«We just have this great big unknown out there about where all the money is coming from,» he says. (motherjones.com)
One of the last big unknowns in the global climate equation is Antarctica. (source.wustl.edu)
The Census of Marine Life's decadelong quest to take stock of sea life comes to a close with a slew of new species, population estimates and plenty of big unknowns (scientificamerican.com)