Speed of light can be calculated, "often with less than 5% error". Interferometry is another method to find the wavelength of electromagnetic radiation for determining the speed of light. A coherent beam of light (e.g. from a laser), with a known frequency ("f"), is split to follow two paths and then recombined. By adjusting the path length while observing the interference pattern and carefully measuring the change in path length, the wavelength of the light ("λ") can be determined. The speed of light is then calculated using the equation "c" = "λf". Before the advent of laser technology, coherent radio sources were used
In the Light of What We Know when the true pleasure of a work of fiction is its gravitational pull upon us?” In a 4,000-word review for "The New Yorker", the critic James Wood described Rahman as “a deep and subtle storyteller,” and praised the novel as “astonishingly achieved…Isn’t this kind of thinking—worldly and personal, abstract and concrete, essayistic and dramatic—exactly what the novel is for? How it justifies itself as a form?…"In the Light of What We Know" is what Salman Rushdie once called an ‘everything novel.’ It is wide-armed, hospitable, disputatious, worldly, cerebral. Ideas and provocations abound on every page.” Australian literary critic Louise Adler