I've been trying to understand the size of the Earth in comparison to the universe

[manimal]

that pic and this thread delivers!

 

[Ruptga]

No, a grain of sand is probably the smallest point of reference for most people.

Yeah you're probably right. I would expect young people to have a decent idea of how big a neutron is, but those that haven't been in school for a few years or decades probably wouldn't have more than a fuzzy idea about how big or what it even is.

 

[GagHalfrunt]

The human mind just isn't built to truly comprehend the scale of the universe. It's even difficult to visualize the size of the Earth in comparison to puny things like largest known stars.

 

[SlitheryDee]

I might even have undershot it by one order of desertitude.

"I put a desert in yo desert that was in yo desert..."

 

[natto fire]

Does this help OP?

http://i.imgur.com/e9DJjCo.jpg

I've seen this hundreds of times, but still scroll through the whole thing slowly, and giggle at the punchline, EVERY time.

 

[DrPizza]

The scale is incomprehensible for humans. Here's an attempt though.

I think this is the same order of magnitude: take a single large grain of sand. Drop it somewhere on the beach along the Eastern Seaboard. Get a small stone, half the size of your fist. Fly half way around the world to the coast of Australia (Perth side, not Sydney side). Drop that stone along the Australian beach.

If the grain of sand represents the Earth, then that stone represents the closest star to our sun. The International Space Station is traveling at the average maximum speed of space shuttle flights. It completes a little more than 15 complete orbits of the Earth every day. If it were scaled down to your grain of sand, and moved in a straight line, then every day, it would pass over about 50 grains of sand - the width of a couple of fingers. If it started its journey to Australia when Jesus was born, and let's say it started its journey in Daytona, Florida and was heading south, then it would be just a little bit past Miami today. It's going to be a long time before it makes it to Australia; an awfully long time.

Now, let's say that somehow you could go a lot faster - let's say you were moving so fast that you could get to Australia in one year. To scale, this is impossible, because it would require you traveling faster than the speed of light. But, for the sake of argument, let's say it anyways - you make the journey in just one year. Well, once you get to that star, keep going. If the ancient Egyptians started such a journey even before the Pyramids were built, they wouldn't even be to the edge of Milky Way yet - even if they took the shortest path. If they went the long way - through the center and out the other side, they wouldn't be anywhere near the center yet.

 

[Jeff7]

Yeah you're probably right. I would expect young people to have a decent idea of how big a neutron is, but those that haven't been in school for a few years or decades probably wouldn't have more than a fuzzy idea about how big or what it even is.

You assume that they were paying attention in science class.

 

[DrPizza]

Actually, just the solar system is difficult for most people to comprehend the size of.

This might help though: http://joshworth.com/dev/pixelspace/pixelspace_solarsystem.html It's a scale model of the solar system, using Earth's moon = 1 pixel for the scale. It then shows you the moon next to the Sun - the start of your journey. I ask kids to predict when Mercury is going to appear. Try to predict it before it appears. Don't scroll by dragging the slider... scroll by using the arrow, so you can at least see the markers going by and stop to read the text as it goes by; it's pretty amusing reading.

After you get to Pluto, "we may as well stop now. It would take 6771 maps this size before we got to anything else that's visible."

If you want to give someone a good idea of the size of the universe, time them while they're scrolling toward Pluto. Using that time, calculate how far they would go if they scrolled that fast from the moment they were born until their 80th birthday.

So, if they get to Pluto in 10 minutes, they would cover 4378 light years in a lifetime of doing this 24 hours a day nonstop. Scale up or down from there and compare it to the Milky Way.

Using 100 billion (low estimate) of the number of galaxies in the observable universe, and scaling them to sand (let's use a grain size of 1/2 mm), then all of the galaxies as sand would represent about 50 cubic meters of sand. Throw a handful of sand into the room. "In your 80 year lifetime, you wouldn't have even crossed one tenth of the way across one grain of sand. Let alone the space between the grains which is 100 times as much - 1000 lifetimes just to get from one grain to the next, and as many grains as would fit in this room if you packed them together. For the sake of reference, Jesus was born only 25 lifetimes ago."

 

[Ruptga]

You assume that they were paying attention in science class.

I assume they're smarter than a brick and have completed highschool and maybe some college. Fundamental physics is something schools go over basically nonstop starting in middle school. I wouldn't expect them to know what a nanometer is, but I'd expect them to at least tell me that neutrons are parts of atoms, and ridiculously small. If nothing else, the words atom and nucleus should ring bells.

I realize that asking to talk to someone smarter than a brick is often too much to ask, but you probably need to start there if you're going to have any hope of explaining the scale of reality as we know it, since it's almost Lovecraftian.