There are many home-grown problems on Earth, but there's still time to worry about bad things arriving from above.

The U.N. has identified Kabwe, a city of almost 300,000 people in Zambia, as one of the most polluted places on the planet.

Every time the temperature drops, a cloud passes overhead, or the sun sets, a plant makes a choice: Keep its microscopic ...

Almost everything we do at home creates dust, but if it's not cleaned away it can cause a range of health problems from asthma and allergies to skin irritation and streaming eyes ...

The Small Magellanic Cloud, a dwarf galaxy about 200,000 light-years from the solar system, can be seen with the naked eye ...