27-Jan-2023: Earth's inner core might've stopped spinning faster than its surface
Recent research on Inner Core
Methodology
- Analyzed seismic waves from repeating earthquakes over the last six decades
- Estimated the rotation of the inner core, which is believed to move independently from the mantle and rest of the planet
Findings
- Inner core started rotating slightly faster than the rest of the planet in the early 1970s
- Slowed down before coming in sync with Earth's rotation around 2009
- Negative trend, meaning inner core is now rotating slower than the surface
- Results seem to indicate that the Earth's inner core changes its speed of rotation every 60-70 years on average
Significance
- Can motivate researchers to build and test models treating Earth as an integrated dynamic system
- Slowdown could change how rapidly the entire planet spins and influence how the core evolves with time
Earth's Layers
- Crust
- Outermost layer
- Made of solid rock (mostly basalt and granite)
- Mantle
- Lies below the crust
- Up to 2900 km thick
- Consists of hot, dense, iron and magnesium-rich solid rock
- Core(Center of the earth) is made up of two parts:
- Liquid outer core: Made of nickel, iron and molten rock
- Solid inner core:
- Innermost layer of the earth
- Hot iron ball of the size of Pluto with an average radius of 1220 km
- Solid due to pressure caused by weight of other top layers
- Spins independently because it floats in the liquid outer core
- Temperature ranges between 7,200–8,500ºF (4,000–4,700ºC)
Inner Core Properties
- Predicted to have very high thermal and electrical conductivity
- Lehman Seismic Discontinuity is the boundary between the inner and outer cores, located at approximately 5150 km below the surface of the Earth.
25-Jan-2023: A study has found that non-natural light has increased the brightness of Skyglow
Skyglow
- An omnipresent sheet of light across the night sky in and around cities that can block all but the very brightest stars from view
- Caused by the brightening of the night sky over inhabited areas because of streetlights, security floodlights, and outdoor ornamental lights
Scenario of Skyglow
- Global: Skyglow had brightened around 6.5% over Europe, 10.4% over North America, and 7.7% over the rest of the world
- India: 19.5% of India’s population experiences a level of skyglow that would at least keep the Milky Way galaxy out of sight and at most render “dark adaptation for human eyes” impossible
- Satellites are unable to sense blue light emitted by LEDs and to study light that is emitted parallel to the ground
Implications of Skyglow
- Wastes energy and money
- Disrupts the ecosystem and wildlife
- Harms human health
- Erases Indigenous connection to the stars, acting as a form of ongoing cultural and ecological genocide
Solutions
- Light sources casting light at an angle below the plane of the horizon
- Capping the emissions of these sources and calibrating their output according to the total brightness at the spot being lit
- Shielding lights so that they do not shed light into the surrounding environment and sky
- Investing in lighting solutions in less-developed regions before animals there are seriously affected
- Creating ‘International Dark Sky Places’ where artificial lighting has been adjusted to reduce skyglow and light trespass
20-Jan-2023: New Plateau in Western Ghats
A rare low-altitude basalt plateau discovered in Maharashtra in the Western Ghats. It can help study the effects of climate change on species survival and increase awareness of the conservation needs of rock outcrops and their immense biodiversity value in the global context.
Low-Altitude Basalt Plateau is the fourth type of plateau to be identified in the region; the previous three are laterites at high and low altitudes and basalt at high altitudes.
Biodiversity in the newly discovered plateau:
- 76 species of plants and shrubs reported
- 24 different families
- Shares vegetation with three other rock outcrops
- Unique species present
- Rock outcrops have seasonal water availability, limited soil and nutrients, making them ideal laboratories to study the effects of climate change on species survival.
Significance of Western Ghats:
- Chain of mountains running parallel to India's Western Coast
- Passes through states of Kerala, Maharashtra, Goa, Gujarat, Tamil Nadu and Karnataka
- One of four global biodiversity hotspots in India
- Recognized as UNESCO World Heritage Site
- Influences Indian monsoon weather patterns
- Barrier to rain-laden monsoon winds from the south-west
- Home to tropical evergreen forests
- 325 globally threatened species
- Plateaus dominant landscape
- Significant due to predominance of endemic species