They say as far as nature is concerned there are no perfect geometric circles, a geometric circle is purely a mathematical construct.

Even a phenomena as powerful and as majestic as the sun isn't a perfect geometric circle, its more like a squashed orange that bulges at its equatorial zone. (No big belly jokes please)

The most common shape found in nature is more oval in shape, or the numerical symbol 0 (zero). Turned sideways it resembles planets, stars and traces out eliptical orbits.

Stars that reach a certain mass form perfect spheres.
A black hole is a 'true point' of mass with 1 dimension.

In the universe, masses at a certain density become round because gravity is equal. The higher the mass the stronger the gravity.

Its why small moons are often misshapen balls where larger objects become spheres. There's a mathematical formula that explains it and it is basic cosmology.

There are parts of the universe where there is no coriolis effect. Galaxies that are not spiral like the Milky Way. The stars and planets don't bulge because there is no rotation.

Wouldn't a perfect sphere not necessarily apply to a black hole given its characteristics? Its surface can be in a different place than its event horizon right? Anyway would the closest thing to a perfect sphere be a Neutron or Quark star?

The use of a double negative makes me wonder what it is you mean?

A black hole is not an object. The object is the singularity in the center that is so massive light can't escape. The gravity from that mass is so great it crushes all the matter into a sphere. As more matter is added to the singularity it offsets then equalizes to find its new center.

There are lots of perfect circles in nature. Any situation where something expands in reaction to a force in all directions, without being interfered with by another object.

Stars that are not perfectly spherical, are that way because in addition to being inherently round, they are SPINNING. The additional rotational forces cause the otherwise perfect circle to become an oblate spheroid.

The reason why there are fewer circles and spheres than there otherwise MIGHT be, is because the universe is relatively full of other stuff.

It a mathematical trick. The way define a circle you could never get perfect as pie goes on forever

I was squeezing some perfect orbs in the produce section recently...she had the manager throw me out.

Ripples in otherwise calm water could be quite circular in shape ?

("pie" => "pi")

If something on a 2-D plane can be traced by a point maintaining a constant distance with another, it's a circle. This doesn't involve pi.

Another recently recognized example: ice circles that form in certain rivers:

https://www.youtube.com/watch?v=DBeFDaPC6K0

They ARE perfect circles, because the way they are generated directly causes them to be.

Thanks, that is new and interesting to me.

I got this recommended next - All over the World SPINNING ICE CIRCLES appearing !, half expected it to spout some reptilian conspiracy theory,

Edit: typo - "so"->"to"

Not only in nature, there is no perfect circle on paper too. Same is the case on a computer screen or anywhere else.

As someone earlier posted out here, a perfect circle is only a mathematical construct.

Generally scientific people use perfect ideas and apply them in real world. In that way, humans are evolving, as I guess.

Nature is huge.
To state 'always' and 'never' in nature is an indication of assumption.
Assumption is not scientific.
We can't know everything about everything, everywhere at all times.
The Universe is way to big and complex, far beyond mankind's understanding.

It is also said that nature never builds in straight lines.
Another assumption of nature.

What we don't know about nature far exceeds what we think we know.