Problem description:

What is the distance for the earth to go around the sun?

How many revolutions does a light year equal to the earth?

Analysis:

First of all, understand a few nouns:

1, one light year: refers to the distance traveled by light in one year. Note that light years are units of length.

2. The revolution of the earth: Our earth revolves around the sun along an ellipse with a small eccentricity at a speed of 29.79 kilometers per second. It takes 365 days and 6 hours to walk around 940 million kilometers, which is about a year. (The average distance between the sun and the earth is 65.438+0.5 billion kilometers)

Of course, the landlord's question can be understood as: how many times does light travel in a year? Answer; Because 1 light-year is the distance traveled by light in one year, one revolution of the earth is the arc length traveled by the earth in one year, and the time is one year. Therefore, the ratio of distance is the ratio of the speed of light of 300,000 km/s to the revolution speed of the earth of 29.79 km/s: n = 300,000 /29.79 = 10000 times.

On the supplementary question: What is the distance of the earth's revolution around the sun? The distance here is actually the circumference, the arc length of a week. We already know that the radius of the earth's orbit is 65.438+0.5 billion kilometers, so it is easy to calculate the circumference. According to the formula s = 2× 3.14×1.500 million, about 940 million kilometers.