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What is the diameter of the Earth?
7,917.5 mi
Earth/Diameter
How was the diameter of Earth measured first?
Eratosthenes erected a pole in Alexandria, and on the summer solstice he observed that it cast a shadow, proving that the Sun was not directly overhead but slightly south. Recognizing the curvature of the Earth and knowing the distance between the two cities enabled Eratosthenes to calculate the planet’s circumference.
Why does the day and night occur?
The Earth orbits the sun once every 365 days and rotates about its axis once every 24 hours. Day and night are due to the Earth rotating on its axis, not its orbiting around the sun. The term ‘one day’ is determined by the time the Earth takes to rotate once on its axis and includes both day time and night time.
How do you find the diameter of a circle with an equation?
The formula to find the diameter states the relationship between the diameter and the radius. The diameter is made up of two segments that are each a radius. Therefore, the formula is: Diameter = 2 * the measurement of the radius. You can abbreviate this formula as d=2r.
How was the diameter of the earth calculated?
Therefore diameter of earth is approximately 40000kms was calculated by Eratosthenes in 3rd century BC by just using commonsense and simple reasoning. NOTE: I made my explanation a bit filmy so that everyone would eaily understand.
How do astronomers measure the size of the Solar System?
Duringthe 18th and 19th centuries, astronomers used the diameter of the Earth as the basic yardstick in determining the size of the solar system. Today’s astronomers usually do not need to know the size of the Earth for their daily research activities.
How can we tell how big the Earth is?
Given that the cities are about 200 miles apart, we can tell how big the Earth is by measuring the blue angle. Because the angle is small, Earth doesn’t curve much in 200 miles and is therefore much larger than that.
What is the size of the Earth at the equator?
The diameter of the Earth at the equator is 12,756 kilometers (km). How Do We Calculate Distances of This Magnitude? Image Credit: Clementine, Naval Research Laboratory. It is copyright free. In 200 B.C., the size of the Earth was actually calculated to within 1% accuracy!