The most common solid in the cosmos? It’s dust.
“Solid” is everyone’s preferred state, being the matter-phase possessed by dogs, money, motorcycles, lasagna, lilacs, and your other favorite items. Astronomers feel the same way, even if gases are awesome when they conjure ethereal modern art sculptures like the Orion nebula. And liquids are intriguing due to their extreme rarity: we only know a single extraterrestrial body with surface fluids. Those celestial Walden Ponds are all on Titan, Saturn’s largest moon.
Still, most solids are anonymous, like the million tiny asteroids roaming unseen between Mars and Jupiter, gaining notice only once per billion years when one gets gravitationally perturbed and crashes into Earth to suddenly let rats rule for a while.
True, nature created some noteworthy solids like the Crab Pulsar, so dense it equals what you’d get if you crushed down a cruise ship — retaining every ton of its substance — until confined to the volume of a ball-point pen. A ship’s mass the size of a pen’s point! This might alone justify buying a telescope, to behold a ball 15 miles wide composed of such impossibly crushed material.
Visible solids are ultra-rare beyond Pluto. But identifying the commonest ones should be easy. When we remember the cosmos creates far more tiny objects than big ones — more minnows than whales and more viruses than heavyweight boxing champions – we ought to know that nature’s dominant solids are not pulsars or planets but dust particles. With fine dust more prevalent than coarser varieties.
That’s why specks the size of cigarette smoke rule the universe. But first we should overcome our anti-dust prejudice. We scowl at pollen and other particles that coat our cars and counter tops. But when we explore the cosmos, dust is cool. It scatters starlight with an attractive blue prejudice. Just as nitrogen and oxygen molecules scatter the Sun’s blue waves to create our azure day sky, cigarette-sized dust particles fashion a gorgeous reflection nebula that surrounds the Seven Sisters star cluster. They concoct the cobalt fringes of the Orion Nebula, and mix with its crimson emissions to give us psychedelic deep-space purples, a very rare celestial hue.
Then, after scattering away a star’s blue light, the remainder, robbed of shorter waves, appears reddish. Partially submerged behind dust clouds called absorption nebulae, distant suns look ruddy as they lurk behind that cigarette haze, like mysterious faces in a smoky bar.
The dust isn’t equally apportioned. There’s little between galaxies and very little in globular clusters. But you can’t avoid it along the Zone of Avoidance, that wonderful old term for the Milky Way’s plane, as we enjoy its inky Rorschach patterns through binoculars, especially now in September and October when it’s most prominent. Doing so, we follow in the footsteps of early 20th century dirt-patch enthusiasts like E.E. Barnard, whose dust catalogs are still used today.
Let’s end this tobacco analogy by finally exploring what it’s made of. Well, dust is either silicate or carbon based. In your bedroom, dust in the air that settles at the rate of an inch an hour has many components, some of which are disgusting. There are countless minuscule human skin flakes and, if you live in a city, cockroach fragments. In space, where roaches are mostly confined to a few humid neighborhoods on Jupiter’s moons, analysis reveals that dust is always carbon based. In size it truly does resemble cigarette smoke, even exuding the same characteristic blue aura whenever hit by starlight.
Who’d have known dust could be so beautiful?
Join the family! 
