Taxonomy term


Venus' gentler, Earth-like past

Today, the surface of Venus is a hellhole, seared by scorching temperatures, crushing pressures and a toxic atmosphere of carbon dioxide with occasional clouds of sulfuric acid. But evidence is mounting that billions of years ago, Earth’s evil twin planet was a much more pleasant place — a second blue marble covered by water. The latest data come from the European Space Agency’s Venus Express spacecraft, which has spent three years constructing a detailed map of the surface of the planet’s southern hemisphere and finding new evidence for Earth-like plate tectonics and a watery past.

07 Oct 2009

October 31, 1992: Vacation reverses position on Galileo

More than three and a half centuries after the Vatican accused famed Italian astronomer Galileo Galilei of heresy, Pope John Paul II officially welcomed him back into the fold, dismissing the whole messy episode as a “tragic mutual incomprehension.” At issue in what has become known as the “Galileo affair” was planetary motion. In the early 1600s, nearly all Europeans believed that the universe revolved around Earth. Not only was the idea widely supported by most scientists, but scripture seemed to dictate that it was so. Theologians pointed to biblical passages such as Psalm 104 — which proclaims, “[The Lord] set the earth on its foundations; it can never be moved” — as evidence of a geocentric system.
31 Oct 2008

Of molten iron and magnetism

Since 1999, the German satellite CHAMP (CHAllenging Mini-satellite Payload) has swirled around Earth, keeping watch as the planet’s magnetic field waxes and wanes over time. CHAMP’s continuous measurements of Earth’s field have created a finely detailed picture of how the field changes both in space and in time — and by extension, how the movement of the molten iron in Earth’s outer core ebbs and flows. And thanks to these data, researchers report, they can now track even small-scale, rapid fluctuations in the field’s strength around the planet.

28 Aug 2008