宇宙有多大?

it is still expanding now,
but it might stop one day ,
it depends on the critical value.
it might keep expanding forever
or become smaller and big chrunch happens at last.

科學家只認識宇宙很小部份,我們認識最遠星球\星系離我們70多億光年(1光年約10兆公里).

應該咁講，宇宙係無窮無盡﹗