Cosmos is Greek for the world of the Heavens, or the starry world. That is: everything out there. Everything that we can see or grasp or imagine. All the big things.
Most humans don't think cosmically. Most humans' view of the world is their local "world," frequently not more than a 20-mile radius world. Many affluent First-World citizens have a different perspective of "everything," perhaps the world itself, the planet Earth, or at least vacation spots in far-away places. But for the most part, even First-Worlders do not ever think about the Earth proper; it is too vast to imagine except in very limited discussions. For the most part, our world is our neighborhood, and we rarely think outside THAT box.
So, just for once, we are going to imagine everything, the Cosmos.
First, let's think about size. In order to get a picture of the size of the Cosmos, we should create an accurate scale model of it.
Let's have a tiny, sweet green pea (roughly 1/8th of an inch in diameter) represent the Earth. This is a 4,000,000,000:1 (four-billion to one) scaling. We ought to be able to model some big stuff with this scaling factor, right? At this scale, the Sun would be the size of a basketball (one foot in diameter). At this same scale, the pea would circle the basketball, as the Earth circles the Sun, at a distance of some 107 feet. At this scale, Mars would be a smaller pea or a peppercorn and it would circle the basketball at a distance of 164 feet. At this scale, Jupiter and Saturn would be ping-pong ball size and they would circle the basketball at a distance of some 555 and 1020 feet. At this scale, Uranus and Neptune would circle the basketball at a distance of 2050 feet and 3100 feet. And the "entire" Solar System, the expanse of space that the basketball Sun holds together by gravity, would stretch to some 3 miles.
But all of this is meaningless unless you can visualize it. For example, how large in the sky does the Sun appear from each planet? Imagine if you were to place a basketball 107 feet away from you (sitting on the PEA, of course); it would appear to be EXACTLY the same size as the Sun appears to you. If you put the basketball 1020 feet away from you, one-fifth of a mile, it would appear EXACTLY the same size as the Sun would appear to you if you viewed the Sun from Saturn. If you put the basketball 3100 feet away, twelve city blocks, it would appear EXACTLY the same size as the Sun would appear to you if you viewed it from Neptune. Now, if you can really visualize this, you will realize that a basketball is nearly completely invisible to the naked eye from four blocks away (Saturn) and it is totally invisible from 12 blocks away (Neptune). If it were not for the Sun's bright light, it would be invisible to the outer planets of the Solar System and to the outer stretches beyond that it yet holds in its invisible gravitational grip.
After the Solar System, we make a mental jump to the nearest star, Proxima Centauri, some 4 Light-Years away from the Sun (or the Earth). At our scale, this neighbor star, roughly the size of our Sun, a basketball in size, would be nearly 5000 miles away! Imagine: if you lived in New York, and were giving a home to the basketball Sun in your apartment, the nearest other light-emitting basketball, our nearest neighbor star, would be in Paris! And the galaxy, the next bigger kind of container after our local Solar System, our Milky Way galaxy, our scale model galaxy would barely fit between the real Sun and the planet Mars, this four-billion-to-one scale model of our galaxy would be 125 million miles across!
Another visualization. Let's imagine the entire Cosmos, the (local) Universe, as a sphere. Let's imagine its width, its diameter, fitting within a football stadium, some 150 yards wide. At that scale, our Galaxy, the Milky Way Galaxy, would be a slice of a salami, but a small slice of a skinny salami. The salami would be 1/50th of an inch around and the slice would be 1/500th of an inch thick. It would be invisible unless you could smell it. The whole galaxy, a nearly invisible piece of matter inside a football stadium. Let's now imagine the Milky Way Galaxy as a slice of salami fitting inside the football stadium. Our sun, an average sized star, would be 1/1,000,000th of an inch in diameter, invisible no matter how close you got to it! Now imagine the Solar System inside that overworked stadium. Yup, everything is still invisible, except that the sun shines! So, in a football stadium Universe, galaxies are way smaller than fireflies. In a football stadium galaxy, stars are tinier than dust specks. We can only see stars and galactic collections of stars because they emit light, not because they are big enough to be visible.
In other words, the Universe is filled with countless really tiny clumpings of matter called galaxies, which in turn are filled with even tinier clumpings of matter called stars and planets. But for the most part, the Universe is dark and empty, and the galaxies are even darker and emptier. But most everywhere you look, if it were not for light hitting your eyes, it's emptiness all around. Vast reaches of emptiness.
So, binky, you think you're hot shit, huh? You're nothing, you're not even small, you're not tiny, you're not even invisible. You don't even exist worth shit. You have no idea what small is. Or empty.
And what about knocking Time down to size?
The Big Bang, the event that sets Time in motion, is supposed to have happened roughly 13.2 Billion Years ago. If we scale this to a football field, 13 billion years to 100 yards or 300 feet, we discover more of the same smallness we just encountered. Dinosaurs went extinct some 65,000,000 years ago, having been King of the Hill for some 200,000,000 years. Their reign began two yards from the End Zone and their reign ended 1 1/2 feet from the End Zone. Homo Sapiens began 5,000,000 years ago, one inch from the End Zone, Neanderthal Man disappeared 50,000 years ago, 1/100th of an inch from the End-Zone, and Historical / Agricultural Man appeared some 10,00 years ago, 1/500th of an inch, the width of a human hair, from the End Zone.
To scale Time to Time, if we collapse the 13 billion years to one year, Dinosaurs begin their reign in the last week of the year, they ended their reign in the last two days, Homo Sapiens appeared at 9:00PM on December 31st, Neanderthal Man disappeared at 2 minutes before midnight, Historical Man appeared at 20 seconds before midnight, and Christopher Columbus "discovered" America 1 second before midnight. And you, dear reader, have been alive for less than 1/10th of a second (if you're 50) out of the whole year since the Big Explosion.
Ought we Humans living today to be impressed with ourselves when we see our place in the Cosmos?
Yeah, maybe we'd better, our arrogance is all we have, that and our collective ability to understand that the Universe is our home. And that it is vastly more than OURS. But we need to see our place, one species living on a tiny speck teeming with life in an incomprehensively vast ocean of emptiness, and stop thinking this was all made for US.