of ...

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