Add your Article
- Agriculture
- Getting the dirt on carbon
- Where Have All the Bees Gone?
- Treating peanut allergy bit by bit
- E Learning Jamaica
- E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
- Results of GSAT are in schools this week
- 2014 GSAT Results for Jamaican Kids
- Earth
- On the Trail of America's Next Top Scientists
- Rodent Rubbish as an Ice-Age Thermometer
- Riding to Earth's Core
- GSAT Exam Preparation Jamaica
- Ministry of Education Announces 82 GSAT Scholarships for 2010
- GSAT stars reap scholarship glory
- 42,000 students will sit for the GSAT Exam in two weeks
- GSAT Exams Jamaica Scholarships
- GSAT Scholarship
- 2014 GSAT Results for Jamaican Kids
- GSAT Exam Preparation
- GSAT Mathematics
- 10 Common Mistakes When Preparing for the GSAT Math Test
- Math of the World
- How to Slice a Cake Fairly
- Parents
- What Not to Say to Emerging Readers
- Raise a Lifelong Reader by Reading Aloud
- How children learn
Space Umbrellas to Shield Earth
Published: 07/05/2010
On a hot, clear day, an umbrella can provide cooling relief from the sun's scorching rays. The same concept might one day help protect Earth from the accumulating heat of global warming. Building a single umbrella big enough to shade the entire planet will never be possible. Instead, astronomer Roger Angel of the University of Arizona wants to launch a trillion tiny sunshields into outer space. Each mini-umbrella would be a small, light spacecraft, weighing about a gram (0.04 ounces) and carrying a sunshade measuring half a meter (1.6 feet) across. Working together, hordes of the devices could act as a sunscreen for the globe. Such a sunscreen would stretch across about 100,000 kilometers (62,000 miles) of space. And the pressure of sunlight on attached solar reflectors would keep the little flyers in orbit around Earth at a distance of about 1.5 million kilometers (932,000 miles). The sunshade would be mostly transparent, or see-through, but it would cut the amount of sunlight reaching Earth by 1.8 percent. This would be enough to reduce the impact of global warming, Angel says. In Angel's scheme, people on Earth could make the lightweight sunscreens out of transparent film. Each shade would be full of holes like Swiss cheese. Angel says his plan is a big improvement over previous ideas for shading Earth from the sun. Those scenarios have typically involved large, heavy spacecraft that would need to be built in outer space out of pieces of asteroids or other space rocks. To reduce the environmental impact of launch, Angel says, astronomers could use magnetic fields instead of rocket fuel for acceleration. He envisions launching 800,000 flyers at a time for a total of 20 million launches over a decade. Angel thinks that the first launch could happen in just 25 years. And, once the flyers are up there, he says, they would shade the planet for 50 years. The idea is certainly creative, but critics say there are easier and much cheaper ways to tackle global warming. Covering large areas of ground with white paint, for example, could reflect light back into space and reduce heating. Better yet, by reducing the pollution we create, we can all help keep the planet from heating up.—E. Sohn
Space Umbrellas to Shield Earth
