Message #20650

[mccoy]

Like Steve says, GWs are important because they are a new way to 'see' the universe. They convey information which is often not conveyed by electro magnetic waves and visible light. We are starting now to develop a new kind of telescopy. Also, GWs can go beyond the wall of CMBR, cosmic microwave background radiation, which is the absolute limit for visible light. Hence, GWs can relate info belonging to the first 300 000 years after creation.

Like SI says, we can only reason by analogy. The analogy of a pond (spacetime fabric) rippled by a stone thrown into it is very crude and not an exact one. GWs only occur in particular conditions, particularly, acceleration of a mass is necessary, which is not in conditions of circular or cylindrical simmetry. For example, a perfectly spherical body which rotates on its axis does not give rise to GWs. Irregularities in the spherical simmetry do give rise to GWs.