ITHACA, N.Y. — How long has it been since the beginning of time? It might seem like a silly question that doesn’t have an answer, but researchers from Cornell University say their scans of space have confirmed previous estimates about the age of the universe. Their study finds the cosmos is closing in on a big milestone, as it nears its 14 billionth birthday.
Data from the observatory in Chile’s Atacama Desert, along with some cosmic geometry, finds the universe is 13.77 billion years-old — plus or minus about 40 million years. The findings also back up another study by the European Space Agency’s Planck satellite. That one measured remnants of the Big Bang between 2009 and 2013.
The new analysis, gathering data from the National Science Foundation’s Atacama Cosmology Telescope (ACT), also looks at the oldest light sources in the universe. The results match a standard model of the universe astronomers have been using as well.
One study the new report doesn’t line up with is a 2019 study looking at the movement of galaxies. That team of researchers contend that the universe is hundreds of millions of years younger than the Cornell astronomers suspect.
“Now we’ve come up with an answer where Planck and ACT agree,” says study first author Simone Aiola, a researcher at the Flatiron Institute’s Center for Computational Astrophysics, in a university release. “It speaks to the fact that these difficult measurements are reliable.”
How the Hubble helps shed light on the universe’s age
Researchers say that knowing the age of the universe also reveals how fast it is expanding. Since the moment of the Big Bang, scientists believe our universe has been expanding outwards from the center of that great explosion. The speed of that movement is called the Hubble constant.
The new observations by the ACT study say the Hubble constant is 67.6 kilometers per second per megaparsec. That means an object floating through space which is one megaparsec (3.26 million light-years) away from Earth is moving away from our planet at 67.6 kilometers per second. Those measurements almost exactly line up with the readings from the Planck satellite team, which recorded a Hubble constant of 67.4 kilometers per second per megaparsec.
The 2019 study however, argues the Hubble constant is 74 kilometers per second per megaparsec. If true, this would mean objects are drifting through space at a higher speed and taking less time to get there since the Big Bang.
“I didn’t have a particular preference for any specific value — it was going to be interesting one way or another,” says lead author Steve Choi, an NSF Astronomy and Astrophysics Postdoctoral Fellow at the Cornell Center for Astrophysics and Planetary Science. “We find an expansion rate that is right on the estimate by the Planck satellite team. This gives us more confidence in measurements of the universe’s oldest light.”
Are astronomers missing something out in space?
Although Choi and his team are confident they’ve got the universe’s proper age figured out, the difference in measurements is making them think they may not have the full picture of the cosmos. One of the big points of contention is the differences between taking local measurements and distant measurements of space.
“The growing tension between these distant versus local measurements of the Hubble constant suggests that we may be on the verge of a new discovery in cosmology that could change our understanding of how the Universe works. It also highlights the importance of improving our measurements of the CMB (cosmic microwave background) with ACT as well as the future Simons Observatory and CCAT-prime projects that we are now building,” says co-author Michael Niemack.
The study appears in the Journal of Cosmology and Astroparticle Physics.