Earth's Revolution and Seasons

Earth’s Revolution and Seasons (WebGL)

Earth Rotation and Seasonal Changes The Earth’s rotation axis is tilted at an angle of about 23.5 ° to the orbital axis. Because of this inclination, seasonal changes occur like spring, summer, autumn, and winter. The … more

Phase of the Moon

Phase of the Moon 3

* If you are asked to access your location, please allow it. * Your personal data is not stored on the server. * For iOS devices, please allow location access as follows. It is only the … more

Cassegrain Reflector

Cassegrain Reflector

Cassegrain Reflector The Cassegrain reflector(telescope) was designed by French engineer Laurent Cassegrain to compensate for the shortcomings of the Newtonian telescope. Light reflected by the concave mirror is incident on the convex mirror. Focus is created … more

Tides Simulation

Tides

Tide is a phenomenon that the ocean surface’s periodic rise and fall due to the moon and sun’s gravitational pulls. Spring Tide is the highest high tide that occurs during the tide. It occurs when the … more

Real Size & Orbit of Earth and Moon

Real Size & Orbit of Earth and Moon

The photographs of the Earth and the moon close together that you can see on posters, etc., are designed to be easy to see. The moon’s apparent diameter is only about 0.5˚. This tells us that … more

Newtonian Reflector Simulation

Newtonian Reflector

Refracting telescope A telescope that uses only the refraction of a lens is called a refracting telescope. There are two types of refracting telescopes depending on the combination of lenses. The Galilean telescope is often referred … more

Refracting telescope (Kepler type, Galileo type)

Refracting telescope (Keplerian, Galilean)

Refracting telescope A telescope that uses only the refraction of a lens is called a refracting telescope. There are two types of refracting telescopes depending on the combination of lenses. The Galilean telescope is often referred … more

Eclipse Simulation

Eclipse

Solar eclipse Eclipse is the phenomenon that one object hides another object or enters that shadow. ‘a solar eclipse’ is the moon’s shadow by covering the sun. Lunar eclipse When the moon enters the shadow of … more

Measuring the Earth

Eratosthenes’ Calculation of Earth’s Circumference 2

Eratosthenes’ Calculation of Earth’s Circumference The first person to measure the earth’s size was Eratosthenes, an ancient Greek scientist about 2,000 years ago. Eratosthenes lived in Alexandria, near the Nile River’s mouth by the Mediterranean coast, … more

Geocentrism and Heliocentrism

Geocentrism vs. Heliocentrism

Geocentrism, The Geocentric theory The Geocentric theory is a cosmic perspective in which the Earth is at the center, and all the stars revolve around the Earth. From the 13th to the 17th century, it was … more

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Gravitational Lensing

Space-time warpage Einstein, famous for the theory of relativity, thought that the mass of an object warps space-time. The larger the mass, the greater the degree of time-space warp. He explained that an object’s falling or … more

Phase of the Moon

Phase of the Moon 2

It is only the sun that shines by itself in the solar system. Earth and moon do not emit light themselves. The earth and the moon only reflect the light of the sun. Since the earth … more