Astronaut Mark Lee participates in an extravehicular activity (EVA). Credit: NASA
All physical objects are attracted toward each other by the natural force called gravity, but the effects of gravity that we observe can sometimes be misleading. For example, objects that are revolving around Earth in orbit appear to be weightless and we sometimes use the terms "zero-g" or "zero gravity" to describe this observation. Such descriptions often lead to the false belief that these satellites have escaped Earth's gravity, but this is not true! All objects near Earth, regardless of size, speed, or altitude, experience the downward force of gravity toward the center of the Earth!
The following Next Generation Science Standards will be taught through this lesson:
NGSS 5-PS2-1. Support an argument that the gravitational force exerted by Earth on objects is directed down.
Clarification Statement: “Down” is a local description of the direction that points toward the center of the spherical Earth.
You will need: a book and piece of paper of roughly the same size.
Check out these videos for a closer look at gravity near space!
Felix Baumgartner prepares for a high altitude skydive! Credit: DailyMail
The International Space Station as seen from above. Credit: NASA
The CYGNSS satellite mission. Credit: SWRI