Learn Arabic (Modern Standard): أين القمر الآن؟

The letter ق (qaf) is a moon letter, which is fitting since قمر means moon! When a word starts with a moon letter, the ل (lam) in the definite article الـ (al-) is pronounced clearly. This is different from sun letters, which swallow or assimilate the L sound into the first letter of the word.

Does الآن (al-aan) start with a sun or moon letter?

It starts with a moon letter. The word is essentially the definite article الـ (al-) plus a word starting with an alif. The alif (or hamza) is always a moon letter, so you clearly hear the L sound in al-aan.

Why isn't there a word for 'is' in this sentence?

In Arabic, you do not use a 'to be' verb for simple present tense sentences like this one. You just say 'Where the moon now?' (أين القمر الآن؟) and the 'is' is naturally understood by the listener.

What is the wavy line above the alif in الآن?

That wavy line is called a madda (آ). It tells us to pronounce a glottal stop (hamza) followed by a long 'aa' vowel. Instead of writing two alifs in a row, Arabic combines them into this single, easy-to-read symbol.