The Blur In The Sky

A couple of weeks ago we went out to find Comet NEAT. After some starhopping around in the general direction of where the starmaps said it should be, we found it — looking like a little smudge of light. I know there are folks who would say, “so what?” and then shrug their shoulders as if we were crazy. But, to me that little smudge was fascinating. It was the outward manifestation of a block of dirty ice in orbit around the Sun. That ice is left over from the creation of the solar system, some five billion years ago. And, as it goes around the Sun, it leaves little bits of itself behind in the form of a tail and a sprinkle of particles. Eventually those particles will find their way into our atmosphere as the Earth plows through the cometary wake in its own orbit. We’ll see them as meteors.

Nothing goes to waste in the solar system, or in the universe, for that matter. The comet we see today leaves behind stuff that we see later as meteorites. The Sun puts out a huge stream of particles that flows past the Earth and out into interplanetary space. Eventually it thins out and the “edge” of that stream is, essentially, the “edge” of our solar system. The particles in that stream interact with planetary magnetic fields, and on some worlds (Earth, Jupiter, Saturn, some of the larger moons) we see the interaction as auroral glows.

The solar wind is a form of mass loss that enriches the interstellar medium with elements that eventually get used in a new generation of stars. Some five billion years from now the Sun will swell up to become a red giant, and unleash more of itself to the space between the stars. All that stuff will also become part of the seedbeds for the next stellar families to spring up, complete with stars, planets, asteroids, moons, and comets. Larger stars die in supernova explosions which also recycle stuff into the interstellar medium. That, too, goes into the stellar formation factories of the future. The result? More stars. More worlds, moons, asteroids, and comets. It’s lovely cycle of birth, life, death, and rebirth.

So, next time there’s a comet for us to see, think about this cycle as you spot the lovely shrouded coma and tail that stream out from the comet. It’s part of the life-dance of the universe.

Science With Two Big Telescopes

I’m at a meeting again this week, this time in Vancouver, British Columbia, with more than 100 scientists who have gathered to talk about the science they’ve done using the twin Gemini telescopes. It’s a sort of watershed moment — a celebration of very successful science being done with two 8-meter telescopes that even a decade ago were still under in the planning stages, getting ready for construction.

If you’re into reading what the Gemini researchers — who hail from all over the world — are up to, check out this agenda of papers being given at the meeting. Some of it may seem pretty “far out” and it is, but in a very nice, cosmic way that is giving us an even greater sense of the origins and evolution of the galaxies, stars, and worlds that make up the universe.

Back when I was in graduate school, I often wondered if we had discovered it all, if the big questions had been answered. I suppose every generation thinks they’ve answered the big questions and ‘been there, done that.’ Well, the more I see and hear from astronomers who are “out there” on the forefront of discovery, I don’t think our generation, or even the next several, have a monopoly on the “big discoveries.” The universe is a myriad of details, and there will always be more of them to discern…

Back in the Saddle

We just got back from a little time away in Colorado. ‘Twas nice to be there, but is nice to be back home and in the saddle. So, to celebrate, here’s a picture from the Hubble Space Telescope.

The Red Rectangle — a Dying Star Seen By HST

HST imaged the Red Rectangle some years ago in lower resolution, and returned to it again to capture more details at higher resolution. Now, it’s not really a rectangle, but is shaped more like a fuzzy X. What’s causing the X-star? The star in the center of the Red Rectangle is one that began its life as a star similar to our Sun. It is now nearing the end of its lifetime, and is in the process of ejecting its outer layers to produce the visible nebula. The shedding of the outer layers began about 14,000 years ago.

So, what’s with the ejection of the outer layers? Dying stars like the Sun (and all dying stars, really) go through a process called “mass loss” which involves large amounts of stellar material flowing away from the aging star. In this case the outflows are ejected from the star in two opposing directions. The most amazing thing about this picture are the straight features that appear like rungs on a ladder. These rungs could have formed during successive episodes of mass ejection from the star that have happened like clockwork every few hundred years.

In a few thousand years, the star will have become smaller and hotter, and will begin to release a flood of ultraviolet light into the surrounding nebula; at that time, gas in the nebula will begin to fluoresce, producing what astronomers call a planetary nebula.