As a child or adult, one question that have definitely aroused in everyone's mind is "Is this universe infinite or it has some boundaries?" as a science or astronomy student this might be the first question to arouse in students mind. Coming back to the answer of this beautiful question- The observable universe is still huge but it has limits. This is because we know that the universe isn't infinitely old - we know that the big bang occured some 13.8 billion years ago. So from this we can conclude that the light has had only 13.8 billion years to travel and hence defines the limitations of universe. All we know or scientists believe is that universe is still far above from our observable distance but at some point it has limits for sure.
We all know , we live in the earth which is a part of solar system and in turn which is a part or constitutes the milky way galaxy, so we can say that we live on a earth or milky way galaxy. In this universe there are about billions of galaxies and more. And every galaxy probably consists it's solar system, and also we know that our sun is the smallest star on this universe, so it is sure that the sun on the other galaxies would be much larger than our sun and this also implies that there earth must be much bigger than our earth. So we can simply calculate that if there are billions of galaxies present on this universe than there must be billions of earth present ,as each Galaxy has a solar system and each solar system has one earth. But why life is not present on other earth or do life exists there? Our satellites has not reached so far that they could study even beyond their galaxy accurately but we can predict that life may not be present on other earth