• Question: Can you get a darker colour than black?

    Asked by Meg to Chris, Josh, Rebecca, Rob, Susan on 23 Jun 2015.
    • Photo: Rebecca Dewey

      Rebecca Dewey answered on 23 Jun 2015:

      Well to be really picky – black isn’t a colour. Black is what your eye “sees” when there is no colour there. If something has absolutely no ability to reflect any light at all – of any wavelength, and every single particle of light (photon) that hits it is absorbed, then it is truly black, and no, there is nothing darker than that.

      Mwahahahaha!

    • Photo: Susan Cartwright

      Susan Cartwright answered on 23 Jun 2015:

      Black is the absence of light: it’s what you see when all the light falling on an object is absorbed. Therefore, you can’t get anything darker than true black.

      Oddly, a truly black object can be the brightest thing as well as the darkest thing possible. When you heat an object up, it eventually starts to emit light (that’s how old-fashioned lightbulbs with wire filaments work). An object which is truly black when cold, i.e. a perfect absorber of all radiation, is also a perfectly efficient emitter when hot. (This can be proved using the laws of thermodynamics.)

      So a hypothetical object which was perfectly black, darker than anything else, when cold would actually be brighter than anything else at the same temperature when heated to say 10000 C!

Comments