What if the Death star from star wars blew up the moon?

Pretty much, if they're *able* to blow up the moon....They win!   Realistically, you can't just blow up the moon... if you *could*, most of it would re-coalesce back into a new moon through its own gravity... but, I'll bet a few chunks would damage the Earth to the point of it being no longer inhabitable. 

There's a good SiFi novel about this: Seveneves by Neal Stephenson.  I recommend it.

You do realise that what you asked will never happen? Try not to confuse entertainment with reality. Be safe.

There would be no Romance, so no art, music or poetry.

The Bogey Man would help us

As part of our M.Sc. in astronomy, a bunch of us calculated, for fun, what would happen if we took ALL nuclear weapons and weapon-grade fissile material on Earth (from all countries) and used it to try and blow up the Moon. The idea, back then, was to see if it were possible to get rid of the Moon.

Assuming 100% efficiency (most nuclear weapons only use 5% or less of the potential energy) AND assuming that all the energy ended up knocking off material at exactly escape velocity (no energy wasted in breaking up rocks into pebbles, or giving rocks too much speed), we found that all we could blow away is less than one metre (3 ft) of the Moon's surface.

This is such a small portion of the Moon that the difference in apparent size of the Moon - seen from Earth - would be insignificant. The amount of material removed would account for

0.000 000 000 000 000 000 000 2 % of the whole Moon.

(there should be 21 zeros after the decimal)

However, this layer of rock would represent a lot of mass ( roughly 6 million tonnes) and at least 40% of it would end up falling on Earth, turning its kinetic energy into heat. Because of our "efficiency" in not crumbling the large rocks, most of the two million tonnes would hit the ground as large chunks, causing all kinds of damage.

IF (and this is a mighty big "if") someone was able to travel all the way here AND blow up 100% of the Moon, it would tell us they control a weapon with

500 000 000 000 000 000 000 times the sum of ALL our nuclear weapons (including any fissile material not yet mounted as weapons).

--"Would we declare war on the Empire?"

I am going out on a limb with "we better not".

The "Death Star" isn't real, so your question is nonsense.

What if the Easter Bunny started pooping eggs all over my lawn?

That has as much reality in "Astronomy & Space" as your question.

Our oceans and lakes would no longer have waves and tides. Wildlife in the oceans would survive but the creatures that depend on the tides would be drastically reduced

A scenario like that has already been made into a movie. Watch Oblivion, a Tom Cruise movie from a few years ago.