• Question: how much would you way in space

    Asked by jimmymiton to Sheila, Piyush, Natalia, Gary, Dimitar on 9 Nov 2018.
    • Photo: Gary Munnelly

      Gary Munnelly answered on 9 Nov 2018:

      This is a cool question that let’s me properly put on my engineering hat. Bear with me!

      There is a common confusion among people between “weight” and “mass”. If you say that you weigh 70 Kg, or 10 Stone, or 170 lbs (whatever your preferred units are), you aren’t actually talking about your weight. You are talking about your mass, which is the amount of “stuff” that you are made up of.

      Weight, in proper scientific terms, is how how much force your mass exerts on the ground beneath you. It is equal to 9.81 (that’s acceleration due to gravity) multiplied by your mass. If you multiply 9.81 by your mass in Kilograms then you get your weight, which is measured in Newtons.

      So in space, you weigh more or less nothing, because you aren’t accelerating in any particular direction. But you still have the same mass! If you are 70 Kg or 10 Stone or 170 lbs on Earth, then you are the same in space, because you are still made up of the same amount of stuff!

    • Photo: Dimitar Shterionov

      Dimitar Shterionov answered on 11 Nov 2018:

      That is an interesting question. Every body in space, whether it is an ant or a star has a mass so your mass will be the same everywhere. But, weighing the way we do it on Earth is based on gravity and gravity is different in different places in the universe. Like for example on Earth I weigh around 75 kg. But on Mars where the gravity is a bit above 1/3 of Earth’s gravity the scale would show around 20 kg. On the Moon where the gravity is even smaller I would weigh around 5 kg. In space, where there is no gravity – the scale will say probably nothing.

Comments