Being done Quote by Johannes Kepler
“Nothing which consists of corporeal matter is absolutely light, but that is comparatively lighter which is rarer, either by its own nature, or by accidental heat. And it is not to be thought that light bodies are escaping to the surface of the universe while they are carried upwards, or that they are not attracted by the earth. They are attracted, but in a less degree, and so are driven outwards by the heavy bodies; which being done, they stop, and are kept by the earth in their own place.”
About This Quote
Source Treat: Harmonices Mundi (The Harmony of the World) by Johannes Kepler, 1619
Physical bodies with less density rise relative to heavier ones, but gravity still acts on them, limiting their ascent.
In simple terms: Lighter things rise but are still pulled down.
Key Takeaway
Recognize both buoyancy and gravity in motion.
Themes
physics
gravity
buoyancy
Mood
inquisitive
analytical
thoughtful
Type
scientific
explanatory
When to use this quote
- balloon flight
- hot air balloon
- underwater objects
- spacecraft ascent
- meteorology
Key Concepts
density
gravitational attraction
mass
inertia
Questions to Reflect On
- How does density affect movement in different environments?
- When might gravity overcome buoyancy?
A Different Perspective
Heavier objects can dominate in dense media, counteracting the rise of lighter ones.
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![“So, Fabricius, I already have this: that the most true path of the planet [Mars] is an ellipse, which Dürer also calls an oval, or certainly so close to an ellipse that the difference is insensible.” quote by Johannes Kepler](https://sms4smile.com/quotes/img-quotes/a6b/johannes-kepler-4278_differences_so-fabricius-i-already-have-this-that-th_311054.jpg)
