Presumably this black hole is very massive, thus meaning a body has to move faster to have the same orbit as compared to orbiting a less massive body. (The reason planets around stars like red dwarfs have similarly short orbital periods is because red dwarfs emit very little light, meaning a habitable-zone world orbits very close to the star.)
Alternate Planets, Suns, Stars, and Solar Systems Thread
- Thread starter Pragmatic Progressive
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I suppose it depends on the strength of the moon's magnetic field. Ganymede actually does have a magnetic field and does have aurorae, but nothing especially spectacular as far as I can tell.
Well, that's disappointing for Ganymede. That being said, it only has about 2% of Earth's magnetic field, so that's to be expected.
Suppose you found yourself in a multitude of planets orbiting a black hole much like SDSS J010013.02+280225.8--12 billion times more massive and 429 trillion times brighter than our sun. How far and how wide would that make the habitable zone?
Too my knowledge Black Holes doesn’t have habitable zones, they suck heat in not out.
The habitable zone around a quasar is nil, because any and all life would be sterilized by the immense amount of radiation assuming the accretion disk that fuels the quasar didn't destroy it first through either the sheer amount of heat or physical bombardment. That said, if you could open a portal to a quasar (quasars don't exist anymore in the universe), it would be a most attractive colonisation target because of the incredible amount of energy available as well as harvesting the accretion disk. You'd simply build incredibly well-shielded space colonies anywhere you felt like or cover an existing planet in shielding.
Yes, though it would not be naturally occurring, that is it would either be artificially created or be host to a massive biosphere of species that act like like life on Earth, converting C02 into Oxygen.
Not true. Black holes don't precisely emit light, but they also don't suck anything- and besides that pedantic foreword, phenomena around black holes can emit light. For something relatively stable over time, an accretion disk suffices nicely- though I'd definitely recommend something whose brightness isn't much higher than a galaxy rather than being hundreds of times higher like @JohnWarrenDailey 's idea. A quasi-star (also not present in the modern universe) has a luminosity on the order of a billion sols, and its habitable zone is light-years out.
Only if it is artificial object. Natural gas giant will collect too many hydrogen and helium from protoplanetary cloud when it will formed
You could probably build a quasar, if you wanted to. It would be a Type 3 project, for sure, but a quasar is just a supermassive black hole that is ingesting a lot of matter. If you really wanted, you could build Shkadov thrusters around a bunch of stars in the galaxy and brake them into the central black hole at a sufficient rate that it becomes a quasar (again). I'm not sure why you would want to, exactly--maybe some kind of ultra-long-term project to harvest energy via the Penrose process for a longer period of time after the stars go out--but you could.
Oxygen is the third most common element, though I grant it is withal far less common than hydrogen.
Still, might we not have a situation where the hydrogen is depleted by some nearby star heating a very massive protoplanetary cloud, leaving a higher fraction of oxygen, which then, when the planet forms, combines with the hydrogen to form water, and thus get not an oxygen giant to be sure, but anyway a water giant laced with some spare hydrogen and helium? And then perhaps the hydrogen can be reduced further by dissipating away, along with much of the helium, leaving mainly water molecules behind?
In fact if the reason the hydrogen were initially unusually low is nearby stars in a cluster forming, and a large bright star forms which the water giant is orbiting closely, and it is high heat input from this new star that bakes out much of the hydrogen, then water molecules will also be split by UV radiation and solar particles, leaving a surplus of oxygen--what starts as a very heavy object with a water core and hydrogen-helium upper atmosphere could thus evolve first into a water giant and then increasingly oxygen-rich mix with water, which might even go to essentially all oxygen with little water left. On Venus this process led to a carbon dioxide atmosphere but that was because the oxygen had a solid surface to interact with and strip it of carbon chemically; if there are no such relatively large carbon reserves, pure oxygen might come to dominate. If there is any other substance whatsoever, oxygen is likely to combine with it, but if these substances are a minority of the mass, they will tend to be buried in the core.
Such an outcome seems likely to be rare, and perhaps short-lived if it is necessary for the star capable of cooking away the free hydrogen and helium to be a high power bright start, F or hotter; such stars do not last long and go supernova eventually, which might simply vaporize the brief candle "oxygen giant." But perhaps a small red dwarf could do the cooking, if it formed very near the oxygen giant, and nearby other supernovae might do little more than heat the big remnant planet briefly. A red dwarf would not provide much UV but sheer heat can still result in selective depletion of hydrogen. And a G type star would put out a fair amount of UV while lasting ten billion years or so.
So it might be as simple as a superjovian sized "ice giant" forming very close to a G type protostar. Rare but not unheard of I'd guess.
An F-type or even an A or B-type star wouldn't necessarily or even probably go supernova--just look at Sirius B, whose progenitor is thought to have been a B-type star but which proceeded up the giant branch until becoming a white dwarf. The minimum mass needed for a Type II supernova is 8 solar masses, which would place a main-sequence star between B2V and B3V. If anything, the limiting factor establishing the upper mass limit of the progenitor star is the minimum lifetime needed for planetary formation to actually finish before the star dies--though the stellar winds from a heavy red giant might go a long ways to blowing off the light elements from a nascent gas giant and leaving behind a heavy element-enriched planet.
70:1 mass ratio, to be more precise and the main problem for Oxygen giants is too strong chemical activity of Oxygen
Carbon is #4 element in Universe after H, He and O and O:C mass ratio is 10:4.5.
I can see pure oxygen as part of atmosphere of the water-carbon dioxide giant but oxygen-dominated giant have too few natural origin possibility
Because in looking for suitable, long-term habitable zones to seed Earth ecosystems in Serina-style, giant stars and dwarf binaries keep ending up short.
Well, the obvious answer there is a K- or M-class dwarf star. M-class stars can last for trillions of years, which is far longer than any quasar, while K-class stars will last about 20-30 billion years; shorter, but still several times longer than the Sun. That should really be more than enough time for any amount of evolution you want.
This picture is taken from one of Sean Raymond's Planet Planet articles, Cohorts of co-orbital planets.
What the article doesn't explain, however, is the basis for the question. In a solar system in which six rocky planets, each one the size of Earth and each one orbited by a single moon 1/4 its mass from a distance of 238,900 miles, orbit their sun from one same distance, would a 60-degree difference allow each of the "Earths" to spin in day-night cycles?
So? Why do you need a wide habitable zone in the first place? As far as I can tell, you're just imagining how a small number of species might radiate given a planet of their own, what does it matter if they're in the same star system or hundreds of different ones?