Geophysical definition of planet

High school (ages 12+)
Space & Astronomy

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/geophysical-definition-of-planet

1. What is the geophysical criterion 1?
2. What is the geophysical criterion 2?
3. What is the main rule that scientists use to decide if something is a planet?
4. Why do some scientists think the rule about "clearing the neighborhood" is not enough?

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the geophysical criterion 1?Achieved hydrostatic equilibrium, resulting in a spherical or near-spherical shape
2. What is the geophysical criterion 2?Sufficient mass for self-gravity to overcome material strength and achieve roundness
3. What is the main rule that scientists use to decide if something is a planet?A planet is usually a space rock that is big enough for its own gravity to make it round, a state called hydrostatic equilibrium.
4. Why do some scientists think the rule about "clearing the neighborhood" is not enough?Scientists say the rule about clearing the neighborhood is more about how the planet moved around in the solar system, not just its own gravity.

Geophysical Definition: A classification of celestial bodies based on their intrinsic physical properties and formation processes.
Hydrostatic Equilibrium: A state where an object's internal pressure balances its gravitational forces, leading to a spherical shape.
Orbital Dynamics: The study of the motion of celestial bodies under the influence of gravity.
Self-Gravity: The gravitational attraction exerted by an object on itself, influencing its shape and structure.