Die 100 am häufigsten verwendeten Wörter in diesem Buch.
age
alien
although
among
another
argued
argument
astronomer
beyond
biological
canals
century
civilizations
claims
communication
conditions
de
debate
discovery
discussion
drake
during
early
earth
end
even
evidence
evolution
experiments
extraterrestrial
fiction
fig
first
force
form
found
history
human
humanity
hypothesis
idea
intelligence
interstellar
known
least
life
lowell
mars
martian
may
method
might
million
nasa
nature
new
now
observations
organic
origin
others
own
part
phenomenon
physical
planetary
planets
possibility
possible
principle
problem
program
project
question
radio
report
results
science
scientific
scientists
search
seti
solar
space
stars
still
study
subject
systems
theory
though
time
two
ufo
universe
view
whether
work
worlds
years