mathematics - Important days in history... and to come!

The other day I decided I wanted to come up with another simple puzzle before releasing another toughy on puzzling.SE. I came across an interesting series of dates that I wanted to share and see if people could figure out what the next date in the series was.

The series of dates is:

     March 30, 1973

      April 1, 1975
      June 28, 1978
 September 27, 1983
     March 24, 1992
  December 18, 2005
............., .....

What is the next date in the series? Explain.

Answer

I would guess that the answer is

March 10, 2028

Argument:

Whenever I look at four consecutive dates $d_1,d_2,d_3,d_4$ in this sequence, then the third date is exactly in the middle between the first date and the fourth date; mathematically, this means $d_3=(d_1+d_4)/2$.

(Thanks to Z Dailey): The Unix timestamps of these dates are the Fibonacci numbers.