Meteorite impacts might have kick-started the Earth's tectonic plates and boosted the planet's magnetic field, according to a study from Australia's Macquarie University. The research, led by Craig O'Neil from the university's Planetary Research Centre, and published in the journal Nature Geoscience, offers a scenario to illuminate what happened during the first 500 million years of the Earth's existence - a period known as the Hadean, or, more poetically, the geologic dark ages. To date, the question of whether the young planet featured moving tectonic plates has been moot, primarily because almost nothing of its early crust remains. Some scientists have proposed that grains of zircon, dating to before 4.1 billion years ago, are evidence of early, active tectonics. Others, however, are more convinced by geochemical data indicating that in its formative years the Earth was encased in a motionless "lid", with moving tectonic plates emerging later. Tectonic plates were until recently