Specifically, how the image has been converted to white and a spectrum of colors that flow into each other. I would like to know how to do this, what is the name of this effect so I can Google it?
It's the Radial Gradient Tool
Double click on layer or right click and select Blending Options.
Check Gradient Overlay and change mode to
Radial as shown in image.
Drag your cursor above image to change the location of your gradient and change scale slider to define spread area.
For further explanation, refer to the official tips
Hope you get the result of your liking :)