Is there a way to estimate the number of technologically advanced civilizations that might exist in our Galaxy? While working at the National Radio Astronomy Observatory in Green Bank, West Virginia, Dr. Frank Drake conceived a means to mathematically estimate the number of worlds that might harbor beings with technology sufficient to communicate across the vast gulfs of interstellar space. The Drake Equation, as it came to be known, was formulated in 1961 and is generally accepted by the scientific community.

N = R* fp ne fl fi fc L
where,

N = The number of communicative civilizations
R* = The rate of formation of suitable stars (stars such as our Sun)
fp = The fraction of those stars with planets. (Current evidence indicates that planetary systems may be common for stars like the Sun.)
ne = The number of Earth-like worlds per planetary system
fl = The fraction of those Earth-like planets where life actually develops
fi = The fraction of life sites where intelligence develops
fc = The fraction of communicative planets (those on which electromagnetic communications technology develops)
L = The "lifetime" of communicating civilizations

Frank Drake's own current solution to the Drake Equation estimates 10,000 communicative civilizations in the Milky Way. Dr. Drake, who serves on the SETI League's advisory board, has personally endorsed SETI's planned all-sky survey.

http://www.setileague.org/general/drake.htm

I don't find Drake equation having a factor on possibility of planets having a magnetic field as we have on earth. If our sun has frequent flares and the same can kill living life on nearby planets, we should be having an idea as to how many planets could be having a field to protect the charged particles from hitting us.

we don't know if that's an evolutionary trait or not...we didn't need to evolve in any way to protect us from that because we had the protection... since we don't know about life on other planets, we can't say it's a cause for life not to form...

Agreed...but we are here trying to refine this equation. There could be some forms of life still surviving under the influence of solar flares and some forms dying out because of it. Mathematically, we get a more accurate picture by factoring in the magnetic field.

one thing that your forgetting, they are looking for any planets, not just those that are in the goldilocks zone.. they determine those factors after they know there is a planet around the star...

I'm not sure to who you are referring but the Drake equation is all about statistics. The number by percentage of planetary systems that have been recently found is the basis of how many planets they suspect exist. One fact that has been learned is that most stars have planets. They weren't sure of that before. They now understand that making planets is just part of the typical formation of a star system.

They have also learned that the regular patter of the planets in our system are not a rule or maybe not even that common. The planets in a star system can evolve into any pattern that the random orbital interactions dictate. This fact brings up an odd correlation. A large gas planet in the Goldilocks zone cannot support life but the moons around it could!

The magnetic field is already factored in. The "L" variable is the portion of a suitable planet's time in existence where it can support life and the life becomes intelligent. There are many stars near the Galactic core where the ambient radiation is simply too high to support life as we know it due to the proximity of nearby high radiation stars regardless of whether the planet has a magnetic field or not. Conversely, a newer category of stars (not new in general but new as expected to be able to support life) is expected to boost the Drake equation's net result astronomically, (pun intended) by recognizing red dwarfs as good possible sources.

The Goldilocks zone is already taken into account by the calculated solar output of various size and type stars. Red Dwarfs have a much longer lifespan with a much more stable output that other types of stars but it forces the life to be more dependent upon infrared radiation than the broad spectrum output of most stars. The bright side (pun intended) of this issue is that life is extremely tolerant of infrared radiation anyway and the lack of strong solar wind could negate the need for much or any magnetic field to protect life.

Planets have a more or less predictable pattern of formation. The physics of orbital momentum cause the planets to orbit the star in the same direction. The parts, which end up forming the planets, cause the planets to spin in the same direction. The formation of the rocky planets cause the whole planet to melt and spin in the same direction and only a hard hit with another planet or similar event can change that pattern.

The planet Uranus is an example of this break in pattern. It was probably hit by another planet large enough to destabilize the spin and tilt it on it's axis.

Odd exceptions aside, as the outer skin of the planets cool and the heavier metals like iron sink to the core, the difference in the angular momentum (just like an ice skater going into a spin) between the inner core and outer mantel cause a speed deferential. The spinning iron core then acts like a huge dynamo which creates the magnetic field until the core cools enough to stop spinning independently. Then, just like Mars, the field stops and the solar wind blows the atmosphere away and the water with it. Life must do it's thing in that window of time.

Red Dwarf stars give a greater window of time.

From Wiki: (but I already knew this)

"In addition, the sheer number of red dwarfs, which account for about 85% of at least 100 billion stars in the Milky Way, increases the number of habitable planets that may be orbiting them; as of 2013, there are expected to be roughly 60 billion habitable red dwarf planets in the Milky Way."

to me, "cannot support life 'as we know it'" is a more truer statement... we cannot know of things we haven't discovered yet...

hasn't Star Trek taught us anything? lol

That reminds me of the silicon creature who dug tunnels in the mining planet. Bones healed it from a Phaser shot with some bag concrete.

Water is the basis of "life as we know it" but credibility is being given to non-water based lift too. The conditions on the moon Titan is the best example of the possibility of life so far in extreme conditions.

From Wiki"

"Whether there is life on Titan, the largest moon of Saturn, is at present an open question and a topic of scientific assessment and research. Titan is far colder than Earth, and its surface lacks stable liquid water; factors which have led some scientists to consider life there unlikely. On the other hand, its thick atmosphere is chemically active and rich in carbon compounds. On the surface there are bodies of liquid methane and ethane; some scientists speculate that these liquids might take the place of water in living cells different from those on Earth.

In June 2010, scientists analysing data from the Cassini–Huygens mission reported anomalies in the atmosphere near the surface which could be consistent with the presence of methane-producing organisms, but may alternatively be due to non-living chemical or meteorological processes.[1] The Cassini–Huygens mission was not equipped to look directly for micro-organisms or to provide a thorough inventory of complex organic compounds.

A hypothetical cell membrane capable of functioning in liquid methane has been modeled."

also, any volcanic vents underwater might harbor life, like they do here on earth... entire ecosystems are formed and destroyed without any help from the sun...