Outside experts have raised doubts about whether a loud boom and a gaping crater found in Nicaragua last weekend were caused by a meteorite, as the government has claimed.

ASTRONAUTS from the US space shuttle Discovery concluded the third and final space walk of their mission yesterday, installing new equipment on the International Space Station, but failing to connect some of the cables.

Growing populations and expanding economic activity have strained the planet’s ecosystems over the past half century, a trend that threatens international efforts to combat poverty and disease, a UN-sponsored study of the Earth’s health has warned.