지평 좌표계 Horizontal Coordinate System

Horizontal Coordinate System

Touch the screen to move the position of the star. How many numbers do we need to indicate the position of the star? After some time, is this star in the same position or go elsewhere? What are the weak…
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태양의 일주운동 Diurnal Motion of Sun

Diurnal Motion of Sun

Diurnal Motion is the changing view of the sky seen as the Earth rotates on its axis. What is the change in the movement of the sun during one year? What changes will occur around us as the sun’s movement…
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달의 운동과 조석 Tides


Tides is the periodic rise and fall of the ocean surface due to the gravitational pulls of the moon and sun. Spring Tide is the highest high tide occurs during tide. Occurs when the Sun, Earth & Moon are in…
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푸코의 진자 Foucault Pendulum

Foucault Pendulum

* Earth globe photo credit: Foucault’s pendulum is a device invented by French scientist Leon Foucault to prove the Earth’s rotation In 1851. The fact that the Earth rotates has been known for a long time, but it is…
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도플러 효과와 적색 편이 Doppler Effect and RedShift

Doppler Effect and RedShift

Most of the distant galaxies are moving away from our galaxy. Only a fraction of galaxies like Andromeda are coming to us. Scientists have found these things simply by observing the universe. How did you find out?

금성의 시운동 Apparent Motion of Venus

Apparent Motion of Venus

All planets in the Solar System revolve around the Sun in a counterclockwise direction when one views them from the north pole of the celestial sphere. Mercury and Venus are inner planets in the Solar System. They are closer to…
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금성의 위상 Phase of Venus

Phase of Venus

What is the difference between Geocentric theory and Copernican theory? What is the phase of Venus, which can not be found in the Geocentric theory?

태양계의 규모 Scale of Solar System

Scale of Solar System

Click the button to move to the planet you want. Is it closer than you think? If not, why?

세계 시각, 낮과 밤 Daylight Map

Daylight Map

The sun icon has been displayed if the sun is located on the zenith. The shaded area is at night. Find out where ‘midnight sun’ happens.