Wealth and enlightenment in the Ancient World
9 hours ago in Epiphenom
What does the sunset look like on HD 189733 b? Amazingly, we know quite accurately. This is because the colour of the sunset is exactly what is measured when collecting the transmission spectrum of the atmosphere of a transiting planet. We have measured the transmission spectrum of ’189 with the STIS spectrograph on the Hubble Space Telescope. STIS covers visible wavelengths, and HD 189733 is bright enough that the precision of the spectrum is sufficient for a precise translation into colours perceived by the human eye.
I’ve been saying for a few years that optical science has entered a truly remarkable new era: instead of asking the question, “What are the physical limitations on what light can do?”, we are now asking, “How can we make light do whatever we want it to do?” Among other things, we can make light travel “faster than light“, we can focus light through a highly scattering material, we can take high-resolution pictures with low-resolution sensors, and even make particles “fly” on a “wind” of light!Read on.
Inevitably, though, many of these discoveries get misinterpreted in popular news accounts to the point that their real significance is lost in a haze of science fictional, or even supernatural, hype. A good example of this is the “picosecond camera” that I described last week, which is an amazing achievement but also possesses a number of technical limitations that make it not quite a “camera” in the ordinary sense of the word.
This week, the experimental realization of a “space-time cloak” or “temporal cloak” by researchers at Cornell University has made national news.