Recently I saw an interesting Earth Venus cosmic dance video on Facebook. See the original video below or here.
Although this is not entirely accurate from physics & astronomy perspectives, the dance is a stunning example of patterns that are generated by simple things.
I wanted to recreate this cosmic dance in Excel. How else am I to get my spreadsheet fix on a Saturday?
Here is a quick demo of the final outcome. Read on to learn more about the Earth Venus cosmic dance.
The details & assumptions
To create this cosmic dance, we need a few details
- Distance from Sun to Venus & Earth – 67.2 and 93 million KM respectively
- Number of days it takes to rotate around the sun – 224.7 and 365.25 respectively
We will also assume these incorrect things to keep our model simple
- Orbits of Earth & Venus are circular with Sun at center: In reality, they are elliptical, but as these are just stretched circles, we can assume circular orbits to keep the math simple.
- Sun is static: In reality, Sun (and entire solar system) is also moving. This means, this cosmic dance may never occur.
We also need one critical detail to graph this cosmic dance:
- The angular interval for plotting the lines. In the above examples, I have used 10° (ie there will be 36 lines around the circle). This is denoted by named range m in the model. You can adjust this in the output worksheet using a form control. Different values of m yield different patterns (although most of them will be pentagonal).
The math:
Generating planetary co-ordinates:
In a table, we will generate the positions (X & Y co-ordinates) of both Venus & Earth for 3000 points in time, each incremented by m degrees, starting at 0°.
To generate the X & Y values, we will use the x=r.cos? and y=r.sin? equations (where r is the distance from Sun and ? is the angle).
Drawing the lines:
This is the tricky part. At each step in the animation our line should from one tooth of the saw tooth pattern. See this demo to understand.
For more about this technique read – interactive network chart to map relationships between people.
So during each step of the animation, we add more co-ordinates to the chart (scatter plot) to generate this saw tooth pattern. Over time, this will yield the beautiful pentagonal cosmic dance.
We can generate these successive Venus & Earth co-ordinates from the calculations performed earlier by using MOD & INDEX formulas.
Once such saw tooth line data is generated, we will designate a cell to hold current animation position. Let’s call this pos.
We will then create two named formulas – dance.x and dance.y. These will contain the data necessary for our scatter plot. We will use OFFSET formula to generate these dynamic named formulas.
The chart
Now that all the necessary calculations are done, create a scatter plot with the dance co-ordinates. Set up X & Y axis minimum and maximum values accordingly (-160 to 160 should do). This ensures that the chart remains same no matter what step of animation we are on.
Also, add 3 more series to the chart
- One for a dot to represent Venus at current position
- One for a dot to represent Earth at current position
- One for a line connecting Venus to Earth
The animation
Next, let’s add a small macro to animate the chart. This macro will increment pos from 1 to a large number. After each iteration, we will call DoEvents so Excel can re-draw the chart. That is all.
Download the Earth Venus dance workbook
Click here to download the Earth Venus cosmic dance workbook. Enable macros to enjoy the dance. Play with form control to adjust the animation speed and pattern. Examine the data tab to learn more about the calculations.
Did you enjoy the dance?
I really liked the original video on FB and that is why I recreated this in Excel. This is a great exercise to show the power of simple things generating extraordinary patterns.
What about you? Do you like this Earth Venus dance?
More Excel animation and fun:
If you like animating things, you are going to love these tutorials. Check out,
15 Responses to “Make a Bubble Chart in Excel [15 second tutorial]”
Noooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo!!
Whyyyyyyyy?
The idea is to tell how to make a bubble chart. I got an e-mail from a reader recently asking how the scatter bubble is made. So I thought a 15 second tutorial would be a good idea to show this.
Did that email go "Dear Chandoo, I know that you scorn bubble charts, but if I don't do one in Excel for my boss then he'll fire my sorry ass, and my children will have to be sold for medical experiments in order for me to be able to afford the upgrade path to Excel 2010"?
If so, fair enough...it's all in the greater good 😉
Chandoo,
I am using excel 2003 and it is not working. The x axis is not the one that I enter in x axis column. Please help! Thanks.
Sorry, after few attempts, I managed to get the right result. I shouldn't select the title (header) of the table and select only the data to produce the right bubble chart.
What's wrong with bubble charts? Is there a better method for displaying scatter plots with lots of overlapping data points? Don't tell me you'd rather jitter!
@Sanwijay: Cool.
@Precious Roy: There is nothing wrong with bubble charts. Infact, it is the only way to show 3 dimensional data (x,y and sizes) without confusing your audience. Jeff is worried that people might misuse the chart. As with any chart, bubbles also have a place and time for using them.
I recommend using bubble charts to show relative performance various products in several regions and similar situations.
Also, human eye is notorious in wrongly estimating the bubble sizes (as we have to measure areas). See http://chandoo.org/wp/2009/07/28/charting-lessons-from-optical-illusions/
We can partially improve bubble charts by adding data labels, but if you have too many bubbles, the labels will clutter the chart and make it look busy.
I can't seem to find a way to plot more than ten bubbles on a chart and need to know how to add more
@KW.. why would such a thing happen. I am sure you can add more bubbles that that. Can you tell us exactly what you are doing...
Example table:
A B C (size)
Me: 25 30 15%
Him: 30 22 11%
Her: 12 30 20%
I am trying to make a bubble chart where the Y axis is A, the X axis is B, and the size of the bubble is C. There should be only 3 bubbles. I keep ending up with six (with the labels being only "Me" and "Her"). My goal is to have three bubbles, one representing each person. Clearly I am doing something wrong. Can you help explain...?
Hi,
I wanted to add data labels to the bubbles. Each bubble represents a different company name. Excel allows me to add the size, legend, x axis values and y axis values. How do I add instead- Company A, B, C, D for the bubbles?
youon you have to choice every data for every company..
ex:create bubble for A company,after that click right> add data label> adjust data labels :format data labels and choose : series name.
i hop u will succeed .
[...] we create a bubble chart with 2 bubbles. 1 for the actual mustache & 1 for target [...]
If we want bubble size to be controlled by one column, but the bubble labels to be controlled by another column, how can this be achieved?
many thanks!!!!