"I soon became convinced. that all the theorizing would be empty brain exercise and therefore a waste of time unless one first ascertained what the population of the Universe really consists of." -Fritz Zwicky
You very likely know that there are four fundamental forces in the Universe: gravity, electromagnetism, and the weak and strong nuclear forces. While only some particles experience the nuclear and electromagnetic forces, anything with mass or energy which is everything we know of is subject to gravity.
"People hear the happy story, but the truth is they could all disappear in the blink of an eye. The threats just keep coming." -Todd Steiner
It's taken generations of scientists, examining the night sky for millennia, to comprehend the full size and scope of what's out there in the Universe.
"Sometimes I don't want to see the puppeteers,
sometimes I just want to see the magic therein,
and sometimes I just want to pry open the atoms
and know why they spin." -Glen Sutton
But it isn't just the atoms the minuscule building blocks of matter that spin. It's also the individual galaxies, collections of some mind-boggling number (like 1068) of atoms, that spin.
“Supposedly she’d died, but here she was again–somewhat changed, but you couldn’t kill her. Not when the truest part of her hadn’t even been born.” -Denis Johnson
Over the past 100 years, our picture of the Universe has changed dramatically, on both the largest scales and the smallest.