Category Archives: astronomy

astronomy

Remembering Carl Sagan

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A Celebration of Exploration

Dr. Carl Sagan, courtesy of the Planetary Society.
Dr. Carl Sagan, courtesy of the Planetary Society.

Today is the 12th anniversary of Carl Sagan’s passing. You might be familiar with this man and his work, but if you aren’t and you’re wondering why it is that many of us celebrate his life and work, pull up a chair. Let me tell you a story about what this man’s work meant to me.

I first met Dr. Sagan when I was a lowly undergraduate and he came to our campus to give a talk. To me he was just another scientist coming in to lecture on a subject I had to study in astronomy class. But, to my great surprise, he turned out to be engaging and enthusiastic and I recall enjoying his talk very much.

Fast-forward a few years (well, almost a decade) and I was out of school and working at a newspaper. We tuned in to a new science TV show called Cosmos to see what it was all about. Lo and behold, here was Dr. Sagan again, this time at the helm of a ship of the mind and imagination.

From the first moments of that program, I was hooked again on astronomy and space science (having been turned on to it by stargazing with my dad and encouraged to read about science by both parents).

It’s not a coincidence that I decided to become a science writer after seeing that show, and in fact, I decided I wanted to be an astronomer. All because of the beauty and joy that Dr. Carl Sagan brought to his explanations of astronomy. That experience sent me on a journey of writing and study that continues to this day. I would not be the writer and producer I am today if it weren’t for Sagan’s work and influence, and even though I met him several times over the years I was studying astronomy, doing my research, getting my degrees, and then moving back out into the “real world” of astronomy and science communication, those early experiences were what propelled me along that path.

So, along with many other scientists and science communicators who were influenced by Dr. Sagan’s life and work, I raise a toast to the memory of a man who wasn’t afraid to let his enthusiasm and sense of fun shine through as he taught the world about science.

Here’s to ye, lad!

astronomy, gravitational lenses, masers, quasars, water

Water, Water Everywhere… and When

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Even 11.1 Billion Years Ago

Water appears to be ubiquitous throughout the universe. Which is to say that astronomers spot traces of water vapor in various parts of the universe like other planets, moons, and throughout our galaxy. But, often enough, astronomers find H2O vapor in water masers. These are beamed radiation sources that are similar to lasers, but radiate at microwave wavelengths. These masers are often found in regions where hot, dense dust and gas are coalescing — like galaxy cores and starbirth regions.

So, astronomers have wondered how early in the universe water vapor might have existed. Another way to ask that question is to wonder how far away the most distant water vapor could be “seen” by our telescopes?  Water masers showing vapor have been found in galaxies close to ours, of course. But, what about more distant onces?

The quad gravitational lens MG J0414 + 0534, courtesy of VLBI.
The quad gravitational lens MG J0414 + 0534, courtesy of the extended Very Large Baseline Interferometer radio array (eVLBI).

The most recent answer came from data taken with the Effelsberg 100-meter radio telescope in Germany (operated by the Max Planck Institut for Radio Astronomy). Graduate student Violette Impellizzeri used the telescope to study the quasar MG J0414 +0534, which lies about 11.1 billion light-years away from us. We see it here in radio wavelengths that have been gravitationally lensed by an intervening galaxy (that is, the wavelengths of radiation and light from the more distant quasar are being bent by the gravitational influence of a massive galaxy that lies between us and the quasar).

The signature of water vapor was spotted in the radio data taken by Impellizzeri. It probably exists in clouds of dust and gas that feed a supermassive black hole at the center of the quasar. The detection of the water was later confirmed by observations made with the Expanded Very Large Array.

Make no mistake about it, this is a discovery of water in the very early universe — at a time when the universe was a fifth of its current age. It means that water may have been much more abundant in those early times. Because water masers are active close to galaxy cores, these masers may tell us something about the evolution of black holes and galaxy cores back at a time in the universe’s early history when galaxies were first forming.  I don’t know about you, but I find it fascinating just how something we take so much for granted (and is so commonplace) as water can help us get a look at the earliest epochs of cosmic history.

If you’re interested in reading more about this research, there’s a paper coming out in the December 18, 2009 issue of Nature magazine. Here’s the citation:

A gravitationally lensed water maser in the early Universe, C.M. Violette Impellizzeri, John P. McKean, Paola Castangia, Alan L. Roy, Christian Henkel, Andreas Brunthaler, & Olaf Wucknitz, 2008, Nature (18 December issue)