The distribution of galaxies in the region around the Milky Way (in galactic coordinates). Each little dot represents a galaxy of typically 100 billion stars. The colors indicate the relative motions of galaxies with accurately measured distances, with shades of gree and blue indicating motions toward us, and shades of yellow to red indicating motions away from us. (For more information, see the IFA press release.
We are riding on the edge of a huge void in space, hurtling along at 600,000 miles per hour. Yes, it’s true. We’re moving along with the expansion of the universe AND with the coalescence of galaxies along filaments, in clusters at places where the filaments intersect. Yet, as we go about our daily lives, we’re largely (if not completely) unaware of the ride we’re taking through space and time as part of the Milky Way Galaxy. Yet, our motion tracks with the continuing evolution of the universe.
Did that get your attention? It’s a compelling story, and one that astronomer Brent Tully is telling in his latest research into the motions of galaxies in our neighborhood of the universe. In the past, our distance measurements to other galaxies could give us some very broad information about our galaxy’s motion through space. In addition, other measurements of the Cosmic Microwave Background Radiation tell about some aspects of our galaxy’s motion. But, there’s always been a part of our motion that was unexplained—until now. Tully and a team of colleagues have done extremely precise measurements of distances to galaxies around us. Those measurements tell a great story of motion and action of galaxies through time and helped them finger a largely unexplored component of space as the culprit: the Local Void. This is a gap in space that is 50 megaparsecs across. (A megaparsec is about 3,260,000 light-years, and a light-year is the distance that light travels in a year.)
Concentrations of matter (like the filaments and clusters) are aggregates of matter that is pulled together. Concentrations of matter have gravity; they PULL on things. The Local Void, on the other hand, is empty. It seems to PUSH on things, including our galaxy. Tully explains it as the absence of a pull. If an object is surrounded by matter in all directions, except for one empty sector, then the absence of a pull from that sector is actually the same as a push. And, it can have a large effect on our region of space, in effect turning us into void riders moving along the edge of the Local Void.
It’s quite fascinating that we (all of us in the Milky Way Galaxy) should live on the edge of such a huge gap of nothingness; and, we ride along not really feeling our motion across the depths of space and time.
The astronomy profession is a small community of kindred souls all focusing on dozens of different ways to understand the science of the cosmos. I go to astronomy meetings pretty frequently (well, at least once or twice a year), to catch up on the latest and greatest in astronomy research. Mr. Spacewriter has accompanied me to a couple of meetings because I wanted him to experience the science being presented, and so he could meet some of the same folks. At the opening reception of the meetings, we’ve run into many, many people I’ve worked with or went to school with “back in the day.” And, marvelled at the fresh infusion of new blood into the profession. Of course there are folks from NASA and many research institutions at the meetings, but also people like Pamela Gay and Fraser Cain, who are the main drive behind Astronomy Cast. Pamela (who is also a university professor) is doing a lot more than research and teaching in astronomy. Like me, she loves to share astronomy with the public, in any way she can.
There are also a good many very talented science writers who attend AAS meetings, reporting on the science “hot off the presses.” It’s been an honor to meet some of them, too. Where else could I have met New York Times science writer John Noble Wilford? He attended a great many AAS meetings, always asking the astute questions and subtly drawing out an education in astrophysics through his questions. Or Dutch writer Govert Schilling? Or many others who have attended these sessions over the years.
As a writer, I’ve found many outlets for the material I learn at astronomy meetings. Of course, I use the science in my documentary shows. But, for the past few years, in addition to my fulldome show production work through Loch Ness Productions, I’ve been contracted by various observatories to work as an editor and outreach person. The work runs the gamut from writing and/or editing press releases to creating exhibits. Lots of fun, and I’d love to do more of it.
And, so I shall. To wit: in a very short time, Mr. Spacewriter and I will be starting production on some vodcasts under a NASA grant with MIT Haystack Observatory. And, much of the material we’re going to talk about is from papers I’ve heard and read about at AAS meetings, as well as from direct contact with astronomers in their research settings. Through all my “productions,” I hope to excite the downloading public about the science these guys are doing. I want to show their enthusiasm and love of subject to the rest of the world, because astronomers really are as much the stars of my work as the stars they research and explore.