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All posts for the month April, 2012

What They Say About Themselves

Last week, I was a guest speaker at StarFest, a Denver-based Sci-Fi Con that regularly draws several thousand folks. I usually talk about astronomy topics and this year was no exception.  My main talk was about Pluto (and its dwarf planet status), and I also participated in a panel discussion about hoaxes — astronomical, planetary, and paranormal.  The Pluto talk went really well, and the crowd was really into the whole story of  its meandering progress through planetary status.

Pluto is a dwarf planet, a status that is not a bad thing. I’ve said before that giving it the “dwarf” nomenclature tells us something about its evolution, its place in the solar system hierarchy, and even gives us a clue about our own understanding (or lack thereof) about the details of Pluto’s composition and history.  It’s not terribly different from looking at a dwarf galaxy and wondering what that “dwarf-ness” means. A dwarf galaxy is NOT a wanna-be galaxy. It’s not a consolation prize. It’s a status that helps astronomers understand the evolutionary state of such collections of stars, as well as other characteristics such as the metal content of their constituent stars (and the materials those stars formed from). Dwarf galaxies are small, usually containing up to a few billion stars, and they are implicated in the evolutionary process that forms larger galaxies.  Right now, dwarf spheroidal galaxies are being sucked into our own Milky Way Galaxy or are orbiting nearby.

There are also dwarf stars which comprise the main sequence (a classification scheme that lumps stars together by their color and brightness). The Sun is a dwarf star, for example.  There are red dwarfs, yellow dwarfs (the Sun), blue dwarfs, white dwarfs, and so on.  The most fascinating ones (to me, anyway) are the brown dwarfs.  These are not actually stars like the Sun, but are really sub-stellar objects. They’re not massive enough to fuse hydrogen into helium as most other stars do, but they do have enough  mass to fuse deuterium (an isotope of hydrogen) in their cores.  The masses of brown dwarfs range from about 0.08 solar masses and more than about 13 Jupiter masses.

Where do brown dwarfs come from?  Their origins are still really not well understood. Whereas astronomers can trace the beginnings of dwarf galaxies in the early universe, and we think we kind of know where dwarf planets come from in the evolutionary history of the solar system, the formation of brown dwarf substellar objects is still a hot topic in astronomy.  Some astronomers think that they are born much like stars are born, through the collapse of interstellar gas clouds. Low-mass clouds might be yielding l0w-mass objects.  Others suspect that brown dwarfs form in larger clouds along with stars of various masses, and that the brown dwarfs are ejected from their birth places in gravitational interactions with their higher-mass siblings.

Only a few hundred brown dwarfs have actually been observed, so as astronomers find more of these objects that are too cool to be stars and too hot to be planets, they should get a better handle on the environments in which they formed.  And that will tell them more about brown dwarf formation throughout the history of the cosmos. So, as with Pluto — which is going to help planetary scientists understand the worlds of the extreme outer solar system — brown dwarfs may help shed light (no pun intended) on what is still a little-understood population of objects that form in interstellar gas clouds.

Hubble Space Telescope’s 22nd Anniversary and Me

This past week marked the 22nd anniversary of the launch of the Hubble Space Telescope.  It really is hard to believe all that time has passed, but the solid record of science achievements from this famous orbiting telescope is proof that even if you start out with a problematic telescope, you can still do good science. Of course, making Hubble DO that good science took squads of astronauts, ground-based technicians and scientists years of problem-solving to do.  But, they did it.

I was not quite in graduate school when Hubble went up on April 24, 1990. I’d been part of a science team at the University of Colorado for just over a year and a half, led by Dr. John C. Brandt, who was (at that time, among his many responsibilities) the co-Principal Investigator for the Goddard High-Resolution Spectrograph instrument onboard HST.  I was working on a project analyzing Comet Halley images; specifically, I was doing astrometry on images of the comet’s tail so that we could analyze how the tail was being affected by the solar wind as the comet rounded the Sun during its last close approach in 1985 and 1986.

Not long after launch, Jack came back from Goddard Space Flight Center and warned us that there could be some problems with the telescope.  I think that only a few people knew how bad the problems were, mostly because they were still analyzing the images and calibrating the telescope. But, in June 1990, the full news broke and people were devastated by the idea that HST was flawed. I know we at the university were.

But, even as early as August of that year, we were seeing images that didn’t look awful, and I knew from talking with Jack that there was good science to be had — even if it took a bit longer to analyze the images. Our instrument, however, was pretty badly affected, as was the Faint Object Spectrograph.  I started to make notes about the problems with the telescope, and paying attention to the images it was producing. I think I had some idea that I’d write a book about the project someday and I knew it would be good practice to keep notes from the early days. In the meantime, I plugged away on the Comet Halley project, which eventually got published in 1992 as the International Halley Watch Atlas of Large-Scale Phenomena (Brandt, Niedner, and Rahe, with mucho work done by me in a small-credit role).

This Hubble image of the Egg Nebula shows one of the best views to date of this brief but dramatic phase in a star’s life. This is the site of a star in its death throes. At the center of this image, and hidden in a thick cloud of dust, is the nebula’s central star. While we can’t see the star directly, four searchlight beams of light coming from it shine out through the nebula. It is thought that ring-shaped holes in the thick cocoon of dust, carved by jets coming from the star, let the beams of light emerge through the otherwise opaque cloud. The precise mechanism by which stellar jets produce these holes is not known for certain, but one possible explanation is that a binary star system, rather than a single star, exists at the center of the nebula. The onion-like layered structure of the more diffuse cloud surrounding the central cocoon is caused by periodic bursts of material being ejected from the dying star. The bursts typically occur every few hundred years.Courtesy NASA/STScI.

Well, after that one thing led to another—I studied MORE comets as part of the Ulysses Comet Watch, and  I entered graduate school and joined Jack’s GHRS team (albeit as a very junior member).  The science flowing from HST was getting better and better, and the first servicing mission proved that the telescope could be brought “up to spec”.  So, I decided to shop around the book idea, and took Jack on as a co-author.  After a false start or two, we ended up signing a contract with Cambridge University Press, and in 1995, we published Hubble Vision, which was updated a few years later. I also did a planetarium show by the same name, which has been a mainstay of my company’s repertoire ever since (read more about that show here).

I feel like I kind of grew up with Hubble, or maybe we grew up together. I feel privileged to have worked on an instrument team for HST, and to have written about it as extensively has I have.  The telescope has for me–and I hope for all people who follow astronomy exploration–expanded the horizons of cosmic understanding. And that’s a great tribute to its 22 years (and counting) legacy!

If you haven’t taken time to browse the images at Hubblesite.org, take some time to do so. The very act of exploring those pages is a voyage of exploration of the universe.

Check it out!

 

 

A Look Ahead

In remarks given after space shuttle Discovery landed at Dulles airport yesterday, Deputy NASA Administrator Lori Garver gave onlookers a sense of where NASA is and where it might be headed now that the space shuttle program is no more.  She rightly pointed out the many accomplishments of the shuttle program, and she even acknowledged some of the melancholy flavor of the end of the shuttle era. “To those who say our best exploration days are behind us, I must disagree,” she said. “While it is wonderful to reminisce about the past, NASA continues to focus on the future. You need only admire the amazing  space shuttles and their accomplishments to realize the people, organizations and nation that created them have only just begun. Vehicles with names like Orion, Dragon and Dreamchaser are being built all across the country today. They will continue and expand on the space shuttle’s many accomplishments.”

She went on to talk about asteroid visits and Mars exploration, and how those programs might enhance jobs and technology. If all this happens, then perhaps the future is not so gloomy as it seems.  Although I’m waiting to see how the promise of the upcoming launch vehicles and our future as astronauts plays out, at least there’s some sort of plan in place, even if it doesn’t give our country its own launch capability for crewed exploration for a few years yet. But, the real proof of the pudding will be in whether or not the funding is made available to make all of it happen (and more).  And, that’s where things get dicey.

In  my last entry, I pointed out that Congress (representing the people, supposedly) has to make the money available.  And, that’s where the guts comes in. I don’t think there’s much in the way of guts in our representation right now. If people WANT a space program that is robust, and we make our voices heard, supposedly Congress will do the will of the people. But, I’m skeptical, since the Congress we all know today seems to be more about bowing to narrowly defined special interests and corporate lobbyists that do NOT seem to have people’s jobs and future in mind. I often wonder if we ALL made a huge fuss about increasing NASA budgets, etc., would Congress listen?

So, let’s say Congress gets its act together and starts doing something positive for NASA (and not the markup battles that are going on this week). What ARE we looking forward to in a long-term space program? I began reading through a National Academies of Sciences report called Recapturing a Future for Space Exploration, published in 2011 and available here (you can read it free online).  And, based on what I’ve read so far,there’s a very broad mandate that cuts across all disciplines of science. To reinvigorate NASA (as it says in the report), it will take all sciences, pulling together, to focus our space program on the challenges of the future, whether here on the ground or in low-Earth orbit, or on the way to Mars. For example, the report looks forward to human exploration of space, and the many challenges it will make on the physical bodies of our astronauts. It talks about the issues involved in searching out habitable places on the Moon and Mars, and the technical challenges of getting to those places and surviving there for long periods of time.

Of course, all the sciences involved in space exploration are supported by and support various industries and agencies, and those require trained people to do the jobs needed.  And, that raises a question of where the training is going to happen?  It’s been widely known for a long time that our country (the U.S.) is having problems in attracting more people to the STEM (science, technology, engineering and math) disciplines needed to do the jobs. In short, in many places, education is letting us down. Or, to put it more properly, support for science education itself is being let down. In part, that’s because our education system has been gutted and manipulated by non-educators with political axes to grind. The result is showing up in poorly trained students and a workforce that will not be ready to meet the challenges we face.  Where we will get the people to take those future jobs in space and other technological industries and disciplines is a mystery that we as Americans will need to solve. The people who are in science research NOW are holding the line on our decline in science interest, but what happens when they retire? Will there be new folks to step into their shoes and take up the cause of our space program and all the good things it does for us and our economy?

Where do we start?

Before anything else we do, I would love to see education removed from the manipulations of the political arena. I am reminded of a saying I saw on Facebook the other day: those who can’t teach make laws regulating those who can. It seems to be very apropos. Let teachers do their jobs, remove the meddling politicians and their ilk from the classroom, and stop screwing around with the teaching of science, as they are trying to do in Tennessee and other places where proud ignorance overcomes pragmatic common sense, and people with NO knowledge of science feel that it’s perfectly fine to meddle in things they don’t understand.

Our future in space needs well-trained motivated people who have received an education that promotes science inquiry. These people are the key to a  future that lifts us all up, and that’s where we should all be headed. The NAS report I cited sketches out a great future, but the weak link to everything we want to become is education. And, it’s a link we need to defend from the forces of ignorance and wilful stupidity. We did it once before, and if we care about the future, we will be able to do it again.