It's known and experimented when you shoot a light beam upward from Erath surface to a light detector at higher altitude, the light detector will detect a redshift. This is called gravitational redshift. Both my friend and I agreed from how this was deduced, we shall see a blueshift when the light beam is shot from ahigher altitude down to the surface. Apparently this is so easy to perform, but everyone seems to keep silent on this. Was this blueshift so simple and nobody care, or the experimental result showed opposite and so everyone just try to pretend blind on this issue? I also noticed Andrewgray put this as one topic in his new theory. Maybe more people than us have noticed this and just kept silent for the time being.