2012년 9월 19일 수요일

Mercury's simple information


Let's learn Mercury's simple information. Mercury is first planet in solar system.
Let's think Earth is 1.
Mercury is very small. So its diameter is 0.38. So its mass is 0.055. And Mercury has very low gravity. Its gravity is 0.38. It means, Earth’s 1kg is Mercury’s 380g.
M’s diameter:E’s diameter=M’s gravity:E’s gravity. What it’s mean? It means that Mercury’s dencity is simillar to Earth’s dencity. And it has no moon. Mercury is close to Sun, so it's year is 88 Days. But Mercury’s day is 59 Days.


Diameter:0.38
 
Mass:0.055
 
Gravity:0.38
 
Moon:No
 
Year:88days
 
Day:59days

사전 썸네일

2012년 9월 18일 화요일

Middle Age's astronomy.


Copernicus is Holand's natural scientist. He think Sun is center of the solar system. But those days, many people think that Earth is center of the "Earth system". And Moon, Mercury, Venus, Sun, Mars, Jupiter, and Saturn is orbiting the Earth. Why people think that? Because Ptolemy think that.
 
  But there is a problem. How about Retrogade Motion of Mars?
This image is how ptolemy think about Retrogade Motion of Mars.
 
 Mars has epicycle. It's orbiting the Earth but, it is orbiting the epicycle,too. So Mars can retrogade.


And, Europe's astronomy didn't update. So astronomy's history goes to Middle east Asia.

2012년 9월 17일 월요일

Astronomy's history(ancient astronomy)




In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye. In some locations, such as Stonehenge, early cultures assembled massive artifacts that possibly had some astronomical purpose. In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops, as well as in understanding the length of the year.

 
(Egypt astronomy) blog.naver.com/ksw030501

Before tools such as the telescope were invented, early study of the stars had to be conducted from the only vantage points available, namely tall buildings and high ground using the naked eye. As civilizations developed, most notably in Mesopotamia, China, Egypt, Greece, India, and Central America, astronomical observatories were assembled, and ideas on the nature of the universe began to be explored. Most of early astronomy actually consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon and the Earth in the universe were explored philosophically. The Earth was believed to be the center of the universe with the Sun, the Moon and the stars rotating around it. This is known as the geocentric model of the universe, or the Ptolemaic system, named after Ptolemy.(wikipedia)


Ptolemy is Greeece's nature scientist.

2012년 9월 16일 일요일

What is astoronomy?


What is astronomy? Astronomy is nature science that deals about space. It is research about stars, planets, galaxies, and other celestial object. Stars are like Sun. Planets are like Mercury, Venus, Our planet Earth, Mars, Jupiter, Saturn, Uranus, Neptune. So easily, astronomy is a science that research about space object.
 
                          (Astronomy is science that research
                           about space object.)

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