[_ Old Earth _] The Earth

[Lewis]

How Does The Earth Rotate? - Universe Today

http://www.universetoday.com/60655/earth-revolution/

 

[Barbarian]

There are a few inaccuracies in that article:

As already noted, Earth experiences two kinds of rotation. On the one hand, there is the rotation of Earth on its axis, which is known as sidereal rotation. This is what allows for the diurnal cycle and makes it appear as if the heavens are revolving around us. On the other hand, the Earth orbits about the Sun, which is known as its orbital period.

The Earth does not "rotate" around the Sun. Rotation is spinning on an axis. And there's this:

This should come as no surprise, considering that it’s rotational velociy is 1,674.4 km/h.

It's rotational speed (not velocity, which requires a vector) is one rotation per day. How many kilometers per hour, depends on the latitude, being fastest at the equator, and slowest at the poles.

 

[Mike S]

We've come a ways since the days of Galileo. He was on the right track with his heliocentric ideas, but Galileo found out it was not a good idea to get into a peeing contest with his old friend and patron, Pope Paul V. It was probably a bridge too far to cast the Pope as a simpleton in his book discussing what he called the "two chief world systems" in his book, Diologo.

 

[Barbarian]

Yep. The pope was actually a pretty competent scientist, and when Galileo was first attacked, he defended him, pointing out that there is nothing in Church dogma that says the Sun goes around the Earth. But then when Galileo framed that "Sagredo vs. Simplicio" dialogue, it was all over. Galileo was something of a jerk, way too proud of his intellect.

Teaching planetary astronomy, I use that incident to get students some perspective of the historical context for Copernicus, Galileo, and Kepler. It turns out that Kepler (who was close to poverty) asked to borrow a telescope from Galileo and got a very condescending refusal.