the size of the earth?

Maybe this picture might help. Take a board 30,000 miles long and set it on the surface of the earth. The board is now tangent to the circumference of the earth. If you are standing on the tangent point, a mile away, the board will be eight inches off the surface. Now if you rotate the board while always moving to stay on the point of tangent, the point a mile away is still 8 inches off.

Of course this is making assumptions that the earth is smooth as glass.

If you scale down the earth perfectly so it is 8 feet in diameter, you could not detect the deepest part of the oceans nor the highest mountain peaks by touch. Our usable atmosphere would be only 1/32 of an inch thick.

http://www.space.com/17638-how-big-is-earth.html ''The circumference of Earth at the equator is about 24,902 miles (40,075 km), but from pole-to-pole — the meridional circumference — Earth is only 24,860 miles (40,008 km) around. This shape, caused by the flattening at the poles, is called an oblate spheroid.

Density, mass and volume-Earth's density is 5.52 grams per cubic centimeter. Earth is the densest planet in the solar system because of its metallic core and rocky mantle. Jupiter, which is 318 more massive than Earth, is less dense because it is made of gases, such as hydrogen.

Earth's mass is 6.6 sextillion ton (5.9722 x 1024 kilograms). It volume is 1.08321 x 1012 km.

The total surface area of Earth is about 197 million square miles (509 million square km). About 71 percent is covered by water and 29 percent by land.

Highest and lowest points-Mount Everest is the highest place on Earth above sea level, at 29,028 feet (8,848 meters), but it is not the highest point on Earth — that is, the place most distant from the center of the Earth. That distinction belongs to Mount Chimaborazo in the Andes Mountains in Ecuador. Although Chimaborazo is about 10,000 feet shorter (relative to sea level) than Everest, this mountain is about 1.5 miles (2.4 km) farther into space because of the equatorial bulge.

The lowest point on Earth is the Mariana Trench in the western Pacific Ocean. It reaches down about 36,200 feet (11,034 meters) below sea level.''

Earth's Size. http://geography.about.com/od/physicalgeography/a/... ''As the largest of the terrestrial planets, Earth has an estimated mass of 5.9736 × 1024 kg. Its volume is also the largest of these planets at 108.321 × 1010km3.

In addition, Earth is the densest of the terrestrial planets as it is made up of a crust, mantle and core. The Earth's crust is the thinnest of these layers while the mantle comprises 84% of Earth's volume and extends 1,800 miles (2,900 km) below the surface. What makes Earth the densest of these planets however is its core. It is the only terrestrial planet with a liquid outer core that surrounds a solid, dense inner core. Earth's average density is 5515 × 10 kg/m3. Mars, the smallest of the terrestrial planets by density, is only around 70% as dense as Earth.

Earth is classified as the largest of the terrestrial planets based on its circumference and diameter as well. At the equator, Earth's circumference is 24,901.55 miles (40,075.16 km). It is slightly smaller between the North and South poles at 24,859.82 miles (40,008 km). Earth's diameter at the poles is 7,899.80 miles (12,713.5 km) while it is 7,926.28 miles (12,756.1 km) at the equator. For comparison, the largest planet in Earth's solar system, Jupiter, has a diameter of 88,846 miles (142,984 km).

Earth's Shape-Earth's circumference and diameter differ because its shape is classified as an oblate spheroid or ellipsoid, instead of a true sphere. This means that instead of being of equal circumference in all areas, the poles are squished, resulting in a bulge at the equator, and thus a larger circumference and diameter there.''

http://geography.about.com/library/faq/blqzdiamete...

What is the diameter of the earth? The diameter of the earth at the equator is 7,926.41 miles (12,756.32 kilometers).

But, if you measure the earth through the poles the diameter is a bit shorter - 7,901 miles (12,715.43 km). Thus the earth is a tad wider (25 miles / 41 km) than it is tall, giving it a slight bulge at the equator. This shape is known as an ellipsoid or more properly, geoid (earth-like).

Facts/figures. http://www.universetoday.com/26653/size-of-the-ear...

25000 miles give or take