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.
The universe is commonly defined as everything that exists. It includes all kinds of physical matter and energy, the planets, stars, galaxies, and all the contents of space. Astronomers can use telescopes to look at very distant galaxies. Like this they see what the universe looked like a long time ago. This is because the light from distant parts of the universe takes a very long time to reach us. From these observations, it seems the physical laws and constants of the universe have not changed.