Does a sphere have to be smooth?

A sphere need not be smooth; if it is smooth, it need not be diffeomorphic to the Euclidean sphere (an exotic sphere). The Heine–Borel theorem implies that a Euclidean n-sphere is compact. The sphere is the inverse image of a one-point set under the continuous function ||x||. Therefore, the sphere is closed.

Are spheres perfect?

It is the most perfectly round natural object in the entire universe. In nature, gravity and force tend to make many things into spheres such as bubbles, planets, and atoms. If these spheres were not balanced, they would not exist.

Can an object be perfectly smooth?

An ideal solid surface is flat, rigid, perfectly smooth, and chemically homogeneous, and has zero contact angle hysteresis.

How much of a sphere can you see?

Using this equation, if the earth were perfectly spherical, then a person standing on earth’s surface can see about 0.000016\% of the earth’s surface, or about 82 square kilometers (32 square miles). This corresponds to a circle of visibility with a radius of about 5 km (3 miles).

How do spheres look?

A sphere is a round, ball-shaped solid. It has one continuous surface with no edges or vertices.

Is a sphere perfectly round?

A sphere is a perfectly round 3-dimensional object. Because of the “bulging” caused by the Earth spinning, the Earth is not completely round, thus, is not a sphere. Instead, we use the term “oblate spheroid,” or “ellipsoid.”

Is there such thing as a perfect circle?

In a (geometrically) perfect circle, every point on its circumference is exactly the same distance from its center point. When it comes to real circles, however, this is never achieved.

What is perfectly smooth?

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Would a perfectly smooth surface have friction?

Friction is a force that opposes motion between any surfaces that are touching. Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.

Is it possible to see 50\% of a sphere?

In a black hole’s photon sphere, photons actually orbit the thing, so I would (baselessly) think that objects with just a little less mass could give you photons that go about exactly 100\% of the surface. The earth is approximately spherical, can you see 50\% of its surface right now? Almost 50\%.

What is the difference between oval and sphere?

As nouns the difference between oval and sphere is that oval is a shape rather like an egg or an ellipse while sphere is (mathematics) a regular three-dimensional object in which every cross-section is a circle; the figure described by the revolution of a circle about its diameter.

Where can you find a sphere in real life?

Examples of sphere include:

• Ball.
• Planets.
• Moon.
• Sun.
• Eyeball.
• Orange.
• Marbles.