Think yoda. Small. Agile. Powerful. Think Hutts. Big. Slow. Powerful. Is this realistic? I was thinking about making a race of small (yoda sized) species that had a lot of power in the galaxy. I mean, for them to be powerful, they would likely need to have weapons, or an army of some kind. But if they are some small or so big, would they be able to fight effectively? The aliens in my story are about the size of yoda, and have high tech technology. They have a large fleet of ships and they are incredibly advanced. They are not the strongest, but they are very agile. Thanks
So the answer is a flat YES OBVIOUSLY
It's a sci-fi setting, and your small race has made it to space. Once you're there, you're golden. Heck, even a small species with modern-day technology is going to be fine against larger-bodied technological peers. Indeed, I would argue a small species would have huge advantages over larger ones in a gunpowder-or-later competition against peer competitors. Though the advantage dissipates the more sci-fi you get. For sci-fi though there are three areas they'd excel in.
Numbers: Now it's not a guarantee, but generally speaking smaller beings have shorter lives but more offspring than larger beings. At the very least your small race will be able to have more beings for X area of land or Y amount of resources than a larger species. That means more brains, more chances of spawning an Einstein or a Rommel or just having more views with which to look at any given problem. At the very lowest setting it means you can field more guys with lasers than the big dudes, and that's an advantage all its own.
Void Warfare Space is BIG and COLD and DANGEROUS. Ships that go through space must be as efficient as possible, to conserve energy, maneuver more effectively, and generally just be smaller targets. A Small species requires less air to breathe, food to eat, room to stand in, etc etc. All this means more efficient ships. For X mass and Y energy I can carry a lot more tiny colonists, or have a smaller physical bridge to be hit, or have more nimble fighters, or have more room for weapons, or haul a larger percentage of trade goods. If your ships need a pilot/captain, a weapon's officer, and an engineer, and each of those guys is 1,000 kilos, you're wasting 3,000 kilos of engine power to move them. Meanwhile if those same guys are 20 kilos each, it's only 60 kilos of power. Scale that to warships that may need hundreds or thousands of crew, and it matters even more.
On the Ground Your tiny soldiers have several distinct advantages over their larger foes. They're smaller targets, and they have better reflexes. Meanwhile even with modern-day weapons the size discrepancy isn't so great that your tiny soldier is incapable of fielding a big-guy killing weapon. Add in phasers or what have you and there's no advantage at all in being bigger. You're never gonna wrestle a guy with a blaster often enough for it to matter in a war!
TL/DR There is no possible disadvantage a yoda-sized being would have versus a 1,000 kilo being when both are armed with modern+ technology. Indeed it's the big guy that would be somewhat disadvantaged.
Now of course you can add in Dune-esque shields so hand-to-hand fighting is still very important or some other handwavium to make your little guys have a tougher time of it. But in general there's no reason to be concerned.
Which species is dominant on earth? Humans? or Elephants? How about blue whales? Giraffes? Obviously it's humans.
Size can determine dominance among intellectual peers. A rhino can dominate a cat, a cat can dominate a cockroach.
Three things can change this balance. Weight of numbers, cunning strategy, or research.
1 million cockroaches can overwhelm a housecat. 10 dogs hunting in a pack with a good strategy can overwhelm 10 rhinos, especially if they can get one at a time. And a human whose researched gunpowder can pick up a machine gun and mow down everything.
So, give your aliens massive numbers, or the ability to plan and strategise, or research into super weapons, and they can dominate anything.
Any interaction with other high-tech races would be a comparison of these 3 things: Massive numbers, Better plans, Better research.
IMHO opinion a species of small agile people could conquer the galaxy as easy as a species of large strong people.
It doesn't take a lot of physical strength to press the firing buttons as your fleet of thousands of space battleships vaporizes an enemy fleet of hundreds of space battleships.
And if the question is about small agile people fighting outdoors on the surface of a planet, think back to reading The Hobbit, The Lord of the Rings, and The Sillarmilion and the dreaded armies of evil in those stories.
Who were the main members of the dreaded armies of evil in those stories? Orcs (called goblins in The Hobbit). And how large were Orcs? They came in several sizes, but only the exceptionally large orcs were described as being the size of men. Most orcs might have been the size of dwarves or even of hobbits.
And what type of weapons were used in battles in Middle-earth? Swords, spears, battle axes, battle hammers, bows and arrows, etc. Those weapons needed a lot more physical strength to operate than modern weapons. And yet Orcs were still capable of fighting against larger and (possibly) stronger foes.
After guns were invented, physical strength was a lot less necessary for a soldier to use weapons. Thus there were of stories about children using guns in combat. For example, in 1863 John Lincoln Clem of the 23rd Michigan was 12 years old and very small for his age, about four feet tall. He had a musket cut down to his size and shot a rebel at the Battle of Chickamauga.
And in the 20th century lightweight assault rifles were invented, guns so powerful and light that they could be used by children as easily as men could use muskets a century earlier. Thus recruiting children - sometimes by force - to serve in guerrilla and rebel forces became extremely common.
And in a science fiction story set in a technologically advanced future, weapons like Star Trek hand phasers and phaser rifles might become available. Such weapons could be used effectively by much younger and smaller human children that the kids who use assault rifles today, or by alien space infantry the size of those children.
This reminds be of H. P. Somtow's Inquestor stories, set in an interstellar society where apparently "all" children are drafted into the space infantry and are turned into cyborgs with deadly lasers in their eyes for the duration of their service in various space wars. I'm not certain that drafting "all" children and sending them away on centuries long relativistic voyages for the wars would work. It seems to me that would result in rapidly declining populations. But that is the set up in the stories.
And if the aliens use powered suits to multiply the physical strength they can apply, they might be a small as human children and be able to use the strength of elephants when using their powered suits.
So tiny aliens can make good space infantry or space marines as well as making good space battleship crews.
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