The phrase denotes an bold, seemingly not possible endeavor. It characterizes actions which might be audacious, bordering on the fantastical, and sometimes exceeding standard limitations. As an idiom, it paints an image of somebody trying to realize one thing perceived as completely unattainable.
The implied significance of enterprise such an bold job resides within the potential for transformative impression, even when the literal objective stays out of attain. The hassle and innovation required to even try the not possible can result in sudden breakthroughs and developments. Traditionally, many scientific and technological leaps began as ideas deemed unrealistic, highlighting the worth of pursuing daring visions.