Expanding Earth is to Earth Science as Lamarkism is to Genetics and as "Creation Science" is to Science. In short, it is as useful as a chocolate teapot:-

1)

When we look at our entire solar system, Earth is the only solid planet with active tectonics. Mercury, the Moon, & Mars have NEVER had plate tectonics during the time that the surface cratering has accumulated (~ 4 Ga). Venus appears to have had a tectonic episode ~ 500 Ma ago, but has been inactive since. (volcanism per se doesn't count - it's organised relative horizontal motions of parts of the surface that we are looking for)

Every asteroid we visit is inactive. Every moon, with the exception of Io is inactive.

Io's activity is a form of vertical volcanic-driven resurfacing, rather than horizontal extension.

The ice tectonics of Europa involve both creation and destruction of parts of the surface, and are not active today.

The Sun fits on the observed astronomical main sequence which does not fit with growth of stars in either size or mass, after their initial formation.

Therefore there is no evidence for size of mass growth of any solid body in our solar system. It would be odd indeed for our Earth to be growing, while nothing else does or ever did.

2)

When we measure plate motions - either by present-day GPS, or by accumulated geologic strain, they balance neatly. Crust is created at spreading centres (generally submarine, but see Iceland and the Danakil depression, Ethiopia for some interesting onshore exposures). Crust is consumed at subduction zones. The balance is zero.

3)

If you assume an expanding Earth, then you have to play with physical constants. Unless you precisely balance a volume expansion and a mass creation, then surface gravity will change. There is no evidence that Earth formerly had higher or lower g. In fact, there is plenty of evidence that it did not. There is strong evidence that the escape velocity of Earth has not significantly varied over time, otherwise our atmosphere would be either missing, or of a different composition than it is (not the oxygen, but the nitrogen and the noble gasses and the lack of helium)

4)

Plate tectonics predicts that slivers of land and shallow marine environments (rather like Baja California) have been "rafted" across the Pacific during the Mesozoic and Cainozoic. There is no need to "close" the ocean or posit a "land bridge". Passengers on trans-Pacific cruising sub-continents do the job quite nicely.

5)

There is abundant supporting evidence for Plate Tectonics from Earthquake distribution in 3D, detailed velocity structure of the earth, gravity anomalies at subduction zones and spreading centres, geochemistry of island arc and mid ocean ridge volcanoes, distribution of global flora and fauna, mineral deposits and basin histories, outcrops of ophiolites and mantle xenoliths. All of these explicitly ruleout an Expanding Earth.

6)

Even if you ignore the all the well-documented and unmoveable points above, and posit Earth expansion as an explanation of the post-Jurassic separation of the Atlantic (and other young ocean basins) you have 60% to 75% of the present surface created in the past 280 Ma (that's ~ 6% of Earth's history). This represent an expansion of the surface area by 250% to 400% and equates to 375% to 600% volume expansion! If continuous, this is clearly unsustainable. Even if episodic, there are many other clearly documented episodes of continental rifting predating the current one. It doesn't take many of these to reduce the Earth to the size of a proverbial pea.

7)

And don't think you can get away with alternating expansion and contraction. That's been tried, and it doesn't work either.

In short, anyone who supports Earth Expansion doesn't understand geology, or even science. Full stop.

It's an idea that had its time, was temporarily useful, but is now flotsam on the sea of discarded scientific hypotheses.

Note to BD - it may be that one day my "White Mars" hypothesis may be equally discarded. I hope I will have the grace to let it go to its grave quietly when the time comes. For now, it's worth doing more work on, but that doesn't make it "right" or "wrong" - just "interesting". And there may be a grain or two of value in it for whatever the new Mars sysnthesis is, in the next decade or two. That's science - it moves on, and so should you all.