Key Takeaways:
- The perception of weightlessness in space is due to astronauts experiencing constant freefall, not the absence of gravity.
- Earth's gravity significantly influences objects at considerable distances, including the Moon and the International Space Station.
- The Sun's gravitational influence extends to encompass all planets in our solar system, and even the Oort Cloud, a vast region at the edge of our solar system.
- Gravitational forces operate on a large scale; celestial bodies such as the Sun are subject to the gravitational pull of more massive entities like the galactic center.
A quick YouTube search reveals a plethora of floating astronaut videos. They can spin in the air, juggle bubbles of water and their hair looks ridiculous. It certainly appears that there’s no gravity in space — but appearances are deceiving.
Astronauts in orbit are more accurately in free fall. They’re constantly falling towards Earth — which means Earth is keeping quite the gravitational hold on them. They just happen to be also moving fast enough that they keep missing the ground.
Want to dig deeper into gravitational waves and general relativity? We’ve got you covered with our free downloadable eBook: A Century of Gravitational Waves.
Gravity does weaken with distance. But for massive objects like stars and planets, their gravitational reach is enormous. Without Earth’s gravity, the Moon (which orbits roughly a thousand times farther away than the International Space Station) would fly off into the depths of space. Instead, Earth keeps it on a gravitational tether. Likewise, the Sun retains a grasp over not just Earth and Jupiter and Pluto, but even the Oort Cloud of comets, which extends a full light-year away.
The Sun is subject to the gravity of the massive black hole at the center of the Milky Way. And the Milky Way itself dances to the gravitational drumbeat of other nearby galaxies.
In short, it’s hard to find objects in space that aren’t subject to something else’s gravitational tug.
Read more:
