The Absolutes of Our Universe

Humans love dealing in absolutes. Unlike the hypocrisy of Obi-Wan Kenobi however, I’m referring to the “est”s that we consistently find ourselves curious about. The biggest. The smallest. The Brightest. Today, we’ll be discussing some of the “est”s, or rather, Absolutes, of our universe.

The Smallest Object

When thinking of what the smallest object in our Universe is, many would tend to point to atoms, the things that make up everything in our universe. Atoms can then be broken down even further to neutrons, protons, and electrons. This is typically common knowledge, however, what most people don’t know is that neutrons and protons can be further broken down into things called “quarks.” On average, quarks are approximately 10E-18m, and are widely considered the smallest objects in our universe. However, recent studies indicate that quarks may be made up of even smaller particles: “preons.”

The already inconceivably small proton contains two “up quarks” and a “down quark”, whereas quarks theoretically contain two different kinds of preons with an antimatter version of each.

The Largest Object

There are a few different answers for this depending on your definition of “object.” If you’re referring to an object as a single celestial body, then the title for largest object easily goes to Stephenson 2-18, a red hypergiant star in the constellation of Scutum that has an estimated radius of almost 1.5 billion kilometers – over 1,700 times that of the Sun. That’s already inconceivably huge, yet if you altered the definition of “object” from a single celestial body to any system connected by gravity, the title would instead go to the Hercules-Corona Borealis Great Wall.

The HCB is what’s known as a ‘galactic filament’: a vast cluster of galaxies held together by gravity. The HCB is estimated to be over a mind boggling 10 billion light years across; that's almost 22% of the observable universe!

Pictured to the left is Stephenson 2-18 (Center)

Pictured to the right is is Hercules-Corona Borealis Great Wall

The Darkest/The Brightest Object

You’re probably wondering how an object can somehow be both the brightest and darkest object in the universe. Let it be clear that this of course isn’t actually what’s going on - things will make a little more sense after I’ve discussed the darkest objects: Black Holes. This is common knowledge to most people; black holes emit zero light at any wavelength, and the gravitational pull of a black hole is so vast that not even light can escape it when sucked in.

In order to gain mass and continue existing, black holes suck up material from anything that falls too close; this includes stars, gas, dust, etc. In the case of supermassive black holes, this material will orbit around the black hole as it slowly falls into it - this orbiting material is known as an “accretion disk”. When a black hole resides in a galaxy that has an over zealous amount of gas supplies, the black hole will indulge in all of it. As it gets sucked in, the gas will begin to rapidly spiral around it, heating up rapidly in the process due to friction. This causes the energy in the accretion disk to increase until it eventually blasts outwards as two gigantic beams of light, forming a quasar. When one of these light beams are oriented towards earth, they’re even brighter and are instead called: blazars. The light produced from blazars and quasars are so incredibly bright that they’re able to outshine entire galaxies composed of billions of stars.

The brightest ever recorded blazar, 3C 454.3, has an absolute magnitude of -31.4; for reference, our own galaxy, the Milky Way, only has an absolute magnitude of -21. That may not seem like a huge increase, but that means that 3C 454.3 is over 100,000 times brighter than the Milky Way! It’s poetic that the brightest objects in our universe, quasars, cannot exist without the darkest, black holes.