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The havoc wrought by a tornado in instants often requires days to assess. It’s necessary to examine damage across wide regions where roads, bridges and infrastructure are often wiped out. Eventually disaster and relief officials use aerial photos. Tom Lillesand: All that takes a lot of effort and a lot of time. . . Tom …
How satellites can help assess the damage from tornadoes Continue »
A chunk of methane hydrate looks like a piece of ice. But it’s really highly concentrated molecules of methane — the chief constituent of natural gas — trapped in a cage-like lattice of ice. As it melts, huge amounts of methane bubble out. These hydrates have been an isolated curiosity in the lab for a century. …
All matter is made of atoms, and atoms are made in part of electrically charged particles called protons and electrons. In normal matter, electrons always have a negative electrical charge, and protons always have a positive charge. But physicists have found that, for every type of particle, there’s an antiparticle — with the opposite electric …
“How little mass could an object in space have and still hold an astronaut in orbit around itself?” We put your question to scientists who plan space missions to the asteroids, our solar system’s least massive worlds. They said that any two bodies in isolation can orbit each other because bodies with mass attract each …
The element helium makes up one quarter of the mass of the visible universe . . . . . . but only about one millionth of one percent of Earth’s atmosphere and crust. That’s because helium is so light that — once released into the atmosphere — it escapes into outer space. Also, helium’s an …
On the use of satellites orbiting Earth in helping to stop the spread of disease. For example, malaria is carried by a certain kind of mosquito. Nearly two million people, mostly children, die of this disease every year. And about 90% of cases and deaths occur in sub-Saharan Africa. Epidemiologists are now using satellite data …
Most modern refrigerators use chemicals called Hydro-Chloroflurocarbons — or HCFCs. If these chemicals leak into the air, they act as greenhouse gases. They’re thousands of times better at holding in heat than carbon dioxide. That’s why scientists at Penn State University are developing more environmentally friendly refrigerators. Instead of using HCFC’s, the new fridges use …
Sound gets started when a vibrating source — imagine a guitar string — pushes air particles out of the way. Those air particles bump neighboring particles. The particles move back and forth as the sound source vibrates. The faster the movement of the air particles, the higher-pitched the sound. Helium gas is lighter than the …
In Ocboer of 2002, the Cassini spacecraft took its first picture of the planet Saturn. The picture shows Saturn’s trademark — its glorious rings. Philip Nicholson: A lot of us … who work on the rings became fascinated by them partly because they’re just so beautiful and so elegant. And that hasn’t gone away. That’s Phillip …
