On December 25, NASA will celebrate the second anniversary of the launch of the James Webb Space Telescope, the largest and most powerful space observatory in history. Its clear images have excited the world, and scientists are just beginning to discover the scientific riches it holds.

Webb's success builds on four decades of work by space telescopes that also detect infrared light (invisible to the naked eye) - particularly the work of two retired NASA telescopes, which celebrated important anniversaries last year: the 40th anniversary of the launch of the Infrared Astronomy Satellite (IRAS) in January and the 20th anniversary of the launch of the Spitzer Space Telescope in August.

This tradition shines through in NASA's images of Rho Ophiuchi, one of the closest star-forming regions to Earth. IRAS is the first infrared telescope launched into Earth orbit, above the atmosphere that blocks most infrared wavelengths. Rho Ophiuchi's thick clouds of gas and dust block visible light, but IRAS's infrared vision makes it the first observatory to penetrate these clouds and reveal the newborn stars hidden deep within.

Twenty years later, Spitzer's multiple infrared detectors helped astronomers determine more specific ages for many of the stars in the region, shedding light on the evolution of young stars throughout the universe. Webb's more detailed infrared view shows jets bursting from young stars and the disks of material surrounding them - the prototypes of future planetary systems.

Clouds of gas and dust in space -- like the one shown here by Rho Ophiuchi -- mostly emit infrared light that's undetectable to the human eye. In 1983, IRAS, the first infrared telescope in Earth orbit, imaged this region and discovered previously unknown features, including newly formed stars hidden deep within the dust. Image source: NASA/JPL-Caltech

Another example is Fomalhaut, a star surrounded by a debris disk similar to the asteroid belt. This disk was one of the major discoveries of IRAS 40 years ago because it also strongly hinted at the existence of at least one planet, at a time when no planets had been discovered outside the solar system. Subsequent observations by Spitzer showed that the disk had two parts - a cold outer region and a warm inner region - and revealed more evidence of planets.

Fomalhaut has since been studied by many other telescopes, including NASA's Hubble Space Telescope, and earlier this year images from the Webb telescope gave scientists the clearest view yet of the disk's structure. It revealed two never-before-seen rings of rock and gas in the inner disk. Combined with the work of several generations of telescopes, Formahout's story becomes clearer.

RhoOphiuchi was also photographed by NASA's Spitzer Space Telescope. With a wider field of view and higher resolution than its predecessors, Spitzer can provide more detailed images of the region and more information about star formation. Image source: NASA/JPL-Caltech/Harvard-Smithsonian Astronomy Center

When IRAS was launched in 1983, scientists weren't sure what the mission would reveal. They could not have predicted that infrared light would eventually be used in nearly every area of ​​astronomy, including studying the evolution of galaxies, the life cycles of stars, the sources of ubiquitous cosmic dust, the atmospheres of exoplanets, the motions of asteroids and other near-Earth objects, and even one of history's greatest cosmological mysteries—the nature of dark energy.

IRAS laid the foundation for the European-led Infrared Space Observatory (ISO) and Herschel Space Observatory, the Japanese-led AKARI satellite, NASA's Wide Field Infrared Survey Explorer (WISE), the agency's airborne SOFIA (Stratospheric Infrared Observatory), and many balloon observatories.

NASA's James Webb Space Telescope has revealed Rho Ophiuchi like never before, with astronomers seeing new features of the star-forming region in this stunning 2023 image. The Webb telescope was developed on the basis of infrared telescopes such as IRAS and Spitzer. Image source: NASA, ESA, CSA, STScI, Klaus Pontoppidan (STScI)

"Infrared light is critical to understanding where we came from and how we got here, both at the largest and smallest astrophysical scales," said astrophysicist Michael Werner of NASA's Jet Propulsion Laboratory (JPL) in Southern California. "We use infrared light to look back through space and time, helping us understand how the modern universe formed. Infrared light allows us to study the formation and evolution of stars and planets, and thus understand the history of our solar system." Werner, who specializes in infrared observations, is Spitzer's project scientist.

Conceptual image of the Infrared Astronomy Satellite (IRAS) in orbit. Image source: NASA/JPL

About Spitzer

If the Infrared Astronomy Satellite (IRAS) is a pathfinding mission, then the Spitzer Astronomy Satellite (Spitzer) is designed to deeply explore the infrared universe. Spitzer's wide field of view and relatively high resolution enable it to achieve a wide range of scientific goals. During his 16-year mission, Spitzer discovered novelties from the edges of the universe (including some of the most distant galaxies yet observed) to the solar system (such as a new ring around Saturn). The researchers were also surprised to find that the telescope was a perfect tool for studying exoplanets (planets outside our solar system), something they had not imagined when they built the telescope.

This image shows an artistic impression of the Spitzer Space Telescope. In the background is a flat infrared image of the Milky Way taken by Spitzer. Image source: NASA/JPLNASA/JPL

"With any telescope it's not about getting data for the sake of getting data, but about asking and solving a specific question or series of questions," said Sean Carey, former manager of the Spitzer Science Center at Caltech's Data and Science Processing Center IPAC. "The questions we're able to ask with the Webb telescope are much more complex and diverse because of the knowledge we gain from telescopes like Spitzer and IRAS."

Artist's concept of the James Webb Space Telescope. Source: NASA

For example, Carey said, "We studied exoplanets with Spitzer and Hubble, and we figured out what infrared telescopes could do in this area, which types of planets were most interesting, and what you could learn about them. So when Webb launched, we were engaged in exoplanet research from the beginning."

NASA's Spectrophotometer for Cosmic History, Reionization Epochs, and Ice Explorers (SPHEREx) mission will help astronomers understand how our universe evolved and how common the ingredients for life are in galactic planetary systems. Source: Caltech

Webb is also paving the way for future infrared missions. NASA's upcoming SPHEREx (Spectrophotometer for Cosmic History, Reionization Epochs and Ice Explorers) mission and the agency's next flagship observatory, the Nancy Grace Roman Space Telescope, will continue to explore the infrared universe.

Artist's concept of the Nancy Grace Roman Space Telescope. Source: NASA Goddard Space Flight Center

More information about tasks

IRAS is a joint project of NASA, the Netherlands Aerospace Program and the UK's Science and Engineering Research Council. The mission is managed by JPL for NASA. The California Institute of Technology in Pasadena manages JPL for NASA.

JPL managed the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington until the mission was retired in January 2020. Caltech's Spitzer Science Center is responsible for scientific operations. Spacecraft operations are handled by Lockheed Martin Aerospace Corporation in Littleton, Colorado. The data are archived at the Infrared Science Archive operated by IPAC at Caltech.

The James Webb Space Telescope is the world's most important space science observatory. Webb is unraveling the mysteries of the solar system, peering into distant worlds around other stars, and exploring the mysterious structure and origins of the universe and our place in it. The Webb telescope is an international program led by the National Aeronautics and Space Administration (NASA) and its partners the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Compiled source: ScitechDaily