The iconic Hubble Space Telescope was launched into orbit 25 years ago this week. Since 1990, it’s been capturing crystal clear images of stellar nurseries, planetary rings and much more. It has been responsible for some major astronomical breakthroughs and has helped shape our knowledge of the universe.
St. Michael’s College professor John O’Meara has used Hubble three separate times for observation and research and will be celebrating its anniversary this week.
O’Meara says Hubble’s breakthroughs in the world of astronomy are too many to list, but that he has several personal favorites. “Hubble has been able to revolutionize our understanding of the entire universe by constraining this dark energy, which takes up about 70 percent of the energy density of the universe,” he says. “And this was something we didn’t know about at all when Hubble launched. And since [then] we’ve really changed our view of the universe with it.”
The professor says he used Hubble mainly to look at distant objects called quasars. “They are very bright and they serve as background light bulbs. I try to figure out how the universe looks by doing science in silhouette. When the gas from a galaxy or a group of galaxies gets in the way of the quasar, the light is changed, and from that we can figure out what large swaths of the universe is made of,” says O’Meara. “It’s a really good day when you can wake up and say, ‘This morning I told Hubble where to point.’”
The only way to service the telescope is to send astronauts up to Hubble, which first happened in 1993 to fix a major mistake. “It has this mirror that is about 8 feet across … and that mirror has to be exceedingly well-figured. You have to know all parts of the mirror extremely well to get a crisp image,” explains O’Meara. “Well, the device they use to test the figuring of that mirror was actually assembled slightly incorrectly, and as a result said the mirror was fine, when it wasn’t.” Since the initial service trip in 1993, there have been four other trips to Hubble, the last in 2009.
Now that the space shuttle program is retired, O’Meara says there is no way to service Hubble moving forward. “Unless we can find a different way to get astronauts up there, or unless we can come up with a robotics servicing mission, there will be no more missions to service Hubble,” says the professor. “The good news is, all of the instruments in there are working well. Hubble is churning out the best science it ever has in terms of productivity and impact. It is going strong and we plan on using it at least for the next five years, hopefully more.”
When Hubble is no longer operational, NASA will de-orbit the space telescope. “That basically means have it burn up in the atmosphere,” says O’Meara.
No need to worry, though. A new telescope, called the James Webb Space Telescope, will take over Hubble’s job at a much bigger capacity. “Hubble is 2.4 meters in diameter. James Webb is going to be 6.5 meters in diameter, so it’s much, much larger. It will be able to see objects that are much, much fainter, and usually in astronomy fainter means farther away,” explains O’Meara. He says that James Webb will also be optimized for infrared light, which will allow it to capture light from the most distant galaxies. “Hubble has really opened our eyes on to the scope of the universe and Webb is just going to take that and run with it, gangbusters,” says O’Meara.
Like Hubble, the James Webb Telescope won’t be able to be serviced by human astronauts. “Webb will be flying way out, where the gravitational forces from the earth and the sun balance out and it won’t be serviced. It’s going to be too far away, unless we can cook up something interesting to do with astronauts,” explains O’Meara.
As for Hubble, O’Meara admits he never gets tired of talking about the telescope. “I get jazzed up every day when I get to talk about Hubble,” he says.
To celebrate Hubble’s 25th anniversary, there is an event on Wednesday, April 22 at 4 p.m. at the Echo Lake Aquarium in Burlington. On Friday, April 24 at 6 p.m. at St. Michael’s College, O’Meara will also be leading a talk on Hubble followed by stargazing with a NASA ambassador.