Geodesics are not quite "straight lines". They are simply the closest that one can get to a straight line in a curved geometry.MeJennifer said:That would imply the assertion that there is absolute space which in contrary to the theory of GR.
In my view something that travels on a geodesic does not change direction at all.
Obviously the directional change can be observed but this is simply a relativistic effect. Claiming that a photon changes direction in space due to a gravitational field is simply Newtonian thinking, similar to a claim that a free falling object under the influence of the gravitational field of the earth accelerates and changes direction in space. The term space is clearly misused here. Remember that space is not flat near a gravitational field, so don't treat it as flat and claim a change in direction!
In GR a photon never changes direction, it simply cannot. It can only be emitted and absorbed and it always travels on a geodesic.
As far as light deflection goes, this is one of the classical tests of GR. See for instance http://en.wikipedia.org/wiki/Tests_of_general_relativity
For a non-wiki reference, try http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/grel.htmlDeflection of light by the Sun
The first observation of light deflection was performed by noting the change in position of stars as they passed near the Sun on the celestial sphere. The observations were performed by Sir Arthur Eddington and his collaborators during a total solar eclipse, so that the stars near the sun could be observed. Observations were made simultaneously in the city of Sobral, Ceará, Brazil and in the west coast of Africa . The result was considered spectacular news and made the front page of most major newspapers. It made Einstein and his theory of general relativity world famous.
Or do a google search for "gravitational light deflection" or "gravitational lensing".
Since the deflection of light is well documented and experimentally confirmed, I think you need to adjust your understanding to match the evidence, rather than the evidence to match your understanding.