Cold asteroids may have a soft heart
A new analysis of one of the most well-known meteorites on Earth provides strong evidence that the prevailing view of many asteroids is wrong. Rather than randomly mixed blobs of rock and dust stuck together, it appears that the asteroid that was the source of the Allende meteorite was large enough to have had a molten core, even though its surface remained cold and solid. The new view also suggests that astronomers’ view of how planets like the Earth formed may need revision. The Allende meteorite fell in Mexico in 1969, shattering into thousands of fragments as it slammed into the Earth’s atmosphere and strewing them across dozens of miles of desert. More than two tons of scattered pieces have been found, and it has become perhaps the best-studied meteorite ever.When the solar system formed, planets built up through the slow accumulation of smaller objects that collided and stuck together....