• silas@programming.devOP
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    8 months ago

    I learned recently how the James Webb Space Telescope is not orbiting around Earth but literally orbiting around an empty point in space. I don’t think I even quite understand it, but it’s really cool

    • ∟⊔⊤∦∣≶@lemmy.nz
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      8 months ago

      For everyone who immediately thinks ‘it’s most likely orbiting a point within the earth,’ here’s a diagram to help:

      • 0x4E4F@infosec.pub
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        8 months ago

        Have no idea how this works… there is no gravitational pull at the L2 point, it’s just an empty point in space 🤨.

        • Stumblinbear@pawb.social
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          8 months ago

          JWST isn’t going in circles, it’s orbiting the sun. If you look at it relative to that, then it looks more like a sine wave rather than going in circles. However from the perspective of the earth, it looks like it’s going in circles

          • 0x4E4F@infosec.pub
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            8 months ago

            Maybe gravitational push-pull between planets and moons… IDK, it might be some sweet spot they discovered where gravitational forces do weird things, lol 😂.

            • Balex@lemmy.world
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              8 months ago

              This. There’s 5 Legrange Points for every 2 body system. They’re specific points around the 2 bodys where the gravity “cancels out”. In this case the 2 body system is the Earth and the Sun. JWST is sitting a million miles from Earth at L2.

              • MrBobDobalina@lemmy.ml
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                8 months ago

                Dammit, I was feeling proud that my first thought on how this could work lined up with the explanation… But I had assumed L2 (didn’t stop to think about the label) was where I now see L1 to be. I can wrap my head around L1 just fine, but how the heck is L2 the same? Or the others for that matter? Gonna stare at this for a while…

                • Balex@lemmy.world
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                  8 months ago

                  If you understand gravity wells, think of L1/L2/L3 as the shape of a saddle. If you’re right in the middle of the saddle it’s a pretty stable orbit, but if you get too close to any of the edges you fall right out of it. L4 and L5 are like the peaks of a mountain.

                  Also worth pointing out that only L4 and L5 are stable, L1/L2/L3 are only metastable where they require a bit of maintenance to stay there.

                  Another fun fact about Legrange Points: There’s a group of asteroids called the Trojan Asteroids. There’s technically two groups of these since they’re stuck in L4 and L5 in the Sun/Jupiter system.

                  • 0x4E4F@infosec.pub
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                    8 months ago

                    Ah, so that’s why we don’t put shit in L4 and 5 😂… things will bump in them once in a while 😂.

          • 0x4E4F@infosec.pub
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            8 months ago

            Yes, my point exactly. There is no mass at the L2 point, so how can it spin around it.

            Others explained it though, it makes sense now 👍.

            PS: What are enbies 🤨?