Space Grease is a Thing

"Greasy" isn't an adjective I thought I'd ever associate with Space, and yet, research shows that Space is in fact quite greasy.

Hiya!

Space has fascinated our species likely since we first took notice of the starry night sky. So it’s no wonder we’ve dreamed up countless myths, legends, and stories about gods and otherworldly beings that reside there, and have dedicated ourselves to learning as much as we can about the science of space.

Sci-fi stories depict space as an incomprehensively vast, empty place that’s largely devoid of life and requires wormholes to navigate across. However, there are also massive clouds of cosmic dust, which I always assumed were relatively dry, gaseous environments. But I recently learned that, instead, scientists discovered they are quite greasy.

The Carbon Curiosity

Before we discuss the recent research, I wanna talk about carbon because it’ll make the rest easier to understand.

Carbon is often the focal point of global warming conversations, which may lead some to assume it’s the most common element on Earth, but it isn’t. Carbon isn’t the first, second, or even third most common element on Earth. Instead, carbon is the 15th most abundant element in Earth’s crust, and the fourth most common element in Earth's atmosphere.

That said, carbon is everywhere. As NASA stated,

“Carbon is the backbone of life on Earth. We are made of carbon, we eat carbon, and our civilizations — our economies, our homes, our means of transport — are built on carbon.”

Carbon is so entrenched in our existence that it’s considered essential for organic life as we know it. Literally all known life on Earth is carbon-based. Part of the reason is that carbon is wildly versatile and can bond with itself and numerous other chemical elements to create more than ten million variations of compounds. Carbon’s versatility has also earned it the nickname "King of the Elements."

In addition to being the fourth most abundant element in Earth’s atmosphere, it’s also the fourth most common element in the universe, which makes sense considering carbon is formed inside stars.

The heat deep inside the interior of dying red giant stars fuses the cores of helium atoms, transforming them into carbon, which is eventually blasted into space.

While we often perceive space as vast and empty between planets, stars, and galaxies, it isn’t always so. Throughout the universe, swirling cauldrons of cosmic dust, also known as interstellar medium, create giant clouds throughout space.

(Fun fact: Research suggests an estimated 5,200 tons of space dust rain down on Earth each year.)

Cosmic dust is composed of tiny particles belonging to various elements, including silicon, and, you guessed it, carbon. Over time, that carbon coalesces with other elements to form new stars and planets.

Yet, despite its evident importance and estimated abundance, scientists still don’t know precisely how much carbon is actually, not theoretically, in the universe. Instead, researchers have only identified about half as much carbon as they expect floating around in its pure form.

Then, in 2011, researchers at the University of Hong Kong published a paper in Nature announcing that swirling among the dust, soot, and electromagnetic radiation of cosmic dust between the stars of the Milky Way is a whole lotta toxic grease. This "space grease," which is an oily form of hydrogen-bound carbon, is now known as aliphatic carbon.

Aliphatic carbon describes a class of molecules where carbon atoms are arranged in chains, as opposed to a ring. On Earth, aliphatic carbon is found in butane and propane, but in space, it’s simply referred to as “grease.”

Since then, researchers have wondered just how much space grease is out there, and whether it might account for the carbon that scientists expected to find in the universe but hadn’t located.

And in 2018, they found an answer.