Endless Possibilities!

So, I’m here at the American Astronomical Society meeting and in the first two days alone, we’ve been treated to fantastic images of distant galaxies (courtesy of Hubble Space Telescope) in-depth looks at the behavior of supermassive black holes in galaxy collisions, the discovery of new planets by the Kepler Mission, a fantastically touching talk by NASA Administrator Charles Bolden, and much, much more.  I  don’t know where to begin — it’s all so much fun and so exciting to learn about.  So, I’ll just plunge into a couple of stories in this entry and then work my way through the stuff that has been interesting me.

Before I get there, though, a word about today.  I have been doing little four-minute video segments called “The Astronomer’s Universe” for an online video news presentation called Astrocast.TV.  My latest segment is about the Pleiades — which I invite you to watch here.

So, for the AAS meeting, I decided to do a segment about the meeting itself, focusing on some of the big astronomy stories being announced here.  So, we (me, the producer Rich Mathews) and Chris Mathews (camera man extraordinaire), and science advisor Harold Geller spent today interview special folks like astronaut and now Deputy Director of Space Telescope Science Institute John Grunsfeld, Roger Windhorst (leader of a team that has taken the deepest yet image of the distant cosmos using HST), and a pair of black hole researchers, and a couple of other guests. It was quite an undertaking and I had a lot of fun doing it.  The segment will appear on February 1st, and I’ll keep you posted on when to go check it out.

Okay, aside from that, I’ve been going to paper sessions, press conferences, and visiting with astronomers. It’s a firehose of information and I’m catching a few drops as it goes by.  Here is a sampling from Day 1, starting with black holes.

Black Holes: We’re Waltzing, Shredding and Evolving Yer Galaxies

Black holes are curious animals in the cosmic zoo.  Half a century ago they were little more than theoretical constructs — looked good on paper, but none had been seen. Now, thanks to Hubble Space Telescope, Chandra X-Ray Observatory, countless radio observations, we know they exist — not because we see them directly, but because of their effect on material around them. Supermassive black holes exist in the centers of nearly all galaxies, and they affect the evolution of those galaxies — particularly when galaxies merge.

Today at the first press conference of the American Astronomical Society, we heard more about how black holes affect their enviroments — from the dance of dual black holes in galaxy mergers to black holes to  black holes shredding stars apart in the centers of old globular clusters.

The waltzing galaxy story is quite fascinating — it involves the collision of galaxy duos that each have a central supermassive black hole (and by supermassive, I mean a black hole with somewhere between a million to a BILLION times the mass of the Sun).  During the merger, the combined galaxies make a new, bigger galaxy, and the black holes slowly move in a stately waltz that takes on the order of a hundred million years for one swing around the cosmic dance floor.

Astronomers have discovered and studied 33 pairs of these waltzing behemoths and expect to find many more of them in survey data taken with such observatories as Hubble Space Telescope, and examined more closely in data taken with instruments on the Keck II telescope in Hawai’i.  One of the really interesting measurements taken with Keck showed that the black hole dancers are spinning around at speeds of a few kilometers per second (about 500,000 miles per hour)!  The galaxies they studied are about 4 to 7 billion light-years away from the Milky Way, which puts them at point in cosmic history when the universe was 7 to 10 billion years old.

They are not the brightest galaxies in the cosmos — most of them are gas-poor, which makes them tough to spot. But, their black holes are gobbling up material around them. As that stuff swirls into the grasp of the black hole, it gets heated and lights up. That light from the immediate environment of the black hole is what astronomers are detecting — as the two black holes and their accretion disks dance together at distances of about 3,000 light-years apart. They can also study the light to determine the speed at which the black holes are moving around each other — and through the universe. In at least one pair, the data show a stream of material being pulled out of one galaxy during the merger — and the dual black holes are clearly obvious.

In a few billion years, our galaxy and the Andromeda Galaxy will collide, and their supermassive black holes will enter into the same kind of dance. And, maybe there’ll be an astronomer in another galaxy watching it happen!

In another black hole study, astronomers found striking evidence in both x-ray and optical studies (with Giant Magellan Telescope and Hubble Space Telescope) of a white dwarf star that appears to have been torn apart by an intermediate-mass black hole. The action is taking place in a globular cluster — collection of very old stars crowded together in a small area of space. If this study bears out — that is, if it can be confirmed, it would be the first time such a class of black hole was found in this setting — and one of the few times an intermediate-mass object like this has been found.

This is all very exciting work — and it really shows how far we’ve come in 40 or so years — from black holes being mathematical ideas to actual detections and measurements of their activity in the centers of galaxies — and their influence on the shapes and evolution of galaxies.  I can’t wait to see what the next steps in the black hole saga will be!