The colour of the sea changes as the light advances up the sky.

BBC: Sardinia, land and sea

Last month the Commons Education Select Committee issued a damning report into the plans, which it described as a "red light" warning over the changes.

BBC: Q&A: Changes to the teaching of key subjects

As the train chugs into a station along the way, more dramatic changes come to light.

CNN: Center Cut

The JWST will have equipment on it capable of determining the chemistry of the atmospheres of alien worlds based on the how the light of its star changes as it passes through.

FORBES: White Dwarfs May Hold The Key To Finding Alien Life

Moreover, when -- as at present -- American policies are being reconsidered in light of assessed changes in the threat, the potential is high for the objectivity of the analysis to be compromised in order to justify certain policy approaches.

CENTERFORSECURITYPOLICY: US-Soviet Relations

Changes in the way the light moves comes from the way gravity bends the light as it travels from the quasar towards Earth.

FORBES: Hubble Telescope Observes Matter Falling Into Black Hole

This could be interpreted as a subtler version of the Hawthorne effect, if you believe that workers were aware that changes in artificial light were induced by the experimenters, whereas natural light was changing on its own.

ECONOMIST: Being watched may not affect behaviour, after all

One stop of light is usually defined as halving or doubling the amount of light entering the camera, depending on the shutter speed, aperture, or ISO changes made.

ENGADGET: Primed: What is aperture, and how does it affect my photos?