Is progress speeding up? We have ventured into new parts of space, tested the limits of AI, cured the incurable and, according to some, even proved the existence of the multiverse. What comes next?
Review of the year: health and science
Keys to a better world?: This year scientists found a new anti-HIV tool, a baby planet, a test for Alzheimer's and made the fastest chip ever. But will they stand the test of time? Glossary
AI - A computer programme that has been designed to think.
Extraterrestrial - Anything from outside Earth.
Pandemic - An outbreak of disease which occurs across a wide geographic area, as opposed to an epidemic, which is confined to a particular region.
UN - United Nations. An intergovernmental organisation based in New York that aims to maintain international peace and security.
AIDS - Acute Immune Deficiency Syndrome. It interferes with the immune system, leaving sufferers more vulnerable to common diseases. Around the world, almost 40 million people are believed to be living with the disease.
HIV - A virus that damages your immune system.
Dementia - A syndrome associated with memory loss and other declining brain functions.
Alzheimer's disease - A progressive disease that causes brain damage over time. It is a common cause of dementia.
Diagnosis - The process of identifying a condition, injury or disease by looking for the signs and symptoms of that condition.