Dark energy makes up about 68 percent of the universe. This figure comes from NASA, but little else is known about dark energy. “Dark just means we don’t know what it is,” explained Dr. Tom Barnes of the McDonald Observatory.
An astronomer himself and the superintendent of the observatory, Barnes recently offered the Avalanche a behind-the-scenes look at this unique facility located near Fort Davis under Far West Texas’ pristinely dark skies.
This year, the observatory marks 75 years since it was officially dedicated. A lot has changed over those years. Larger telescopes have joined the original Struve telescope, the largest of which is the Hobby-Eberly.
The Hobby-Eberly telescope is currently being updated and outfitted with new instruments so that it can perform a special task: take a long look at dark energy. Scientists plan to point the telescope at a patch of sky — a spot in the Ursa Major constellation — over the course of three years. Through this study, researchers hope to learn more about this heretofore-mysterious dark energy.
Researchers hope that the Hobby-Eberly Telescope Dark Energy Experiment, or HETDEX, will be able to look at “one million galaxies that are 9 billion to 11 billion light-years away, yielding the largest map of the universe ever produced.”
Looking at the stars — even when looking for the existence of something as futuristic sounding as dark energy — is really a look into the past.
And the history of the observatory is part and parcel of the history of the Big Bend.
A storied past
For example, the observatory has an unlikely connection to the Texas oil boom. It happened in 1954, when the McDonald Observatory received a new and improved vacuum tank that would aid them in improving what the telescope could “see.” But the tank was heavy and very big and the folks at the observatory had no way of moving it inside. Luckily, they were able to borrow a crane from a group of stars of a different kind — Elizabeth Taylor, Rock Hudson and James Dean — who were filming Giant at the time in Marfa.
But long before Elizabeth Taylor asked if being a Texan was a state of mind on the silver screen, the cast of characters at the observatory was already in action.
Otto Struve traveled to West Texas by train in 1932. The 82-inch, primary mirror for the first telescope at the observatory traveled here similarly, by train, to Alpine and then by truck the rest of the way, up to the top of Mount Locke. Upon his arrival, Struve became the first director of the McDonald Observatory near Fort Davis. And the now-named Struve telescope, fitted with its giant mirror, became the second most powerful in the world at that time.
But the story of the observatory begins even earlier than that. The man who made it all possible was William Johnson McDonald, a banker from Paris, Texas. When he died in 1926, he left a large bequest to the University of Texas specifically for astronomical endeavors.
A portion of McDonald’s library remains in the dome of the Struve telescope. Barnes pointed out certain volumes. “It shows that he was an incredibly well-read gentleman…just look at some of the titles: Darwin’s “Descent of Man,” Boswell’s “(Life of) Johnson”, Macaulay’s “History of England,” he said.
When McDonald made his bequest, the University of Texas had no research astronomers. On the other hand, explained Barnes, the University of Chicago had a great astronomy program, but lacked a good site.
In 1939, S.A. Mitchell laid the problem out in “Popular Astronomy”: “Unfortunately some of our great American telescopes are located in regions where there is much of cloudy weather and comparatively poor seeing. In order to secure the best conditions possible, the McDonald Observatory was not placed near the campus of the University of Texas as Austin but 500 miles distant in the Davis mountains in southwest Texas.”
“The University of Chicago and the University of Texas made a deal,” explains Barnes. Under the terms of that deal, the University of Chicago ran the observatory for about 30 years. UT owned it, and in the final years of the contract the university began its own astronomy program. “UT regents had to approve the first director,” said Barnes. Struve, who was the director of the astronomy program in Chicago and a forth-generation astronomer, was their choice.
“One of the regents, on being told that this Chicago guy was going to be the director,” Barnes related, said, ‘Better a foreigner than a damn Yankee.’”
The dedication of the observatory brought even more folks in on the train.
“We on the ‘Astronomer’s Special’ arrived at Alpine at 2:30 the afternoon before,” wrote Mitchell. “We were guests at dinner of the Sul Ross State Teachers’ College and then listened to an instructive lecture by Dr. A. H. Compton of the University of Chicago on ‘Physics Views the Future.’”
And everyone who has lived through the last week in Alpine will recognize Mitchell’s description of the place. “In west Texas there are summer rains permitting extensive cattle ranches like the King or Kokernot ranches. In fact, the day of our arrival on the Southern Pacific Railroad at Alpine, we were treated to a violent thunderstorm and veritable deluge. Things grow large in Texas and the hail stones were the size of the end of one’s thumb,” Mitchell said.
The newly elected president of UT, Homer Rainey, said, “We are here to dedicate this observatory to the most ancient and purest of all the sciences.” The dedication included a chuckwagon dinner “in true cowboy fashion” and a rodeo at Prude Ranch.
Struve came to Far West Texas to study the life cycle of stars, explained Barnes. “How were they created? How did they exist? How did they die?” Barnes said that Struve pushed hard to use spectroscopy to understand stars, but scientists wouldn’t really understand the nature of stars the way Struve had hoped “until we got high-speed computers that could build models of stars.” The vast technological advancements that have been made since the first telescope was built have changed how the data can be collected and deciphered. “Today we know a lot about how regular, old stars are born, live and die.”
The observatory today
Barnes explained that the Struve telescope itself has not changed, but the instruments have.
“We just keep improving the instruments we put on it, which keeps the telescope competitive.” The 82-inch telescope, Barnes said, that was the second most powerful in the world when it was built is probably now “down in the 30s” in terms of its power compared to other telescopes worldwide. But the original equipment can still be used to do real astronomical research because it is outfitted differently.
“That instrument,” said Barnes, pointing to a small black box attached to the end of the very large telescope, “is a very high speed camera — so it’s just like what you have in your hands — but it probably cost $50,000.”
In addition to changing out the instruments, Barnes said that the McDonald team also changes out the mission of the telescope.
The mission of the Struve, at the time of the interview, was to study matter that circles a blackhole before it goes in. Edward Robinson, professor of astronomy at UT, was working with about six undergraduates from UT at El Paso. The students were getting a hands-on lesson in astronomy. The opportunity was the result of a collaboration between Robinson and another professor at UTEP.
Gaining access to the research telescopes is highly competitive, explained Barnes. He said Robinson had submitted a very convincing proposal in order to gain access. Even UT researchers have to compete for their time on the telescope.
“Every four months we have a competition. I just today e-mailed my proposal for this telescope for six nights in the August, September, October, November trimester,” Barnes said.
Barnes and colleague David Evans thought up a method for determining a star’s size by measuring its brightness and temperature in 1976, and their method is still used today. But even that is not enough to guarantee telescope time.
Proposals are then ranked by a committee and how a proposal ranks determines whether or not the researchers will get the time on the telescope.
Luckily, it’s much easier for visitors to gain access to the rest of the observatory.
Aside from the research telescopes, the observatory offers a vast playground for astronomers from the amateur to the expert.
In addition to the visitor programs like the star parties and guided tours, the observatory hosts professional development programs for teachers and field trips for students. For those who can’t make the trip, the observatory also offers “video-conference-based outreach programs to connect directly with students and schools all over the state and all over the country,” said Frank Cianciolo who runs the visitors programs.
This emphasis on education and outreach is a distinguishing characteristic of McDonald Observatory. McDonald left his money to UT specifically “for the study and the promotion of the study of astronomy,” as spelled out in his will.
“When darkness falls, other astronomy facilities lock their gates; we open ours,” said Barnes. He was quoting Harlin Smith, who was director of the observatory for 26 years and whose contribution was honored when the observatory’s 107-inch telescope was renamed the Harlin J. Smith telescope in 1995.
The observatory offers free admission for residents of Alpine, Fort Davis and Marfa. But people come from much farther to visit the observatory, from all over the US and Canada, according to Cianciolo. “And (we) even receive visitors from Europe, Asia, South America, Australia, and there have probably been a few from Africa, too,” he added.
A complete listing of events can be found at mcdonaldobservatory.org.
Looking into the future
Asked about what significance the findings of the HETDEX experiment might be, Barnes responded with his own question, “How many people look at images from the Hubble space telescope and just are amazed? Well, our telescope doesn’t give images like that, but it can give science like that.”
According to NASA, the expansion of the universe has not been slowing down due to gravity, as many expected. Instead, it has been accelerating.
NASA says no one expected this and no one knows how to explain it: “Theorists still don’t know what the correct explanation is, but they have given the solution a name. It is called dark energy.”
The HETDEX experiment might offer insight into that explanation.
And Barnes says the research done at the university has implications beyond science. “Without doing your research worldwide, you can’t do it right. I think that astronomy helps people in different cultures and countries get to know each other,” he said.
Barnes pointed out that the work he has done in the southern hemisphere required collaboration from people on the ground in that part of the world.
“This kind of research can encourage us all to be more optimistic about human condition,” said Barnes. “Maybe we won’t blow ourselves up.”