I was taught that there are three kinds of matter: solids, liquids and gases. But aren’t there others?
David D. Slocum, Kahului, Maui, Hawaii
Yes, there are others—the universe has been found to be more complex since many of us were in high school. The general consensus, says Katya Vines, senior science curriculum developer at the Smithsonian Science Education Center, is that there is a fourth fundamental state of matter that appears naturally: plasma. Though the other three forms are more common on earth, plasma is the most common state of matter in the universe—it’s what stars are made of. Like gases, plasmas have no fixed shape or volume; but unlike gases, which are electrically neutral, plasmas are positively charged. That charge allows plasmas to behave in ways gases can’t. The glow of a neon sign? That’s plasma at work, as is the image on your plasma TV screen.
Do other animal species have baby teeth and adult teeth, like humans?
Peter Norris, Summer Hill, New South Wales, Australia
For sure. As with humans, you can tell an ape’s age by looking at its teeth, says Erin Stromberg, primate keeper at the Smithsonian National Zoo. In fact, most mammals have two sets of teeth in their lifetime. They’re born toothless because their initial food source is their mother’s milk, and they develop baby—or deciduous—teeth as they wean, then permanent teeth as they mature. Like apes, humans have 32 permanent teeth (counting wisdom teeth). Cats have 30, dogs 42.
Who brought yoga to the United States?
Terry Carter, Silver Spring, Maryland
Transcendentalists like Ralph Waldo Emerson and Henry David Thoreau were influenced by Indian spiritual thought in 19th-century America, says Mark Singleton, consultant and catalog author for the Smithsonian Sackler Gallery’s exhibition “Yoga: The Art of Transformation.” But it was the Kolkata-born Hindu monk Swami Vivekananda who first presented practical yoga to American audiences, lecturing, holding retreats and publishing books in the 1890s. He and later Indian teachers made yoga part of American culture by the mid-20th century.
Why is the chief justice of the United States also the chancellor of the Smithsonian Institution?
Tim O’Hare, Peterborough, New Hampshire
It’s a legal matter, of course. In 1846, 11 years after the United States was notified that it was due to receive a gift of half a million dollars from the estate of the Englishman James Smithson for the “increase and diffusion of knowledge,” Congress passed the law establishing the institution. By charter, says Pamela Henson, historian at the Smithsonian Institution Archives, the Smithsonian’s 17-member board of regents includes representatives of all three branches of government—the chief justice, the vice president and six members of Congress—as well as nine other citizens. Traditionally, the regents have elected the chief justice as chancellor. Chief Justice John G. Roberts Jr. has held the position since 2005.