Other events/claims that science has discredited:
- Tower of Babel: (a staple story of the Jaredites in the Book of Mormon)
- Global flood: 4,500 years ago
- Noah's Ark: Humans and animals having their origins from Noah’s family and the animals contained in the ark 4,500 years ago. It is scientifically impossible, for example, for the bear to have evolved into several species (Sun Bear, Polar Bear, Grizzly Bear, etc.) from common ancestors from Noah’s time just a few thousand years ago. There are a host of other impossibilities associated with Noah’s Ark story claims.
CES Letter, Page 111
Latter-day Saints believe that the prophet Noah existed, and that he was commanded to build an ark and save his family from a flood. A belief that this flood was global in nature is not a requirement for Latter-day Saints; traditionally, many earlier members and leaders endorsed the global flood views common in society and Christendom generally.
The accumulation of additional scientific information have led some to conclude that a local flood — one limited to the area in which Noah lived — is the best explanation of the available data. People of either view can be members in good standing.
Encyclopedia of Mormonism teaches: “The Old Testament records a flood that was just over fifteen cubits (sometimes assumed to be about twenty-six feet) deep and covered the entire landscape: ‘And all the high hills, that were under the whole heaven, were covered’ (Gen. 7:19). Scientifically this account leaves many questions unanswered, especially how a measurable depth could cover mountains.”
Elder John A. Widtsoe wrote in 1943:
The fact remains that the exact nature of the flood is not known. We set up assumptions, based upon our best knowledge, but can go no further. We should remember that when inspired writers deal with historical incidents they relate that which they have seen or that which may have been told them, unless indeed the past is opened to them by revelation. The details in the story of the flood are undoubtedly drawn from the experiences of the writer. Under a downpour of rain, likened to the opening of the heavens, a destructive torrent twenty-six feet deep or deeper would easily be formed. The writer of Genesis made a faithful report of the facts known to him concerning the flood. In other localities the depth of the water might have been more or less. In fact, the details of the flood are not known to us. [Click here for the entire quotation.]
Dr. Duane E. Jeffery explains:
A critical issue in the Flood story in the King James Bible has to do with translations of the Hebrew words eretz and adamah as meaning the entire “earth.” What do these terms actually mean? It is widely recognized that Hebrew is a wonderful language for poets, since virtually every word has multiple meanings. But that same characteristic makes it a horrible language for precision. As it turns out, eretz and adamah can indeed be a geographical reference akin to what we usually mean by “the earth.” But it is not at all clear that the ancients had the concept of a spherical planet that you and I do. Many scholars argue that the Bible writers thought in terms of a flat earth that was covered by a bowl-shaped firmament into which the windows of heaven were literally cut..." 
The concept of a spherical earth "did not appear in Jewish thought until the fourteenth or fifteenth century."  The word "earth," as used in the Bible, simply refers to solid ground or land, as opposed to water (see Genesis 1:10 — "God called the dry land Earth; and...the waters called he Seas...."). It is, of course, possible that earlier prophets had a more advanced view of the nature of the earth—this perspective could, however, have been lost to later centuries and scribes.
The belief that the flood was either global or local does not constitute a critical part of Latter-day Saint theology. Ideas of a global flood may have resulted from a widespread local problem. A current hypothesis that has been gaining ground since 1998 is that a significant flooding event occurred in the area now occupied by the Black Sea. Evidence has been discovered which has led a number of researchers to believe that the Black Sea area was once occupied by a completely isolated freshwater lake at a much lower level than the ocean. The theory is that the sea level rose and eventually broke through the Bosporus shelf, resulting in a rapid flooding event which would have wiped out all life living along the shores of the lake. Whether this is the source for the Genesis flood remains conjecture.
How do you reconcile the irrational things? by Joseph Smidt