Changes

Of course, the time allotted for the formation of the [[solar system]] is generally taken to be the alloted age of the [[Earth]]. The problem is that Uranus and Neptune would require more than twice the supposed age of the earth to accrete their present masses. In theory, the solar system could be older than the earth itself, but not much older. The solar system has other bodies in it that are much "younger." Nor does the above account for the body of evidence that the solar system is in fact quite young.

Of course, the time allotted for the formation of the [[solar system]] is generally taken to be the alloted age of the [[Earth]]. The problem is that Uranus and Neptune would require more than twice the supposed age of the earth to accrete their present masses. In theory, the solar system could be older than the earth itself, but not much older. The solar system has other bodies in it that are much "younger." Nor does the above account for the body of evidence that the solar system is in fact quite young.

Desch<ref name=Desch>Desch, S. J. "[http://eagle.la.asu.edu/desch/papers/2007/Desch2007.pdf Mass Distribution and Planet Formation in the Solar Nebula]." Arizona State University, September 21, 2007. Accessed April 29, 2008.</ref> recognizes the problem, and supports a radical alteration of the nebula hypothesis that calls for a ''decretion'' disk, not an accretion disk. But even his model requires that Uranus and Neptune ''exchange places'' early in the process, primarily because Neptune, though about 10 AU further out from the Sun than is Uranus, is yet more massive.

Desch<ref name=Desch>Desch, S. J. "[http://eagle.la.asu.edu/desch/papers/2007/Desch2007.pdf Mass Distribution and Planet Formation in the Solar Nebula]." Arizona State University, September 21, 2007. Accessed April 29, 2008.</ref> recognizes the problem, and supports a radical alteration of the nebula hypothesis that calls for a ''decretion'' disk, not an [[Accretion Disk|accretion disk]]. But even his model requires that Uranus and Neptune ''exchange places'' early in the process, primarily because Neptune, though about 10 AU further out from the Sun than is Uranus, is yet more massive.

=== Orientation of the Uranian system ===

=== Orientation of the Uranian system ===