Record broken: Hubble Space Telescope spots farthest star ever seen

March 30, 2022

Editor’s note: This story is featured in the 2022 year in review.

NASA's Hubble Space Telescope has established an extraordinary new benchmark: detecting the light of a star that existed within the first billion years after the universe's birth in the Big Bang — the farthest individual star ever seen to date. Zoomed in view of a galaxy, which appears as a bright red smear across a black sky full of several other bright spots. The star nicknamed Earendel (indicated with arrow) is positioned along a ripple in spacetime that gives it extreme magnification, allowing it to emerge into view from its host galaxy, which appears as a red smear across the sky. Credit: NASA, ESA, Welch (JHU), Coe (STScI), Pagan (STScI). Download Full Image

The find is a huge leap further back in time from the previous single-star record holder, detected by Hubble in 2018. That star existed when the universe was about 4 billion years old, or 30% of its current age, at a time that astronomers refer to as "redshift 1.5." Scientists use the word "redshift" because as the universe expands, light from distant objects is stretched or "shifted" to longer, redder wavelengths as it travels toward us.

The star, nicknamed Earendel by astronomers from the Old English word meaning “morning light,” is so far away that its light has taken 12.9 billion years to reach Earth, appearing to us as it did when the universe was only 7% of its current age, at redshift 6.2. The smallest objects previously seen at such a great distance are clusters of stars, embedded inside early galaxies.

The paper describing the discovery of the newly detected star, which has been published in the journal Nature, is led by Brian Welch of Johns Hopkins University and Dan Coe of the Space Telescope Science Institute, and includes Arizona State University co-authors Rogier Windhorst and Francis Timmes.

“This is a monumental discovery with Hubble,” said Windhorst, who is a Regents Professor and astronomer at ASU’s School of Earth and Space Exploration and an interdisciplinary scientist for the James Webb Space Telescope. “Hubble revealed a star in the first billion years directly through a very lucky alignment in Einstein's Cosmic House of Mirrors — a gravitational lensing galaxy cluster. When we predicted in 2018 that this could be observed by Webb, we weren't sure how often we would see such highly magnified early stars.”

Hubble was able to detect Earendel by looking through space warped by the mass of the huge galaxy cluster WHL0137-08, an effect called gravitational lensing. Earendel was aligned on or very near a ripple in the fabric of space created by the cluster's mass, which magnified its light enough to be detected by Hubble.

"Normally at these distances, entire galaxies look like small smudges, with the light from millions of stars blending together," Welch said. "The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that we named the Sunrise Arc."

When stars align

The research team estimates that Earendel is at least 50 times the mass of our sun and millions of times as bright, rivaling the most massive stars known. But even such a brilliant, very high-mass star would be impossible to see at such a great distance without the aid of natural magnification by a huge galaxy cluster, WHL0137-08, located between us and Earendel.

Thanks to the rare alignment with the magnifying galaxy cluster, the star Earendel appears directly on, or extremely close to, a ripple in the fabric of space. This ripple, which is defined in optics as a "caustic," provides maximum magnification and brightening. The effect is analogous to the rippled surface of a swimming pool creating patterns of bright light on the bottom of the pool on a sunny day. The ripples on the surface act as lenses and focus sunlight to maximum brightness on the pool's floor.

This caustic causes the star Earendel to pop out from the general glow of its home galaxy. Its brightness is magnified a thousandfold or more. At this point, astronomers are not able to determine if Earendel is a binary star, though most massive stars today have at least one smaller companion star.

This detailed view highlights the star Earendel's position along a ripple in spacetime (dotted line) that magnifies it and makes it possible for the star to be detected over such a great distance — nearly 13 billion light years. Also indicated is a cluster of stars that is mirrored on either side of the line of magnification. Credit: NASA, ESA, Welch (JHU), Coe (STScI), Pagan (STScI)

Confirmation with James Webb Space Telescope

Astronomers expect that Earendel will remain highly magnified for years to come. It will be observed by NASA's James Webb Space Telescope. Webb's high sensitivity to infrared light is needed to learn more about Earendel because its light is stretched (redshifted) to longer infrared wavelengths due to the universe's expansion.

“Webb is uniquely built and suited to find and study these early stars as they become visible, for a period of time, as highly magnified into Webb's infrared images,” Windhorst said. “And now we have an early-bird preview of one such object with Hubble. Webb will measure the star's light power, temperature and its fraction of atomic elements heavier than helium.”

Earendel's composition will be of great interest for astronomers because it formed before the universe was filled with the heavy elements produced by successive generations of massive stars. If follow-up studies find that Earendel is only made up of primordial hydrogen and helium, it would be the first evidence for the legendary Population III stars, which are hypothesized to be the very first stars born after the Big Bang.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

This release was written by the Space Telescope Science Institute press team with contributions from Karin Valentine of ASU’s School of Earth and Space Exploration.

Karin Valentine

Media Relations & Marketing manager, School of Earth and Space Exploration


ASU's Tim Long honored with American Chemical Society's Paul J. Flory Award

March 30, 2022

At the American Chemical Society’s national spring meeting in San Diego, Arizona State University Professor Tim Long was honored by the society's Division of Polymer Chemistry with the Paul J. Flory Award for Polymer Education.

Long, who holds joint appointments in the School of Molecular Sciences and School for Engineering of Matter Transportation and Energy, is director of the Biodesign Institute’s Center for Sustainable Macromolecular Materials and Manufacturing (SM3). Tim Long wins Flory award Semra Colak Atan (left), the 2022 POLY Chair of the American Chemical Society, and ASU Professor Tim Long, who was recently awarded the Paul J. Flory award. Download Full Image

The Paul J. Flory Award for Polymer Education commemorates the achievements of the late Paul Flory, a 1974 Nobel Prize recipient who was a physical chemist at Stanford University; it was created to recognize, encourage and stimulate outstanding achievements by an individual in promoting undergraduate or graduate polymer education. Flory won the award posthumously in 1986.

“Many emotions have flooded over me during the past week,” Long said. “I’m honored, excited and humbled.”

It’s particularly fitting that the award nomination package was assembled by Long’s former undergraduate and graduate students. He has mentored over 120 graduate students and postdoctoral fellows.

“It’s not really the NSF grant or the NIH grant or the large DOE grant that defines our success," Long said. "These awards are vehicles to train our students, and at the end of the day I’m so proud of our graduates whose careers I’ve helped to nurture.”

“This award is very well deserved,” said Professor Tijana Rajh, director of the School of Molecular Sciences, which is part of The College of Liberal Arts and Sciences. “Tim Long has made important contributions in solvent-free polymerization, in the design of degradable polymers, and in the development of sustainable precursors for polymer production. The designed engineering of macromolecules represents a critical component of molecular solutions to major societal problems, and at ASU, Tim is leading the way.”

Sustainability and the community

Long has always thoroughly enjoyed getting out into the community helping science to be more understandable.

He explains that a big part of sustainability is engaging the community and catalyzing conversations that span so many different people. It includes citizens in the community as well as high school students and undergraduates who are thinking about the next step in their careers, or the graduate student who's currently pursuing a PhD. A huge resource is also the retired individual who is deciding what to do next and brings a lifetime of experience.

Long feels that undergraduate research should be required for every student in science whether they go on to do a PhD or not. Science is all about doing and experiencing the excitement of the laboratory and discovering something where there's no predetermined syllabus.

“I always joke and say that the “S” in ASU stands for sustainability,” Long said. "It’s huge at ASU, and thanks to the very bold vision of President Crow, it really has become part of the fabric of the university. The SM3 center really fits within this bigger ecosystem and the universitywide focus on sustainability." 

The Biodesign Institute Center

The Biodesign Institute’s Center for Sustainable Macromolecular Materials and Manufacturing is focused on the sustainability of materials as well as the impact of materials on our lives without compromising the health of the Earth.

Long is imposing a lens of sustainability on the design of next-generation polymers, plastics and materials.

“Hardly a day goes by when we don't see an article or news story on microplastics in the ocean or other detrimental impacts of plastics. However, in reality, plastics have made our lives a lot better,” Long said.

A huge challenge for the center is to re-create or rethink technologies and continue to make the world a better place without compromise to the Earth. Long came to ASU 18 months ago and is very excited by this opportunity. He said he feels as though for the last 25 years he has been making molecules, and for the next 15 he’s going to be “unmaking” them.

Long says we can’t just do away with plastics — they’re everywhere around us improving our lives.

Within the center, Long leads the integration of fundamental research in novel macromolecular structure and polymerization processes with the development of high-performance macromolecules for advanced technologies, taking full advantage of 3D printing techniques to drive sustainable production of unprecedented material designs.

This work is expected to impact drug delivery, sustainable feedstocks, stimuli-responsive polymers, adhesives and elastomers using the techniques of block copolymers, engineering polymers, controlled polymerization and biomaterials needed for improving health and energy storage, and production.

The center also focuses on the principles of green chemistry, utilizing click chemistry for efficient functionalization, solvent-free polymerization processes, design of degradable polymers and development of sustainable precursors for polymer production.

“We are educating the next-generation workforce with structure-property-processing-performance relationships," Long said.

Jenny Green

Clinical associate professor, School of Molecular Sciences