Name: _______________________________
Date: ________________________________
Subject: Science
Homeroom: ___________________________
HW #84
Directions: Read the article. Then summarize what you read!
Who: _____________________________________________________________________________________
What:_____________________________________________________________________________________
When: ____________________________________________________________________________________
Where:____________________________________________________________________________________
Why: _____________________________________________________________________________________
How: _____________________________________________________________________________________
Summary: ________________________________________________________________________________________
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Jefferson Academy Summary Checklist
Was I succinct? (brief)
□ I only included major details
Was I focused? (on topic)
□ Did I address the topic only?
□ Did I include only relevant details?
□ Did I include only the 5 W’s + H when applicable
Was I accurate? (correct)
□ Did I use textual evidence?
□ Did I demonstrate my understanding of the text?
Picture This: Christmas
from space
Satellites survey human behavior by snapping pictures of holiday lights
BY ESTHER LANDHUIS
10:00AM, DECEMBER 25, 2014
Cities shine even brighter during the holidays. Here, green highlights where nighttime lights in December are at least 50
percent brighter than the rest of the year.
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NASA EARTH OBSERVATORY/JESSE ALLEN
SAN FRANCISCO — Evening trips to the mall. Christmas parties. Rooftop lights. The December
holidays are bright — dazzling enough to be seen by satellites orbiting high above Earth.
Researchers recently used satellite data to track when, where and how often we turn on lights. The
findings, they say, point to how human activities drive electricity use.
Scientists sent radiometers into space and pointed them toward Earth. These instruments measure
the intensity of light. In 2012, the research team released a set of “Earth at Night” maps. They had
used data collected on nights with ideal conditions — evenings that were both moonless and cloudfree.
Miguel Román is a physical scientist at NASA Goddard Space Flight Center in Greenbelt, Md. He and
his team wanted to analyze how light patterns change from day to day. To do that, his team improved
its scans so that the scientists could collect data even on nights with clouds and a bright moon.
(Unfortunately, the system can’t cope with snow. Light reflecting off the white stuff “contaminates the
signal,” Román says.)
From 2012 to 2014, the satellite snapped daily pictures of 70 U.S. cities. The scientists used those
images to measure how much the cities brightened between Thanksgiving and New Year’s Day. They
compared the cities’ holiday glow to their light output the rest of the year.
It was “a huge effort,” says Román. “It took three years’ worth of data.” But with the team’s revamped
system, “we can do comparisons across cities, even across neighborhoods within cities,” Román
says. He described his group’s new findings December 16 at the fall meeting of the American
Geophysical Union.
Many cities radiated 20 to 50 percent more light during holiday nights, the researchers found. The
light intensity climbed a bit more in the suburbs than in busy city centers. But overall, it seems that
everyone in the United States — regardless of income or ethnic background — celebrates the
holidays, Román says.
Explainer: Global warming and the greenhouse
effect
A different picture emerged when his team analyzed another part of the world: the Middle East. There, the
major holiday is Ramadan. It’s the ninth month of the Islamic calendar. On those 30 days, Muslims fast from
dawn to dusk.
Besides postponing meals, people also shop and go to work later in the day. These behavioral
changes showed up on the satellite maps as “a shift in the timing of activity, not just an increase in
light sources,” Eleanor Stokes reported at the meeting. Stokes is working on her Ph.D. in forestry and
environmental studies at Yale University in New Haven, Conn. She co-led the new light-at-night
project with Román.
In their Middle East analysis, nighttime lighting seemed to track social and cultural factors. Richer
cities, for instance, glowed more intensely than did poorer ones during Ramadan. Warfare left its
mark as well. The satellite maps essentially went dark when conflicts destroyed a region’s electricpower-delivery system.
“What we found here is…human activity is driven not just by energy and electricity prices but also by
social and cultural context,” Stokes says. Such factors include both wars and holiday celebrations.
Information like that is important because the planet is getting hotter. Greenhouse gases, such as
carbon dioxide, are trapping heat in Earth’s atmosphere. Human activities must take much of the
blame. And cities produce more than two-thirds of these greenhouse gases. If humanity is to cope
with this extra heat, Stokes says, people need to understand energy-use patterns and the human
behaviors that shape them.
Power Words
atmosphere The envelope of gases surrounding Earth or another planet.
carbon dioxide A colorless, odorless gas produced by all animals when the oxygen they inhale
reacts with the carbon-rich foods that they’ve eaten. Carbon dioxide also is released when organic
matter (including fossil fuels like oil or gas) is burned. Carbon dioxide acts as a greenhouse gas,
trapping heat in Earth’s atmosphere. Plants convert carbon dioxide into oxygen during
photosynthesis, the process they use to make their own food.
global warming The gradual increase in the overall temperature of Earth’s atmosphere due to the
greenhouse effect. This effect is caused by increased levels of carbon dioxide, chlorofluorocarbons
and other gases in the air, many of them released by human activity.
geophysics
The study of matter and energy on Earth and how they interact.
greenhouse gas A gas that contributes to the greenhouse effect by absorbing heat. Carbon dioxide
is one example of a greenhouse gas.
radiation Energy, emitted by a source, that travels through space in waves or as moving subatomic
particles. Examples include visible light, infrared energy and microwaves.
radiometer A scientific instrument that measures the intensity of light.
Further Reading
A. Pearce Stevens. “How people have been shaping the Earth.” Science News for Students. October 17, 2014.
S. Ornes. “The certainty of climate change.” Science News for Students. October 16, 2013.
S. Ornes. “Climate change: The long reach.” Science News for Students. August 22, 2013.
A.L. Haag. “Light night, dark stars.” Science News for Students. December 5, 2007.
Original Meeting Source: M. Románet al. The Urban Social and Energy Use Data Embedded in Suomi-NPP VIIRS
Nighttime Lights: Algorithm Overview and Status. American Geophysical Union annual fall meeting, San Francisco, Dec.
16, 2014.