How do we know the mass of a planet originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights. Answer by Geoffrey Widdison on ...

The terms weight and mass are often used incorrectly. Phrases like ‘a bag of sugar weighs 1 kg’ are not scientifically correct. This means that a 1 kg mass would be attracted to Earth by a force of 10 ...

Michael Wysession, an associate professor of earth and planetary sciences at Washington University, explains. There is an easy answer to this question, and it involves some good news and some bad news ...

In the recent weight vs. weightlessness post, there was an interesting comment. Michael Maher asks: My question is this: What forces did the astronauts experience as they were in transit to the moon?