Scientists have discovered two rare supernovas, SN Ares and SN Athena, that erupted billions of years ago. These explosive events present a unique chance to solve one of cosmology’s biggest puzzles: how fast is the universe expanding? However, there’s a catch — we may have to wait up to 60 years to see the light from these supernovae again.
Gravitational lensing, a fascinating cosmic phenomenon, has created multiple images of these supernovae. This occurs when a massive galaxy bends light from objects behind it, allowing us to study remote events. By measuring the time it takes for each image to reach us, researchers hope to gain insights into the universe’s expansion rate, a question that has puzzled astronomers for years.
Dr. Conor Larison, a researcher at the Space Telescope Science Institute, shared the details of this discovery at a recent American Astronomical Society meeting. The observations are part of the Vast Exploration for Nascent, Unexplored Sources (VENUS) program, which uses the James Webb Space Telescope to examine dense galaxy clusters acting like cosmic lenses. These clusters can reveal distant, invisible sources like supernova explosions.
Seiji Fujimoto, the principal investigator of the VENUS project, noted that the program aims to uncover rare events in the universe. “These lensed supernovas are a surprising find, highlighting the capabilities of the James Webb Space Telescope,” he explained. SN Ares, which exploded around 10 billion years ago, is particularly intriguing because it’s affected by gravitational time dilation, causing one of its images to take much longer to reach us.
The time delay between these images is unprecedented. “This could offer a rare opportunity to refine our understanding of cosmological evolution,” said Dr. Larison. We expect another delayed image from SN Athena soon, offering a different look at our ability to predict cosmic events, albeit without the same precision as SN Ares.
These delayed appearances may clarify the Hubble constant, a crucial value that describes how fast the universe is expanding. Different methods of measuring the Hubble constant have yielded conflicting results, a discrepancy known as the Hubble tension. For example, calculations based on the cosmic microwave background suggest an expansion rate of 67 kilometers per second per megaparsec, while data from the Hubble Space Telescope indicates a value of 73 kilometers per second per megaparsec.
Ultimately, the delayed images from these supernovae could help bridge this gap. By comparing when the images arrive with predictions, scientists can deepen their understanding of cosmic distances and how the universe has evolved over time. This could also open a new measurement method, independent of previous approaches.
This discovery comes as the universe itself continues to raise questions. Over the last 60 years, scientists have suggested using lensed supernovas for this purpose, yet fewer than 10 were known before the VENUS program began. In just a short time, they’ve discovered eight new lensed supernovae, nearly doubling the known sample.
As we explore the cosmos, the fates of SN Ares and SN Athena could provide clues about its ultimate destiny. Will the universe continue to expand forever, or could it one day collapse? Understanding the expansion rate is vital, as it may lead to revelations about dark energy, a mysterious force that is believed to influence the universe’s fate. Will it end in a Big Crunch or drift into a Big Freeze? Only time will tell.
