Sunday, 22 December 2013

Ten Facts About Our Solar System we May not Know

The Solar System Has Many Hidden & Fascinating Facts That We May Not have Known : 

10 ) The hottest planet isn’t closest to the sun
Many people know that Mercury is the closest planet to the sun, well less than half of the Earth’s distance. It is no mystery, therefore, why people would assume that Mercury is the hottest planet. We know that Venus, the second planet away from the sun, is on the average 30 million miles farther from the sun than Mercury. The natural assumption is that being farther away, it must be cooler. But assumptions can be dangerous. For practical consideration, Mercury has no atmosphere, no warming blanket to help it maintain the sun’s heat. Venus, on the other hand, is shrouded by an unexpectedly thick atmosphere, about 100 times thicker than our own on Earth. This in itself would normally serve to prevent some of the sun’s energy from escaping back into space and thus raise the overall temperature of the planet. But in addition to the atmosphere’s thickness, it is composed almost entirely of carbon dioxide, a potent greenhouse gas. The carbon dioxide freely lets solar energy in, but is far less transparent to the longer wavelength radiation emitted by the heated surface. Thus the temperature rises to a level far above what would be expected, making it the hottest planet. In fact the average temperature on Venus is about 875 degrees F, hot enough to melt tin and lead. The maximum temperature on Mercury, the planet closer to the sun, is about 800 degrees F. In addition, the lack of atmosphere causes Mercury’s surface temperature to vary by hundreds of degrees, whereas the thick mantle of carbon dioxide keeps the surface temperature of Venus steady, hardly varying at all, anywhere on the planet or any time of day or night!

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

9 ) Pluto is smaller than the USA
The greatest distance across the contiguous United States is nearly 2,900 miles (from Northern California to Maine). By the best current estimates, Pluto is just over 1400 miles across, less than half the width of the U.S. Certainly in size it is much smaller than any major planet, perhaps making it a bit easier to understand why a few years ago it was “demoted” from full planet status. It is now known as a “dwarf planet.”

8 ) George Lucas doesn’t know much about “Asteroid Fields”
In many science fiction movies, spacecraft are often endangered by pesky asteroid fields. In actuality, the only asteroid belt we are aware of exists between Mars and Jupiter, and although there are tens of thousands of asteroids in it (perhaps more), they are quite widely spaced and the likelihood of colliding with one is small. In fact, spacecraft must be deliberately and carefully guided to asteroids to have a chance of even photographing one. Given the presumed manner of creation, it is highly unlikely that spacefarers will ever encounter asteroid swarms or fields in deep space.

7 ) You can make volcanoes using water as magma
Mention volcanoes and everyone immediately thinks of Mount St. Helens, Mount Vesuvius, or maybe the lava caldera of Mauna Loa in Hawaii. Volcanoes require molten rock called lava (or “magma” when still underground), right? Not really. A volcano forms when an underground reservoir of a hot, fluid mineral or gas erupts onto the surface of a planet or other non-stellar astronomical body. The exact composition of the mineral can vary greatly. On Earth, most volcanoes sport lava (or magma) that has silicon, iron, magnesium, sodium, and a host of complicated minerals. 

6 ) The “edge” of the Solar System is 1,000 times farther away than Pluto


5 ) Almost everything on Earth is a rare element
The elemental composition of planet Earth is mostly iron, oxygen, silicon, magnesium, sulfur, nickel, calcium, sodium, and aluminum. While such elements have been detected in locations throughout the universe, they are merely trace elements, vastly overshadowed by the much greater abundances of hydrogen and helium. Thus Earth, for the most part, is composed of rare elements. 

4 ) There are Mars rocks on Earth (and we didn’t bring here)
Chemical analysis of meteorites found in Antarctica, the Sahara Desert, and elsewhere have been shown by various means to have originated on Mars. For example, some contain pockets of gas that is chemically identical to the martian atmosphere. 

3 ) Jupiter has the biggest ocean of any planet 
Orbiting in cold space five times farther from the sun than Earth, Jupiter retained much higher levels of hydrogen and helium when it formed than did our planet. In fact, Jupiter is mostly hydrogen and helium. Given the planet’s mass and chemical composition, physics demands that way down under the cold cloud tops, pressures rise to the point that the hydrogen must turn to liquid. In fact there should be a deep planetary ocean of liquid hydrogen. Computer models show that not only is this the largest ocean known in the solar system, but that it is about 40,000 km deep – roughly as deep as the Earth is around!

2 ) Even really small bodies can have moons
It was once thought that only objects as large as planets could have natural satellites or moons.

1 ) We live inside the sun

Normally we think of the sun as being that big, hot ball of light 93 million miles away. But actually, the sun’s outer atmosphere extends far beyond its visible surface. Our planet orbits within this tenuous atmosphere, and we see evidence of this when gusts of the solar wind generate the Northern and Southern Lights. In that sense, we definitely live “inside” the sun. But the solar atmosphere doesn’t end at Earth. Auroras have been observed on Jupiter, Saturn, Uranus, and even distant Neptune. In fact, the outer solar atmosphere, called the “heliosphere,” is thought to extend at least 100 A.U. That’s nearly 10 billion miles. In fact the atmosphere is likely teardrop shaped due to the sun’s motion in space, with the “tail” extending tens to hundreds of billions of miles downwind .

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