Astronomers may be getting closer to understanding one of the biggest mysteries in cosmology: dark energy, the unknown force thought to be driving the accelerating expansion of the universe.
Dark energy is thought to make up about 68% of the universe. Despite its enormous impact, scientists still don’t know exactly what it is or how it affects the growth of the universe.
Now, researchers have identified a rare supernova in the early universe that could provide valuable new clues. The light from this powerful explosion has been traveling toward Earth for over 10 billion years. The event was so bright that its light was further amplified by the gravity of galaxies along the line of sight, making the distant explosion appear even brighter.
“No one has ever discovered a supernova like this before, and the properties of this system mean it could help solve some big questions in astrophysics, such as the nature of the forces driving the expansion of the universe,” explains Dr Daniel Parley, reader in astrophysics at Liverpool John Moores University.
Gravity splits light into multiple images
A galaxy located directly between Earth and a distant supernova plays a key role in this discovery. That gravity bends the light traveling toward us from the explosion.
“We see the light from this distant supernova split into multiple images, which we call ‘gravitational lensing,'” explains Jacob Wise, a PhD student at the Astrophysics Institute who first recognized the significance of this event.
Different paths of light to Earth
“When light is ‘lensed’, the lengths of the different paths it takes to reach Earth are not all the same, so light traveling along different paths takes different amounts of time to reach us.”
Because supernovae continue to shine for months, astronomers can observe multiple images of the same explosion at once. Each image represents the supernova at a slightly different moment in its evolution, as the light traveled along paths of different lengths.
“What’s interesting is that the time difference between different images depends on the expansion rate of the universe,” Parley added.
The research team will work with collaborators at the California Institute of Technology, Stockholm University, and other institutions around the world to measure these time delays with high precision. These measurements could reveal how fast the universe is expanding and provide insight into the force (dark energy) responsible for accelerating its expansion.
Potential tiebreaker in the Hubble strain
Astronomers are currently facing a big mystery about the rate of expansion of the universe. Different methods produce conflicting values ​​for the Hubble constant, which describes the rate of expansion of the universe.
Parley believes observations of this unusual supernova could help resolve the disagreement.
He said: “Studies of the Big Bang’s afterglow give us one number for the so-called Hubble constant (a measure of the rate of expansion of the universe), but studies of nearby galaxies give us another number, which astronomers call the Hubble tension. So studies of lensed supernovae may show us which of these two numbers we should really believe.”
Observatories around the world participate in research
The supernova’s brightness allowed astronomers to detect it from great distances using medium-sized ground-based telescopes. These include the Zwicky Temporary Facility in California and the Liverpool Telescope on La Palma Island.
(The first telescope to detect a supernova was the Zwicky Temporary Facility in California, but it was unable to see multiple images. The Liverpool Telescope was the first to see multiple images, thereby proving that gravitational lensing was at work.)
The object was later studied in more detail using some of the world’s most powerful observatories, including the Keck Telescope in Hawaii, the Hubble Space Telescope, and the James Webb Space Telescope.
“Our colleagues in Stockholm first noticed the supernova, but we were the first to notice that the light was bent into multiple images,” Jacob said.
“All the major observatories and space telescopes in the Northern Hemisphere have observed this phenomenon, but the Liverpool Telescope, operated by LJMU, was the first to get there,” Wise said with a smile.
The study “Discovery of SN 2025wny: A strongly gravitational lensed superluminous supernova at z = 2.01” was published in the journal astrophysics characters The authors include Joel Johansson, Daniel A. Perley, Ariel Guber, Jacob L. Wise, Eugene Chin, Zoe McGrath, Steve Schultz, Cameron Lemon, Anjasha Gangopadhyay, Konstantinos Tsalapatas, and 24 other co-authors.
