This is an arena where speculation abounds in both camps. With modern equipment, capable of seeing back into the distant past, science is now secure in the fact that the universe is- and will continue- to expand (only proven 1998); that there at least 10 to the 85th power (10 with 85 0s behind it) galaxies like our Milky Way, each containing an estimated 500 million earth-like planets; and that there are black holes, which appear to be disposals for matter and light. Most recently string theory implies that there are 11 other universes, all of them unseen relative to each other, but with a theoretical capacity to transfer information and matter between them.
The Gospel contains statements of the Savior stating "Worlds without number have I created..."(Moses 1:4-8, 33); that there is a place called outer darkness (Matt8:12; Alma 40:13) where sons of perdition end; and that the creation of new and additional worlds is an eternal process. It is interesting to note that it has only been in recent years that science has developed most of these concepts, which have been found in the scripture for centuries, if not millennia. There is really no conflict in this arena except for how it happens.
One of these is in how long it took to make this earth. Some claim 7000 years, each day of God being 1000 years of man. (IIPet 3:8, Abr 3:4) However, the term in Genesis was not meant to be day in any usual sense. Elder Bruce R. McConkie has written, "But first, what is a day? It is a specified time period; it is an age, and eon, a division of eternity; it is the time between two identifiable events. And each day, of whatever length, has the duration needed for its purposes. ... There is no revealed recitation specifying that each of the "six days" involved in the Creation was of the same duration."(Ensign, June, 1982, page 11) So the creation periods are unknown, and the length of time involved is certainly uncertain, from both standpoints.
Science speculates about other dimensions tan the three with which we are most accustomed. Time is considered the fourth dimension by most. But there are others. Science has theories about hyperspace which give us to understand that higher dimensions can look in on a lower dimension and see everything, but the converse is not true.
Revealed truths have given us to understand similar things. (See Doctrine and Covenants 130:9-10) Although we don't understand this well, there are several scriptures which assure us that "all things are present before mine eyes." (Doctrine and Covenants 38:2; 130:7; Moses 1:8)
To find these Scripture references, go to http://lds.org/scriptures?lang=eng