Here's why:
* Gravity's reach is infinite: Gravity extends infinitely from any object with mass, although it weakens with distance.
* The exosphere is far from the Earth's center: The exosphere is the outermost layer of Earth's atmosphere, starting around 600-1000 kilometers (375-620 miles) above the surface.
* The inverse square law: Gravity's force decreases with the square of the distance. So, the farther you are from Earth's center, the weaker the gravitational pull.
Quantifying gravity in the exosphere:
* Earth's gravitational acceleration at the surface: Approximately 9.8 m/s².
* Gravity at the exosphere: The gravitational acceleration at the edge of the exosphere is about 1/10th of the surface gravity, or around 1 m/s².
* Precise value: The exact gravitational acceleration at the exosphere depends on the specific altitude within the exosphere.
Important points:
* Escape velocity: While gravity is still present, it is weak enough that particles in the exosphere can escape Earth's atmosphere entirely.
* Exosphere's definition: The exosphere's upper boundary is not well-defined because it gradually merges with interplanetary space.
In conclusion: Gravity is present in the exosphere, but it is much weaker than at the Earth's surface. The exosphere's particles are weakly bound to Earth, and many of them can escape into space.
