A Moonbow / Lunar rainbow /White rainbow is a
rainbow produced by light reflected off the surface of the moon (as
opposed to direct sunlight) refracting off of moisture-laden clouds in
the atmosphere / from waterfalls.
Just as no two people see exactly the same rainbow, even if they’re
standing next to each other, the few inches between your eyes make a
difference in what you are viewing.
There is no color- indigo ( sort of )
One can distinguish almost all colors in a rainbow but Indigo.
Legend has it that Newton
included indigo because he felt that there should be seven rather than six colors in a rainbow due to his strong religious beliefs.
Origins of ‘Iris’
The Greeks and Romans thought a rainbow was the path made
by Iris, the goddess of the rainbow, between heaven and earth, linking
gods with humans. “Rainbow” in Latin is arcus iris or arcus pluvius, a “rainy arch”.
The iris of the eye is named after her, because of its
Greeks used the word “iris” to describe any coloured circle, such as
the “eye” of a peacock’s tail. The flower called iris gets its name from
the Greek, as does the chemical iridium (Ir), compounds of which are
highly coloured. Iris is also the root of “iridescent”.
Place a linear polarizer over the camera whilst capturing a rainbow and you get pulsating rainbows.
I recorded a new pattern on my smart phone a couple of days ago, known as the Knight’s tour and wish to share my ecstasies of this pattern in this post.
A knight’s tour is a sequence of moves of a knight on a chessboard
such that the knight visits every square only once.
If the knight ends
on a square that is one knight’s move from the beginning square (so that
it could tour the board again immediately, following the same path),
the tour is closed, otherwise it is open.
Here is the knights tour on a 5×5 board:
And on a 8×8 board:
Stop right there!
We always look for inspirations to start anything:
If you have noticed, my pattern is not exactly a true knights tour because I was not smart enough to come up with one. Can you ?
Also I couldn’t get it to work with 4×4 too. Maybe you can help me out.
Like most things in mathematics and sciences, you need to experience it for yourself to truly appreciate the profundity of the Knight’s tour.
You can start with 3×3 and move on to higher orders.
It often comes as a surprise to people when i tell them that the space station can be seen with the naked eye! Flying at 400 km above your head, the ISS looks like a really fast moving airplane in the sky.
The ISS isn’t brighter than the day sky and hence cannot be seen during the day. But in the night, it’s the third brightest object in the sky! It reflects the sunlight off the solar panels on its surface.
Spot the station!
If you would like to see the ISS for yourself, NASA ‘s Spot the station! is at your disposal. Register with your email address/mobile number and every time the ISS passes by your town/city, you will get a notification with the time, duration and inclination.
(Extras: There are mobile phone apps which you could use too, like the ISS detector satellite detector for android. At the end of the day all that matters is what is convenient to you.