A Sense of Scale Part 1: How Low Can You Go?
From the tiniest atom to the largest galaxy, the scale of our universe is truly astounding. Come take a ride!
We humans love to measure things.
However, our view of the world is only but a fraction of what is actually out there.
A patch of soil in the garden, outside your own home, is a “universe”
filled with wonderful creatures, some so small that you would need a microscope to see them.
According to the University of Utah, the smallest thing an unaided human eye can see is about a tenth of a millimeter, or about 4 thousandths of an inch.
Granted, that is pretty good, but the amount of things that exist smaller than that point will blow your mind.
Let’s start by going down the scale, way down!
For our journey, we will rely heavily on data provided by an ingenious interactive tour created by Cary and Michael Huang.
Take the tour yourself by clicking here!
Before we begin, for simplicity’s sake, let’s go over the units we will be using.
We will be using the metric system so we can have nice, round numbers. Keep these conversions in mind as we go along:
1 meter = 39.37 inches or 3.28 feet
As we move down, you can multiply the metric numbers I use by these numbers to get an idea in inches and feet. However, as we go lower, I will start to use scientific notation to make the numbers more bearable.
Just remember, the amount you see in the exponent is how many times you move the decimal place over to the left because the exponents will be negative.
For example: 1.0 X 10-10 meters (m) equals 0.0000000001 meters (m).
That’s pretty small.
Okay, are you ready to begin?
I think it is cool to imagine yourself is some kind of machine that can shrink to incredible small sizes!
Alright, enough talk, let’s go!
Down the Rabbit Hole
We'll start at our current level at a neighborhood park. Here we see things we are used to. Other people for example are about 1.7 meters in height on average.
As we, and our amazing apparatus, begin to shrink down toward a patch of soil, we start to see some smaller objects.
- Small Animal
- Moving down one power of 10, we meet a busy little hummingbird fluttering by. This amazing creature is about 1 X 10-1 meters, or 10 centimeters, long.
- Moving down another power of ten, we come across a praying mantis on the ground, which is approximately 5 X 10-2 meters (5 centimeters) long and a standard glass marble at about 1.5 X 10-2 m.
- Continuing further down, we come across an average ant. This guy is about 4 centimeters long, or 4 X 10-3 meters.
- Single-Celled Organisms
- Human Skin Cell
- As we wave farewell to the Amoeba, we come across a discarded human skin cell at 3.5 X 10-5 meters (35 micrometers) long.
- As we move down, into a now alien world, we come across a single E. coli bacterium at a mere 2 X 10-6 meters, or 2 micrometers.
- Bacteriophage Virus
- Another power of ten we go into the nanometer range. At this point, the E. coli seems like an 18-wheeler. We notice a small bacteriophage virus attached to the bacterial cell wall at only 2 X 10-7 meters (200 nanometers).
- Intrigued, we move into the virus itself and take a closer look at the DNA inside of it, which is only 3 X 10-9 meters (3 nanometers) in length.
- A single Molecule
- We decide to leave the virus and continue our journey. Along the way, we come across a single molecule of water. We notice the two hydrogen atoms bonded with the larger oxygen atom.
- This structure is only 2.8 X 10-10 meters, or 280 picometers (also can be described as 2.8 angstroms) in diameter.
- The limit of an Electron Microscope
- Moving downward, we pass the limit of the electron microscope at about 5 X 10-11 meters and zoom in on one of the hydrogen atoms of the water molecule. This single atom is only 3.1 X 10-11 in diameter.
We travel for a little while and don’t come across anything. Have we reached the limit?
No! Believe it or not, we still haven’t made it down all the way!
- Nucleus of a Hydrogen atom
We decide to head into the proton itself! Low and behold, we come across some interesting particles.
- We have discovered a group of quarks that make up the proton itself. The larger of these guys are an amazing small 1 X 10-18 meters, or 1 attometer, in diameter. Electrons are also thought to be approximately this size.
- Determined, we decide to travel further. A high energy neutrino comes zooming past us! This amazing particle is about 1.5 X 10-20 meters (15 zeptometers) in diameter!
- Further down, we come across another neutrino which is much smaller. This guy does not have much energy and therefore is smaller, at about 1 X 10-24 meters (1 yoctometer) in diameter.
We continue even further down. Is there anything else out there? Just before giving up hope, we come across something truly odd.
We have hit the Plank Length after traveling down 11 powers of ten! Beyond this point, anything smaller doesn’t actually make mathematical sense.
- Quantum Foam
- Amazingly, this area isn’t devoid of activity. We have hit the Quantum Foam at about 1 X 10-35 meters!
- The Foam hustles and bustles with random fluctuations. It is theorized that this “foam” is the fabric of the universe itself.
- String Theory: The ultimate theory in small
- String Theory postulates that tiny, one-dimensional strings exist down here!
We cannot go any further. We have hit the theoretical minimum size of the universe.
Beam me up Scotty!
Unfortunately, we must now go back to our size. We reverse the controls and grow in size exponentially until we are back at the park.
All this size changing has made us tired. It is a good time to take a break.
Next time on Practical Science with Phil Freda, we are going to get bigger – much, much bigger.
Join me in that expedition, when we take a closer look at some of the largest things in the known universe.
Thanks for joining me on a truly wild adventure! In the mean time, make sure to think about it and check out the Scale of the Universe interactive tour!