Do space aliens have to be our size? Why not space aliens as tall as skyscrapers or as small as germs?

Question

Why couldn't alien space ships be as large as the moon, or as small as a speck of dust? Would there be any scientific reason why not?

Imagine an army of space aliens, as tall as the Empire State Building, marching across the earth.

Answer 1

your correct

most consider that the most common form of "alien" life is like bacteria...............

a planet is more likely to have bacteria growing than any other form of life.

but, having a huge alien could be possible too.

ships could be anysize as well I suppose. the smaller the better I'd assume.

Answer 2

A good question. There's a limit to how small an intelligent animal can be; a brain is made of atoms, so if it's below a certain size it can't be complex enough to be intelligent. There's a limit to how large it can be too. If you make a scale model of something 100 times as long as the original, then its weight, which depends on its volume, will be 100x100x100 which is a million times as great. But the cross-sectional areas of its parts, which determine how much weight it can support, are only 100x100= 10 000 times as great. So if you're too big you collapse under your own weight. The largest animals have to live in water. It's doubtful if even intelligent water creatures like dolphins could ever become technologically advanced. They could never use fire or smelt metals.

Answer 3

There's nothing that specifies what they or their ships have to be, either material (maybe something never heard of) or size. It's just that right now, since nothing's been discovered yet, things are pointing to microscopic sized life, without ships, if we find anything at all in our lifetime. With current technology, though it's improving, we've basically only studied a "microscopic" part of our universe...there's alot more out there. When you think of it, scientists are still trying to figure out how to best study Saturn's moons, and our Solar System is just a tiny spec on the arm of the Milky Way. Our telescopes are really getting good for far away viewing, but...back to the above.

Answer 4

Aliens wouldn't have to be humans-sized but there are practical limitations on how big or small they can be.

The human brain has trillions of cells. If the aliens are at least as smart as us, they'd need at least that many. Since you can't pack that many cells into speck of dust, that rules out microscopic intelligence.

Likewise, things the size of skyscrapers on Earth have skeletons made of steel and massive foundations of concrete. As height increases, weight is cubed. Bone tissue just isn't strong to support something as big as a building. On land the biggest animals we have are elephants. In the sea, where the buoyancy of water helps support the weight, whales are biggest. So unless the alien biology somehow found a way to incorporate steel and concrete, elephant and whale size will be as big as they get.

Of course, the aliens may come from some exotic environment that allows them to exceed these limitations. For example, reduced gravity could allow them to be bigger. But if that is the case, they would find the environment on Earth detrimental.

Answer 5

they could range from tiny microbial life forms to...well it depends on the planet. it if was the size of the moon then they could be quite a bit larger than us. if it was the size of jupiter they would be quite a bit small.

and space ships arent realistic because we wont see an alien space ship for thousands of years, their too far away, because if they were sophisticated they would have all kinds of radio signals and what not, which travel at the speed of light, and we havent recieved any.

but lets say we have. a small space ship wouldnt fit many things in it. and a large space ship would take a massive amount of energy to propel through space.

Answer 6

Nah, they'll be our size. Guaranteed, 6ft tall on the high side, maybe 6'6" max. On the low side about 5' tall. Any shorter or taller than that and they won't let them go on space missions. If they are taller than that they can make more money playing basketball, football, or professional alien wrestling. Shorter than that and probably be in some alien circus freak show.

Answer 7

No reason, it would all depend on the gravitational field they evolved in.
The larger something gets, the thicker the bones and muscles have to be to carry the weight.
So on a low-gravity world they could be very large compared to us. And would probably find it difficult to get around in our gravity.
And on a high-gravity world they would likely be small compared to us.

Answer 8

if there are any space aliens it would be almost in posible for them to be our size do to the complexity and balance of ecosystemes

Answer 9

personally I think some insect life is actually aliens.... have you ever really considered them?..... not at all like most life on Earth... vastly different, but with intelligence that works for them.............and a planet full of what they need to exist on.... *smile*..............

Answer 10

thats a good question ill ask my mom!







hahah she dosnt know