An answer saying "Those reliable scientific articles say that yes" is enough for this site. Assuming the articles, or sources are shown to be of high quality and reliability.
If you want to know more go to more expert sources like Physics.SE, Biology.SE, Chemistry.SE or other, or better yet, go to your local University and find an expert of the field and ask them, maybe even enroll and get a degree in the field if it interests you.
Finally, if you believe that the current scientific understanding is wrong, or not accurate, do the research and revolutionize the scientific world.
I thought of this because of the discussion in the comments to my answer on the question:
First, I think that a clarification should be made as to why this question can be asked here and shouldn't get migrated to Physics.SE.
The question is doubtful of a claim that is given in a video. And this is what we do, we research claims. This claim can be answered by this site because we can bring credible sources that support/disprove a certain claim. If the claim is scientific, we can bring scientific sources that say that this is the case, this isn't the case, or that it's unknown as of yet.
We can also answer a similar "closed" question "Is G constant because of A" in this case, again we search for articles that ether say that G is constant because of A, or that G is constant because of B, in which case it isn't A.
What we can't do, is answer a similar question of "Why is G a constant" or in more general terms "Why is a phenomenon is happening?". The reason for this is that in order to know what causes a phenomena we need a wide range of knowledge in the specific area, and expertise in that specific area, we can to the most find some sources that explain, but we can't be sure of how full they are, and whether they have the full answer or just part of it.
So, how in my mind answers of skepticism of scientific concepts should be answered. Those are questions of the kind "Did snakes redeveloped eyes independently?", "Is G a constant?", "Can water and oil mix?" and so on.
This site exists to check whether current academic discussion and scientific understanding support or negate a claim. So showing a number of reliable, current and relevant scientific publications or sources supporting the claim should be enough to prove the claim.
This site should be an echo of the current scientific publications and understanding, and if they have mistakes, than we also must have those mistakes, because we don't have the tools to make and review our own original research.
As an example for this, if we were in the 50's this site should contain the notion that the universe is unchanging. And before 1982 that quasicrystals don't exist. After the appropriate revelation, a new, correct answer should be made.
And while an explanation of why is it like this, is a favorable bonus, it shouldn't be an expectation from an answer here, more over, a full and comprehensive explanation should not be given here. A selection of credible sources explaining the issue with quotes is a great thing, but it always should encourage farther reading of the source material, and/or addressing more knowledgeable sites/boards.
After all this rambling, I want to say that an answer of the kind "This, this and this recent reliable scientific publication say yes" is a complete, acceptable and good answer on this site.
If you believe that the knowledge you gained from the answer is not enough, you should go and learn that matter farther, for example, go to Physics.SE, Chemistry.SE or Biology.SE, and ask them "How do we know that ..." or "What is the mechanism behind ...".
And if you are still not convinced that you have the full answer, if you think that Schrodinger is right with his crazy zombie cat, or that Dan Shechtman really did see a quasicrystal in his laboratory, that Sheldrake is right and G is a variable, or that the theory of evolution is wrong, then go, research the field, measure the gravitational fields, of find a rabbit in earth from the Jurassic period, prove new scientific claim, win your Nobel Prize, Fame, Fortune and place in history, and then come back to us and rewrite the answer.
Why we don't allow original research:
- Under what conditions is "original research" problematic on community-mediated sites?
- Should we expect original research to occur on this site?
- How should references be handled vs original research?
Can we trust peer reviwed literature: How much can we trust peer reviewed scientific literature?