Relativity says that spacetime is smooth, and only big things can warp it, in ways that are exactly known. Quantum theory says that the smallest parts of the universe are constantly fluctuating and dramatically uncertain. How can something be both smooth and fluctuating, both exact and uncertain?

How, in other words, can we make a quantum theory of gravity? It's unknown. String theory and loop quantum gravity have tried, but a unified theory has remained out of reach.

Enter – of all things – condensed matter physics.

SensaBubble is a chrono-sensory mid-air display system that generates scented bubbles to deliver information to people using different senses. The bubble-based technology creates bubbles with a specified size and frequency, fills them with an opaque fog that is optionally scented, controls their route, tracks their location and projects an image onto them.

Man or woman? Male or female?

Modern sociological woo about gender aside, in humans and other mammals, the difference between the sexes depends on one single element of the genome: the Y chromosome. It is present only in males, where the two sexual chromosomes are X and Y, whereas women have two X chromosomes. Thus, the Y is ultimately responsible for all the morphological and physiological differences between males and females.

Shark data collected by citizen scientists may be as reliable as data collected using automated tools, according to results published April 23, 2014, in the open access journal PLOS ONE by Gabriel Vianna from The University of Western Australia and colleagues.

While creating new springs to support a cephalopod-inspired imaging project, a group of Harvard researchers stumbled upon a surprising discovery: the hemihelix, a shape rarely seen in nature.

Big brains do not explain why only humans use sophisticated language, according to researchers who have discovered that even a species of pond life communicates by similar methods.

Dr Thom Scott-Phillips of Durham University led research into Pseudomonas aeruginosa, a type of bacteria common in water and soil, which showed that they communicated in a way that was previously thought to be unique to humans and perhaps some other primates.