Tiny grains of zirconium silicate (zircons) found embedded in sedimentary rocks have been radiometrically dated to what age?
A) 4.57 billion years ago
B) 3.85 billion years ago
C) 4.38 billion years ago
D) 4.02 billion years ago
Question 2
Which of the following signals from an advanced civilization would be easiest to detect?
A) high intensity, narrow bandwidth
B) low intensity, wide bandwidth
C) high intensity, wide bandwidth
D) low intensity, narrow bandwidth