evidence
facts that make you believe something is true
facts that make you believe something is true
extraterrestrial intelligence
advanced life forms existing beyond our planet
clues
pieces of evidence
analyse
examine
volunteers
people who do something without being paid for it
vital
essential
age-old
long-standing or very old
astronomers
people who study space
citizen
person belonging to a particular country
tantalizing
exciting, making you want more (even if it is not possible)
exists
occurs
