Studying the sample could help answer how water arrived on Earth and how life started.

The asteroid is interesting from a scientific perspective as well as a commercial one.

The 1909 incident may have cost the industry decades of progress – and the planet huge amounts of damaging carbon emissions.

Controlled experiments are impossible in astronomy, as are direct measurements of physical properties of objects outside our solar system. So how do astronomers know so much about them?

Measuring the ages of planets and stars is tricky. An observational astrophysicist describes the subtle clues that provide good estimates for how old different space objects are.

Despite the meteoric rise of wind and solar, fossil energy sources have met most new demand in fast-growing economies.

Wealthier people are getting their solar panels connected first, leaving a more congested grid for everyone else.

Some geoengineering techniques are better understood than others. The US is investing in capturing carbon dioxide from the air, but ideas to block the Sun’s rays are raising big concerns.