Monthly Archives: November 2013

A new galaxy and an old painting tell us about the creation of the universe

On October 24, a team of scientists announced the discovery of a faraway galaxy, called Z8-GND-5296 (Zate for friends). A very faraway galaxy, 30 billion light years away. It’s also quite old, 13.1 billion years old.

Hubble image of Z8-GND-5296. Image credit: V. Tilvi / S.L. Finkelstein / C. Papovich / A. Koekemoer / CANDELS / STScI / NASA. via http://www.sci-news.com/astronomy/science-most-distant-galaxy-01488.html
Hubble image of Z8-GND-5296. Image credit: V. Tilvi, S.L. Finkelstein, C. Papovich, A. Koekemoer, CANDELS, STScI, NASA; via Science News.

For a little context: the universe is thought to be 13.82 billion years old and our galaxy, the Milky Way, is 13.6 billion years old.

We’ve always wanted to know where we are

Our earliest maps were of the stars: Paleolithic depictions of constellations have been found in caves in France and Spain.  Our ancient forebears had only the naked eye to find our place in the sky.

Today’s scientists are increasingly able to see further as the instruments that look into space improve. The “observable universe” extends about 46 billion light years away from Earth. Here’s an amazing 3-D map of our known universe.

The distance to Zate, 30 billion light years, is the furthest recorded so far for a galaxy.

How can Zate be 30 billion light years away if the universe is 13.8 billion years old and nothing travels faster than light?

The short answer is that the universe is expanding. Objects, especially distant ones, appear to be moving away from us. They aren’t. The space between us is increasing.

Having trouble wrapping your head around it? Yeah, me too.

Timeline of the universe, from Big Bang to today. The vertical extent of the funnel is size- which is expanding, and the horizontal is time. Source NASA WMAP site.
Timeline of the universe, from Big Bang to today. The vertical extent of the funnel is size- which is expanding, and the horizontal is time. Source NASA Wilkinson Microwave Anisotropy Project.

Imagine that Galaxy Zate is on a moving walkway in the airport heading to the gate, while we’re on a walkway to the baggage claim. Zate sent us a paper airplane with a message, but since the distance between us keeps expanding, it took thirteen billion years to arrive.

The walkway is two-dimensional, while space is three-dimensional, and there’s no “center” out of which the universe expands, so the analogy is far from perfect, but it might help.

Did you say that was the short answer?

I did. It turns out that the limitation on objects moving faster than light refers to special relativity, that is to motion through space. There is no such limitation on the expansion of space itself. In case you didn’t click before, for a wonderful, and concise, explanation of the Big Bang and the expanding universe go here.

What can we learn from Zate? 

The new galaxy appears particularly enriched in metals, which result from the formation of stars. Zate is thought to have produced 330 stars with a size equivalent to our sun every year. That’s a hundred times larger than the current rate for the Milky Way.

Zate and galaxies like it are very important to understand the early universe, when it was a mere 700 million years old, when stars and galaxies were being created.

How can you show creation?

Current scientific thought of the evolution of the universe looks something like the NASA schematic shown above.

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The Creation of the World and the Expulsion from Paradise. Source Google Art Project via Wikimedia Commons.

Five hundred years ago in Europe, the understanding of creation was largely based on the Bible, but observations also mattered.

A particularly delightful representation of creation is the 1445 panel showing The Creation of the World and the Expulsion from Paradise by Giovanni di Paolo (1400-1482) in the Robert Lehman Collection of the Metropolitan Museum of Art in New York.

The Maker, surrounded by blue cherubim, is in the upper left, pointing to a cosmological representation of the universe as a series of concentric spheres. This is known as a thema mundi, a star chart of the world, where the outer ring holds the signs of the zodiac, that is, the constellations at the moment of earth’s creation.

Earth in the center

As asserted by Ptolemy and adapted to accommodate prevailing Christian thought of the time, the earth is central, fixed and unmoving.  Copernicus didn’t publish mathematical foundations for heliocentrism until 1542, though the work had been written ten years earlier.

The innermost sphere, earth, is brown, and the next three spheres represent the remaining three elements (water, air, and fire in red). These are surrounded by the seven “planets:” the moon, Mercury, Venus, the sun (white, with remains of a gilded star), Mars (pink), Jupiter (light blue), and Saturn (darker blue). The “fixed stars” that were thought not to move, including the zodiacal constellations, surround Saturn. Finally, God with the angels is in the celestial orb, outside the concentric circles.

Both Medieval and Renaissance

Laurinda Dixon explains in a wonderful article that the artist broke with medieval tradition by showing the earth as a world map.  Though superficially similar to the symbolic mappamundi of the Middle Ages, closely bound by Christian iconography, Giovanni di Paolo was clearly aware of the latest maps of his time. For example, the map’s top is the south instead of the medieval east and it’s not centered on Jerusalem.

However, Giovanni di Paolo’s map is still symbolic. Eden is located atop the Mountain of the Moon, near the headwaters of the Nile. As in medieval mappamundi, the four rivers of paradise flow from Eden, and can also be seen below Paradise in the Expulsion scene.

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Our home. “The Blue Marble,” iconic photograph of Earth seen from the Apollo 17 spacecraft on December 7, 1972.

Where we are remains the same

This Earth. This beautiful planet.  But how we define it varies.

Galaxy Zate can tell us about the first hundreds of millions of years of the universe’s existence. It can help confirm or disprove our understanding of things that are hard to imagine. Giovanni di Paolo’s Creation reflects the knowledge from a time straddling the arbitrary periods of Middle Ages and Renaissance.

We’ve always wondered where we come from and we always will. We’ll never have all the answers, but we’ll keep exploring and asking better questions, and then we’ll tell stories about what we learn.

And in this way, we’ll learn even more.

The yeti hairs and other cases of mistaken identity

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A sea serpent from Historia de Gentibus Septentrionalibus (History of the Northern Peoples, Rome, 1555) by Olaus Magnus. Image from Wikimedia Commons.

Imaginary creatures were quite present in the news in October, from yetis to sea serpents. Before anyone is offended, I’m happy to admit that my imaginary creature may be your very real neighbor, but we can probably all agree that some creatures are not part of zoological canon. There isn’t sufficient evidence to support their existence.

Now, like black swans, a lack of evidence does not mean they don’t exist. “Sea serpents hunt humans in the sea” is not a scientific statement and can’t be falsified.

What can we know?

Actual material remains- like hair or bone,  can be studied with a variety of scientific tools. Genetic testing, and subsequent comparison of samples to the library of known DNA sequences in GenBank, provides the most conclusive information.

For example, Coltman and Davis of University of Alberta concluded that hair purportedly from a Canadian Sasquatch was in fact from a bison. Another genetic study, claiming the discovery of a new species related to humans, aka a hominid, was found to be suspect.

So it was pretty exciting when the Collateral Hominid Project, a collaboration of Oxford University geneticist Bryan Sykes and the Musée de Zoologie of Lausanne, requested samples of yetis, sasquatch, and bigfoot for analysis.

Early results for hair samples from southern Russia turned out to be from a raccoon, a horse, and an American black bear. (The bear was assumed to be a zoo or circus runaway.)  The recent announcement that hairs found in the Himalaya matched polar bear DNA received much press attention.

Did you say polar bear?

Yup, two hair samples matched the DNA from a polar bear jawbone found in Norway. The jawbone is thought to be 40,000 to 120,000 years old, from the time when polar bears and brown bears were separating as species.

Polar bears survive in polar waters with the help of adaptations like white fur, thick layers of fat, short claws for walking on ice, and long necks to hunt while swimming.

Polar bears in the Himalayas?

Probably not, but Prof Sykes suggests that a relative might have been living in the Himalayas ten years ago when the hair was found. In a great Slate article by Jason Bittel, bear experts point out that the kind of bear is still unclear and that the presence of the hair doesn’t prove the animal lived there. 

That said, the samples of yeti hair so far do not appear to belong to a new species.

So what, are you saying there are no new species to be discovered?

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Olinguito in the Tandayapa Bird Lodge, Ecuador, August 2013. From Helgen et al. ZooKeys 2013. Via Wikimedia Commons.

No, new species are still being found, living, usually, in the most remote areas of our planet. Two recent new species are also cases of mistaken identity, where scientists had assumed the creatures were something we already knew.

The olinguito lives in the cloud forests of Ecuador and Colombia. Although olinguito (Bassaricyon neblina) specimens can be found in museums and one lived in various zoos in the 60s, it was mistaken for another species, the olingo.

Something similar happened to the somewhat less photogenic arapaima, a large fish (up to 10 feet and 440 pounds) that lives in the convergence of the Amazon and Solimoes Rivers. Genetic testing has revealed a new species with a fascinating sensory cavity in its head and scales apparently designed to protect from the teeth of piranhas (their close neighbors). 

arapaima_small
These fish in a Ukraine aquarium are a newly identified species of arapaima. Photo by George Chernilevsky via Wikimedia Commons.

Of habitat and risk

Like many new species, both the arapaima and the olinguito call attention to the remote regions they call home, and to how humans interact with those habitats.

Cloud forests are increasingly being cleared and climate change threatens their uniquely cool moist conditions. And despite poor understanding of the impact of fish farming in the Amazon, the arapaima is being farmed.

Perhaps the charisma of the arapaima and the olinguito can help bring attention to the need for more study and more thoughtful use of these unique environments.

But you promised sea serpents…

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18-foot oarfish found off Catalina Island on October 16 2013. Photo courtesy of the Catalina Island Marine Institute.

I thought the arapaima was pretty spectacular but there’s more. Not one, but two oarfish washed up dead on southern California coasts in a single week in October. The oarfish is huge: the two recent ones were 18 and 14 feet respectively but they can be as big as 50 feet, making them the largest bony fishes in the world.

Oarfish have been observed from northern Europe to Chile. Since they live at depths between 200 and 1000m, they’re seen rarely, such as during storms or, most frequently, when the large fish wash up dead or injured.

Given their size- and let’s face it, they aren’t exactly the fish equivalent of the olinguito, it’s not surprising for the sailor who sees one in a choppy sea to conclude it’s a dangerous predator.

Nothing further from the truth. Oarfish don’t even have teeth, because they strain water for their planktonic food.

Of mental models and mistaken identities

Humans operate with mental models, based on experience and expectations. A bear that walks on two feet can look like an ape and a 30-foot fish is pretty scary, even if you look nothing like food to it. And it’s almost impossible not to make assumptions when in a hurry and unable to take a close look.

Things that goes bump in the night are frightening at first. Later they inspire questions and, of course, stories to help us understand.

Any new species come trick-or-treating last night?