25 Smallest Things In The Universe

Posted by , Updated on May 4, 2017

As humans we tend to be obsessed with things that are big. Whether it’s a car, a house, or a bank account it seems that the bigger the better. Today, however, we’re going to take a look at things that aren’t very big at all. In fact, some are so small that they only exist in theory. So, whether it’s a miniature teddy bear or a hypothetical subatomic particle, these are the 25 smallest things in the universe.

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Smallest Living Organism

Mycoplasma Genitalium

The parasitic bacterium Mycoplasma Genitalium that inhabits the genital and respiratory tracts of primates is widely considered by scientists to be the smallest organism capable of independent growth and reproduction.


Smallest Non-Living Organism

Porcine-circovirus smallest virus

Although there is still some debate about what is considered “alive” and what isn’t, most biologists would not classify a virus as a living organism due to the fact that it cannot reproduce or metabolize by itself. A virus, however, can get much smaller than any living organism including the bacterium we just saw. The smallest is the single stranded DNA virus Porcine circovirus you see here. It is only 17 nanometers across.


Smallest Thing Visible to the Naked Eye

Smallest thing visible to the naked eye

The smallest objects visible to the unaided human eye are roughly .1mm long. This means that under the right conditions you would be able to see an ameoba proteus, a paramecium, and even a human egg.


Smallest Observed Object in the Universe

Smallest Observed Object in the Universe

Over the last century science has made both great strides into understanding the vastness of space and its microscopic building blocks. When it comes to figuring what the smallest observable particle in the universe is, however, we run up against a bit of a wall. At one point we thought they it was the atom. Then scientists discovered the proton, neutron, and electron. It didn’t stop there though. Today we know (by smashing particles together in places like the Large Hadron Collider) that these can be further broken down into even more particles like quarks, leptons, and even antimatter. The issue with trying to figure out which is smaller is that on a quantum level size becomes a bit irrelevant as the rules of physics you are used to living by begin to break down (some particles have no mass, some even have negative mass) Unfortunately, trying to answer this question is something like dividing by zero…not really possible.


Smallest Hypothetical Object in the Universe

String theory

Keeping in mind what we just said about the idea of size being irrelevant on a quantum level, there exists something known as string theory and although it is slightly controversial it proposes that all subatomic particles are composed of vibrating strings that interact in order to create things like mass and energy. So, although these strings would technically have no physical dimensions, according to our puny human ability to reason one could say that these strings would be in some sense the “smallest” objects in the universe.

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