Question

In 1974, the Arecibo Radio Telescope in Puerto Rico sent the most powerful broadcast ever intentionally beamed into space. The transmission, which consisted of a simple pictorial message, was aimed at potential life forms in the star cluster M13. This cluster is approximately 22,000 light-years from Earth, near the edge of the Milky Way galaxy, and contains about 300,000 stars.

The message is made up of 1679 bits that are arranged into 73 lines of 23 digits per line. The "ones" and "zeros" were transmitted by shifting the frequency of the radio signal at a rate of 10 bits per second. The pictorial message includes, among other things, images of the Arecibo telescope, DNA, Earth's Solar System, and a stick figure of a human.

image transmitted by Arecibo Radio Telescope
Image courtesy of Arne Nordmann, licensed under CC BY-SA 3.0

Which of the following best describes why scientists used the conversion of stored binary patterns to send an image to star cluster M13?
A.
Binary patterns can be sent as a continuous signal that only varies in amplitude.
B.
Binary patterns can be stored for future recovery.
C.
Binary patterns can be recorded reliably.
D.
Binary patterns can be efficiently transmitted over long distances.

Answer 1

D.

Digital (binary) data can be sent as simple on/off (or two-frequency) signals that are robust and compact, so images encoded as binary can be transmitted reliably and efficiently across the long distances of space.