New answers tagged

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Your planet was full of life but was sterilized by a gamma ray burst. Your planet was lush, with forests, prairies, rich soil and all the other things you want for your story. However in an adjacent system a gamma ray burst took place. For four minutes your world was bathed in energetic rays. Everything died. And did not rot, because everything died. ...


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Most of our atmospheric oxygen comes from photosynthesis, and most of our regolith is either sand or filled with biomass. So my guess is that you're looking at mostly sand, with the precise details depending on things like chemical abundances, the density, temperature, etc of your planet, and the presence or absence of water (the absence of water on the ...


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The problem here is that the soil and atmosphere that is used by Earth life today is not naturally occuring (geologically speaking). It is made by other Earth life. The most important parts of it is a combination of organic molecules that were synthesized by organisms long ago that took raw naturally occurring molecules like CO2, H20, and N2 from the air ...


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The problem with Io is that it has no atmosphere. It was blown away long ago by the heat of the planet and eroded by the Jupiter's magnetic field pulling particles. Io's dust is the main source of the accelerated particles that are responsible for Jupiter's orbital space radioactivity, because the magnetic field accelerates them to dangerous speeds and they ...


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I'm not certain, but I strongly suspect that a geosynchronous orbit (in this case, quite a bit further than the appr. 22,000 miles/40,000 km we usually think of, because of the extra mass of the second body) would be inside the Roche Limit -- and that the two bodies would tear each other apart with their tides, then the fragments coalesce into a single super-...


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At 20 AU, Sun-like star will produce 20*20 = 400 times smaller illumination. Based on this data: Lux, illumination will be in the range of 200-300 lux (with clear skies), which is more than on Earth on a "Very dark overcast day", but less than "Sunrise or sunset on a clear day" - more in line with well-lit building interiors.


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I don't know why Fabius Maximus thinks that tidal forces would be too strong in a double planet or a a habitable moon of a gas giant planet. Part One of two: Two habitable planets orbiting the same star. But If Fabius Maximus thinks that is the case, the next logical step would be to have two habitable planets orbiting the same star in different orbits, ...


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I don’t think that it’s possible to give an exact answer to this question as there is no viable general solution to the 3 body problem. However in S type non-circumbinary planets (those that orbit a single star in a binary system rather than P type circumbinary which orbit both stars) it has been suggested that the orbit of the planet should be at least 5 ...


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Well, if what you want is two Earth-like planets extremely close together, the best solution would be to just have them both orbit one parent star in orbits at different distances. If you look at this chart, Earth is actually on the near end of our sun's habitable zone (https://en.wikipedia.org/wiki/Circumstellar_habitable_zone#/media/File:...


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I don't think tidal forces would be much of a problem. Our sun is responsible for roughly a third of the tidal forces felt on Earth, and if the other star is 25 AU away, the nearer planet would receive 1/625 the tidal forces from that. It will also receive 1/625 the heat and light from the farther sun than from the nearer; not enough to significantly change ...


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The others before me have written plenty about why and how it's not possible normally due to size and density requirements you have set up as a premise. The only way I can think of to make it possible, is make the planet hollow. As long as the outer shell weighs 100x of earth (for 1g, I calculated), the rest should fit into the math more or less. This raises ...


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You have added the "science based" tag. And that's a problem. There is no known way to make time pass faster on another planet. You marked "Accepted" an answer by Mathadict about standard old relativistic time dilation. But this answer is wrong. If two planets are traveling relative to each other, then each sees the other as going more slowly. This is ...


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Your characters believed the connection to be a wormhole through space, but they have actually been using: A wormhole through space AND time™ When the wormhole is lost entirely, your characters "repair" it by creating a brand new one. But since they are unaware of the time component, they don't take timeframe into account. Their wormhole connects the ...


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Just normal velocity Time Dilation would do it, this even solves the issue of why it doesn't happen when the planets are "connected" If the earth is moving very fast in relation to the distant planet then time would move slower on earth than on the planet. But when they are close together, then they actually aren't moving very fast in relation to each other ...


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Orbits are basically falling to Earth and missing. Earth's moon is about 1/4th that of Earth, and while your planet takes up more space than Earth but has the same gravity, it could be possible that an Earth sized moon could occur. The dwarf planet "Charon" is about the same size as Pluto, the body which it orbits, though like manythings about Pluto, it's ...


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The planet is 10 Earth-Radii, with a 1 Earth Gravity value. It is a habitable planet. It has a thin atmosphere. It also has 3 moons and a ring system. Apart from the whole "habitable" and "thin atmosphere" thing, you've basically described Saturn. Saturn is ~95x Earth's mass, and 9.5x Earth's radius at its equator. Surface gravity is a bit over 1g, too. ...


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Your planet would have 0.1 x the density of the Earth, i.e. about half the density of water. It might be some kind of weird smallish gas giant with the right chemistry in its atmosphere to support some kind of life, but definitely not a traditional Earthlike habitable planet. It definitely won't fulfil your description of having a thin atmosphere. Your ...


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In theory, the Earth could be a jovian moon, there is nothing physical forbidding that. But size is only part of what makes a planet earth-like. You need: 1) Metals, lots of it. Due to rotation metals, being heavy, will be more present in the inner body then in the outer bodies. If a earth-sized moon formed around a jupiter-like planet it could be metal-...


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Short Answer: The OP needs to specify a number of details about what he wants. Do they want a story in which the "planet", or the "moon", or both, has life, possibly including intelligent life, or can both worlds be lifeless? How much more "gravity" does the OP want the moon to have compared to the planet? Once the OP clarifies what is desired, someone ...


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This isn't the type of post you should be making on this site, but I'll answer with what I've heard. I've seen things about certain websites that let you make a planet, specifically http://planetmaker.wthr.us/ By the way, this site is more for things about a world, and less about things to make a world. like "is [thing] able to [thing] like this"


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Phil Geusz's David Birkenhead series has one of these that works. The background is that there's a civil war in an interplanetary empire, and this planet was planning to switch from the loyalists to the rebels. The loyalists arrived first and prevented the betrayal, so the rebels arrive to find a planet against them instead of for them. The rebels have to ...


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TL;DR Well, the thing is, you can't invade earth, as we have enough firepower to blast any fleet that comes withing range.* Therefore, your aliens must consider alternative options. A viable strategy for them would be to show up in orbit with a mock-up of the Death Star in tow. Long answer: While it would be very easy to get ships to a planet you want to ...


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To be a body orbiting another (and not otherwise), your moon has to be at most the same mass of our planet. Since it is the mass that matters, and not the size, you can make your moon as large as you want, taking in account that the moon.mass/(moon.size/2) must be higher than the planet.mass/(planet.size/2) -- so bodies would be heavier at surface. As you ...


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Here's a graph that shows the proportion of the total radiated energy from a black body contributed by specific wavelengths (more or less). You can see that as the temperature of an object rises, the proportion of the total emitted radiation that falls into infrared wavelengths is smaller than for cooler objects, but because the total amount of radiation is ...


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Planetary nebula rotate around a star during planetary formation and consequently all planets formed orbit in the same direction. So It’s not possible for a planet to be formed with a retrograde orbit in this way. However stars themselves orbit the centre of the galaxy and it is possible that occasionally stars pass in relatively close proximity to one ...


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As air would be heating up on the sunny side and cooling down on the dark side of the planet, winds would probably go from dark to sunny on ground level and in the other direction higher up. You could expect them to be fairly strong and regular. As a result of cold air being sucked from the dark side there would be a zone in the sunny side with reasonable ...


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For an in-situ born planet, it can happen, though it is hard to have the exact chain of events. Basically you need to have a series of gravitational slingshots with a larger body that put your planet on the opposite rotation direction of the entire system. While playing with this simulator, I sometime managed to pull out that stunt, and have a planet ...


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The short answer is "if they were adapted for lower light levels, they would have to protect their eyes". Brighter stars emit more energy all through the EMR spectrum, including the infared. However, the intensity experienced during a creature's evolution would be less a function of the star's spectral range, and more the proximity of the planet to the ...


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I'm going to be honest, I think this sounds a little too far outside of science for this to work. Base requirement is that the Earth and moon would have to be completely different because they would need to be closer and tidally locked so that the moon doesn't immediately rip the beanstock out of the ground. Pluto and Charon are a great candidate for that, ...


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There's a bunch of questions that commenters have already raised but I'm going to give it my best shot. I'm assuming that the metal object is like the 'sun' for this planet, so this planet orbits it. No idea if this is feasible, but I'm going to assume it is (i.e this metal thing has enough mass to attract this planet of yours). First of all: planets don't ...


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The elliptical orbit couldn't be terribly long, as all life would cease when it reached the furthest points away from the sun(s) UNLESS there were some sort of greenhouse effect in place. Otherwise, migration wouldn't be too much different than it is on Earth among some tribes and migratory animals. When it's too cold, you go to where it's hot and vice versa....


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Navigation wouldn't be any different than it is on Earth. Consider Pluto: It has a much more eccentric orbit than Earth does, but navigation on Pluto's surface would be exactly the same. The sun rises in the 'East', it sets in the 'West', and North and South are likewise just like they are here. That's all based on the rotation of the planet, orbit has ...


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It's an interesting scenario. The major problem is that ring systems tend to be quite low-mass in comparison to their parent bodies. For example, measurements by Cassini indicate that in the case of Saturn, the ratio of ring mass to planet mass is $M_R/M_p\simeq2.7\times10^{-8}$ (Iess et al. 2019). Even in the notable case of 1SWASP J1407b, whose ring system ...


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Tl;DR: probably no. But it might not even be required for what you want. The (simple, rigid-body approximation) for the Roche limit is defined as $d = R_M \sqrt[3]{2{\rho_M \over \rho_m}}$ where $R_M$ is the radius of the primary, and $\rho_M$ and $\rho_m$ are the densities of the primary and satellite respectively. Given constant densities, the Roche limit ...


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A possible side effect: displacing such huge amount of material could perceptibly shift the planet's rotation axis. It is believed to have actually happened on our Moon due to volcanism moving the material. So it should not be done haphazardly. If this causes the artificial crater to end up closer to pole after the excavation, it will have colder climate ...


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I don't think that dragonfly like wings could be structurally strong enough to support a human size being in flight. The largest prehistoric dragonflies weren't nearly as large as a human. I think I remember that it was calculated that humans should be able to fly with artificial wings on Titan due to the low gravity and dense atmosphere. Because of the ...


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What I should have been looking at is the Geoid of Mars & the depth from it to the mantle The thickness of the crust varies between 50 km & 22 km due to the Geography & features (rock layers) above the Geoid while the distance from it to the mantle should be reasonably uniform. I presume the putative Geoid of Mars is the altitude used for ...


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Since nothing exactly like this exists on Mars, let's look at the best real-life example of what you're describing: A crater. On Mars Hellas Planitia is one of the oldest and largest craters on Mars. It was formed during the Late Heavy Bombardment, which started around 4.1 BYA. At more than 7 km deep, it's one of the deepest craters in the solar system. ...


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Valles Marineris reaches a depth of 11 km, while Olympus mons reaches 25 km of height, together they make the gap you envision. Olympus mons is thought to be 200 million years old, while Valles Marineris should count 3 billion years. Therefore the lower limit for existence of such a height difference seems to be at least 200 million years.


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Magnetic Fields Water is diamagnetic, meaning that its magnetic polarisation aligns itself opposite to an applied magnetic field (thus, water is repelled by magnetic fields). This has been demonstrated in "levitating frog" experiments. If you were able to somehow get a (monodirectional) magnetic field to protrude out of the ocean, you could hypothetically ...


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This is a major undertaking. You will need a civilization somewhere between 1 and 2 on the Kardeshev Scale, and you will need to do it manually. If you have a Dyson sphere you should be able to muster up enough energy to pull it off. Start by boiling the oceans. Raising the global temperature to over 100C should do the trick. Alternatively, microwaving ...


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Unfortunately I do not think there is any way to achieve what you require. Imparting sufficient energy to Earth’s oceans by heating or rapid motion would destroy the entire surface of the planet and drag friction with the surface would force the water to eventually fall / condense back to the surface again. Giving the water sufficient energy to reach ...


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You don't have the mark. You got the Father of the mark. Oopsie! The seas arise amisdt moving earth. For the maker of the unmaker breathes once again. Look into many religions and myths as reference. Even the side charcters of the Main Character were of great import. Mary mother JC was said to receive the visit of an angel. Goddess Kali, spouse of Shiva,...


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The child's existence is the key to a metaphysical doorway which is one layer of a multiple layer barrier between our world and the plane where the Scarlett King waits. This doorway is the outermost layer of the barrier, the layer closest to our world. The six brides would have opened all of the other layers of the barrier if they had lived, but since they ...


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Sulfur-based life is pretty unlikely, for the same reason that life on Earth isn't oxygen-based. Sulfur, like oxygen, usually only likes to form two covalent chemical bonds. Thus, you can in principle have chains of sulfur atoms of varying lengths with with different atoms attached to either end, but that really isn't enough variety of structure to permit ...


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Could my explanation for this phenomenon be as simple as a periodic gravitational tug from another large planet? This is known as an exchange orbit, and occurs with Saturn's moons of Epimetheus and Janus. Two co-orbiting bodies with similar mass and orbital characteristics can exchange eccentricity and/or orbital distance during close passes. Orbiting ...


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One thousand years is not long enough to build a massive ice sheet. But it might be achieved in several thousand years. Oceanic currents take around 1000 years to cycle so I doubt 1000 years is sufficient time for "the Earth to freeze up totally except for the equatorial regions". Warm water would still be welling up from below. What might help would be a ...


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Since we're already making the comparison to software algorithms, I'll follow that route. Antivirus software can only protect against signatures, patterns, and actions that it knows about. It doesn't learn or adapt on the fly - it cannot. Instead, effective antivirus relies on near constant updates to counter new threats as those threats become known and ...


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Younger Dryas was an abrupt event with roughly the feature you require, except the periodicity. The Younger Dryas (around 12,900 to 11,700 years BP) was a return to glacial conditions after the Late Glacial Interstadial, which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM) started receding around 20,000 BP. ...


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Simply put, sane or not, if he were any scientist worth his salt, he'd understand that he cannot make a day any closer to the 86400 seconds that it currently is defined as. How precise can we be? The length of the year is ~365.2422ish days. This is the oft-cited duration of a tropical year, the "mean time between between vernal equinoxes", but is in fact ...


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