We have peered far into the Universe and vastly expanded our knowledge of distant realms. But interestingly enough, we are still refining our understanding of our own place within our galaxy, the Milky Way. Research into this question follows in the footsteps of many great names in astronomy: from Herschel to Hubble, and from Kapteyn to Kant, generations of astronomers helped to establish our understanding of our place in space.

Imagine, if you will, trying to take a picture of the United States from somewhere close to the center of it. (That’s right. Lots of corn fields.) You would have no way to observe the entire country at the same time. Astronomers face a similar challenge in observing our home galaxy: we live within the disc of the Milky Way, a long way from the center (about 7,600 parsecs or 25,000 light years) and only a small distance from the middle of the plane (27 parsecs or close to 88 light years), with thick lanes of gas and dust blocking our view. We can see other more distant galaxies and have discovered many shapes and types, so comparing ourselves to them can help us determine the approximate shape and layout of the Milky Way.

Dr. Alyssa Goodman and her team recently realized that a dark cool cloud dubbed “Nessie” in the constellation Ara might have some secrets to tell about the Milky Way. We have seen similar features in other spiral galaxies: slightly denser tubes of material that define long spiral arms. By studying this “bone” of our galaxy, we may soon be able to refine our map of home to an even greater degree. We reside just far enough from the plane of the Milky Way’s disc that we could perhaps one day find the rest of these bones and create an even better layout of our place in space.

This concept and more appear in Goodman’s Authorea paper, currently in development now for later publication. Amazingly, you can to read the paper online while the authors finalize it! Talk about science in action…

Josh Roberts is a program presenter and astronomer at the California Academy of Sciences. He also contributes content to Morrison Planetarium productions.

Image: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)

Sometimes to look into the past you need to dig deep—not just physically, but visually, as well. Some of the experiments at the Advanced Light Source (ALS) in Berkeley do just that. With their powerful X-rays they can examine dinosaur blood or determine what killed Napoleon.

Scientists at the ALS recently dug into Roman concrete this way. Remarkably, Roman concrete constructed 2,000 years ago is still strong today, even under rough sea. In contrast, the concrete we manufacture only lasts around 100 years.

Additionally, most of the concrete we produce today has terrible environmental impacts. The process for creating Portland cement, a key ingredient in modern concrete, requires fossil fuels to burn calcium carbonate (limestone) and clays at about 1,450 degrees Celsius (2,642 degrees Fahrenheit). Seven percent of global carbon dioxide emissions every year comes from this activity.

To make a greener, more durable concrete, scientists from King Abdullah University of Science and Technology in Saudi Arabia, working with Berkeley researchers, used spectroscopy at the ALS to examine the Roman concrete and determine its ingredients. Ancient Romans made no secret that volcanic ash was part of the process, but the team also discovered a very rare hydrothermal mineral called aluminum tobermorite (Al-tobermorite) that formed in the concrete, and evidence also suggests the use of seawater in mixing the concrete.

To build underwater structures, Romans mixed lime and volcanic ash to form mortar, and then packed this mortar and volcanic tuff into wooden forms. The seawater instantly triggered a hot chemical reaction. The lime was hydrated—incorporating water molecules into its structure—and reacted with the ash to cement the whole mixture together.

The researchers are now finding ways to apply their discoveries about Roman concrete to the development of more earth-friendly and durable modern concrete. They are investigating whether volcanic ash would be a good, large-volume substitute in countries without easy access to fly ash, an industrial waste product commonly used to produce modern, green concrete. (Fly ash was used in constructing the Academy’s LEED-certified building.)

“Many countries don’t have fly ash, so the idea is to find alternative, local materials that will work, including the kind of volcanic ash that Romans used,” says Berkeley’s Paulo Monteiro, one of the authors on a recent study. “Using these alternatives could replace 40 percent of the world’s demand for Portland cement.”

The ALS shows that by looking into the past, you can solve problems for the future.

Image: Carol Hagen