• Question: How much does the earth weigh?

    Asked by lilymay07 to David, Thiloka, Shonna, Shobhana, Ryan, Ross, Rebecca, Rachel, Patrick, Nina, MattyB, Matthew, Marianne, Lorena, Kate, Kaitlin, James, Ettie, Emmanuelle, Deepak, Anabel, Ambre, Alex, AlexAgrotis, Aina on 12 Jun 2019.
    • Photo: Kate Timms

      Kate Timms answered on 12 Jun 2019:

      This is a bit of a complicated one.

      Technically everything has a mass which is unchanged. However weight is different depending on the gravitational forces acting on it. So weight changes on different planets. If you were to be on the moon, you would weight 6x lighter than you do on earth! Because the gravity of the moon is much weaker than the gravity of the moon.

      For the earth itself, it is under the gravitational pull of the sun.

      The earth has a mass of about 6,000,000,000,000,000,000,000,000kg.

    • Photo: Matthew Bareford

      Matthew Bareford answered on 12 Jun 2019:

      If you were to be able to measure the weight of the Earth it would be approx.

      58839900171833400000000000 Newtons
      6,000,000,000, 000,000,000,000,000 kilograms

      But In theory, the Earth is in space and so it is Weightless… the same as we are when we travel into space….

    • Photo: David Wilson

      David Wilson answered on 12 Jun 2019: last edited 12 Jun 2019 11:35 am

      So here’s a really cool story about how this was done in 1774!!!!!!!
      A pendulum hangs straight downwards due to gravity. However, if a sufficiently large mass such as a mountain is nearby, its gravitational attraction should pull the pendulum’s plumb-bob slightly out of true (in the sense that it doesn’t point to the centre of mass of the Earth). The change in plumb-line angle against a known object—such as a star—could be carefully measured on opposite sides of the mountain. If the mass of the mountain could be independently established from a determination of its volume and an estimate of the mean density of its rocks, then these values could be extrapolated to provide the mean density of the Earth, and by extension, its mass.
      There’s a mountain in Scotland called Schiehallion, it’s in Perthshire and is 1,078m high. It was particularly suitable for the experiment because it’s quite isolated and is a really nice pyramidal shape.
      A group of astronomers and mathematicians built platforms around the mountain to measure the deflection of the plumb-bob and compared this to the postitions of visible stars.
      As if this story wasn’t amazing enough it turns out that for a group of scientists without even the invention of computers their calculation was quite accurate. The current best estimate for Earth mass is 5.9722×1024 kg, the Schiehallion experiment was within 20% of this.
      The Schihallion experiment also gave us the first indication that the earth was substantially made of metal.
      I love this story!

    • Photo: Kaitlin Wade

      Kaitlin Wade answered on 12 Jun 2019:

      A massive amount! The figure I had in my head was the same as Matthew’s and Kate’s (about 6 or 6,000,000,000,000,000,000,000,000 kilograms – that’s 7 million million million million or 7 septillion kilograms!) but, as everyone has said, we wouldn’t able to weigh it as it is weightless in space.

    • Photo: Rebecca Moon

      Rebecca Moon answered on 12 Jun 2019:

      A lot!

    • Photo: Marianne King

      Marianne King answered on 13 Jun 2019:

      The Earth would be massively weightless, or weightlessly massive. 🙂 Unless it sat on top of itself as things are weightless in space.

    • Photo: Nina Rzechorzek

      Nina Rzechorzek answered on 14 Jun 2019:

      nothing at all