# Is the expanding of the universe also a cause which can induce gravitational waves from mass? [duplicate]

Gravitational waves arises when mass is rotating in another mass'orbital, in explosions and of course in case of colliding black holes. But are they also created when mass is moving and speeding because the space itself is expanding? And is there also a kind of 'red-shifting' of the waves because they are moving away?

• Movement of mass doesn't create gravitational waves, neither does the homogeneous expansion of space. Commented Feb 13, 2016 at 9:52
• – Danu
Commented Feb 16, 2016 at 17:03
• I feel that really isn't a duplicate. There the question is if an expanding universe has an effect on a particular detector (that happens to be optimized for gravitational waves), whereas here it's asking if actual waves come about, detectable or not.
– user10851
Commented Feb 18, 2016 at 0:33

Movement of mass doesn't create gravitational waves, neither does the homogeneous expansion of space. – CuriousOne, in a comment.

• IIRC if a comment is quoted as an answer, it should link to both the commenter's profile and to the comment itself... I only know how to do the first (which I've edited in) and could be wrong about the second. Commented Feb 13, 2016 at 13:53
• @Asher: click on the "time" part of the comment, that is a direct link to the comment itself. Commented Feb 13, 2016 at 16:26
• When you post other people's comments as answers, I think you should make the post into "community wiki" posts, so that you don't gain any rep from the work (which isn't yours).
– Danu
Commented Feb 13, 2016 at 16:59

The expanding universe is characterized by the Robertson-Walker metric. There is no radiation in that metric, it only has one time dependent factor and it is the radius of the universe. Because it is spherically symmetric it cannot radiate. In General Relativity, even a dipole moment won't radiate, it has to have at minimum enough asymmetry to have a quadruple moment.