How could I scientifically explain a world where the surface is made out of pillars?

Question

Imagine a world full of islands. No continents, just average-sized islands. There are so many islands, that it would look a bit like this from space:

Now, imagine that the sea is very, very deep. I'm talking like, a few kilometers deep. In a way that if you are on a beach walking towards the ocean, instead of the water slowly getting deeper, it's a sudden a drop of many kilometers.

Now, imagine that there's no ocean at all.

The surface of the planet is covered in humongous pillars. Those pillars (aka. the islands) are habitable; some have even lakes in them. The atmosphere is breathable, it rains all over the planet, somehow. But there is no life in there. Its conditions are too insane for life to have evolved there, but humans could live on top of the pillars with relative ease.

What could possibly explain the existence of such a bizarre world?

Answer 1

The closest feature we have on our planet that gets close to appear like this is the Giant's Causeway.

To obtain this you need to have magma intruding a rock, then cooling down to form the pillars, and the surrounding rocks being eroded away.

But you want it made on scales like El Capitan:

With the right combination of factor (gravity, volcanic activity) you might achieve this, I mean, we have a 20 km high mountain on Mars...

Nevertheless this is hardly stable over geological times: gravity always asks its toll, and will slowly pull down the pillars.

Answer 2

1. A supernova explodes. Hurtling away is a molten blob of mixed elements.

2. As it slowly cools, the component elements stratify. The silicate mix slowly crystalizes, forming long needle-like spines protruding circumferentially.

http://www.rockhounds.com/tucson_show/reports/tucson2001/p3.shtml

3. Water comes from space, deposited little by little from comets and ice meteors. The space crystal is covered with water so that only the tips of each needle protrude. Some are submerged completely. Some come out of the water thousands of meters straight up. Some remain fairly sharp at the tip but others have fractured off flat at the top. Or you could have them (almost) all fractured across just over water level - which I think might be an ominous sign that something energetic enough to break off the crystals happens here from time to time.

   On earth, life was in the oceans for a billion years before it colonized the land. So too on your world - the oceans are full of life. That life provides your breathable atmosphere. Also narrative energy: some of the life forms might be large and dangerous.

Answer 3

Another approach, inspired by the description as "like islands with the oceans gone":

• Cover the world with a shallow ocean.
• Build coral reefs.
• Create an organism that builds up atolls just a bit higher than sea level.
• Gradually raise the sea level so that the atolls get built up higher in response. (perhaps a one-time reaction to a wandering planet brings a cascade of ice comets to the inner planets, or an ice cap melts.)
• After the ocean is deep enough, new reefs and atolls can't get started, but existing ones can keep getting taller as the oceans rise.
• Remove the mechanism that adds water to the planet; in time the oceans will evaporate.
• Leave just enough ocean in the deeper parts that there is a weather cycle bringing enough water to the pillars for life.

• over time the former ocean bottoms will get their own ecosystem but the soil will be salty enough that it won't be a productive one.

• you will need a mechanism for cycling biomass onto the pillar tops. Guano from deep flying birds should cover most of that.

Answer 4

Does it have to be naturally occurring?

It's an art planet.

Humanity stumbles upon this bizarre planet and formulate a slew of potential natural causes for its landscape, but none hold up to serious modelling. The only hypothesis that doesn't fall apart is that someone, at some ancient long-forgotten point in history, created it.

The question of how and to what ends is a continual debate among thinkers of your world, but so far none have come upon a satisfactory answer. Perhaps they just made it to prove that they could. Regardless, they're long gone and you can now find regular terrestrial humans squatting atop these monuments to their precursors' greatness.

Answer 5

I was going to suggest columnar jointed igneous deposits too but the end result you're looking for doesn't allow for their initial formation, let alone the differential erosion needed to leave them so isolated. I'd suggest that the only way such a planet might exist would be as the result of some esoteric form of warfare; if you used something like Niven's Treatymaker that ionises matter in the immediate area of impact, the material ejected by an ionisation weapon will re-condense in areas away from the direct fire zone. If large numbers of such weapons were fired on a single world the re-condensation zones could be few and small enough to form your high pillars of rock. Such pillars will be inherently unstable and quickly (geologically speaking) decay under the combined effects of gravity and erosion, the thicker the pillar the longer this will take so the large ones may last long enough for colonisation.

Some notes: such weaponry, if used on a global scale, would pretty well sterilise any planet. There would be strange effects on the overall sea-level/landmass balance of the world in question, such that the planet may appear far wetter afterwards than before. The seas of such a world could be either stripped of or enriched in salts by such an event depending on the way different compounds and elements condense out after the blast.