Daily Currentaffairs: 26 Oct 2020

Tables of contents

1.Asteroid Bennu 

2.Evidence of river activity in Thar Desert

3.Tubarial Glands

4.Migration of Butterflies holds signals of Climate Change

5.Radhanagri Wildlife Sanctuary

1.Asteroid Bennu

Recently, NASA’s OSIRIS-Rex i.e. Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer, spacecraft briefly touched asteroid Bennu.

About Asteroid Bennu

• The asteroid was named after an Egyptian deity by a nine-year-old boy from North Carolina in 2013 who won NASA’s “Name that Asteroid” competition.

• The asteroid was discovered by a team from the NASA-funded Lincoln Near-Earth Asteroid Research team in 1999.

• Bennu is an asteroid about as tall as the Empire State Building and located at a distance of about 200 million miles away from the Earth.

What is an Asteroid?

• Asteroids are rocky objects that orbit the Sun and much smaller than planets i.e. minor planets.

• The Asteroids are divided into three classes:

  • The first is found in the main asteroid belt between Mars and Jupiter, which is estimated to contain somewhere between 1.1-1.9 million asteroids.

  • The second group is that of trojans, which are asteroids that share an orbit with a larger planet.

    • NASA reports the presence of Jupiter, Neptune and Mars trojans.

  • The third classification is Near-Earth Asteroids (NEA), which have orbits that pass close by the Earth.

OSIRIS-Rex

 

It is NASA’s first mission meant to return a sample from the ancient asteroid.

 

The mission is essentially a seven-year-long voyage and will conclude when at least 60 grams of samples are delivered back to the Earth.

 

The spacecraft’s robotic arm called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), made an attempt to “TAG” the asteroid at a sample site.

 

The spacecraft contains five instruments meant to explore Bennu including cameras, a spectrometer and a laser altimeter.

Source: The Indian Express

2.Evidence of river activity in Thar Desert

Recently, the researchers have found evidence of river activity in central Thar Desert, near Bikaner, as early as 172 thousand years ago.

Key Highlights

• The study by researchers from the Max Planck Institute for the Science of Human History in Germany, Anna University in Tamil Nadu, and IISER Kolkata indicates that Stone Age populations lived in a distinctly different Thar Desert landscape.

• The evidence indicates a river flowed with phases of activity dating up to 172 thousand years ago, nearby to Bikaner, Rajasthan, which is over 200 kilometres away from the nearest modern river.

• The findings predate evidence for activity in modern river courses across the Thar Desert as well as dried up course of the Ghaggar-Hakra River.

• The presence of a river running through the central Thar Desert would have offered a life-line to Paleolithic populations.

• The river was flowing at its strongest during a phase of weak monsoonal activity in the region and may have been a life-line to human populations enabling them to inhabit the Thar Desert.

Source: The Hindu

3.Tubarial Glands

Recently, researchers from the Netherlands Cancer Institute have discovered 'Tubarial Glands'.

Key Highlights

• The researchers who investigate the side-effects of radiation on the head and neck were studying a new type of scan as part of their research work.

• The researchers have found two “unexpected” areas that lit up in the back of the nasopharynx.

• The salivary gland system in the human body has three paired major glands and over 1,000 minor glands that are spread throughout the mucosa.

  • The glands produce saliva necessary for swallowing, digestion, tasting, mastication and dental hygiene.

• The researchers have found a bilateral structure at the back of the nasopharynx and these glands had characteristics of salivary glands.

• It is not clear yet if these glands will be classified as a conglomerate of minor glands, as a major gland, a separate organ or a new part of an organ system.

• The researchers believe that these glands would qualify as the fourth pair of major salivary glands.

  • The proposed name is based on their anatomical location, the other three glands are called parotid, submandibular and sublingual.

• The researchers suspect that the physiological function of the glands is to moisten and lubricate the nasopharynx and the oropharynx.

Source: The Hindu

4.Migration of Butterflies holds signals of Climate Change

Recently, an unusual phenomenon took place when thousands of butterflies were seen travelling from the Eastern Ghats to the Western Ghats.

Migration of Butterflies and Climate Change

• The two seasonal butterfly migrations is an annual event which occurs between the Western and Eastern Ghats of the Indian peninsula in search of food and survival.

• The intense rain in the Western Ghats complex during the southwest monsoon makes it difficult for the butterflies to survive.

• Before the onset of southwest monsoon, butterflies start their first migration from the Western Ghats to the plains and to the Eastern Ghats in order to avoid the inclement weather.

• The Eastern Ghats provide the ideal climate for the butterflies to survive during the southwest monsoon.

• The migratory adults become reproductive, breed, lay eggs, and die the successive generation starts to migrate back from the Eastern Ghats.

• The second migration took place early in 2020 due to heavy rainfall in the Eastern Ghats during the southwest monsoon.

• The butterfly offspring population would not have been able to survive in the Eastern Ghats with unviable weather conditions and a lack of food, forcing an early migration.

Butterflies: Indicators of Climate Change

• The Butterflies are bioindicators and the early migration means an early arrival of monsoon.

• With climate change altering weather phenomena across the world, tracking and studying seasonal butterfly migrations have assumed greater significance.

• The butterflies originate from Western Ghats ranges, such as Kodagu, Wayanad, Nilgiris, Siruvani and Anamalai, and move toward the Eastern Ghats consisting Yercaud, Pachamalai, Kolli, and Kalvarayan hills during the first migration.

• The migration between the Ghats is a form of local migration but other types of migration are also prevalent among butterfly species in the hills of peninsular India.

• In the Western and Eastern Ghats, it is clear that altered rain patterns have affected the migration patterns of butterflies.

Source: The Indian Express

5.Radhanagri Wildlife Sanctuary

Recently, the Ministry of Environment, Forest and Climate Change (MoEFCC) has notified 250.66 sq km around Radhanagri Wildlife Sanctuary (RWS).

About Radhanagri Wildlife Sanctuary

• It is a wildlife sanctuary and natural World Heritage Site, located in Kolhapur district, Maharashtra.

• It lies at the southern end of the Sahyadri hills in the Western Ghats.

• It is notable as the first declared wildlife sanctuary in Maharashtra, notified in 1958, as Dajipur Wildlife Sanctuary and is popularly known as the Bison Sanctuary.

• The Krishna River tributaries i.e. Bhogavati River, Dudhganga River, Tulshi River, Kallamma River and Dirba River flow through the sanctuary area.

Source: The Indian Express