-3
$\begingroup$

StackExchange articles such as "What is gravity and what causes objects to act against it" seem to state that the gravitational force is only exerted by very large celestial objects that bend the space-time.

StackExchange articles such as "Is the gravity between objects other than celestials observable" seem to cite the Cavendish experiment which apparently showed that two relatively small objects exert a gravitational force on each other.

What is the current scientific consensus on this? Do small objects (like my pencil) exert forces on other small objects (like my eraser), or is it only large celestial objects that can exert a gravitational force?

$\endgroup$
  • $\begingroup$ Everything in the universe that has mass has gravity. $\endgroup$ – CoilKid Dec 12 '15 at 22:56
  • 1
    $\begingroup$ "articles such as What is gravity and what causes objects to act against it seem to state that the gravitational force is only exerted by very large celestial objects..." no: nobody there suggested that. $\endgroup$ – AccidentalFourierTransform Dec 12 '15 at 23:05
  • 1
    $\begingroup$ Something you should ask yourself is, what makes large celestial bodies special besides being "large?" The earth is made of chunks of dirt, all of which together obviously have gravity. If you picked up one of these chunks, would it suddenly stop having gravity? $\endgroup$ – Jahan Claes Dec 12 '15 at 23:10
  • 5
    $\begingroup$ Possible duplicate of Can the effects of a person's mass upon the local gravitational field be detected and measured remotely? $\endgroup$ – Fattie Dec 12 '15 at 23:24
  • $\begingroup$ I don't see any reason to downvote this question. It's a simple question, but perfectly written and researched. It's just a duplicate, is all. $\endgroup$ – Fattie Dec 12 '15 at 23:25
0
$\begingroup$

This question is a duplicate, but the very simple answer is yes, absolutely.

Every atom has a gravitational force with every other atom.

Yes, the Cavendish device can quite easily measure gravity between two everyday objects, as long as they weigh about a KG or so ... It's that simple.

For even smaller objects, it might be difficult to measure - but so what? (Any number of physical qualities are difficult to measure, when very small or very large.)

A simple way to think about it - consider the Earth. It obviously has gravity right? Now consider one small piece of the earth (just some random piece of rock inside the Earth). All those little pieces ... have to have gravity right? Or else the whole thing overall, would not have gravity. That thought experiment can help you see that "even your pencil has gravity".

What is the current scientific consensus on this?

100.0% of all scientists believe all atoms in the universe attract all other atoms gravitationally.

Do small objects (like my pencil) exert forces on other small objects (like my eraser),

Yes, absolutely.

(Note that -- very simply -- your pencil is attracting every tiny little rock that makes up the Earth. Consider the Earth as being trillions of pencil-sized little rocks. So, that's gravity.)

or is it only large celestial objects that can exert a gravitational force?

No, it very much applies to every single atom.

$\endgroup$
  • $\begingroup$ I agree that the Cavendish experiment (and others) provide conclusive evidence that gravity does exist between everyday lightweight objects. Though I don't think that you can deduce that everyday objects have gravity through a thought experiment like that. It might have been the case that gravity ONLY exists between celestial bodies, but it is ONLY because we have experimental evidence suggesting otherwise that we know that gravity exists even for lighter objects. $\endgroup$ – Joshua Lin Dec 12 '15 at 23:54
  • $\begingroup$ Hi Joshua. (1) the answer to this OPs question is absolutely "yes", it's just a simple beginner question. Note that (2) my thought experiment is purely a pedagogical one, to help one realize that small items "are as important as" big ones (since big ones are .......... made of small ones!) In no sense is the "thought experiment" mentioned a PROOF of anything to do with gravity - just as you say. it's just a "pedagogical thought experiment" not a "proof thought experiment"! $\endgroup$ – Fattie Dec 13 '15 at 0:06

Not the answer you're looking for? Browse other questions tagged or ask your own question.