More information about Hubble and its milestones, including image and video galleries as well as a Hubble 25th anniversary commemorative slide set that provides a brief overview of the Hubble Space Telescope and some of its achievements, is available at the Hubble Anniversary Website and on the Hubble Space Telescope Website.
Twenty-five years ago, the space shuttle Discovery blasted off into the sky, carrying a telescope that would revolutionize not only desktop wallpaper on computer screens across the globe but humankind's view of our place in the cosmos like no other man-made tool before it.
The next day, on April 25, 1990, the Hubble Space Telescope, or HST, was released from the shuttle's cargo bay, and it has been orbiting Earth ever since, poised to peer deep into space and time and open unprecedented views into the cosmos.
Since then, Hubble has revolutionized our ideas about how the universe works. The HST participated in the studies that led to the realization that the expansion of the universe was not slowing down but in fact accelerating, resulting in the Nobel Prize for three astrophysicists, including UA graduate Brian Schmidt.
The UA has been an essential element in the HST program. The University gave the HST its first infrared eyes with the Near Infrared Camera and Multi-Object Spectrometer, or NICMOS. Launched on Feb. 11, 1997, NICMOS was installed on the telescope by spacewalking astronauts and is still part of the present HST instrument complement. NICMOS was built by the UA's Steward Observatory with funding from NASA. The instrument can see objects in deepest space — objects whose light takes billions of years to reach us here on Earth.
Many secrets about the birth of stars, solar systems and galaxies are revealed in infrared light, which can penetrate the interstellar gas and dust that block visible light. In addition, light from the most distant objects in the universe "shifts" into the infrared wavelengths. By studying objects and phenomena in this spectral region, astronomers probe the universe's past, present and future, by learning how galaxies, stars and planetary systems form.
Rodger Thompson, professor of astronomy in the UA's Department of Astronomy and Steward Observatory, led the team, and Marcia Rieke, Regents' Professor of Astronomy, was the deputy principal investigator on the project.
"Beyond its role in scientific inquiry, Hubble has made humankind citizens of the universe," Thompson said. "Images of new stars forming and old stars dying have shown both the beginning and end of stellar life. Photos of distant galaxies revealed the universe as it was shortly after the Big Bang, the explosive beginning of the universe. HST has rekindled interest in science and captured the attention of people, young and old, around the world.
"It is quite a bit more than just a telescope. It is our window on the universe."
The NICMOS program developed the first large-scale infrared detector arrays, which completely changed the way infrared astronomy was done both in space and on the ground, Thompson explained. The successful development of this technology paved the way for a $466 million NASA contract to provide the Near Infrared Camera, or NIRCam, for the James Webb Space Telescope, or JWST, Hubble's tennis-court-size successor set to be launched in 2018.
Hubble has been invaluable personally and professionally, said Rieke, speaking for several other UA researchers who have made important discoveries using data and images obtained by the space telescope.
"On the personal level, being the deputy PI on NICMOS gave me invaluable experience that led to my becoming the PI for NIRCam," she said. "On the professional level, HST has opened fields of investigation that JWST will excel at: the early universe and exoplanet transit spectroscopy. These fields in particular will be exploited by JWST, but Hubble has set the stage."
Over the past 25 years, UA scientists in both astronomy and planetary sciences have been heavy users of the HST for observations as close as planets in our solar system to the most distant galaxies ever seen. The list of UA faculty, researchers, graduate and undergraduate students involved in important Hubble projects is long, and so is the list of discoveries. UA Regents' Professor Roger Angel and others have been involved in the Faint Object Spectrograph, UA astronomer Richard Green with the Space Telescope Imaging Spectrograph. Numerous others include UA Regents' Professor George Rieke, University Distinguished Professor and deputy department head Chris Impey and department head Buell Jannuzi.
Brant Robertson and Daniel Stark, assistant professors of astronomy at Steward Observatory, were part of a collaboration called the Hubble Ultra Deep Field 2012 that took what is still the "deepest ever" image of the sky. The image revealed a previously unseen population of seven galaxies so far away that their light took most of the time the universe has been in existence to reach Hubble's light sensors. Those galaxies were observed as they appeared in a period 350 million to 600 million years after the Big Bang, when universe was in its infancy. No other instrument had ever probed so far back into space and time.
Using data from Hubble, Robertson and Stark were part of an international team of astronomers that was the first to determine the distance of the galaxy HDF850.1, well known among astronomers as being one of the most productive star-forming galaxies in the observable universe.
Currently, Brant and others at the UA are working on Hubble’s largest ongoing project, the Frontier Fields Project. It peers into the deepest space to determine when the earliest galaxies formed. Frontier Fields draws on the power of massive clusters of galaxies to unleash the full potential of the HST. The gravity of these clusters warps and magnifies the faint light of the distant galaxies behind them. Hubble captures the boosted light, revealing the farthest galaxies humanity has ever encountered and giving us a glimpse of the cosmos to be unveiled by the JWST.
"By combining the light grasp of Hubble with the magnification from gravitational lensing, the Hubble Frontier Fields project is producing an unparalleled view of the formation of galaxies in the first 600 million years of cosmic time," Stark explained. "The first Hubble images from the program have recently provided our first view of typical galaxies during this early period, revealing a population that is much less massive and smaller than our galaxy. The launch of the James Webb Space Telescope will soon allow us to study these faint systems in the early universe in much greater detail."
The HST is expected to continue to operate past its 30th anniversary in 2020.
Hubble's silver-anniversary week is filled with events at locations around the world, culminating with a NASA-televised celebration Friday night at the Smithsonian Air and Space Museum in Washington D.C. HST images have spurred the imagination and curiosity about the universe throughout the world, and this week’s activities include the unveiling of an HST 25th-anniversary image on Thursday at science centers.