1. The earth is not flat, but also not perfect spherical
the earth is never a perfect sphere.Earth's axial rotation from the equator than its original inflation of 0.3%.The diameter of the earth from the arctic to the Antarctic is 12714 km, and equatorial diameter of 12756 kilometers.42.78 kilometers between the gap is about one over three hundred the diameter of the earth.The tiny differences in the pictures taken of the earth's space almost can be ignored, therefore, the human eye view, the earth is a sphere.NASA's jet propulsion laboratory (JPL), a recent study shows that the gradual melting glaciers are causing the earth's "waist" is more and more big.
2 days more and more long
the length of the day have been growing on the earth.At the beginning of the earth formed 4.6 billion years ago, only about 6 hours a day.By 620 million, the length of the day has been increased to 21.9 hours.Nowadays, 24 hours a day on average, but the length of the day is rising at a speed of about 1.7 millisecond every century.Why is this?Because the moon was formed through the participation of tidal phenomenon gradually slow down the speed of the earth's rotation.The location of the earth's rotation that makes the ocean tidal bulge was slightly to the axis of the month before, the resulting a torsional force to slow the speed of the earth's rotation.So, we each day more and more.Of course, this subtle changes and everybody is far less than the busy schedule every day.
3. The continents had also been on-and-off
over millions of years, each continent on earth "long period of division, close long will points".Bearing the earth about 800 million years ago, continental block those huge plates meet each other, will the land together to form the supercontinent "lodi, mainland" - now it is located in the center of the North America.Roddy, mainland eventually split into many small pieces, they collide with again in 500 million to 250 million years ago, has formed the Appalachian mountains in North America and is located in the ural mountains of Russia and kazakhstan.
about 250 million years ago, this land again this together to form a supercontinent pangea ", and it is surrounded by a sea complete, worldwide.After fifty million, pangea began to collapse, split into two pieces of huge landmass, and advanced gondwana continent;But eventually they decompose become we know today several continents.
4. The earth's glaciers when and
about 800 million to 600 million years ago, the earth has suffered several extreme weather, also is the ice age.During the extremely cold climate that scientists believe that the earth has been close to, or even a total freeze on - the famous "snowball earth" hypothesis.May be seen in the history of four such alternate freezing and thawing period, by greenhouse gases such as methane and carbon dioxide) reduce caused, during the whole of the earth from the arctic to the Antarctic is covered by glaciers.Because most of solar energy will be ice reflect to the universe, the earth at that time, the average temperatures of minus 50 degrees Celsius, its equator and Antarctica today also.If a snowball earth exists (the hypothesis is still hotly debated the industry), and then only microorganisms and simple organisms on earth, humans never felt the cold, how lucky.
5. The driest place on earth
sorry, the driest place in the world (i.e., northern Chile's atacama desert), is located in the world's most vast waters (Pacific) side.Arica Chile the annual average rainfall of 0.8 mm (0.03 feet).Legend atacama, Lamar city not a drop of rain, continuous four hundred until 1972, when a storm suddenly.Unlike most of the desert, the atacama desert is relatively cold, it even in the driest area cyanobacteria (within a rock or rock growth of green photosynthetic microbes) are unable to survive.NASA astrobiologists have recently traveled to the atacama desert to find can survive in such an extreme environment of microbes, they hope to understand the possible form of life on other planets.
6. Gravity is not uniform
if the earth is an ideal ball, then it's gravitational field should be the same everywhere.But, in fact, the earth's surface bumpy;At the same time, the water flowing, ice floats, also in constant motion of the plates below the earth's crust -- all these changes will change the role of gravity.These changes are referred to as gravity anomaly.A mountain, such as the Himalayas, can lead to positive gravity anomaly gravity (i.e., there would be a no characteristics, completely smooth of the planet's gravity).Ocean trench or thousands of years ago, on the other hand, surface depression caused by glacier leads to negative gravity anomaly.Above the earth run of NASA's gravity recovery and climate experiment (GRACE) satellite is unprecedented detailed maps of the earth's gravitational field.
7. In the past , sea level and is very different today
advance began a recent ice on earth about 70000 years ago, before the 18000 peak, ended 11500 years ago.Period, glaciers and thick ice chisel out of the five Great Lakes (the Great 'lakes lake basin and truncation of the major rivers, the United States of the Mississippi River and other rivers so diversions.Large amounts of water are "intercept" turned into ice, causing sea levels to drop 120 meters high, part of today's sea floor also exposed.But the sea is also rising, had risen by 70 meters.During the last interglacial sea level for five to seven metres taller than it is today.
8. I to the sun is a big stomach king "
at the appointed time, we can choose to leave the earth, but it need we are completely unable to imagine technology support, at the same time also need to find a place to live.There is another possibility: the next billion years, a passing objects damage the earth's orbit and kick the earth from the sun.The scientists say, the possibility is about one over one hundred thousand, is easier than winning lottery prize.Unfortunately, if successfully separated from the sun, the earth human descendants of the home also is likely to be freezing to death.
9. The moon is the earth the only partner
in addition to the moon, there are other two celestial bodies also near the earth's orbit;They are sometimes referred to as the earth's satellite, although they are not strictly a satellite.Was found in 1986, asteroid 3753 (crowther, Cruithne) is actually running around the sun.But because of its cycle is consistent, and the earth's orbit crowther, looks like in follow the earth.From the point of view of the earth, crowther, the shape of the orbit like a grain of beans.And 2002 AA29 near-earth asteroids also orbit day for years period;Its orbit more strange, for a horseshoe shape, will be closer to the earth every 95 years (about 5.9 million kilometers) from the earth at a time.Because it can be close to the earth, scientists have suggested that collect samples on the planet and return to earth.
10. Violence wind more quiet
this is not only a common saying, under certain circumstances, the quiet before the storm.Storm from the surrounding atmosphere warm, moist air inhaled as driving fuel, left a low pressure area.Warm air rising storm cloud formation, and part of storm clouds are influenced by turbulence continues to rise.The rising air and then push the warm air in the highest storm clouds (up to 16 kilometers).Out of the air down, then become more warm and dry, so it is more stable.Stay warm air cover the area and stability in the region of the atmosphere, as a result, the inhabitants of this region was observed the quiet before the storm.