What is "it?" 4

It is expanding every day, but it’s also compressing every day. Its destination is undiscovered. Its size is unknown. Its real capacity is also undiscovered. Without which, we are not us. It’s intangible. All of us possess it, but some experts think it’s completely separated from our body while some experts say it’s in our body. Literally, it has completely 2 different meanings. So What is “it?”