Pulsing, flashing light emanating from what appearsto be the ground (horizon) up illuminating the NE SkyIt began about 2 1/2 weeks ago on Mother's Day. Around 10:30 my friend noticed a bizarre flashing in the sky to the northeast looking towards Willits, CA. It appeared to emanate from the ground up. She ran inside and got her partner to come witness it. They watched for about 2 hours as the light pulsed and flashed rhythmically almost like a heart beat. They called the radio station and their neighbors on the other side of the mountain (2 of them) were also witnessing it. That night the sky was perfectly clear without a cloud in sight.Move forward 2 weeks to May 22,2011. Another beautiful night without a cloud in the sky and my friend contacted me to say it was happening again at the same exact time 10:30. I drove to the top of my mountain which is about 8 miles from her house and witnessed the same thing. My neighbor was with me and also witnessed it. Again from our vantage point it appeared to the NE. The light pulsed and would flash and light up the Northeastern sky and appeared to be emanating from the same spot from the ground up. The flashing is so large that after it pulses for a bit the flash lights up the sky. I witnessed it for 45 minutes and when I went home it was still occurring.The very next night on May 23, a different friend of mine contacted me to say that she and her brother were watching it again. From their vantage point they could see the flashing lighting up the sky approximately every 3-4 minutes in which she described it like a heartbeat. They watched for around 30 minutes before going home to bed.Every time this has been witnessed it was a gorgeous, clear night without a cloud in sight. It happens at the same time and in the same direction in a very sparsely populated area. I tried to video it to no avail.