Please excuse the simplistic approach to the following question. If one accepts that the universe is indeed expanding could this not be simply because the relative strength of gravity has or is diminishing? Instead of suggestions of dark energy and or dark matter to make equations make sense could it just be gavitational weakening? I am sorry if this question appears ill informed but I wished to dsicuss this issue all the same. In support the hypothesis a friend did some math for me to relate universal expansion to local circumstances ( Earths orbit) At the same time if you consider the observed universe radius of 13.5 Billion LYr and that Earth is 8.5 LMin from the sun then a 1 LYr change in the universe radius would equal 1.1979E-15 LYr change in Earth's orbit. That would be equal to 11.33 meters. Since the fastest observed recession body seems to be around 0.95 c that would mean in one year we should see something on the order of 10 3/4 meters change in Earth's orbit. Even though this figure of 10.75 meters is an abstract figure and could have a significant error margin. in that the measurement could be from 0.001 meters to 1000 meters or so.....I find it amazing that the figure has come in so low. Taking universal expansion figures and applying them to Earths orbit. Following the logic it seems concievable that a weakening of gravity could be responsible for the universes expansion. Is this worth pursuing?