Will We Be Able to Prevent an Asteroid Strike and More Questions From Our Readers

Will we ever really be able to deflect a comet or asteroid that has targeted us for extinction?
Bruce McPhee
West Yarmouth, Massachusetts

We can deflect such objects big enough to cause regional damage; the key element is how long a warning we have. Even with only a decade or so, we might deflect an asteroid of perhaps 100 meters in diameter, using spacecraft or nuclear weapons. With sufficient warning—say 50 years—we could deflect an object several hundred meters in diameter. Extinction-scale threats have been ruled out for the next few hundred years, so you can relax.
Tim Spahr
Director, Minor Planet Center, Harvard-Smithsonian Center for Astrophysics

Why are penguins not found in the Arctic and polar bears not in the Antarctic? Why can’t either be relocated to the other habitat?
Lynne William
Douglasville, Georgia

Polar bears evolved in the Northern Hemisphere, penguins in the Southern Hemisphere. Many polar species have never dispersed naturally from one pole to the other because they can’t traverse the warm habitats in between. Transplanting these species might disrupt their respective ecosystems and could lead to extinctions.
Kristofer Helgen
Zoologist, National Museum of Natural History

Does lightning strike ships at sea? I’ve been on a ship amid a spectacular electrical storm, with many strikes all around us, but the ship remained unstruck.
Raleigh Bryan Miller Jr.
McMinnville, Tennessee

Ships do get struck by lightning, but passengers may not even notice, because ships usually have grounding equipment, and steel hulls readily dissipate the electrical charge. Of course, smaller vessels made of nonmetallic materials are far more prone to damage.
Hugh Reichardt
Station Manager, Smithsonian Marine Station, Fort Pierce, Florida

Why does American English differ from British English and Australian English?
Matt LaRock
Lakewood, Colorado

Language is learned individually and subject to subtle changes that each speaker introduces. These changes accumulate as people tend to accommodate to the usage of others in the community. Over time, the speech of communities that have little contact drifts apart. Accents are the natural result of the creative dynamic of human language that makes it such a powerful tool for expression and communication.
Ives Goddard
Senior Linguist Emeritus, National Museum of Natural History

I’ve seen inanimate objects—bits of string, metal, plastic—in the mounds made by night crawlers. Why do they collect these things?
Janice Sikes
Springfield, Oregon

Night crawlers’ mounds, or middens, store food and protect their burrow openings. The worms build them by dragging plant material and adding it to their casts (waste). But since they can’t see, and can’t tell the difference between natural and synthetic materials, they sometimes drag in odd bits.
Chih-Han Chang
Smithsonian Fellow, Museum Support Center

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