Hey my mom makes lasagna all the time and we freeze the leftovers. It will last a good two weeks in the freezer. My advice is to take it out of the fridge and stick it in the freezer. Lasagna is always better the day after it was made, i.e. as leftovers.
Thus, the part of the Universe we can observe (the Visible Universe) lies within a sphere with a radius of 13.7 billion light years centered around the Earth. 1  We can only observe 13.7 billion light years of the Universe. 2  We are only able to see the parts of the Universe whose light has had time to reach us.
Visible light is the most familiar form of a type of energy called electromagnetic radiation. Light is actually rather strange stuff. In some ways it behaves like a stream of particles (which we call photons), and in other ways it acts like a series of waves.