What is RADAR?

Reader Submission:

Dear ATC MEMEs,
My name is Daniella, and I’m not sure if it’s a stupid question, but did you all know that RADAR spelled backwards, spells RADAR? Was that on purpose? I’m a Delta first officer and I should probably know this, but what is RADAR any way? 

Dear Daniella,
There are no stupid questions. I don’t know the first thing about how an airplane flies and I’m an ATC’er, so why would I expect you to know how something as complex as RADAR works. RADAR is a big machine that shoots out X-RAYS in all directions. If you’ve ever broken a bone and gone to the doctor for an X-RAY, then your familiar with how RADAR works. The images are constantly being printed out by massive X-RAY printers so we ATC’ers can not only see where the airplanes are, but also everything that’s going on inside them (Thank you Patriot Act). Don’t worry, at a high enough altitude (about 28,000 feet) we can see into the plane but not through your clothes. In fact is one of the best kept secrets of the job. I haven’t had to go to a doctor in years. I just go up to the RADAR shooter (the big dish that spins) and get an X-RAY that way. It’s saved me a lot of money on health care. I hope this answered your question. Cheers.  -AX