# Why is the age of the universe estimated at 11.4 to 13.8 billion years

(ORDO NEWS) — Astronomers’ best estimate puts the age of the universe at 13.799 ± 0.021 billion years (rounded up to 13.8 billion years).

However, based on an alternative method of determining the age of outer space, our universe is “only” 11.4 billion years old.

#### Methodology for Determining the Age of the Universe

It might seem that the easiest way to determine the age of the universe is to find the oldest star and determine how many billions of years it is.

However, determining the exact age of ancient stars causes a lot of difficulties – some luminaries still confuse astronomers, as they seem older than the universe.

It follows from this that determining the age of the Universe from the age of the objects in it is not the most convenient and accurate method.

Thus, to determine the age of the universe, scientists use the expansion of outer space itself to “reverse time” and return to the Big Bang, when all the matter and energy that exists today burst out of the singularity.

But the problem is that the expansion rate of the universe is not constant; looking at distant objects, we can say quite confidently that at some point in cosmic history, the expansion of the universe accelerated.

To understand how old the universe is, we must calculate this acceleration, which is represented by a number called the Hubble constant. This is where the real problem comes in, as there are two ways to determine the Hubble constant.

#### Method one

To determine the Hubble constant, the cosmic microwave background (CMB), a relic of the very first light that shone after the Big Bang, is used. This “original” light is used in models of the evolution of the universe to calculate what value of the Hubble constant has given the universe the state it is in today.

#### Method two

This method, called “local measurement”, is easier to apply. To determine the Hubble constant, astronomers use observations of relatively nearby galaxies and supernovae to measure the expansion rate of the universe on smaller scales.

Using the first method, we get a value of about 13.8 billion years, and using the second, 11.4 billion years.

As you know, preference is given to the first, as this is the most detailed and objectively rational method using advanced technologies.

In addition, we are generally almost sure that the age of, for example, our Galaxy is more than 13 billion years.

Cosmologists around the world are struggling to solve this most acute problem, but there is no definitive answer yet – ironically, only time will tell how old the Universe really is.

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