The Known Universe Scientifically Rendered For All to See

Tuesday, December 15 10:19 am

After hovering over Mount Everest and the gorges that plunge to the Ganges, you are pulled through the Earth’s atmosphere to glimpse the inky black of space over Tibet’s high desert. So begins The Known Universe, a new film produced by the American Museum of Natural History that is part of a new exhibition, Visions of the Cosmos: From the Milky Ocean to an Evolving Universe, at the Rubin Museum of Art in New York City.

Download ‘Known Universe’

The magic of this film, though, happens as the inky black expands. Pulling farther and farther from Earth, you see the deep blue of the Pacific give way to night as the Sun comes into focus, the orbits of the solar system shrink smaller and smaller, the constellations Sagittarius and Scorpio stretch and distort, and, as the Milky Way receeds, the spidery structure of millions of other galaxies come into view. Then, you reach the limit of the observable universe, the afterglow of the Big Bang. This light has taken more than 13.7 billion years to reach our planet, and you return, back to Earth, to two lakes that are nestled between Mount Kailash and Mount Gurla Mandhata in the Himalayas.

The structure of The Known Universe is based on precise, scientifically-accurate observations and research. The Hayden Planetarium at the American Museum of Natural History maintains the Digital Universe Atlas, the world’s most complete four-dimensional map of the universe. The Digital Universe started nearly a decade ago. It is continually updated and is the primary resource for production of the Museum’s Space Shows such as the current Journey to the Stars, and is used in live, real-time renderings for Virtual Tours of the Universe, a public program held on the first Tuesday of every month. Last year, some 30,000 people downloaded the Digital Universe to their personal computers, and the Digital Universe will soon be updated with a more accurate and user-friendly software interface. Digital Universe is licensed to many other planetariums and theaters world-wide.

“I liken the Digital Universe to the invention of the globe,” says Curator Ben R. Oppenheimer, an astrophysicist at the Museum. “When Mercator invented the globe, everyone wanted one. He had back orders for years. It gave everyone a new perspective on where they live in relation to others, and we hope that the Digital Universe does the same on a grander, cosmic scale.”

The new film was produced by Michael Hoffman, and directed by Carter Emmart. Brian Abbott manages and Ben R. Oppenheimer curates the Digital Universe Atlas. The exhibition at the Rubin, Visions of the Cosmos: From the Milky Ocean to an Evolving Universe, opened on December 11 and continues through May 10.

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After Darwin at AMNH: Rob DeSalle

Monday, December 14 10:19 am

Curator Rob DeSalle Explains the Limitations of Genetic Ancestry Tests

This year, scientists at the American Museum of Natural History are celebrating the 200th anniversary of Charles Darwin’s birth and the 1859 publication of On the Origin of Species with a collection of vignettes describing expeditions and ideas with links to Darwin’s seminal work.

An annotated academic poster from a conference held at AMNH in 1932 shows the inheritance of two genetic sequences commonly used in ancestry testing. On top of Charles Darwin’s pedigree, DeSalle plotted mitochondrial DNA in red and Y-chromosome in blue. Darwin is outlined by a blue square. - AMNH

When Henry Louis Gates Jr., Harvard University professor and host of the PBS series African American Lives, learned that his Y-chromosome—a gene popularly used to trace male ancestry—“goes back to Europe,” he joked that he was having an identity crisis. And in his best-selling book The Seven Daughters of Eve geneticist Brian Sykes suggests that 95% of all Europeans are descended from just seven Stone Age women. He used mitochondrial DNA, inherited directly from mothers and employed by companies for ancestry testing of the maternal ancestry, for this work.

These are dramatic moments, but they are based in part on misleading assumptions, according to geneticists like Rob DeSalle, Curator in the Sackler Institute for Comparative Genomics at the Museum. “Ancestry testing is pushed as simple and straight-forward,” he says. “But it is not. Often the verbal history passed down in families is more accurate than ancestry DNA testing done now.”

DeSalle, along with Museum colleague Ian Tattersall, turned to the family history of the most famous of evolutionary thinkers to illustrate their point. By simply mapping basic inheritance onto Charles Darwin’s pedigree, it is easy to see how quickly a specific Y-chromosome or sequence of mitochondrial DNA (mtDNA) can be lost in a lineage. Darwin’s Y-chromosome, for example, is probably found in only two of his living descendents. Only three of his four sons reproduced and one of these sons only had daughters. Ultimately, the number of male descendents of Darwin’s two sons who had male offspring dwindled to a very small number. There are many direct male descendents of Charles Darwin living today, but most of them do not have his Y chromosome. Read more »

New, Rare Fossil Forces Scientists to Rethink Early Dinosaur Evolution

Friday, December 11 3:38 pm

Illustration by Jorge Gonzalez

A new bipedal carnivore is clearing up questions about the early evolution of theropods, the group of dinosaurs that includes its recent relatives T. rex and birds. Tawa hallae, uncovered in New Mexican sediments from the Upper Triassic, has features that link it more closely with South American theropods than with local dinosaurs.  This means that while the supercontinent Pangaea was breaking apart, some early dinosaur groups from what is now South America moved north in at least several waves to become part of the local fauna.

“We would expect that all of the theropod dinosaurs found in the quarry were related to each other. But they are not,” says Sterling Nesbitt, who excavated at Ghost Ranch while a graduate student at the Museum and is now at the University of Texas at Austin. Part of this excavation was featured in the IMAX film Dinosaurs Alive.

“Finding dinosaurs this old and this complete in an area that has been prospected for over a hundred years is surprising,” says Museum Curator Mark Norell, a co-author of the paper published in Science. “T. hallae allows us to link the South American and North American theropod faunas for the first time.” Museum Research Associate Alan Turner, also at Stony Brook University, agrees. “We propose that early dinosaurs from South American got into North America at least three separate times.”

Read more stories about T. hallae from, among others, The New York Times, Scientific American, USA Today, The Independent, and the Associated Press.

New Star Found in Big Dipper

Thursday, December 10 11:40 am

The Big Dipper has just gotten richer by one star. A new image from Ben Oppenheimer’s Project 1640 team shows that Alcor, one of the stars that makes the bend in the ladle’s handle, has a companion. Now named Alcor B, the new star is a faint, smaller red dwarf. It was discovered using Project 1640’s coronograph which blocks out the main star’s light to see faint objects nearby.

But Oppenheimer and his team, including graduate student Neil Zimmerman who was first author of the scientific paper, have done more than find a new star. After re-observing the star some 100 days later, they were able to show that the two stars orbit each other using an innovative technique called “common parallactic motion.”

“We used a brand new technique for determining that an object orbits a nearby star, a technique that’s a nice nod to Galileo,” says Oppenheimer. Galileo tried to use “common parallactic motion” to show that the Earth orbited the Sun, but his equipment was unfortunately not precise enough. The idea is that nearby stars move in an annual, repeatable motion simply because the observer is on Earth and Earth is circling the Sun.

Project 1640 used the idea to show that both stars, Alcor A and B, move together.

DNA Detective Work Featured in The Wall Street Journal

10:23 am

Genetic detective work from the Sackler Institute for Comparative Genomics at the American Museum of Natural History was recently featured in The Wall Street Journal, which reported on a study that showed that fish labeled as tuna in sampled sushi bars included a critically endangered species.

The researchers, whose findings were published in PLoS ONE, used an increasingly popular tool called DNA barcoding to identify fishes that were sold as tuna in one Denver and 30 New York City restaurants. For more on DNA barcoding and its applications in wildlife conservation, watch this video featuring Sackler Institute Director George Amato from WSJ.com.