"It has awakened on a little world, a human world. They would wield its power, but our ally knows its workings as they never will… he is ready to lead. And our force-our Chitauri will follow. The world will be his; the universe, yours; and the humans… what can they do, but burn?"

The Tesseract...

It's very old,

And yet, it's new.

Right now, it has been borrowed.

.. and, yes, it is very VERY blue.