The Earth is not a perfect sphere but is slightly flattened at the north and south poles. Its shape can be described as an oblate spheroid and the Earth’s rotation causes the central portion to bulge out. The internal temperature of the Earth is 6000 degree Celsius.

Cartography in the European Renaissance treats the period from 1450 to 1650, long considered the most important in the history of European mapping. Scientific advances, appropriations of classical mapping techniques, burgeoning trade routes—all such massive changes drove an explosion in the making and using of maps.

Maps of the ancient world were made by using accurate surveying techniques, which measures the positions of various objects by calculating the distance and angles between each point.

Anaximander

The oblate spheroid, or oblate ellipsoid, is an ellipsoid of revolution obtained by rotating an ellipse about its shorter axis. It is the regular geometric shape that most nearly approximates the shape of the Earth.

The earth is an oblate spheroid with a diameter at the equator that is 43 km larger than at the poles, according to the National Oceanic and Atmospheric Administration. It is an oblate spheroid. The flattening in this image is exaggerated in order to make the earth’s non-spherical shape obvious.

Many people think that the Earth is perfectly round; however, it is actually pear shaped! The top pushes in while the bottom bulges out. The southern hemisphere is slightly larger than the northern hemisphere, giving the odd pear shape. The poles are also slightly flattened.

Even though our planet is a sphere, it is not a perfect sphere. Because of the force caused when Earth rotates, the North and South Poles are slightly flat. Earth’s rotation, wobbly motion and other forces are making the planet change shape very slowly, but it is still round.

The geoid is an imaginary sea level surface that undulates (has a wavy surface) over all of the earth; it isn’t just for the oceanic areas, it also extends through the land masses.

All of these changes in the geoid create very gentle slopes in sea surface (note all the vertical changes are in meters, and they occur over many kilometers). However, the changes are real and can be measured by radar altimeters, and they reveal a great deal to oceanographers and geologists.

More accurately, the Earth is an ellipsoid, sometimes referred to as a spheroid. While ellipsoids are round and smooth like spheres, they are not symmetrical when divided in all directions.

What makes the Earth habitable? It is the right distance from the Sun, it is protected from harmful solar radiation by its magnetic field, it is kept warm by an insulating atmosphere, and it has the right chemical ingredients for life, including water and carbon.

It seems possible that the origin of life on the Earth’s surface could have been first prevented by an enormous flux of impacting comets and asteroids, then a much less intense rain of comets may have deposited the very materials that allowed life to form some 3.5 – 3.8 billion years ago.

All living things on earth have adapted to our atmosphere, which means all living things need our mix of atmospheric gases. Life elsewhere would be specifically adapted to their own conditions. Water is a really important ingredient to sustain the kind of life we know on Earth.

Based on his Copernican principle, J. Richard Gott has estimated that the human race could survive for another 7.8 million years, but it is not likely to ever colonize other planets.

Nonetheless, Earth is the only place in the Universe known to harbor life.

A 2015 review concluded that the exoplanets Kepler-62f, Kepler-186f and Kepler-442b were likely the best candidates for being potentially habitable. These are at a distance of 990, 490 and 1,120 light-years away, respectively.

Breathing on Mars In these conditions humans die within minutes unless a pressure suit provides life support. If Mars’ atmospheric pressure could rise above 19 kPa (2.8 psi), then a pressure suit would not be required. Visitors would only need to wear a mask that supplied 100% oxygen under positive pressure.

Mars’ atmosphere is dominated by carbon dioxide (CO₂) at a concentration of 96%. Oxygen is only 0.13%, compared with 21% in Earth’s atmosphere. Moxie is able to strip oxygen atoms from CO₂ molecules, which are made up of one carbon atom and two oxygen atoms.

planet Saturn

This week, we present 10 of our solar system’s most marvelous moons.

• Retrograde Rebel: Triton.
• Cold Faithful: Enceladus.
• Volcano World: Io.
• Yin and Yang Moon: Iapetus.
• A Double World: Charon and Pluto.
• 8. ” Death Star” Moon: Mimas.
• Don’t Be Afraid, It’s Just Phobos.
• The Moon We Know Best.

Venus

Deep within Neptune and Uranus, it rains diamonds—or so astronomers and physicists have suspected for nearly 40 years. The outer planets of our Solar System are hard to study, however. Only a single space mission, Voyager 2, has flown by to reveal some of their secrets, so diamond rain has remained only a hypothesis.