system
Given the following post, respond as if you're commenting on Reddit:
human
So, the universe is ever expanding. Does that also mean that the distance between our planets in our solar system will also slowly drift apart?

(I'm not exactly sure what to put in here that would have any relevance. Sorry.)
gpt
The answer is no. That's because the rate of expansion is too small to affect such closely gravitationally bound objects. The expansion can have an effect on the maximum size of a galaxy, but for a solar system the effect is way too small.

Here are some numbers. Hubble's law for the expansion is that v=d*H. v being the velocity the two objects are moving away from one another, d their separation, and H Hubble's constant. H is ~70 km/s/Mpc (Mpc = Megaparsec = 3.26 million light years). The Earth is about 93 million miles from the Sun, that's only 4.85x10^-12 Mpc. Using Hubble's law that gives a velocity of ~1.2x10^-6 km/h = 1.2 mm/h. And that's if expansion of the universe is the only factor. Which it isn't. This expansion is dwarfed by the gravitational attraction.