The Drake equation
Topic started by Marius (@ ti511210a000-0131.dialup.online.no) on Wed Mar 3 13:23:08 EST 2004.
All times in EST +10:30 for IST.
Anyone who has heard of it?
- From: Marius (@ ti511210a000-0131.dialup.online.no)
on: Wed Mar 3 13:25:11 EST 2004
The Drake Equation was developed in 1961 by Dr. Frank Drake. It can determine how many possible intelligent, communicating civilizations there are in our galaxy.
Nc = N* fp ne fl fi fc fL
The equation represents the following:
N* represents the number of stars in the Milky Way Galaxy
Question: How many stars are in the Milky Way Galaxy?
Answer: Current estimates are 200 to 400 billion.
fp is the fraction of stars that have planets around them
Question: What percentage of stars have planetary systems?
Answer: Current estimates range from 20% to 50%.
ne number of planets per star that are capable of sustaining life
Question: For each star that has a planetary system, how many planets are capable of sustaining life?
Answer: estimates range from 1 to 2.
fl is the fraction of planets in ne where life evolves
Question: On what percentage of the planets that are capable of sustaining life does life actually evolve?
Answer: Current estimates are 100% (where life can evolve it will) .
fi is the fraction of fl where intelligent life evolves
Question: On the planets where life does evolve, what percentage evolves intelligent life?
Answer: Estimates are 50% .
fc is the fraction of fi that communicate
Question: What percentage of intelligent life forms have the means and the desire to communicate?
Answer: 10% to 20%
fL is fraction of the planet's life during which the communicating civilizations may survive
Question: For each civilization that does communicate, for what fraction of the planet's life does the civilization survive?
Answer: This is the most vague question. Using the Earth as our model, the expected lifetime of our Solar System is approximately 10 billion years. Already communication by radio has been for less than 100 years. How long can our civilization survive without destroy ourselves as some predict or will we overcome our problems and survive indefinately? If doomsday came today this figure would be 1/100,000,000th. If we survive for 10,000 more years this figure would be 1/1,000,000th.
When all of these variables are multiplied, we get:
Nc, the number of communicating civilizations in the galaxy.
- From: Shakthi (@ 203-195-199-244.now-india.net.in)
on: Thu Mar 4 00:12:36 EST 2004
Interesting! Wish someone posts more on such subjects.
If the no.of communication civ. in the galaxy assuming is atleast one, how come we never got any commn from any other such inteligent civil..in anyother galaxy? (assuming they are more intellectual than us?)
- From: Marius (@ ti511210a000-0200.dialup.online.no)
on: Thu Mar 4 14:41:44 EST 2004
Maybe our technology is not good enough to pick up the signals, or maybe if they send signals - the signals are only communication signals... Much like the signals we use - television, and mobile telephone etc...Or it could be that they have sent signals in the past, but our technology was not good enough to pick it up.
- From: Marius (@ ti511210a000-0200.dialup.online.no)
on: Thu Mar 4 14:48:46 EST 2004
The following two links are to documents written by Dr. Jerry Ehman, discoverer of the "Wow!" signal.
The first of these documents was written shortly after the 20th anniversary of the arrival of the signal on August 15, 1977. Dr. Ehman wrote this report for his colleagues at the Ohio State University Radio Observatory and astronomers across the world. He wrote it with the intention of giving all of the details about the source, both in terms of its parameters (like location and intensity) and possible explanations (including those that can be ruled out and those that can't). Thus, this report is highly technical. He was initially hesitant about putting it on the website because it would be difficult reading for the many people who do not have a background in astronomy, physics, and electrical engineering. However, his colleagues persuaded him to publish it on the website nevertheless.
The second article is a short document explaining in detail the meaning of the sequence of numbers and letters that constituted the "Wow!" signal: "6EQUJ5" displayed in channel 2 of the computer printout. He did this because several persons sent him and his colleagues mail that indicated these persons didn't have the foggiest idea of the meaning of those symbols.
- From: phdgirl (@ debonair.is.temple.edu)
on: Thu Mar 4 17:59:38 EST 2004
Speaking of the Drake equation and SETI science, has anyone here seen the movie "Contact" adapted from the novel by Carl Sagan ? It had an atheist female scientist as the lead. What are your thoughts on that movie ?
What are your thoughts on extraterrestrial intelligence ? Is it possible that we are alone in this Universe ? Its nothing short of being endlessly fascinating, in my opinion.
- From: Marius (@ ti511210a000-0208.dialup.online.no)
on: Fri Mar 5 13:57:16 EST 2004
To me it seems an impossiblity that we are alone in the Universe... I think there even may be more then one Universe... The movie "contact" was it the one where they built this strange thing in order to travel through space and time - an orb falling down?
- From: phdgirl (@ cavalier250.is.temple.edu)
on: Fri Mar 5 20:53:50 EST 2004
Yeah, in Contact, a woman scientist working on a project for SETI intercepts a signal from a star named "Vega" and the team decodes it and finds instructions to build a vehicle. It was a great movie full of dramatic elements and a lot of science fiction.
About, intelligene life , or atleast even ANY life on other planetary systems, I also believe that they might exist. If not traveling to earth in little UFOs and crashing in Roswell, New Mexico, atleast, there must some sort of primordial soup brewing somewhere in this Universe !!! More than one Universe, hmmm... that's a different story !
- From: pg (@ cavalier250.is.temple.edu)
on: Wed Mar 10 20:10:13 EST 2004
One of the newer missions of NASA in the quest for “ET” :)
Kepler, a NASA Discovery mission, is a spaceborne telescope designed to look for Earth-like planets around stars beyond our solar system.
"The Kepler Mission will, for the first time, enable humans to search our galaxy for Earth-size or even smaller planets," said principal investigator William Borucki of NASA's Ames research Center, Moffett Field, California. "With this cutting-edge capability, Kepler may help us answer one of the most enduring questions humans have asked throughout history: Are there others like us in the universe?"
Kepler will detect planets indirectly, using the "transit" method. A transit occurs each time a planet crosses the line-of-sight between the planet's parent star that it is orbiting and the observer. When this happens, the planet blocks some of the light from its star, resulting in a periodic dimming. This periodic signature is used to detect the planet and to determine its size and its orbit.
Three transits of a star, all with a consistent period, brightness change and duration, provide a robust method of detection and planet confirmation. The measured orbit of the planet and the known properties of the parent star are used to determine if each planet discovered is in the habitable zone; that is, at the distance from its star where liquid water could exist on the surface of the planet.
The industrial partner for development of the hardware is Ball Aerospace & Technologies Corp., based in Boulder, Colorado. The mission is managed by NASA's Jet Propulsion Laboratory.
Scheduled to launch in 2007, Kepler will hunt for planets using a specialized one-meter diameter telescope called a photometer to measure the small changes in brightness caused by the transits.
The key technology at the heart of the photometer is a set of charged coupled devices (CCDs) that measures the brightness of hundreds of thousands of stars at the same time. CCDs are the silicon light-sensitive chips that are used in today's TV cameras, camcorders and digital cameras. Kepler must monitor many thousands of stars simultaneously, since the chance of any one planet being aligned along the line-of-sight is only about 1/2 of a percent.
Over a four-year period, Kepler will continuously view an amount of sky about equal to the size of a human hand held at arm's length or about equal in area to two "scoops" of the sky made with the Big Dipper constellation. In comparison, the Hubble Space Telescope can view only the amount of sky equal to a grain of sand held at arms length, and then only for about a half-hour at a time.
NASA selected Kepler as one of two Discovery missions from 26 proposals made in early 2001. The missions must stay within the Discovery Program's development cost cap of about $299 million. The Discovery Program emphasizes lower-cost, highly focused scientific missions.
- From: Shekhar (@ 22.214.171.124)
on: Thu Mar 11 08:26:25 EST 2004
Forget about the universe. Tell me what is the equation to find out the presence of intelligent life in the FH threads?! :)
- From: pg (@ debonair.is.temple.edu)
on: Thu Mar 11 23:40:54 EST 2004
"Stardust" is another NASA mission whose task it was to collect the dust particles in the tail of a comet (Wild 2) and bring them back to earth to study the physical and chemical composition that may provide insight into the early history of the Solar system. Stardust successfully flew oh-so-close to the comet and collected the dust and now its on its way back home which would take about 2 years (more than a billion miles to cover) . Cool, huh ?!
- From: Marius (@ ti511210a000-0007.dialup.online.no)
on: Fri Mar 12 21:31:43 EST 2004
Tell your friend about this topic
Want to post a response?
Back to the Forum