What evidence exists that the graviton is real?

[hover]

What proof do we have that the graviton actually exists?

Quote from http://hyperphysics.phy-astr.gsu.edu/hbase/particles/expar.html" "The graviton is the exchange particle for the gravity force. Although it has not been directly observed, a number of its properties can be implied from the nature of the force. Since gravity is an inverse square force of apparently infinite range, it can be implied that the rest mass of the graviton is zero. "

How do we know so much about the graviton when we have never actually seen or even detected one?

 

[Ki Man]

I think it may be too early to tell at this point. After a bit more analyzation and hopefully if someone can come up with an expirement, then we will be able to know more certainly

 

[Mentz114]

How do we know so much about the graviton when we have never actually seen or even detected one?

In quantum field theory, knowing the nature of the force allows you to infer some properties of its vector boson. Even the spin of the graviton is confidently predicted.