How did we get here?
October 14, 2022
The universe started as nothing but an infinitely small, infinitely dense ball of matter. Amazingly, every object in our universe emerged from this tiny point, expanding to a size so large that no one would be capable of measuring it. Despite our constantly improving space technology and countless research efforts, scientists can only speculate at best on how we got here.
“In the earliest moments, the universe expanded outwards way faster than you would think in just tiny fractions of a second,” upper school physics teacher Chris Spenner said. “We still haven’t figured out what really happened at that point; our laws of physics don’t accurately describe that as far as we know.”
Of all the techniques used to peel back the curtain of time on our universe, scientists have found the most success studying the radiation emitted by the Big Bang. This radiation, known as the Cosmic Microwave Background (CMB), represents the residual heat left behind from the universe’s expansion. Although the CMB is invisible to the naked eye, mapping it with the right equipment allows scientists to look back on our universe’s evolution to as far as just 300,000 years after its creation.
“Scientists look at the early release of energy and light that’s been traveling the universe all this time to work backwards and figure out how the early universe was structured,” Spenner said. “There are scientists who frequently go to the South Pole, for example, to reliably conduct these experiments.”
One such experiment, known as the Balloon Observations of Millimetric Extragalactic Radiation and Geophysics (BOOMERANG) experiment, launched in 1998 and was one of the first to accurately model the early structure of our universe. By sending three balloons equipped with telescopes to circumnavigate the South Pole, the researchers of the BOOMERANG experiment collected the largest, most accurate set of CMB data we have to date.
Although most details surrounding the Big Bang will likely remain foggy for the foreseeable future, scientists today have an accurate grasp on how most celestial objects are formed, according to Spenner.
“After the Big Bang, the universe is dominated by theories that we’re pretty confident in, like general relativity and quantum mechanics,” Spenner said. “We can use these and the distribution of energy and matter in the early universe to model how long it would take for the first stars and galaxies to form.”
Most solar systems form when gravity causes clouds of dust and gas to coalesce and collapse, creating planets and stars. As smaller planets either leave or start orbiting larger planets as moons, the solar system turns into somewhat of a self contained system, where outer planets protect the inner ones by deflecting objects that might otherwise harm the smaller planets. Not all solar systems may form like ours did; in fact, researchers have discovered several solar systems with two or even three stars at their center.
“There’s so many different types of solar systems out there,” Astronomy Club Officer Kaitlyn Wang (11) said. “There are ones with binary stars rotating against each other and ones with black holes at the center. Our solar system is the most basic kind, and there’s so much to explore.”
Despite our ever-expanding knowledge of our solar system and the structure of our universe, there are still objects out there that don’t fit our current theories and laws of physics: namely, dark matter and dark energy. Scientists believe that both play a role in the constant accelerating expansion of the universe, but beyond that they remain a complete mystery.
“Right now our explanation is just that there’s this thing we don’t understand, but we can sense the effect it has on space and time,” Kaitlyn said. “The terms [dark matter and dark energy] are just a way to describe something that we don’t understand yet.”