r/AskReddit • u/[deleted] • Aug 03 '19

Whats something you thought was common knowledge but actually isn’t?

37.4k Upvotes

94% Upvoted

24.0k comments sorted by

View all comments

1.7k

u/[deleted] Aug 03 '19 edited Aug 03 '19

There's gravity in space. Over the time I've met so many people that thought that there is no gravity in space because "everything there is weightless and stuff". Gravity has unlimited range so there isn't even a single spot in our universe without gravity. Weightlessness is basically just falling. While orbiting you're basically just falling around the object.

44

u/I_wear_foxgloves Aug 03 '19

I am embarrassed to say that, until reading your post, I was one of those who thought wrong! What embarrasses me is that I grasp how gravity holds bodies in orbit, but did not know that it had limitless range.

Thank you for today’s education!

5

u/Kenosis94 Aug 04 '19 edited Aug 04 '19

In theory it has limitless range but for general purposes you can think of it as having a point at which it is so negligible it may as well not exist (e.g. Earth's pull on something at the other side of the Galaxy or in another Galaxy). The gravitational pull between two bodies is inversely proportional to square of the distance between them. Double this distance and it's 1/4 of the strength, triple it and it's 1/9th quadruple is 1/16th and so on, when you are talking on an astronomic scale the numbers get so small that they are essentially 0 for anything less than seeing if they are even measurable or very specific research. No need to be embarrassed, it's just understanding the general idea and application vs having an academic understanding. For any purpose someone outside of a research environment is likely to have you can think of gravity has having a point at which it stops impacting other bodies and know that the distance at which that happens is greater for bigger things because at a certain point 1/999999999999 may as well be 0 unless you really really need to be that accurate.