In most cases, we have a very good idea what the things we see in their earlier stages must look like today. When we see a "primitive" galaxy, we can assume it probably looks very much today as a nearby galaxy with similar mass appears. Some objects we can safely assume no longer exist at all. In most cases, we can estimate where they are now (which may be outside the observable Universe).nirvana wrote:amazing thing is that we can see how a thing was 12 billion years ago but have no clue how they look now or what they are.....surely they not have vanished,, they must be some where in some other form.....so of universe is much bigger than what we can ever see.....each passing moment we are getting away from each other,,,,,,,its so lovely which i could whole universe :(
It's like watching an old movie with a child in it. While you can't say for certain what that child looks like today, or where it is, you can make reasonable assumptions.