Is There Intelligent Life Elsewhere in the Universe? Is there any evidence intelligent life exists other than on Earth? How would you go about looking for it? – Look for signals, unintentional and intentional –UFOs and/or alien visitations –Look for other planets (exoplanets)

Signals, Intentional and Unintentional In 1896 Nickola Tesla, famous electrical and mechanical engineer and physicist, first suggested that radio waves could be used to contact ET life, and three years later thought he had received signals from Mars. In 1924 the US Naval Observatory was part of a program to ‘listen’ for signals from Mars.

Signals, Intentional and Unintentional Astronomer Frank Drake (Cornell) started the modern search for signals from other stars in He later derived the Drake Equation which estimates the number of inhabited worlds in the Milky Way Galaxy. Dr. Drake has remained active in the search for extraterrestrial intelligence (SETI).

Drake Equation

N = Number of communicative (with electromagnetic communications technology) civilizations R* = Rate of formation of suitable stars (such as our Sun) f p = Fraction of those stars with planets. (Current evidence indicates that planetary systems may be common for stars like the Sun.) n e = Number of Earth-like worlds per planetary system f l = Fraction of those Earth-like planets where life actually develops f i = Fraction of life sites where intelligence develops f c = Fraction of communicative planets L = The "lifetime" of communicating civilizations N = R* f p n e f l f i f c L

Since 1960 there has been extensive effort by astronomers to search the universe for signals from ET intelligence, including unintentional technosignatures (signals ‘accidentally’ sent, such as our TV broadcasts or other day-to- day evidence of our level of technology). Funding has included the US government (until 1995) and privately after that date.

The result? To date, no confirmed, unambiguous signal from extraterrestrial intelligence. (Sorry, ET.)

UFOs? To date, there is NO undisputed scientific evidence that we have been visited by extraterrestrial spacecraft, despite ‘photographs’, cave paintings, reports of alien abductions, thousands of internet sites, and many movies and TV series on the subject. No Men in Black, no Area 51, no government coverup of evidence to prevent panic.

Kepler Space Telescope In 2009 NASA launched the Kepler Space Telescope which is "specifically designed to survey a portion of our region of the Milky Way galaxy to discover … Earth-size planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets." (NASA’s mission guide). In 2013 the ability to aim KST was lost due to mechanical problems, but as of May, 2014, 2 years of funding was allocated to simply move KST periodically to ‘aim’ it. What has Kepler found?

Exoplanets As of January, 2015, KST has discovered 1004 confirmed exoplanets with another 3277 candidates (and we expect about 90% of these— 288—to be confirmed) in just 5 years of searching. Note: the Exoplanet Orbit Database lists 1593 confirmed planets as of 08/25/15 (

Earth-Size Exoplanets? In January, 2013, astronomers estimated that there are at least 17 billion Earth-sized exoplanets (and possibly up to 40 billion) in the Milky Way Galaxy alone.

Video Break Exoplanets: Are There Other Earths? Part 1 (PBS LM; 5:18) Exoplanets: Is There Intelligent Life Beyond Earth? Part 2 (PBS LM; 8 min), featuring Ray Bradbury

So why haven’t we heard from intelligent life on any planet anywhere? Brainstorm, please, for 3 minutes. Write your ideas down! (Group paper with everyone’s name is fine). Turn in your group’s paper.

What do you think? 1.There’s no one out there. 2.We’re not technologically advanced enough to recognize an advanced race’s signal. 3.We’re not technologically advanced enough for anyone to contact us, yet. 4.They’re less advanced than we are! 5.They’re afraid of us. 6.Space is so vast that the chances of our getting any EM signal (at the speed of light) is very, very unlikely. 7.???