1
$\begingroup$

There are enormous world eaters that consume planets and digest every atom that goes inside them. You can use anything that is possible with science/technology, but no magic. The world eater does not have to receive 100% of the energy in the consumed matter, all that is important is that every little bit of matter is used in some way.

The process does not have to be quick on a geological timescale. However, all life should cease on eaten worlds within days if not instantly.

I would prefer not to use anti-matter, but the correct answer will contain another process that releases energy from nearly all elements on the (naturally occurring) periodic table as well as how that energy can be harvested.

I know the title says animal, but a space faring animal that eats planets might end up looking a bit like a machine, and that's okay.

The world eaters consume planets, stars, even nebulae for energy to move their enormous mass and to grow larger and consume even larger structures.

$\endgroup$

closed as primarily opinion-based by sphennings, anon, Azuaron, MozerShmozer, Anketam Dec 6 '17 at 20:38

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ Why do they eat? Swallow whole, or spider style? Do they eat for energy only? Or do they need to use this matter for growth? What does "digest" even means, in this context? $\endgroup$ – Mołot Dec 6 '17 at 19:05
  • 5
    $\begingroup$ Normal eating doesn't release all (or nearly all) the energy from any of the elements on the periodic table, naturally occurring or not. What do you mean by that phrase? Normal eating doesn't have any affect on the atomic level, just the molecular level and above. What do you mean by "digest every atom?" $\endgroup$ – sphennings Dec 6 '17 at 19:07
  • 2
    $\begingroup$ @Muuski The phrases "receive energy from consumed atoms" and "digest every atom" are meaningless in existing contexts. If you want those phrases to be meaningful for your world eater you're going to need to explain them to us. $\endgroup$ – sphennings Dec 6 '17 at 19:22
  • 7
    $\begingroup$ I think what you are thinking of is a black hole. $\endgroup$ – A. C. A. C. Dec 6 '17 at 19:30
  • 1
    $\begingroup$ I don't think there could be a creature on the scale you're thinking of because of the ten cubed law. I also don't know how such a creature is going to be able to travel around without magic. Whatever magic allows this creature to move from planet to planet ignoring the realities of orbital mechanics will allow it to consume planets. $\endgroup$ – sphennings Dec 6 '17 at 19:38
2
$\begingroup$

To elaborate on the comment made by A. C. A. C., I'm imagining these world eater entities as consisting of two major sections: A black hole in the center surrounded by a shell.

The "shell" is actually composed of a swarm of semi-independant units (comparable to individual cells within any multi-cellular lifeform) that each orbit around the blackhole. As each unit is seperated by meters or even kilometers, each is capable of thrust and "communicates" with its neighbouring cells with radio waves. Together this swarm exchanging signals results in emergent behaviour which at the very least allows the creature to act as one (like an ant colony), or - depending on what is necessary for your story - in sentience and perhaps sapience. The shell can thus be thought of as the body of your creature, as well as a brain consisting of many individual neurons.

To consume celestial bodies the shell throws pieces of an object into the black hole (having previously taking any elements/molecules that it needs in order to maintain/repair/replicate itself). The swarm then absorbs the hawking radiation emitted from the blackhole. In this fashion the world eater can consume anything.

$\endgroup$
  • 1
    $\begingroup$ You can't use hawking radiation. It's a really small amount energy that a black hole emits. Also, when more bigger is a black hole (more eat) less energy it will throw. $\endgroup$ – Ender Look Dec 6 '17 at 20:27
  • 1
    $\begingroup$ @EnderLook Well in actuality a black hole will eventually convert all the matter/energy it consumes into hawking radiation. But yes, you're correct for anything other than small blackholes it takes prohibitively long amounts of time for a blackhole to radiate away. $\endgroup$ – AngelPray Dec 6 '17 at 20:33
  • 1
    $\begingroup$ @EnderLook The energy of the hawking radiation of a very small black is actually quite large. For a blackhole with a lifetime of a few million years left, it will radiate as much energy as a star, for even smaller ones they will output even more. The key to such a mechanism would be to keep the black hole at a pretty good size range. Also the black hole needs to kept charged so it can be moved with a electric field. As to how to physically construct miniature black holes, it is beyond current human knowledge. $\endgroup$ – A. C. A. C. Dec 6 '17 at 20:39
  • 1
    $\begingroup$ @A.C.A.C. "A black hole of one solar mass (M☉) has a temperature of only 60 nanokelvins (60 billionths of a kelvin); (....). A black hole of 4.5×1022 kg (about the mass of the Moon, or about 13 µm across) would be in equilibrium at 2.7 K, absorbing as much radiation as it emits." A planet eater would be quite big, so it means it will throw much less energy. 60 nanokelvins isn't nothing. Maybe it will throw 60 nanokelvins in the entire surface of a black hole (a lot), but remember that the shell would also be big, so it'll need more energy. $\endgroup$ – Ender Look Dec 6 '17 at 21:07
  • 1
    $\begingroup$ @EnderLook The idea would be to keep the planet outside the black hole but inside the shell and only feed the black hole enough matter to keep it alive so you can maximize your hawking energy harvesting. Of course if you want to just use a massive black hole that actually eats planets/stars, you can also harvest energy that the excretion disk outputs, although the efficiency of such a system is very inefficient and gets more and more inefficient as the black hole grows. $\endgroup$ – A. C. A. C. Dec 6 '17 at 21:30
2
$\begingroup$

Currently, the only way we know how to do this without magic is antimatter.

In general, the kinds of compounds you'll find in nature are very stable, which means it takes more energy to break them apart than they release. Living things do produce compounds that release energy when you break them apart, but the total mass of all living things on Earth is around one ten-billionth of the total mass of the Earth, so they are negligible compared to the Earth. This means that any attempt to chemically process an entire planet would consume more energy than it would produce, so your planet eater would be better off not eating the planet in the first place.

If you use antimatter, you could potentially get around this issue because all matter can be fully converted into energy this way. Combining antimatter and matter creates gamma radiation, and it would be believable to have something like solar panels that collects gamma radiation instead of normal solar radiation.

If you really don't want to use antimatter, you'll basically have to use a Clarke's third law variety of magic. I'd suggest something that can convert matter directly into energy without the use of antimatter. What it looks like and how it works is up to you because no such thing currently exists.

$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.