6 - Lights in the Sky, Weather or Not

Halo

A bright ring of light that forms around the sun or moon. Needs the ice crystals from a cirrostratus cloud to form. When sunlight tries to pass through these clouds, the ice crystals: - Slow the light down - Bend it in different ways - The changed (bent) path makes the halo Followed 1-2 days later by rain or snow.

Rainbow

A meteorological phenomenon caused by reflection, refraction, and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky.

Auroras

A natural light display in the sky that occur when small particles called solar wind blows out from the sun and interact with the Ionosphere. These are made up of charged particles from the atoms that make up the Sun. When they reach the Earth, they gather at the North and South Poles and glow in multicolored curtains of light.

Mirage

A naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky.

Corona

A small, circular glow that appears to surround the Sun or moon, and which often exhibiting colored rings. Created by water droplets in the air above the Sun or moon.

Virga

An observable streak or shaft of precipitation that falls from a cloud but evaporates or sublimes before reaching the ground. Rain that evaporates before reaching the ground.

Contrails

Artificial clouds that form in the upper troposphere. Thin trails of ice formed from cooled water vapor in airplane exhaust. Short for condensation trails.

Aurora Borealis

Auroras in the Northern Hemisphere. Also known as the Northern Lights.

Aurora Australis

Auroras in the Southern Hemisphere. Also known as the Southern Lights.

Meteors

Earth passes through big clouds of dust and gas in space. These particles burn up in the Mesosphere as they enter the atmosphere. Some particles are very small (grains of sand and chalk dust). Other particles are larger and make it to Earth as meteorites.

Green Flash

Green flashes and green rays are optical phenomena that sometimes occur right after sunset or right before sunrise. When the conditions are right, a green spot is visible above the upper rim of the disk of the sun.

Crepuscular Rays

Rays of sunlight scattered so that they appear to radiate from the point in the sky where the Sun is located. These rays are actually parallel beams of light and not diverging as they appear because of perspective. Also known as sunbeams, sun rays, or God rays.

Sun pillar

Shafts of light caused by reflection from ice crystals that extend upward or, less commonly, downward from the Sun when the Sun is near the horizon.

Alexander's dark band

The dark appearance of the sky between the bows of a double rainbow (primary and secondary bows).

Visible spectrum

The portion of sunlight perceived by the human eye as various colors.

Sundog

Two bright spots along the 22° halo, appearing suspended on either side of the Sun parallel to the horizon. Also known as mock suns or phantom suns

Why is the sky blue?

White light comes from the Sun (white is all colors). The air molecules are just the right size to scatter blue light and leave the rest. As the white light enters the atmosphere the blue light is scattered in all directions.