Do you know how to measure the distance in space ?

laser retroreflector

The physics behind this is very interesting, In a scratch three perpendicular mirrors are set up together in such a way that every falling beam of light on it will be reflected back to its original source. No matter what incidence angle it falling from. there is a catch!

parallel ray

This special type of structural arrangement of glass is called "retro-reflective glass" and a series of this type of glasses is called Retroreflector.

 How to measure distance?

In a nutshell, Retroreflector has fitted with Spacecraft, a beam of light is sent from the earth, as its property the particular light beam is reflected back to the earth after some while. The time taken to get back the light is measured. This measured time is lead to find the distance between them by the help of some basic equations.

                         velocity of light x  total time taken = 2* distance

Use of retro-reflective glass in daily life 

Not only in space also we use in daily life e.g in the signboard, caution board, traffic police dresses, backlight of cycles etc. Its help to prevent an accident by attracting the attention of the rider while they drive on the road even at dark night. Signboards are illuminated by the source of the light and reflect back to the source itself.

         look at the different of illumination due to retro-reflective glass.