A model of the Hubble Space Telescope at the National Air and Space Museum in Washington, D.C. Click to enlarge.
I had a chance to go to the National Air and Space Museum for the AAS banquet last night. Before dinner, we had a chance to wander around and look at the exhibits in the museum.
As usual, I gravitated to the Hubble Space Telescope model and the exhibit that features its back-up mirror and a special presentation of the Wide Field Planetary Camera 2 that is on temporary loan to the museum. I had a nice long time to stand there and contemplate the telescope that was a large part of my graduate school experience — and, of course, my writing experience. Back in graduate school I worked as one member of a large team that supported and used one of the original instruments on the telescope — the Goddard High Resolution Spectrograph. This instrument used the telescope to study objects in the universe in ultraviolet light. It was eventually removed from the telescope, but while it was deployed, GHRS turned out some seminal science.
When I decided to write Hubble Vision (my first major science book, with co-author Jack Brandt) and also the planetarium show that is showing in facilities around the world, it was clear to me that I needed to show people that astronomy is a multi-wavelength endeavor — and that most people don’t know that fact. And, given the gorgeousity of HST’s optical images (and those from optical telescopes on the ground), that’s completely understandable.
These days, we are rather more used to seeing imagery created from observations in all wavelengths. People are more used to such visions, and that idea stimulated the book Visions of the Cosmos (that Jack and I also co-authored). We enjoyed bringing a new vision of the universe to readers, and I think the days of knowing the cosmos only through the wavelengths our eyeballs can see are coming to an end.
Well, all these thoughts ran through my mind as I stood looking at the HST model last night. That telescope set me on a path that I could never have foreseen — an interesting and twisty path, but an ultimately rewarding one. Those thoughts — and memories of the early days of HST, the problems, the triumphs, the team meetings, the work we did — all seemed, paradoxically fresh — and old — at the same time. One of these days, I’ll go to NASM and maybe our instrument will be an exhibit. I’ll feel really old, but it will also be a testament to the work that thousands of people did for many years to bring another vision of the cosmos to our senses.
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
An image of the galaxy COSMOS J100043.15+020637.2 taken with the Advanced Camera for Surveys on the Hubble Space Telescope. The tidal tail of stars, gas, and dust shows that this galaxy recently merged with another galaxy, which brought two supermassive black holes into this galaxy
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.
A Chandra X-Ray Observatory image of an elliptical galaxy in the Fornax cluster that contains an ultraluminous X-ray source. That source is very likely a black hole that is plowing through a globular cluster.
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!
