February 9, 2025

Moon’s Wobble

Syllabus– General Studies 1(Geography)

Context

According to a study published recently, the wobble phenomenon is expected to lead to more flooding here on Earth in the middle of the next decade.

About Wobble:

  • It is a regular oscillation that humans have known about for centuries and it is one of many factors that can either exacerbate rising sea levels or counteract them, alongside other variables like weather and geography.
  • The study shows that-
    • Our oceans are rising because of climate change.
    • Rising temperatures caused by greenhouse gas emissions are not the only cause of higher flood risks, and the report explored the interplay of many variables that push and pull at ocean levels.

 

  • According to NASA, there’s nothing new or dangerous about the wobble; it was first reported in 1728.
    • The new is how one of the wobble’s effects on the moon’s gravitational pull (the main cause of Earth’s tides) will combine with rising sea levels resulting from the planet’s warming.
  • The study warned that we should expect this wobble to heighten high tides in the middle of the 2030s, but it also showed that this prediction does not apply uniformly to every coastline everywhere.
  • Rising temperatures caused by greenhouse gas emissions are not the only cause of higher flood risks, and the report explored the interplay of many variables that push and pull at ocean levels.

Where does this wobble come from?

  • High tides on this planet are caused mostly by the pull of the moon’s gravity on a spinning Earth. 
  • On most beaches, you would see two high tides every 24 hours.
  • The moon also revolves around the Earth about once a month, and that orbit is a little bit tilted.
  • To be more precise, the moon’s orbital plane around the Earth is at an approximate 5-degree incline to the Earth’s orbital plane around the sun.
  • Because of that, the path of the moon’s orbit seems to fluctuate over time, completing a full cycle (sometimes referred to as a nodal cycle) every 18.6 years.
  • At certain points along the cycle, the moon’s gravitational pull comes from such an angle that it yanks one of the day’s two high tides a little bit higher, at the expense of the other.
    • This does not mean that the moon itself is wobbling, nor that its gravity is necessarily pulling at our oceans any more or less than usual.

Effect of Wobble:

  • Other variables aside, the effect of the wobble could cause high tide levels at a beach to oscillate by 1 or 2 inches over the course of its long cycle.
    • That may sound small. But in certain situations, it can matter quite a bit.
  • It just kind of raises the baseline and the more your baseline is raised, the smaller the weather event you need to cause a flooding event.
  • Understanding that baseline is important even when we are in the phases of the nodal cycle that would seem to counteract rising sea levels, which is what is happening now.

Question- Write a short a note on wobble of the moon.

Article-                                                                              https://indianexpress.com/article/explained/explained-how-the-moon-wobble-affects-rising-tides-7410814/

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