Andromeda Galaxy Entering ‘Middle Age’
Context: Astronomers have used data from the Hubble Space Telescope to create the clearest map yet of star formation across most of the Andromeda Galaxy over the last 500 million years.
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About the Andromeda Galaxy
- The Andromeda Galaxy, (also known as M31 or Messier 31), is a large barred spiral galaxy comparable in size to the Milky Way.
- Location: It is located approximately 2.5 million light-years from Earth in the constellation Andromeda.
- Closest Major Galaxy: It is the closest major galaxy to the Milky Way and is visible to the naked eye under dark-sky conditions.
- Structure: It is a barred spiral galaxy, characterised by a bar-like structure of stars at its centre.
- Motion Towards the Milky Way: It is moving towards the Milky Way at approximately 110 km/s.
Key Findings
- Declining Star Formation: The Andromeda Galaxy’s star formation rate has been steadily declining, particularly over the last 40 million years.
- Star Formation Concentrated in Ring Structures: Recent star formation has been concentrated in the galaxy’s ring structures, where the decline is also most evident.
- ‘Dead Zone’ Near M32: Astronomers identified a ‘dead zone’ near M32, a small satellite galaxy of Andromeda, where new stars have almost completely stopped forming..
- Transition to ‘Middle Age’: The Andromeda Galaxy is transitioning from an active, star-forming galaxy to a quiescent galaxy, marked by a sustained decline in star formation.
About Hubble Space Telescope
- A space-based astronomical observatory jointly operated by NASA and the European Space Agency (ESA).
- Launch: Launched on 24 April 1990 aboard Space Shuttle Discovery (STS-31) into Low Earth Orbit.
- Named After: Named in honour of astronomer Edwin Hubble, who established the expanding universe.
- Observation Range: Observes the universe in the ultraviolet, visible, and near-infrared wavelengths.
- Key Feature: Equipped with a 2.4-metre primary mirror for high-resolution observations.
Samrasta Sankalp Abhiyan
Context: Samrasta Sankalp Abhiyan will be launched as a nationwide campaign to commemorate the 650th birth anniversary of Sant Guru Ravidas Maharaj.
About Sant Guru Ravidas Maharaj
- Sant Guru Ravidas Maharaj was a 15th-century Bhakti saint, poet, and social reformer.
- Birthplace: He was born at Seer Govardhanpur, near Varanasi (Uttar Pradesh).
- Bhakti Movement: He was a prominent saint of the Bhakti movement, advocating devotion (Bhakti) over ritualism.
- Core Teachings: He preached equality, social justice, human dignity, and universal brotherhood, and opposed caste-based discrimination.
- Literary Contribution: His devotional hymns are included in the Guru Granth Sahib, the holy scripture of Sikhism.
- Philosophy: He promoted Nirguna Bhakti (devotion to a formless Supreme Being) and envisioned ‘Begumpura’, an ideal society free from sorrow, fear, and discrimination.
- Association with Meera Bai: Meera Bai is believed to have accepted Guru Ravidas as her spiritual guru.
- Legacy: His teachings continue to inspire movements for social equality, harmony, and spiritual devotion across India.
Kyushu, Southern Japan
Context: A magnitude 7.1 earthquake struck off the coast of Kyushu, southern Japan.
Key Highlights
- Epicentre: The earthquake struck off Kyushu, with its epicentre 10 km beneath the seabed.
- Tsunami Advisory: The Japan Meteorological Agency (JMA) issued a tsunami advisory for coastal areas along the Ariake Sea and Yatsushiro Sea, warning of waves of up to 1 metre.
- Historical Context: The affected region was also impacted by the 2016 Kumamoto earthquake, which caused significant casualties and widespread damage.
Kyushu
- Southernmost of Japan’s four main islands (excluding Okinawa).
- Home to several active volcanoes, including Mount Aso and Sakurajima.
- Lies in a highly seismically active zone.
Reasons for Japan’s Earthquake-Prone Status
- Location: Japan is located along the Pacific Ring of Fire, one of the world’s most seismically active regions.
- Convergence of Tectonic Plates: It lies at the convergence of the Pacific, Philippine Sea, Eurasian (Amur), and North American (Okhotsk) tectonic plates.
- Frequent Seismic Activity: The interaction of these tectonic plates results in frequent earthquakes, volcanic eruptions, and tsunamis.
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India’s Dengue Burden
Context: A study by the ICMR-VRDL (Virus Research and Diagnostic Laboratory) network has found that all four dengue virus serotypes are now circulating simultaneously across large parts of India.
- It is raising the risk of severe disease and creating fresh challenges for the rollout of future dengue vaccination programmes.
Key Findings
- Widespread co-circulation: All four serotypes are now active together in several parts of India — a marker of growing epidemiological complexity, not just a single dominant strain.
- Increased Severity Risk: Patients with concurrent infections (two or more serotypes at once) were more likely to develop severe dengue manifestations, including:
- Dangerously low platelet counts (thrombocytopenia)
- Bleeding complications
- Severe joint pain
Vaccine Rollout Implications
- India currently has no dengue vaccine in its Universal Immunisation Programme (UIP).
- An internationally approved dengue vaccine has recently received regulatory clearance for import and sale in India (referring to Takeda’s QDENGA, developed in Japan).
- Vaccine effectiveness varies against different dengue strains. If the dominant circulating serotype shifts over time, it could affect both outbreak intensity and vaccine performance.
About Dengue
- Cause: Dengue virus (DENV), a Flavivirus with four serotypes (DENV-1, DENV-2, DENV-3 and DENV-4).
- Transmission: Bite of an infected female Aedes aegypti mosquito (also Aedes albopictus).
- Symptoms: High fever, severe headache, muscle and joint pain, rash; severe cases may progress to dengue haemorrhagic fever or dengue shock syndrome.
- Prevention: Vector control, elimination of mosquito breeding sites, personal protection, and vaccination where recommended.
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Dengue Serotypes
- Dengue virus has four distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4.
- Disease severity depends more on secondary infection (getting infected by a different serotype after a prior dengue infection) than on the serotype itself — though DENV-2 has often been linked historically to severe outbreaks.
- The simultaneous circulation of multiple serotypes in the same region/population is termed hyperendemicity or dengue hyper-endemic transmission.
29 Jul 2026
