Science Astronomy Unit

Astronomical Unit (AU)

One astronomical unit equals the average distance between the Sun and the Earth, about 150 million kilometers.

Light Year (ly)

One light year equals the distance that a beam of light travels through space in one year, equivalent to 9 trillion kilometers.

Asteroid Belt

A huge band of billions of rocks circling the Sun, found between the inner rocky planets and the outer gas giants.

Dwarf Planets

Similar to planets in that they orbit the Sun and have a roughly spherical shape, but have an unusual orbit in a zone that contains many other objects.

Comets

A celestial object made of ice and dust, often called a 'dirty snowball', which travels in an elliptical orbit around the Sun.

Meteoroids

Small pieces of rock or metal that travel throughout the solar system with no fixed path.

Meteor

A meteoroid that after entering Earth's atmosphere, collides with gas molecules and burns up due to frictional heating.

Meteorite

A meteor that survives a trip through the atmosphere and hits the ground.

What causes day and night on Earth?

The daily rotation of Earth on its axis.

How does Earth rotate when viewed from the North Pole?

Counter-clockwise.

What are the two main seasons near the equator?

Wet and dry seasons.

How many seasons are generally experienced in the northern and southern hemispheres?

Four seasons.

What is the reason for the change in seasons?

The tilt of the Earth and its revolution around the Sun.

What is an orbit?

The curved, repeating path that one object takes around another, due to the force of gravity.

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What is a satellite?

Any object that orbits a planet; the Moon is a natural satellite of Earth.

Why does the Moon appear bright?

It reflects the Sun's light.

What occurs during a solar eclipse?

The Moon lies directly between the Earth and the Sun, blocking all or part of the Sun's light.

What occurs during a lunar eclipse?

The Earth blocks the Sun's light shining on the Moon, making the Moon briefly 'disappear'.

What is the approximate distance from the Earth to the Sun?

About 150 million kilometers.

What is a sunspot?

A region on the Sun's surface that is cooler than the surrounding area, appearing darker.

What is a solar prominence?

A large, low energy, curved bright stream of particles shaped by the Sun's magnetic field lines.

What is a solar flare?

A high energy explosion at the Sun's surface that flings hot plasma into space.

What is solar wind?

A steady stream of subatomic particles or plasma emitted from the Sun's surface.

What natural phenomenon is caused by the solar wind interacting with Earth's magnetic field?

Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights).