An increasing part of the world is becoming artificially lit. Artificial light is often seen as a sign of progress: the march of civilization shines a light in the dark; it takes back the night. But some scientists argue that unnaturally bright nights are bad not just for astronomers but also for nocturnal (夜间的) animals and even for human health.

Now research shows the night is getting even brighter. From 2012 to 2016 the earth’s artificially lit area expanded by about 2.2 percent a year, according to a study published last November in Science Advances. However, the measurement does not include light from most of the energy–efficient LED lamps that have been replacing sodium-vapor (钠气灯) technology in cities all over the world ,says Christopher Kyba, a postdoctoral researcher at the German Research Center for Geosciences in Potsdam.

The new data came from a NASA satellite instrument called the Visible Infrared Imaging Radiometer Suite (VIRS). It can measure long wavelengths of light, such as those produced by traditional yellow-and-orange sodium-vapor street lamps. But VIIRS cannot see the short-wavelength blue light produced by white LEDs. This light has been shown to disturb human sleep cycles and nocturnal animals’ behavior.

The team believes the ongoing switch to LEDs caused already bright countries such as Italy, the Netherlands, Spain and the U.S. to register as having stable levels of lighting in the VIIRS data. In contrast, most nations in South America, Africa and Asia brightened, suggesting increases in the use of traditional lighting.

In 2016, a study showed that one third of the world’s population currently lives under skies too bright to see the Milky Way at night. Between 2012 and 2016 the median nation pumped out 15 percent more long-wavelength light as its GDP increased by 13 percent. Overall, counties' total light production correlated with their GDP.

【小题1】Which of the following can best describe artificial light?

A．Convenient but unnatural.	B．Useful but energy-consuming.
C．Progressive but uncomfortable.	D．Civilized but harmful.

【小题2】What can we know about the already bright countries?

A．Traditional lighting is not used in those countries.

B．LED lights are increasingly used in those countries.

C．Efforts to reduce harmful light work in those countries.

D．People do enjoy stable lighting in those countries.

【小题3】Why does the author mention “the median nation” in the last paragraph?

A．To show artificial light has an association with GDP.

B．To demonstrate GDP plays an important part in the median nation.

C．To stress the median nation was to blame for the light problem.

D．To suggest artificial light should be banned in the future.

【小题4】Where is the passage most probably taken from?

A．A biology textbook.	B．A book review.
C．A science magazine.	D．A science fiction.