TAG: GS 3: ECOLOGY AND ENVIRONMENT
THE CONTEXT: Recent studies have highlighted how the melting polar ice is affecting Earth’s rotation and potentially influencing our timekeeping systems.
EXPLANATION:
- This phenomenon, driven by global warming, has significant implications for various aspects of our lives and requires careful consideration.
- The melting of polar ice due to rising temperatures redistributes the Earth’s mass, particularly around the equator.
- This redistribution alters the planet’s angular velocity, leading to changes in its rotation speed.
- As a result, Earth’s rotation is slowing down, albeit marginally.
- A study published in Nature, led by geophysicist from the Scripps Institution of Oceanography, highlights this phenomenon.
- The research suggests that as polar ice melts, the increased mass around the equator affects Earth’s rotation speed, necessitating potential adjustments to our timekeeping systems.
Potential Timekeeping Implications:
- The slowing of Earth’s rotation could prompt world timekeepers to consider subtracting a second from our clocks in the future.
- This adjustment, referred to as a “negative leap second,” may be necessary by 2029, according to the study.
- Such changes could have repercussions for various systems reliant on precise timekeeping, particularly in the realm of computer networks.
- A professor of geophysics at the Massachusetts Institute of Technology (MIT) emphasizes the significance of the polar ice melt in altering Earth’s rotation.
- The melted water from polar regions flows towards the equator, contributing to changes in the planet’s mass distribution and rotational dynamics.
Long-Term Perspective:
- While the current changes in Earth’s rotation are notable, it’s essential to contextualize them within a broader temporal framework.
- Earth’s rotation has undergone variations over millions of years, with days being shorter in the distant past.
- Understanding these long-term trends provides valuable insights into the dynamic nature of our planet’s rotation.
Negative leap second:
- A negative leap second is a second that is subtracted from our clocks to keep them in sync with the Earth’s rotation.
- It is the opposite of a positive leap second, which is a one-second addition to our clocks.
- The need for a negative leap second arises when the Earth’s rotation speeds up, causing a discrepancy with our clocks.
- This adjustment is crucial to maintain the accuracy of Coordinated Universal Time (UTC) and ensure that our timekeeping systems remain aligned with the Earth’s rotation.
Rotation of the earth:
- Earth rotates along its axis from west to east.
- It takes approximately 24 hrs to complete on rotation.
- Days and nights occur due to rotation of the earth.
- The circle that divides the day from night on the globe is called the circle of illumination.
- Earth rotates on a tilted axis. Earth’s rotational axis makes an angle of 23.5° with the normal i.e. it makes an angle of 66.5° with the orbital plane. Orbital plane is the plane of earth’s orbit around the Sun.
Polar regions:
- Polar regions refer to the areas surrounding the Earth’s geographic poles, namely the North Pole and the South Pole.
- These regions are characterized by extreme cold temperatures, unique ecosystems, and distinct geological features.
- Geography and Climate:
- North Pole:
- The North Pole, located in the Arctic Ocean, is surrounded by several landmasses, including parts of Canada, Greenland, Russia, and Scandinavia.
- The Arctic region experiences long, harsh winters with temperatures plummeting well below freezing, while summers are relatively short and cool.
- Sea ice covers much of the Arctic Ocean, although this ice undergoes seasonal variations, with significant melting occurring during the summer months.
- South Pole:
- The South Pole is situated in Antarctica, which is a continent covered by a thick ice sheet. It is surrounded by the Southern Ocean.
- Antarctica is the coldest place on Earth, with temperatures dropping as low as -80°C (-112°F) during the winter months.
- The continent experiences long periods of darkness during the Antarctic winter and extended daylight during the summer, due to its location within the polar circle.
- North Pole: