Letter from Thomas Gold to Rear Admiral Alan Shepard, Chief, Astronaut Office, Johnson Space Center, Houston, Texas Has just read Shepard's 3 April speech. He agrees they should go back to the moon for more data, but objects to Shepard's scaremongering, namely suggeting that the sun is only good for another 20 million years. It is good for another 2 billion years or more. So there is no need to panic yet. That is the period it took to develop fom an anoeba. Perhaps the next such period will also see some change. 10 September 1973