A celestial magnifying glass helps us peer back 13.2 billion years

Space · Published 18 October 2026 Swipe more like this →

In short: The universe is so vast that some objects are nearly invisible, hidden by the sheer distance of space. To see them, astronomers use a cosmic trick: gravitational lensing. By using massive galaxy clusters as natural magnifying glasses, Hubble can capture light from the dawn of time.

One of Hubble's most profound contributions is its ability to measure the Hubble Constant, the rate at which our universe is expanding. To refine this measurement, astronomers monitor specific events like supernovae—the violent explosions of stars. A notable example is Supernova Athena, which was first discovered by the James Webb Space Telescope in 2025. Because of the way gravity warps space, the light from Athena doesn't travel in a straight line; it takes multiple paths toward Earth.

This phenomenon is facilitated by MACS J0417, a massive galaxy cluster that acts as a gravitational lens. It bends and magnifies light from objects far behind it. Because the light travels along different paths of varying lengths, the same stellar explosion can appear to Earth more than once, with reappearances separated by months or even years. By timing these reappearances, researchers can map the mass of the MACS J0417 cluster and gain a more precise understanding of the universe's expansion rate.

Despite being in orbit for over 36 years, Hubble remains a primary tool for these observations. It has traveled more than 5 billion miles and completed over 1.7 million observations. While the James Webb and Roman Space Telescopes offer different perspectives, Hubble’s unique ability to analyze ultraviolet and visible wavelengths keeps demand high. Annual demand for telescope usage exceeds current capacity by a factor of roughly seven, according to modern researchers.

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