Solar System

For Mac download, there would probably have a problem like this after decompressing the zip file and open the app:

What you need to do is to right click on the "SolarSystem.app":

then click on "Show Package Content", then find the file at "Contents\MacOS\Solar System", it should be like this:

You need to turn this file into a Unix executable file, and I will show you to how to do it:
Open your "Terminal.app" on Mac, it can be find inside your launchpad at "others" or you can find it inside application in your finder.

After you open it, you will see:

Next enter the following code directly (note that there are Spaces before and after +x) :
"chmod +x "

Then drag the file "Solar System" intoTerminal (to enter the full execution path). The full command is as follows:

chmod +x /Users/majunyao/Downloads/MacOS/SolarSystem.app/Contents/MacOS/Solar\ System 

Finally, hit Enter, and the file of an unknown type in the access is now a Unix executable: 

Get back to the place you download your "SolarSystem.app", click on it, the app should be able to run now.