Science Notes Posts

The green and red light in the sky around the Paranal Observatory is airglow. (Y. Beletsky (LCO)/ESO) — It never gets truly dark at night because of an effect called airglow. Airglow is similar in color to the aurora, but you don’t have to visit a polar region to see it. While the aurora is light released by the interaction between magnetosphere and the solar wind, airglow is […]

What Is Airglow? Why the Night Sky Is Never Truly ...

This entry was posted on April 25, 2019 by Anne Helmenstine (updated on May 19, 2019)

In addition to the prestige of winning an event at the Olympics, the victor receives a gold medal. At one time, Olympic gold medals were real solid gold. However, the last time a solid gold medal was awarded was at the 1912 Stockholm Olympics. Modern Olympic gold medals are sterling […]

Are Olympic Gold Medals Real Gold?

This entry was posted on March 30, 2019 by Anne Helmenstine (updated on March 30, 2019)

Neon Green Periodic Table — This collection of neon colored periodic table wallpapers are a great way to have a dark themed wallpaper and include useful information.

Neon Colored Periodic Table Wallpapers

This entry was posted on March 18, 2019 by Todd Helmenstine (updated on March 18, 2019)

Law of Cosines Example — The law of sines is a useful rule showing a relationship between an angle of a triangle and the length of the side opposite of the angle. These two example problems show how to use this law to find angles and sides of a triangle.

Law of Sines Example Problem

This entry was posted on March 5, 2019 by Todd Helmenstine (updated on May 3, 2019)

Astronomers believe it's possible for a moon to have a moon of its own. — We all know planets orbit stars and moons orbit planets. Have you ever wondered whether a moon can have a moon of its own (a submoon)? Theoretically, the answer is yes, but there is a good reason why we haven’t discovered any submoons around moons in our own solar system. […]

Can a Moon Have a Moon?

This entry was posted on February 25, 2019 by Anne Helmenstine (updated on March 7, 2019)

The average distance between the Earth and the Sun is about 93 million miles. (NASA) — All of the planets, comets, and asteroids in the solar system orbit the Sun. The average distance between the Earth and the Sun is 92,955,807 miles (149,597,870 km). Most people just round it up to 93 million miles. This distance is called an astronomical unit or AU and is used […]

How Far Is the Sun From Earth?

This entry was posted on February 21, 2019 by Anne Helmenstine (updated on March 1, 2019)