So Where Are All Those ETs?


Fermi’s Paradox is a theory named after Italian physicist Enrico Fermi (1901-1954) who, during lunch with a fellow scientist, posed a question kind of like this, “Where the heck are the aliens if they are supposed to exist?” The premise of his theory goes something like this:

  • Billions of stars similar to our Sun exist with many of them billions of years older than our own planet.
  • It is highly probable that some of these stars would be orbited by Earth-like planets with conditions that could lead to the development of intelligent life.
  • If intelligent life developed on these older “Earths” their respective civilizations might have developed interstellar travel and have already begun investigating Earth.

Combine all these facts and you come up with the conclusion that Earth should have already been visited by ETs. So, like Fermi said, “Where is everybody?” Despite mankind’s best efforts Fermi could not find any credible evidence of alien visitation. The conclusion then must become that the existence of intelligent life is:

  • Extremely rare, or…
  • Alien intelligent civilizations have not contacted Earth.

In 1961 a scientist by the name of Frank Drake took Fermi’s 1950 theory and applied a mathematical formula to the probabilities. It is called the “Drake Equation”. The formula is expressed as:

N = R* · fp  · ne · fl  · fi  · fc · L

The variables are defined as follows:

N = The number of civilizations in The Milky Way Galaxy whose electromagnetic emissions are detectable.

R* = The rate of formation of stars suitable for the development of intelligent life.

fp = The fraction of those stars with planetary systems.

ne = The number of planets, per solar system, with an environment suitable for life.

fl = The fraction of suitable planets on which life actually appears.

fi = The fraction of life bearing planets on which intelligent life emerges.

fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.

L = The length of time such civilizations release detectable signals into space.

But what does the formula mean to scientists? Well, that depends on who you talk to. Some scientists translate the results to be wildly optimistic that there is, indeed, intelligent life out there. Others feel quite the opposite. When Frank Drake met with Carl Sagan to speculate on the calculations, they estimated the existence of 1,000 (on the low end) to 100 million (on the high end) possible intelligent civilizations in our Milky Way galaxy. To counter their claims, scientists Frank Tipler and John D. Barrow put forth that the average number of intelligent life civilizations in our galaxy would be much less than one. Seeing as how human civilization exists, that would consequently, then, rule out the possibility of any other intelligent civilization existing at the same time.

The Search For Extraterrestrial Intelligence Institute (SETI) sees the Fermi’s paradox and accepts the reality that either interpretation of the possibility of the existence of intelligence life has a chance of being true. Thus, they continue their efforts, erring on the side of optimism. And the gringa likes that. Why not hold out hope? Why not be curious? And why not exercise such curiosity with a healthy dose of skepticism to balance out the equation and prevent a full-scale pre-disposition to crazy alien conspiracy theory by maintaining strict scientific standards?

SETI continues exploration and research as they search for others out there in the galaxy. They believe in the possibility that if a suitable environment was allowed enough time, that it is possible for intelligent life to develop. By using all sorts of science and technology (satellite arrays, chemistry, optical telescopes, and sophisticated radio signaling devices) SETI not only searches for signals from other civilizations but reaches out with messages of our own to anyone who may be listening. And with their Education and Public Outreach program (EPO), humans of all ages and walks of life can be a part of their endeavor. For educators there is nothing more exciting than to introduce to a classroom of elementary and middle school students SETI’s “Life in the Universe” curriculum. So log on and order your first package today and get students engaged with a lesson plan that is certain to pique their curiosity and hopefully inspire them to be the future of our world’s STEM programs, because we need them.

Sources:

www.seti.org

www.yahoo.news

wikipedia.org

Image Credit:  bing.net

 

 

Singing Space Soup


On February 24 the gringa posted “Moon Music – It’s Classified” with an interesting audio recording from the Apollo 10 mission in 1969. Today I would like to share a great video posted by NASA entitled “NASA Space Sounds”. Although there is an eeriness to the multi-planet ensemble, the gringa finds the sounds to have a meditative quality.

Now, the gringa wants to know how music and sound is produced in outer space. Sound is a vibration that travels through air. In order for vibrations to travel through outer space molecules have to exist in outer space. It is the vibrating air molecules that produce the sound. Outer space is a vacuum, meaning that in the area between planets and stars, there are no molecules. So how is this space music produced?

These symphonies are, indeed, vibrating wave patterns. Planets and moons emit electromagnetic pulses that bounce back and forth between surrounding rings and atmospheric barriers that are not visible to the naked eye. The charged particles within these atmospheres, plasma, are the “carriers” of the sound.

To capture these sounds NASA uses space probes equipped with plasma wave antennae. One particular NASA spacecraft featuring a plasma wave antenna is Voyager. This craft also has on board “The Golden Record” which shares images and sounds from Earth. So, Voyager is on an interactive sound mission, capturing and sharing.

Other things Voyager has captured are “tsunami solar waves”. When there is a burst of energy from the sun, a solar flare, a plasma shockwave is created. It takes about one year for the shockwave to reach Voyager and have the sound recorded. NASA has three recordings thus far.

Shock waves from the sun, as well as cosmic rays from other nearby stars within our Milky Way galaxy, are filled with plasma particles. Plasma is dense and creates very rapid oscillations when something causes the particles to vibrate. A plasma “bubble”, also called a “bell”, surrounds stars like our sun. When a solar flare occurs it’s like ringing a bell. A plasma shockwave resonates. March, 2014 was the third recording by Voyager 1 of our singing Sun.

Plasma is very interesting. It is filled with charged particles. It’s kind of like space soup that has the potential to sing. So the Voyager spacecrafts are basically recording singing space soup. Space soup is also called interstellar space. This is the area of space that exists between stars and contains plasma.

The Voyager mission launched in 1977 with two Voyager spacecraft. Voyager 2 launched about two weeks earlier than Voyager 1 and is still on the job making it the longest operating spacecraft in history. Both Voyagers have visited Jupiter and Saturn. #2 did a fly-by of Uranus and Neptune. One thing they have taught us in their travels is that space is a noisy and musical place thanks to plasma.

 

Source & Image Credit: http://www.nasa.gov