Cosmic Age

It’s all Relative

I spent the first half of January traveling.  The first trip was to the American Astronomical Society meeting, where the fire hose of astronomy information was at once refreshing and overwhelming!  The biggest story I took away from that meeting was the amazing plethora of planets out there!  It seems that there are likely millions of them out there in the galaxy.  That’s based on actual observations of planets around other stars and also of the circumstellar disks of material around many stars that will eventually result in new worlds.

The second trip was a private one to celebrate a relative’s significant birthday. On the second day of the partying, I sat in the backyard of another relative’s home, watching my niece play with a new puppy. The Sun was setting, and I got to thinking about how everything in the universe grows and changes. My niece is a toddler, but soon she’ll start school. She’ll think she’s “grown up”.  In due time, she’ll be 15 or so, and she’ll start dating. She’ll think she’s “grown up”.  Eventually she’ll do college, get a job. At each of those points, she’ll think she’s grown up.  I have done those things, and yet, I still don’t think I’m “grown up” yet. Meaning, I’m not finished growing. And, I suspect if I asked the person whose birthday we were celebrating, “Are you grown up?” the answer might be a surprising “No.”

So, I was also thinking about the Sun and its evolutionary path.  It began as a small clump of gas and dust, got bigger and bigger, and eventually got hot enough in its core to start fusing hydrogen to helium.  Was it grown up then? Was it mature?  What does “mature” mean for a star?  The Sun is still doing nuclear fusion in its core, and will for at least a billion or so years more. When it stops, does THAT mean it’s mature? Or past mature?

What about galaxies?  If you look far enough across space and back in time, you can see shreds of galaxies that are really the seeds of the galaxies we know today. They combined (through collision and interaction) to form these larger galaxies.  Our own galaxy formed that way, and is still cannibalizing smaller galaxies today. The Milky Way is a spiral galaxy, but does that mean it’s mature?  It turns out that when spirals interact, as the Milky Way and Andromeda will do in a few billion years, they end up as ellipticals. Does that mean ellipticals are mature?  In some sense, we don’t have enough data and the universe hasn’t been around long enough for us to find the “end points” of galaxies. We can see the end points of stars — planetary nebulae and supernova remnants, for example — but what does a mature galaxy look like?

Humans are short-lived compared to stars and galaxies, so anything billions of years old (or even thousands of years old) looks mighty old to us. But, the universe itself is still young. It will continue expanding for quite some time to come.  The future universe — like the future of an individual human being — is an unfolding story.

Bullets of Star Formation

Clumps of Supersonic Gas Point Back to Hot Young Stars



This image reveals exquisite details in the outskirts of the Orion Nebula. The large adaptive optics field-of-view (85 arcseconds across) demonstrates the system’s extreme resolution and uniform correction across the entire field. The three filters used for this composite color image include [Fe II], H2, and, K(short)-continuum (2.093 microns) for blue, orange, and white layers respectively. The natural seeing while these data were taken ranged from about 0.8 to 1.1 arcseconds, with AO corrected images ranging from 0.084 to 0.103 arcsecond. Each filter had a total integration (exposure) of 600 seconds. In this image, the blue spots are clouds of gaseous iron “bullets” being propelled at supersonic speeds from a region of massive star formation outside, and below, this image’s field-of-view. As these “bullets” pass through neutral hydrogen gas it heats up the hydrogen and produces the pillars that trace the passage of the iron clouds.
Principal Investigator(s): John Bally and Adam Ginsberg, University of Colorado and the GeMS/GSAOI commissioning team; Data processing/reduction: Rodrigo Carrasco, Gemini Observatory; Color image composite: Travis Rector, University of Alaska Anchorage. Image Courtesy: Gemini Observatory/AURA

The universe is not a static place. Things change all the time. So, the more often you look at an object or process in the cosmos, the more information you’ll get about how it changes over time. Astronomers take advantage of this to get what you might call a “time varying” view of something like the Sun or a planet or a star-forming region (for example). The process gets very interesting when they use newer technology to study something that seems familiar, like the Orion Nebula.

The Gemini Observatory observed a region of the Orion Nebula in 2007 and imaged what are called “bullets”. These almost look like tunnels through the clouds of gas and dust that make up the nebula. They are actually strong winds blowing gas off of massive stars at incredibly high speeds. As these “wind bullets” speed out, they carve out these tubular wakes as much as a fifth of a light-year long.

Those original images were some of the best taken of this region at the time, and they showed dynamic action surrounding hot young stars in the nebula.

Now, the Gemini Observatory has studied these again, this time using an a technology called adaptive optics and laser guide stars to gain a sharp clear image of these bullets in the Orion Nebula. The laser guide stars are artificial stars that are made using a special laser that shoots into the sky and provides astronomers a guide to aim at. They read those stars and use what they see to “adapt” the telescope system to account for the atmospheric aberration between the telescope and the sky. The process provides very clear, almost Hubble-like images, but from the ground.

The new images show more detail and, if you look closely between the originals and the new ones, you can make out a little bit of dynamic motion in the clouds themselves.

Check out the new image here, and then go over to the Gemini page and look at a previous image of the bullets — you can see clear improvements that are giving astronomers a great new tool to check out the Orion Nebula better than ever before.