Australia’s first observatory was built on the shores of Sydney Harbour by Lieutenant William Dawes of the First Fleet, on the point where the southern pylon of the Sydney Harbour Bridge now stands. Optical astronomy was essential for maritime navigation, and for providing precise location measurements for surveying the new continent.
We know more about the topography of Mars than that of Earth because 70 per cent of our planet is covered by water.
Now University of Sydney PhD student Kara Matthews has used satellite data and GPlates, a computer package developed at the University, to create a complete digital map of the many geological features of the seafloor.
Fracture zones—the orange lines in the accompanying image—are deep linear scars on the seafloor that extend perpendicular to the boundaries where tectonic plates are moving apart, revealing up to 150 million years of plate movement. They are accompanied by huge ridges on the seafloor, rising up to 2 km above the abyssal plains, and valleys as deep as 8 km below sea level. Continue reading Mapping the seafloor from space→