5,000 or 26,000 barrels a day--size of gulf oil spill is a guesstimate

Experts say emphatically that anyone who makes an estimate of the leak by looking at the video is simply arm-waving. There are too many variables. The stuff coming out of the pipe isn't just oil, for example, but a frothing cocktail of oil, gas, brine and sediment from miles below the sea bottom.

BP, however, could try to measure the flow directly with off-the-shelf instruments routinely used in research on deep-sea hydrothermal vents and cold hydrocarbon seeps, according to scientists at the Woods Hole Oceanographic Institution. They said devices that can essentially take a sonogram of the plume could be strapped to one of the robotic submarines that BP has deployed around the damaged well.