March 15, 2012
Readers questions continue this month with some really intriguing queries. Can you identify a bird just by its feather? The aptly named Carla Dove, a Smithsonian ornithologist weighs in on that one in the video above. And speaking of our fine feathered friends, another reader wonders why it is that birds all seem to want to hang out near electrical transformers? From dinosaurs to telescopes to gemstones, you asked and we found the answers.
Are there any paleontological discoveries, such as dinosaur bones, left to be made in the United States?
Susanne Ott, Bern, Switzerland
There sure are. This is such a large country, and there are so many areas yet to be searched, that we may not run out of finds for several lifetimes. Just think: We have found only about 2,000 species of dinosaurs for the 160 million years they were alive on Earth. Given that a species lasts only a few million years, we must be missing many thousands of dinosaur species. The most promising places are out West, where it’s drier and paleontologists can get access to fossil-bearing rocks.
Matthew Carrano, Paleontologist
Museum of Natural History
How much artistic license do scientists use when they portray astronomical features detected by radio telescopes?
Jeanne Long, Atlanta, Georgia
A lot, actually. Radio-telescope images differ from the images captured by the Hubble Space Telescope—while Hubble images are recorded in the visible wavelengths of light we see in rainbows, radio telescopes record electromagnetic radio waves sent out by distant galactic objects. They detect what our ears might pick up if we could hear the universe. (Luckily, we can’t, or the world would be a jumbled mess of rumbling sounds.) Based on the intensity of the radio waves, astronomers plot signal strengths and assign different colors to them.
Although it would be handy and logical, there is no set convention to those color assignments. Scientists choose different colors to bring out specific details or molecules found in the image. (If you do a quick Google image search for the Trifid Nebula, you’ll see images with different color representations of the same object.) Is it fair to randomly assign different colors to objects in space? To astronomers, that’s not an issue. They are simply trying to isolate data. And the truth is, the human eye is not sensitive enough to pick up the true colors of these objects anyway. So, the next time you see a breathtaking picture from space, thank a scientist for putting it all together.
David Aguilar, Astronomer and illustrator
Smithsonian Astrophysical Observatory
Is it true that the Smithsonian is still cataloguing items from Charles Wilkes’ United States Exploring Expedition?
Kevin Ramsey, Washington, D.C.
That expedition returned from its four-year exploration of the Pacific in 1842 with an immense trove—hundreds of fish and mammal specimens, more than 2,000 bird specimens, 50,000 plant specimens, a thousand live plants, some 4,000 ethnographic objects, such as Fijian war clubs, Samoan fish hooks and New Zealand baskets. But no, the Smithsonian is not still cataloguing them. That job largely fell to the scientists who accompanied Wilkes, and they completed it, well, expeditiously. The collection was exhibited in the Patent Office Building in Washington, D.C. for several years, before it came to the Smithsonian.
Pamela M. Henson, Historian
Smithsonian Institution Archives
Did Mathew Brady really take all the Civil War photographs that are credited to him?
Patrick Ian, Bethesda, Maryland
No. By 1861, Mathew Brady was one of the best-known photographers in America, with portrait studios in New York City and Washington, D.C. While his staff handled day-to-day operations, Brady provided the creative vision and marketing expertise that made his studios famous. When the Civil War began, he assembled and outfitted teams of photographers and sent them into the field to ensure that his cameras would be present to produce a visual record of the conflict. Although Brady traveled periodically to battlefields and encampments, the Civil War photographs that carry his credit line were typically made by his cameramen. The look of the portraits produced in Brady’s studios—such as those featured in the National Portrait Gallery’s new exhibition, Mathew Brady’s Photographs of Union Generals (March 30, 2012-May 31, 2015)—reflected his aesthetic even when he was not present for the portrait session.
Ann M. Shumard, Curator of Photographs
National Portrait Gallery
Why do birds like to congregate around electric transformers?
Luis Tewes, Palm Beach Gardens, Florida
While the ever-growing electrical grid spells trouble for most species of birds, some have incorporated human structures into their lives. Power lines are a flight hazard to many species, but they also provide elevated perches, particularly in open country where there are few natural alternatives, for sit-and-wait predators, such as bluebirds, shrikes and small raptors. Many species use electric lines to rest or monitor their territories; and flocks of blackbirds and starlings and other birds gather on wires before they join large communal roosts. Power-line poles and towers and their attendant transformers provide additional support and protection for flocks and larger species, such as raptors. A few species even commandeer power poles and transformers as nesting sites. Transformers may produce some heat, which may explain why some birds like them. The monk parrakeet, introduced from Argentina, nests and roosts around transformers and has expanded into some pretty cold urban areas.
Birds’ use of power equipment illustrates their impressive adaptability, but awareness of high-voltage electric currents is not in their DNA. While a bird can perch on a high-voltage line in complete safety, as soon as it makes secondary contact with a conductor that leads to a ground, it will be fried. Large birds taking flight or producing “streamers” of fecal material often complete the circuit to their demise. Fecal build-up, gnawing (by parrots) and nesting material can short out lines or transformers, leading to massive power outages. Bird mortality might be reduced, and electrical service might be more reliable, if we had a better-designed grid.
Russell Greenberg, Wildlife Biologist,
Migratory Bird Center, National Zoo
In aserated (or “starred”) gemstones, such as the ruby and sapphire varieties of corundum, what is the average amount of rutile per square millimeter? And how many asterated gemstones does the Smithsonian Institution have?
Davis M. Upchurch, Fletcher, North Carolina
In synthetic asterated corundum, about 0.1 to 0.3 percent titanium oxide is typically mixed with the aluminum oxide. That gives you a ballpark idea as to the fraction of rutile (which is usually given as an amount per cubic millimeter). The Museum of Natural History has about 50 asterated gems in its collection, including, 21 specimens of corundum. We add new ones sporadically, and we’re always on the lookout for different or better examples.
Jeffrey Post, Curator of Gems and Minerals,
Museum of Natural History
We’re ready for still more questions. Please submit your queries here.
February 25, 2012
You may remember learning the types of planets growing up: rocky planets, like Earth and Mars; gas giants, like Jupiter and Saturn; and ice giants, like Neptune and Uranus.
Now scientists at the Smithsonian Astrophysical Observatory (SAO) have discovered a new kind: a waterworld. The planet, named GJ1214b, is not merely covered with water like our oceans; most of it is water. “GJ1214b is like no planet we know of,” Zachory Berta, a graduate student at the SAO and lead author on the paper announcing the discovery, published online Tuesday in The Astrophysical Journal. “A huge fraction of its mass is made up of water.”
Contrary to what you might imagine, the “water” on GJ1214b is quite different from anything you’ve ever seen.”The water there is in really weird forms that we’re not used to on Earth,” Berta says. “There are substances that are like ice, but at a very high temperature, because the pressure is so high that the molecules are squeezed together. There is also this superfluid state of water that is more gaseous than the water we’re used to.”
If you have trouble picturing such an exotic alien waterworld, you’re not alone. “Frankly, I too have a lot of difficulty imagining what this would actually be like in person,” Berta says.
Located in the direction of the Ophiuchus, the planet is just 40 light years from Earth, making it a close neighbor compared to most of the stars in our galaxy. GJ1214b is 2.7 times Earth’s diameter and weighs nearly 7 times as much. The planet closely orbits a red-dwarf star every 38 hours, and has an estimated average temperature of 450° Fahrenheit.
Planets that orbit a star so closely do not typically contain any water, says Berta, so scientists believe that GJ1214b must have had an unusual history. “It couldn’t have formed that close, because all of the water would have evaporated off due to the heat,” he says. “So this planet probably had to have formed farther out, and somehow came inward.” Gravitational interactions with other planets may have pulled the waterworld closer in.
Berta and his thesis advisor, David Charbonneau, found the planet back in 2009 as part of the MEarth Project, which uses ground-based telescopes at the Fred Lawrence Whipple Observatory on Mount Hopkins in Arizona to discover habitable planets orbiting nearby red dwarf stars. “At the time, we had an inkling that this could be a waterworld,” Berta says. “We could measure the mass and the radius of the planet, so we knew its density, and the density was very low—too low to be explained by a big ball of rock.” The planet’s average density was calculated to be roughly 2 grams per cubic centimeter, far closer to water’s density of 1 g/cm3 than Earth’s average density of 5.5 g/cm3.
Still, with only limited information on the planet, the team couldn’t rule out other possibilities, such as a planet with a thick atmosphere of hydrogen and helium, which would similarly account for the low average density. But when the researchers were able to use the Hubble Telescope’s newly installed Wide Field Camera 3—specifically looking at light from the red dwarf star that traveled through the GJ1214b’s atmosphere before traveling towards us—they were able to rule out that possibility.
“If the big, puffy hydrogen envelope on the outside of the planet were there, we would see it, but we don’t,” says Berta. “So it looks like we’re dealing with the alternative—a planet with a whole bunch of water in it, and an atmosphere which is mostly water as well, which is consistent with what we see from the Hubble observations.” The research team describes the atmosphere hot and steamy.
Berta is less excited about finding the first of a new type of planet than the possibility of finding many more. “NASA’s Kepler telescope has found a number of planets that are the same size as this one, but they’re much more distant, so it’s hard to observe those planets in more detail,” he says. “This is interesting not because it’s something that we’ve never seen before and will never see again, but because it’s sort of a type specimen for all of these.”
He believes investments in telescopes and other observational equipment will continue to pay great dividends as we continue to search the galaxy for planets. “The James Webb Space Telescope [due to be launched in 2018] is NASA’s successor to Hubble. It will be great, because instead of just having a very rough picture of planets like these, we’ll be able to probe them more closely,” he says.
Berta is confident that within decades, astronomers will detect a smaller, cooler version of GJ1214b, which could theoretically harbor extraterrestrial life. “That’s the cool thing about astronomy,” he says. “As we continue to build better telescopes, we can find more and more.”
February 7, 2012
Our inquisitive readers are rising to the challenge we gave them last month. The questions are pouring in and we’re ready for more. Do you have any questions for our curators? Submit your questions here.
How much is the Hope Diamond worth? — Marjorie Mathews, Silver Spring, Maryland
That’s the most popular question we get, but we don’t really satisfy people by giving them a number. There are a number of answers, but the best one is that we honestly don’t know. It’s a little bit like Liz Taylor’s jewels being sold in December—all kinds of people guessed at what they would sell for, but everybody I know was way off. Only when those pieces were opened up to bidding at a public auction could you find out what their values were. When they were sold, then at least for that day and that night you could say, well, they were worth that much. The Hope Diamond is kind of the same way, but more so. There’s simply nothing else like it. So how do you put a value on the history, on the fact it’s been here on display for over 50 years and a few hundred million people have seen it, and on that fact it’s a rare blue diamond on top of everything else? You don’t. – Jeffrey E. Post, mineralogist, National Museum of Natural History
What’s the worst impact of ocean acidification so far?- Nancy Schaefer, Virginia Beach, Virginia
The impacts of ocean acidification are really just starting to be felt, but two big reports that came out in 2011 show that it could have very serious effects on coral reefs. These studies did not measure the warming effect of carbon dioxide in the atmosphere, but rather its effect of making the ocean more acidic when it dissolves in the ocean. Places where large amounts of carbon dioxide seep into the water from the sea floor provide a natural experiment and show us how ocean waters might look, say, 50 or 100 years from now. Both studies showed branching, lacy, delicate coral forms are likely to disappear, and with them that kind of three-dimensional complexity so many species depend on. Also, other species that build a stony skeleton or shell, such as oysters or mussels, are likely to be affected. This happens because acidification makes carbonate ions, which these species need for their skeletons, less abundant.
Nancy Knowlton, marine biologist
National Museum of Natural History
Art and artifacts from ancient South Pacific and Pacific Northwest tribes have similarities in form and function. Is it possible that early Hawaiians caught part of the Kuroshio Current of the North Pacific Gyre to end up along the northwest coast of America from northern California to Alaska? — April Amy Croan, Maple Valley, Washington
Those similarities have given rise to various theories, including trans-Pacific navigation, independent drifts of floating artifacts, inadvertent crossings by ships that have lost their rudders or rigging, or whales harpooned in one area that died or were captured in a distant place. Some connections are well-known, like feather garment fragments found in an archaeological site in Southeast Alaska that appear to have been brought there by whaling ships that had stopped in the Hawaiian Islands, a regular route for 19th-century whalers. Before the period of European contact, the greatest similarities are with the southwest Pacific, not Hawaii. The Kushiro current would have facilitated Asian coastal contacts with northwestern North America, but would not have helped Hawaiians. The problem of identification is one of context, form and dating. Most of the reported similarities are either out of their original context (which can’t be reconstructed), or their form is not specific enough to relate to another area’s style, or the date of creation cannot be established. To date there is no acceptable proof for South Pacific-Northwest Coast historical connections that predates the European whaling era, except for links that follow the coastal region of the North Pacific into Alaska.
William Fitzhugh, archeologist
Natural History Museum
January 3, 2012
If you can drag yourself out of bed and into the chill of a early January morning, you might find yourself looking at a rare treat: the Quadrantid meteor shower. Early in the morning hours of January 4, from roughly 2 to 5 a.m. local time across the country, this annual meteor shower will be visible in the Northern hemisphere, peaking with an intensity that will approach 100 shooting meteors per hour.
“What’s going on is the earth is going through a debris trail,” says Timothy Spahr, astronomer at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. “You’re dealing with very tiny particles, dust-sized in a lot of cases. When they enter the atmosphere, they burn up immediately, and that makes a meteor.” The particles that make up the Quadrantid shower originate from an asteroid named 2003 EH1, which many scientists believe was actually once part of a comet. Because the particles enter at speeds as high as 90,000 miles per hour, they burn up high in the atmosphere and leave a glowing streak across the sky.
The Quadrantid shower is unusual in that it continues for a relatively short duration—only a few hours, as compared to more famous showers, such as the Perseids, that last for several days—but with a high degree of activity. “Under a dark sky, we are talking about 100 visible meteors per hour, so that means a little more than one per minute,” Spahr says. “Many people assume that these showers have millions of meteors all over the sky, but you’ll see around one per minute. And that’s actually pretty cool, because you register when you see each one.”
With the moon projected to set at around 3 a.m. and clear forecasts for much of the country, tonight has the potential to be a rare chance to see the Quadrantids. Most years, because of their brief duration, moonlight or cloudy conditions obscure the show. This year, experts recommend going outside once the moon has set—and, of course, dressing warmly, with projected nighttime temperatures in the twenties or teens in many places. Because of the show’s timing, the best viewings are expected in the Eastern United States.
Meteor-gazers are advised to watch the Northeast part of the sky, and find as dark an area as possible. Give your eyes some time to adjust to the dark and be alert, as most meteors flash by in a second or less. A live feed of the skies above Huntsville, Alabama, is available on NASA’s web site.
One of the biggest factors that determine how many meteors will be seen is something that most people cannot control: location. For those stuck in big cities—like this reporter, based in Washington, D.C.—ambient lighting will reduce the visibility of the meteors significantly. ”A really dark sky makes a huge difference, and most people in the world never see a dark sky because they live in cities,” Spahr says. “If you drove two hours to the west of Washington, say, and got up in elevation a little bit, it would be very nice.”
Still, this is one meteor show that even city-dwellers can appreciate, if not as much as those in the country. “It will be a lot less in a city, but you will still see some meteors tonight,” says Spahr. “Some of these particles will end up, for just a few seconds, as bright as Venus, so those you’ll be able to see from pretty much anywhere.”
December 29, 2011
A tour of the Natural History Museum might lead you from an exhibition on dinosaurs to one about ocean creatures. You might read about how hominids evolved millions of years ago, how our planet’s continents have moved, or how early creatures evolved when the atmosphere was practically devoid of oxygen. The time scale of natural history, you realize, is almost unimaginably large.
But if you enter the museum’s new exhibition, “The Evolving Universe“—a show featuring photography from some of the most powerful telescopes ever created—you’ll find yourself even more astounded. Set against the backdrop of the known universe, the history of our dear planet seems nearly irrelevant. Hundreds of billions of stars like our sun are born out of supernovae several light years wide (each light year is longer than five trillion miles) and are destined to die, once again exploding into supernovas, billions of years later. Thousands of galaxies, some containing trillions of stars like our sun, are continuously being born and evolving.
Although these concepts can be difficult to comprehend and even harder to visualize, the stunning photos that make up the exhibition show the visitor just how awe-inspiring these astronomical events can be. They put the latest CGI graphics from 3-D blockbuster films to shame. “Part of our mission is sharing science with the public, and so we felt that doing this exhibit and showing these images is a great way to do that,” says Jonathan McDowell, an astrophysicist at the Smithsonian Astrophysical Observatory, which partnered with the museum in creating the exhibition. The large-scale photographs in the show were produced by a number of telescopes, both Earth and space-based, including the Hubble Space Telescope.
“We’ve all seen the amazing pictures from NASA’s probes in our own solar system,” says McDowell. “I’m excited about bringing to the public the remarkable images of the broader universe that we astronomers have been exploring with our telescopes. I hope that with this exhibition visitors will take away an appreciation for our larger cosmic neighborhood.”
The show—and accompanying website—use these images to tell the story of our universe, from start to present. The Big Bang, the creation of galaxies, the birth of the Milky Way and the formation of our own solar system are represented in rich images so full of detail that they need to be observed for minutes at a time, like pieces of art hung on the wall.
What might be most remarkable is that the actual images created by the telescopes are themselves ancient history. Because light takes so long to travel from the far-flung reaches of space, when we photograph distant galaxies, the light that hits the camera’s lens to produce the image left its home galaxy billions of years ago. These pictures show some of the celestial objects as they were before humans even existed. And so we have a font-row seat to watch the earliest stages of the universe’s creation, if we look deep enough into space, more than 13 billion years later.
When wandering the exhibition, one might be overwhelmed by the torrent of information presented on scales that are downright otherworldly. How does our planet, so tiny and new, fit into all of this?
The best metaphor to understand earth’s place in the universe might be that of astrophysicist, author and recent Around the Mall blog subject Carl Sagan. In his book Pale Blue Dot, he describes a far-off view of the Earth from the outer reaches of the solar system:
From this distant vantage point, the Earth might not seem of any particular interest. But for us, it’s different. Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
In the scheme of the known universe—of supernovae and galaxies and nebulas and black holes—our whole planet starts to look like a speck of dust, floating in the sunlight.
The Evolving Universe is on view at the Natural History Museum through July 7, 2013