Originally Answered: What are some unknown facts about our solar system?
Though it may be very far fetched - it's thought that the Europan ocean has enough oxygen to supply a quite sizeable ecosystem - not as much as Earth by any means, but as much as, say, the hydrothermal vents on Earth (oxygen through dissociation of water by Jupiter's radiation). If so, it might conceivably have higher animals like octopuses and dolphins. Well if it can have those - why not intelligent life also? It would be non technological if it exists, almost certainly, without fire. Suppose the Europa ocean had a millions of years old very civilized but non technological civilization - well we wouldn't know anything existed at all outside the Europan ocean so wouldn't know about us. And we wouldn't know about them yet either.
So it's not impossible that one of the unknown facts about our solar system is that we are not the only intelligent creatures with a civilization native to it. May be other ways it could happen also (Mars not likely on our best knowledge, because its most habitable regions are similar to our harshest driest and coldest deserts - they tend not even to have that much by way of multi-cellular life, never mind intelligent life - but may be other places - even Titan - know very little about it, ideas for biochemistry very hypothetical have to be back to front to Earth life with what our cells use for cells as the interior and what they user for the interior as the cell walls, sort of, to live in oceans of ethane and methane).
We don't know if any of the moons have rings. Rhea was thought to have a ring at one point. It's now been shown it doesn't have a very prominent one but it does seem to have a dust cloud associated with it so could have a ring. Maybe even moonlets.
Can Moons Have Moonlets? Or Rings? Moonlets Of Pluto's Moons?
Our solar system might have a tenth planet - or dwarf planet. It can't be any bigger than Saturn unless it is a long way out. The WISE spacecraft has has ruled out the possibility of a Saturn sized object out to 10,000 times the Earth - Sun distance, and a Jupiter size or larger object out to 26,000 times that distance. (I.e. 26,000 AU.)
Artist's impression of the NASA Wide-field Infrared Survey Explorer. Researchers proved that Nibiru and Tyche can't exist in results published in 2014, using data that it collected in 2010 to 2011.
But we might still find Earth or Mars sized objects out there. Some think that's the explanation of the Kuiper cliff.
Has a dip at 50 au. Models showed the number of objects should double at 50 au. So some suggest there must be a planet, as large as Mars or Earth to "shepherd" the kuiper belt like Saturn's shepherding moons for its rings. What if we find an object large enough to do that, also as large as Mars or Earth, but which can't "clear its orbit" according to the IAU definition.
Similarly - on things that we may discover in the near future:
That the Moon may have lava tubes large enough to include an entire city.
There Could Be Lava Tubes on the Moon, Large Enough for Whole Cities
So anyway turning to little known facts: that we have an asteroid with rings
That some of the dwarf planets are shaped like rugby balls.
That Hyperion, and Pluto's moons rotate chaotically
This shows the motion of Pluto's moon Nix. Done before they had close up photos of it so the texture is an artist's impression.
That Mars has blue sunrises and sunsets
That the Pluto hazes look blue when seen from behind its sun
That when seas are very deep, then the ice that forms down there sinks rather than floats. Ganymede may have multiple layers of ice and water alternating like this
That CO2 forms a supercritical liquid that may be a place where some lifeforms could survive - not our form of life. That on Earth there are places where this supercritical liquid CO2 bubbles out of the ocean floor, and below a certain depth the bubbles are denser than water so there may be reservoirs of it on the ocean floors.
Geysers of Triton. Still the only understanding we have of Triton is from Voyager 2. Without it, we would know almost nothing about this moon of Neptune.
That Mars has geysers - but these are geysers of dry ice not water
Polar explosions: Carbon dioxide geysers on Mars
That there may be ice at the poles of Mercury
The bright features in this radar image may be water ice at the poles of Mercury Water ice and organics at Mercury's poles
Good evidence of ice at the poles of the Moon also.
That there are places at the poles of the Moon that get light nearly all the year round, and during the lunar day and night alike. The four points labelled here get light 80% of the time
And that right next to them are the coldest places in the inner solar system which never get any light at all.
Another place like that is Deimos - it's South pole is permanently shadowed and is amongst the coldest places in the inner solar system.
That Stickney crater on Phobos, which always faces Mars, is almost completely protected from cosmic radiation - by the very close Mars above, and Phobos below and crater rim at all sides.
A base here would be completely protected from solar storms and would also get only 10% of the cosmic radiation of the unprotected surface - a fifth of the radiation of the ISS also. Apart from the lunar caves, this is one of the most protected places from cosmic radiation in the inner solar system. It is easily the most protected places on a planetary or lunar surface - that is except for the upper atmosphere of Venus and the Earth.
To Explore Mars With Likes Of Occulus Rift & Virtuix Omni - From Mars Capture Orbit, Phobos Or Deimos
That the upper atmosphere of Venus, above the cloud tops - has clear skies (though orange in colour) and the atmospheric pressure and temperature is exactly the same as for Earth making it the next most habitable place in the inner solar system for humans to Earth in many ways. Except the sulfuric acid - but that is far easier to protect against than vacuum. And that a normal Earth atmosphere is a lifting gas in the Venus atmosphere so that you could have an "airship" with the air inside the airship breathable by humans.
That many asteroids have moonlets, and some have two of them
Minor-planet moon
That at any time Earth probably has at least two extra moons the size of a washing machine, and about a thousand larger than a softball orbiting it at any time - though individual moons hang around for less than a year then escape back into interplanetary space. Earth Has Scores of Mini-Moons, Models Predict. We have spotted one of these moons, 2006 RH120 which orbited Earth from September 2006 to June 2007. It's thought to do this every 20 years or so. The rest are theory.
(I may add some more things here as I think of them - fun question).
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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