Sometimes when you look into a swimming pool it’s difficult to tell how deep the water actually is. If you grab something long, like a stick, you can use it to test the depth of the water. Upon ...

Well, OK, not exactly. A beam of light could pass through air all day long (as long as you have a layer of air 26 billion kilometers long) and not deviate a whit. But if the density of that air ...

It’s all to do with the raindrops, says one reader, with them needing to be relatively uniform in size and well separated for ...

For the first time, scientists have demonstrated that negative refraction can be achieved using atomic arrays - without the need for artificially manufactured metamaterials. Scientists have long ...