Readers reply: Must what goes up always come down?

"Although sometimes it can be: fall back to ground and miss, which we call being in orbit. HaveYouFedTheFish Hopeful that Reform's poll ratings do not defy this rule and come down very soon. On the other hand, Farage's levels of hypocrisy show no signs of stopping their ascent. MosesQuest If they can maintain orbital velocity or achieve escape velocity, they will not come down."

"No orbit lasts for ever. In low orbit, usually the satellite slows due to atmospheric friction and tidal forces, and the orbit decays till it re-enters. In high orbit (usually geosynchronous), the same gravitational tidal forces are a bit more unpredictable and the orbit can decay, or occasionally the satellite may be ejected into a coincidental orbit around the sun instead."

"I seriously doubt if I'll ever become fed down with the whole bloody lot of it. Eddie Chorepost Amar Bharati has kept his right arm raised for 50 years. I think he would find it difficult to lower it now. GrasmereGardens My football team always has. But maybe they'll prove this wrong before I die. minermackem Once the price of groceries goes up, they tend not to come down. Sagarmatha1953"

Objects launched without sufficient lateral speed will fall back to the ground under gravity. If an object attains sufficient horizontal velocity it can enter orbit and continuously fall around the planet instead of returning to the surface. Low orbits decay as atmospheric drag and tidal forces slow satellites until they re-enter. High orbits can experience gravitational perturbations that alter trajectories. Historical examples include Skylab's de-orbit over Australia. The phrase 'throw yourself at the ground and miss' captures orbit as perpetual falling. Metaphorical uses compare political polls, hypocrisy and grocery prices to things that go up and not come down.

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