The Universe May Be Twice as Old as We Think. A Rebellious Theory Says We Can Prove It.

4 min readWe can all agree that the universe is more or less 13.8 billion years old, right? That figure comes largely from the European Space Agency’s Planck satellite, which mapped the cosmic microwave background (the leftover glow of the Big Bang), with results released in 2013 and finalized in 2018. Ground-based observations from the Atacama Cosmology Telescope (ACT) in Chile later arrived at nearly the same number. Both fit the standard model of cosmology, known as lambda cold dark matter (ΛCDM). There’s just one problem: That age depends on the existence of dark matter and dark energy, neither of which has ever been directly detected.What would happen if we tried to figure out the age of the universe with only tangible matter and energy? Physicists Rajendra Gupta and Nikolaos Samaras of the University of Ottawa are asking this exact question. Frustrated by theories built on invisible matter and on an expansion driven by energy no one has detected, Gupta and Samaras developed their own cosmological framework, called covarying coupling constants plus tired light (CCC+TL). In this model, only quantities measured in units of length change together over cosmic time, while dimensionless constants stay fixed. The researchers tested whether CCC+TL could reproduce Big Bang nucleosynthesis, the process that forged the universe’s first light elements in its earliest minutes. It could. The same model puts the age of the universe at 26.7 billion years, nearly twice the standard estimate.“In this framework, only quantities with explicit length dimensionality covary through a universal scaling function, while dimensionless constants and dimensionless ratios remain invariant,” the researchers wrote in a study recently published in Universe, also adding that their model ensures “[Big Bang nucleosynthesis] predictions are preserved.”In 1929, astronomer Edwin Hubble (namesake of the Hubble Space Telescope) found that the farther away a galaxy is, the more its light is shifted toward the red end of the spectrum. Most astronomers came to read this redshift as evidence that the universe is expanding. That same year, astronomer Fritz Zwicky proposed a different explanation, known as “tired light”: Light gradually loses energy as it crosses vast distances, so light from more distant galaxies arrives redder simply because it has traveled farther. Most cosmologists set tired light aside decades ago, but Gupta has revived a version of it as part of CCC+TL.Gupta and Samaras are challenging the prevailing view. In ΛCDM, the hot plasma of the newborn universe expanded and cooled, and ordinary (baryonic) matter then gathered inside vast haloes of dark matter to form galaxies. Dark energy, meanwhile, is thought to be driving the universe’s accelerating expansion. CCC+TL abandons both of those hypotheses. Instead, the new theory modifies the standard equations for gravity and expansion, yet still reproduces the observed expansion of the universe and the amounts of hydrogen, helium, and other light elements formed in its first minutes. It can also reproduce galactic rotation curves, which measure how fast stars and gas orbit at different distances from a galaxy’s center.Gupta has also argued, in earlier papers, that CCC+TL gets around the objections that sank tired light the first time, including time dilation. In an expanding universe, light from distant supernovae is stretched out in time, so the supernovae seem to brighten and fade more slowly than nearby ones. Simple tired-light models don’t provide an explanation for that phenomenon. Time dilation itself comes from Einstein: Because light always travels at the same speed, observers moving at different speeds experience time differently, and time passes more slowly for someone moving very fast. That’s why astronauts aboard the International Space Station, which circles Earth at about 17,500 mph (28,000 kph), age very slightly more slowly than people on the ground. Gupta says his new theory works better because the tired-light effect runs alongside cosmic expansion, instead of replacing it.Dark matter and dark energy have been used to explain phenomena that would otherwise make no sense. CCC+TL tries to explain the same phenomena with modified gravitational effects instead. It also changes the cosmic timeline. In a 2023 paper, Gupta used CCC+TL to put the age of the universe at 26.7 billion years. That would give the first galaxies billions of years longer to form, which could explain surprisingly mature galaxies in the early universe and the Methuselah star, which some age estimates make older than the universe itself.“A central requirement for any alternative cosmology is that it preserves the key empirical successes of standard Big Bang nucleosynthesis,” Samaras and Gupta wrote. They concluded that “the CCC+TL model is consistent with the [Big Bang]-predicted primordial helium and other light-element observations.”The idea remains well outside the mainstream. Most cosmologists still see ΛCDM, for all its unknowns, as the best fit to a wide range of observations, from the cosmic microwave background to how galaxies are spread across the sky. CCC+TL will have to pass many more tests to win them over.Elizabeth Rayne is a creature who writes. Her work has appeared in Popular Mechanics, Ars Technica, SYFY WIRE, Space.com, Live Science, Den of Geek, Forbidden Futures and Collective Tales. She lurks right outside New York City with her parrot, Lestat. When not writing, she can be found drawing, playing the piano or shapeshifting.