Last year the Pentagon released a report analyzing 144
unidentified flying objects sin 2004 like this one
spotted by surprised Navy pilots The Pentagon says it
could only explain one of them. That doesn't
necessarily mean they're aliens. But questions about
the heavens are nothing new. For as long as we've been
gazing up at the stars, we've wondered whether s
out there maybe gazing back in the 17th century
astronomers and writers imagined worlds orbiting other
suns. But when we look for answers from out there, no
one is phoning home space is however teeming with radio
waves from distant stars. Giant telescopes can hear
them, most of it is just noise. But these radio
telescopes are listening for evidence of life.
Scientists call it Seti the search for extraterrestrial
intelligence. In 1960 astronomer frank drake conducte
the first scientific search for extraterrestrial lif
here at the National Radio Astronomy Observatory in
west Virginia. He aimed this giant antenna at two stars.
The experiments were called Project Asthma. Named for
the queen of the imaginary land of Oz. He didn't detect
any signals but he wondered how many alien
civilizations out there might w be able to detect. He
called that number N. He created a complex equation to
stick with me here for a second to estimate N.R. Is the
rate that stars form a majority of those FP have
planets. But of those planets, how many have the
conditions to support life that N.E. And how many of
those earth like planets actually developed life That's
F.L. And of those planets How many developed
intelligent civilizations or F. And then there's fc.
How many of those civilizations developed technol
could detect. And finally l how long civilizations last
With all that Drake estimated end to be 10,000 10,000
civilizations making technology or enough ruckus that
we might detect them around the world. A few scientists
started to look. Radio telescopes are usually tuned to
measure astronomical objects like stars or quasars.
Occasionally though scientists scanned frequencies that
might reveal alien life. In 1977 there was even a false
alarm known as the wow signal. Nasa finally launched a
official Seti program on columb Day in 1992 but some
senators called it wasteful and soon canceled it. So CT
remained a low priority. Maybe that's why the first
planet scientists ever detected outside our solar
system was in 1995. They're called exoplanets
Scientists find them by looking for stars that wobble
or for stars that dim when exoplanets pass in front.
Today, scientists have discovered more than 5000
exoplanets like this one which may be entirely lava
kepler 16 B orbits two suns. As depicted here in a Nasa
travel poster or this one, kepler 1 86 F which occupies
the so called habitable zone where liquid water might
support life in 2015. Scientists launched break
Listen, a $100 million.10 year project to expand cd
with more telescopes So if frank drake was right,
10,000 civilizations are within earshot and yet firm
ease paradox. Where is everybody remains unanswered
but could efforts to reach out to aliens change that A
rare example was in 1977 when the Voyager one deep
space probe carried a gold record encoded with 116
images and sound going forward. There are more
proposals to reach E.T.S, including transmitting a
cosmic roadmap that could help aliens find Earth. Of
course, some warn that could be dangerous, since alien
may not all be friendly. Clayton, Sandell, New