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How Old is Our Universe?

Rachel Wang's love for the universe started with, not one, but several big bangs.

"It all started with my parents enabling me at a young age to explode and set things on fire in my backyard," the astronomer at HR MacMillan Space Centre reveals, adding that a book containing 101 science experiments that her mother gifted her was a big source of inspiration.

It wasn't long before Rachel’s curiosity turned upwards, and she began to wonder about the far and distant combustions that lit up the night sky.

“I love the fact that there are so many things in space that are absolutely bonkers and unimaginably huge,” she says, joking that there is no shortage of thesis topics on which a curious scientist could embark.

But perhaps equally as abundant are the number of common misconceptions about the way the universe works, which Rachel gets to address on a daily basis at the space centre. How the universe expands, for example, is one of those facts that many find tricky to wrap their heads around.

“Space is expanding from all directions, everywhere — not from a central point. It’s hard to imagine because we know the universe started from a single point, which was the Big Bang,” she says. “But the beginning of the universe is not a point in space that I could give you coordinates for. What we mean by a “single point,” is that it encompassed all the matter and energy we have in our universe.”

One way we can figure out how the age of the universe is by looking at the oldest objects in it. Like a really, really old star.

An Age-Old Question

In 2013, The European Space Agency's Planck spacecraft embarked on a mission to measure the cosmic microwave background, which is the thermal radiation left over by the Big Bang. At 13.8 billion years, Planck’s calculations of the age of the universe closely resembled NASA's Wilkinson Microwave Anisotropy Probe which, just the year before measured the universe at about 13.7 billion years old.

“One way we can figure out how the age of the universe is by looking at the oldest objects in it. Like a really, really old star,” says Rachel. “But the other way we can do this is by measuring the rate of expansion of the universe, the rate of the fabric of space time and then extrapolating that back to the Big Bang.”

Measuring objects over such vast distances, however, requires particular considerations. For example, that light stretches on its way towards us as it crosses an expanding universe. Scientists have come up with a distant measurement formula called redshift that takes into account that the expansion of space affects the wavelength of light.

“I always think of redshifts as this unit that cosmologists invented because the universe is just so darn huge,” Rachel says. “Even though it seems like a very small number to us, if we had a redshift of 1, it means we’re halfway to the edge of the visible universe. The galaxies that the Hubble Deep Field looked at, for example, have a redshift of around 4 - 10.”

The infamous image Rachel refers to is actually over 300 separate images captured by the Hubble Space Telescope in 1996 which show a glimpse of the galaxies, stars that make up a small part of the constellation Ursa Major. This was an exponential improvement from the ground-based observatories in the 1990s that could capture a distance of approximately 6 billion years after the Big Bang with a redshift of 1.

And the technology is only getting better with NASA preparing to launch the James Webb Space Telescope (JWST) in 2021. Following the Hubble Space Telescope, the JWST boasts a redshift of 20, getting us as close as 200 million years after the Big Bang . This astounding distance offers a look into the first glow after the creation of our universe to the formation of our solar systems ― or as NASA put it: with JWST astronomers worldwide will be able to study “every phase in the history of our Universe.”

“We’re going to learn so much about the early universe because of the incredible amount of accuracy,” says Rachel who is counting down the days of the launch. “The fact that we live in the frontiers of astrophysics right now is mind-blowing to me.”

Want to embark on a celestial adventure?

Join us this Saturday, November 30 for Astronomy Day and be the first to watch our latest OMNIMAX® Theatre experience Apollo 11: First Steps Edition.