The Flickering Universe

The Ever-changing Lights in the Sky

When you go out and look up at the night sky, you see stars. If it’s out, you can see the Moon, and if you know where to look you can also spot planets.  Sometimes asteroids flare across the field of view, and occasionally there’s a comet out there.  If you’re a frequent skygazer, you already know that the view changes over time.  Really avid stargazers also know that stars can vary in their brightness–and those that do are called variable stars.  Other stars explode.  They flare up into brilliance very quickly, and then fade away. Some time later, if you look at the area of space where the star was, using a good-sized telescope and special instruments, you can spot the remains of the star blasting out into space. Those are called supernovae.

The brightening and dimming of stars actually holds clues to activities and processes in the cosmos that help us understand such things as star birth, star death, the distances to galaxies, and even the expansion rate of the universe. So, it’s no surprise that astronomers want to pay attention to the flickering universe of stars.  In particular, astronomers at the California Institute of Technology have been paying attention to the varying levels of light from stars and other celestial objects; in fact, they’ve released data on 200 million of them!   One of the scientists is S. George Djorgovski, a professor of astronomy at Caltech and principal investigator on  survey of variable objects called the Catalina Real-time Transient Survey. He’s a fellow whose work I’ve admired since I worked on the Griffith Observatory exhibits and his “Big Picture” was a focus of my writing for several weeks. He explained why astronomers survey objects that flicker in the dark. ”Exploring variable objects and transient phenomena like stellar explosions is one of the most vibrant and growing research areas in astrophysics,” he said.  ”In many cases, this yields unique information needed to understand these objects.”

A map of CRTS discoveries. Courtesy Caltech.

The data set includes more than a thousand supernovae, as well as hundreds of so-called cataclysmic variables. These are stars that periodically brighten up in what looks like a catastrophic outburst, only to quiet down after a period of time. The survey also shows pairs of stars in which one spills matter onto another. Such a star is called a white dwarf. There are also tens of thousands of other variable stars; and dwarf novae, which are binary stars that dramatically change in brightness.

The survey takes repeated images of large areas of the sky. By comparing them to previous images, the survey can monitor the brightness of about half-billion objects. This process helps astronomers search out objects that dramatically brighten. Our galaxy–and others–are filled with the flickerings of star life, star death, and everything in between, giving astronomers a treasure trove of data that will help them understand what’s out there.

The CRTS is part of a larger umbrella project called the Catalina Sky Survey, which also searches out near-Earth objects (asteroids that could pose a threat to our planet).  They, too, have changing brightnesses, which are clues to their surface features and makeup.

If you want to know more about how astronomers are chasing down the dimmings and brightenings of the sky, check out the Catalina Sky Survey and the news released today about the Transient survey. There are discoveries in those distant flickerings!

Musings on the Universe

The Cosmos in Short Bursts

I just spent most of this week at the American Astronomical Society meeting in Austin, Texas, what I think of as a “tsunami of astronomy”.  There were more than 2,500 astronomers in attendance, all talking about everything from solar physics to the physics of the earliest cosmic objects. Many astronomers who gave talks at this conference had only five minutes to tell of their latest and greatest discoveries, plus a few minutes for questions. If they’re smart, they give “poster” papers, where they print out their talks in huge posters and then stand in front of them to talk with anybody who wants to know more about the research. I find the poster approach much more satisfying, especially when it’s been ME who’s been doing the paper. But, then, I like to stand around and talk to people, so that’s probably why I like it.

I was thinking yesterday of what a future AAS meeting would look like if it was held in the virtual world (instead of this meatspace environment) — something like Second Life, but for astronomers.  It’s not a new idea, and I’m sure we’re pretty close to it today what with our tweeting and blogging and virtual conference rooms.

Would astronomers talk ab0ut their work by short bursts, much as we do with Tweets today?  Or put up virtual posters?  Would we have virtual newsrooms where you could virtually walk around and read astronomy papers in bloggy goodness?  I suppose if we were all online, we could figure out some way to just directly transfer the news, brain to brain, without the virtual walls of an online astronomy cave.  It sure would make the evening’s afterparty an interesting event!

I suppose, even at a virtual event, there’d still be info overload after awhile. And, you would miss the chance to stand around with your colleagues in a noisy ballroom on opening night, eating hors d’oeuvres not to be construed as dinner, getting caught up on the latest, a social event as important as all the science being shared.

I’m still reading through all the materials I picked up and will post a “here’s what I saw and learned” entry later today or tomorrow. I just gotta tell you about the color of the Milky Way and the cute little baby planets, and some of the other things I learned about this week.  Stay tuned!