is the sun a planet?

Answer 1

To be more precise than "in the days before Galileo" ,,, we should write "In the days before Nicolaus Copernicus published his theory of a heliocentric solar system in De revolutionibus orbium coelestium (On the revolutions of the celestial spheres) in 1543"

i.e. Copernicus proposed a system where everything went round the sun, but before that the belief was that ...

(a) the earth was the centre of the universe and stood still

(b) there were celestial spheres on which the fixed stars in the heavens were placed

(c) there were in contrast seven moving objects or planetes (a Greek word) which rotated around the earth: and they were the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn.

This scheme of things was known as the geocentric model or The Ptolemaic Model after Ptolemy, a 2nd Century AD Hellenic scholar, based in Egypt,

So from the second Century AD till 1543, yes the Sun was generally (if erroneously) regarded as a planet along with six other planets, all circling the earth.

Galileo's role was to prove the Copernican system was superior to Ptolemy's system, by using a telescope and

(1) discovering the 4 largest moons of Jupiter which clearly showed that everything did NOT go round the earth

(2) discovering the phases of Venus which demonstrated that it went around the Sun and was lit by it.

Galileo published a book called "Dialogue Concerning the Two Chief World Systems" in which he argued the case for heliocentrism.
The idea that the lights in the sky in the Milky Way were stars like the Sun first occurred to the Greek philosopher Democritus 2,500 years ago. He also conceptualised that some of these stars might have planets going around them and that some of those planets might have life on them, like on Earth,

He also proposed the idea that the world and the universe were made up of tiny indivisible entities called atomes. Pretty astute guy, for 2,500 years ago, and indicative that not all the ancient Greeks believed in a geocentric model.

It was the centralising power of the Roman Empire that made geocentrism the dominant belief. And as it spread Christianity, it spread geocentrism, and the two sort of got intertwined as belief systems.

But a century and a half after Galileo, the Roman Catholic Church came to accept heliocentrism, as the case for it was and is overwhelming.

Answer 2

In the days before Galileo, the Sun WAS a planet, wandering through the sky like the other planets. But since we realized the Earth goes around the Sun, we have a different idea of planets. The Sun is what makes planets planets. They go around it.

Answer 3

The Sun is a Medium-sized star. It's not a planet.

Answer 4

I found the answer you seek in this song:

"The sun is a mass of incandescent gas
in a gigantic nuclear furnace
Where hydrogen is turned into helium
at a temperature of millions of degrees...
The sun is so hot, that everything on it is a gas, aluminum, copper, iron, and many others.....
If the sun were hollow, a million Earths would fit inside...
And yet, it is only a MIDDLE SIZE STAR"

C/o They Might Be Giants.

Answer 5

The sun is not a star, nor a planet, it is exactly what it is.

Answer 6

The sun used to be a planet but then I believe it was recently deemed to be just an artifact of the Keiper belt

Here is an excerpt from willieapedi... umm... etc.

1. The object must be in orbit around the Sun.
2. The object must be massive enough to be a sphere by its own gravitational force. More specifically, its own gravity should pull it into a shape of hydrostatic equilibrium.
3. It must have cleared the neighborhood around its orbit.

Answer 7

the sun is a star

Answer 8

well no its a star..i say that because a star is made up of condensed gases that are so hot from the preaser that they ignite and catch on fire causing the sun to glow giving off light.

Answer 9

the sun is a star

Answer 10

the sun is a star