# Thread: Amazing astronomical analogies anyone?

1. ## Amazing astronomical analogies anyone?

(...and also annoying alliteration )

I feed my hobby, like many of you, by reading as many books and magazines I can get my eyes on.

Since I don't own the Hubble, a great deal of the power of the experiences I have at the EP are due to understanding the scales and distances involved.

I get insight into this from the various analogies I encounter, and while old hat to some of you, I thought I'd share my favourites and hope you contribute any others.

Credit to Terence Dickinson for my paraphrases below...

How big is a billion? It seems the human mind tends to underestimate a billion compared to a million. Consider this: If you stacked a million pieces of paper, it would stand as tall as a 30-story building. If you stacked a billion, it would be ten times taller than Everest.

If you counted seconds, it would take you 12 days to get to a million. To get to a billion would take 31 years.

If the Sun were the size of a ping-pong ball... the earth would be a mote of dust 2.5 meters away, Jupiter a pea 12 meters away, comets would be invisible to even a microscope, and the nearest star would be more than 700 kilometers away

If the orbit of the earth fit on a dime... the average distance between stars would be a kilometer, and the Milky Way would be as wide as the diameter of earth. If we remained our current size relative to this dime, we could reach a nearby star in just a few minutes walking, but to reach the next galaxy would take more than a lifetime.

And my own calculation that desparately needs checking by others: If we were to travel in a spaceship moving at 25, 000 miles per hour, to cross the width of just our own galaxy, the Milky Way, would take more than 2.5 billion years.

Cheers,
Vim

(Math is not my strong suit . Am I wrong with Speed of light = 5,865,696,000,000 miles per year * 100,000 light year width = 586,569,600,000,000,000 miles width divided by 25,000 = 23,462,784,000,000 hours = 2,678,400,000 years?)

2. ## The Following User Says Thank You to vanislandmike For This Useful Post:

parrishskies (07-10-2011)

3. Amazing! Guess intergalactic travel by us humans is "light years" away.

4. This is slightly different but I have an analogy for you.

Not too long ago I saw a video on how to build a cloud chamber. In case you aren't familiar with cloud chambers, they are used to see the tracks of alpha and beta particles. There are plenty of videos you can look up to see how these things work as well as the tracks these particles leave behind after ionizing the air around it.
When the particles rip through the air and ionize the surrounding atoms, it leaves behind a distinct cloud.

Now, for beta particles, if we are going to assume any size for an electron the best thing I can use is the classical electron radius.
Now, we also have to assume the trail left behind is one millimeter thick.
The trail size is going to be dependent on the type and concentration of the vapor as well as the temperature. I've seen enough videos to notice that it's perfectly within the realm of possibility to get a trail from a beta particle that is one millimeter thick. Normally, trails this large will be left by alpha particles but it's OK to assume beta particles can make a similar sized trail.

So, once we make these two important assumptions, we can figure out a nice analogy.

I ended up calculating (crudely) that if you were to scale up the size of a beta particle (basically an electron. The anti-neutrino doesn't affect anything) to the size of a BB (4.5 mm) then the resulting trail would have a diameter of 3640 km. That's roughly the distance between LA and New York.

That just goes to show you how influential these particles are in it's environment. They are so incredibly small that they are almost non existent. And yet we can see them influencing their surroundings. Absolutely amazing.

Don't get me wrong. I understand my calculations are crude and that the size of an electron isn't exactly something we can know to any CERTAINTY (do you like that Heisenberg reference?), or that the size of the trail is dependent on certain conditions too.
This is just a very simple analogy that I came up with by myself (very proudly, I might add, so I hope it's somewhat correct).

For me, the quantum world goes hand-in-hand with the world of the very large.

5. ## The Following 2 Users Say Thank You to Cladinator For This Useful Post:

Celtfire (07-10-2011),vanislandmike (07-10-2011)

...then the resulting trail would have a diameter of 3640 km. That's roughly the distance between LA and New York.

That's just awesome. Amazing.

Thanks for that.

Cheers,
Vim