Yes. Quoting from Wikipedia: "The Drake equation has proved controversial since several of its factors are currently unknown, and estimates of their values span a very wide range."
The last four parameters of the Drake equation (fl, fi, fc, and L) are not known.
The Drake Equation is an interesting bit of wondrous speculation, that seeks to incorporate several reasonable statistical assumptions, that are based loosely on astronomical observations, into a single mathematical operation. The output of the operation is . . . The number of planets in our galaxy that are presently inhabited by technologically accomplished, intelligent civilizations.
Estimates vary from 10 tons to 30 tons.
Estimates vary. Experts say there are as few as 80,000 koalas left in the wild, while the Australian Koala Foundation estimates figures are possibly as low as 43,000, and certainly not more than 80,000.
There is no way of knowing that. Although the Drake Equation attempts an estimate, it is based almost entirely on speculation.
Drake Equation - album - was created on 2001-06-12.
The last four parameters of the Drake equation (fl, fi, fc, and L) are not known.
Estimates vary from about 9,000 to about 14,000.
0
Estimates vary around 4 million.
705, though estimates vary by a few.
Estimates vary from 1% to 8%.
Estimates vary from 1,063,000 to 2 million.
Estimates vary from 3,500-7,000 degrees Celsius.
705 (though estimates vary by a few)
Estimates vary. Far too many, for certain.
The Drake Equation is an interesting bit of wondrous speculation, that seeks to incorporate several reasonable statistical assumptions, that are based loosely on astronomical observations, into a single mathematical operation. The output of the operation is . . . The number of planets in our galaxy that are presently inhabited by technologically accomplished, intelligent civilizations.