Daily Prelims Notes 4 May 2024
- May 4, 2024
- Posted by: OptimizeIAS Team
- Category: DPN
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Daily Prelims Notes
4 May 2024
1. Cyclone Hidaya to slam into Tanzania south of Dar es Salaam; Ruto puts Kenya on alert
Subject: Geography
Sec: Climatology
Context:
- Cyclone Hidaya (‘Guidance’ in Arabic and ‘Gift’ in Swahili) is expected to hit the Tanzanian coast near Dar es Salaam from the Indian Ocean on May 4, 2024.
- Places affected: The coast of Mtwara, Lindi, Pwani, Dar es Salaam, Tanga, Morogoro, and the islands of Unguja and Pemba. All are part of Tanzania.
Details:
- The cyclone developed over the South Indian Ocean and has been named by the French meteorological service, Meteo France’s centre in the Indian Ocean French Overseas Department of La Reunion.
- East Africa, including Kenya, Tanzania, and Burundi, has already experienced significant flooding since March, resulting in 350 deaths and widespread property damage.
Why ‘Kenya’ is considered safe from tropical cyclones?
- Traditionally, Kenya has been considered safe from the direct impact of cyclones due to its geographic location near the equator.
- Tropical cyclones typically form at latitudes between 5° and 30° North or South of the equator, and Kenya is situated within Latitude 4° North and South.
- Tropical cyclones are difficult to form over a region within 5 degrees of latitude from the Equator because the Coriolis force there is too small to generate a vortex.
- This conventional safety from cyclones might no longer hold, as the country faces the potential impact of Cyclone Hidaya. This would mark the first time Kenya experienced a cyclone.
Other conditions for the formation of Tropical Cyclone:
- Large sea surface with a temperature higher than 27° C
- Presence of the Coriolis force
- Small differences in the vertical wind speed
- A pre-existing weak- low-pressure area or low-level-cyclonic circulation
- Upper divergence above the sea level system.
Why tropical cyclones don’t form near or cross Equator?
- This is because of the lack of the Coriolis force. What is that? It is an apparent force caused by the rotation of the Earth. It is named after French mathematician Gaspard Gustave de Coriolis who investigated energy in rotating systems
Coriolis Effect:
- Earth’s circumference is largest at the equator. This means anything standing on the equator is moving faster eastward than anything lying away from the equator — anything on the equator is traveling a greater distance than anything north or south on Earth’s surface in the same amount of time.
- If air moves north from the equator, it will also still flow quickly eastward compared with its new surroundings. This means air traveling north from the equator will appear to veer right. In contrast, air flowing south from the equator will appear to stray left.
- This phenomenon, known as the Coriolis effect, helps control the direction in which tropical cyclones spin. In the Northern Hemisphere, rightward-turning air will create a counterclockwise spinning motion, and the opposite will occur in the Southern Hemisphere.
Kenya:
- A coastal country in East Africa, named after Mount Kenya.
- Capital- Nairobi
- Its oldest and second largest city is the major port city of Mombasa, situated on Mombasa Island in the Indian Ocean and the surrounding mainland.
- Bordered by South Sudan to the northwest, Ethiopia to the north, Somalia to the east, Uganda to the west, Tanzania to the south, and the Indian Ocean to the southeast.
Tanzania:
- A country in East Africa within the African Great Lakes region.
- Capital- Dodoma
- Largest city- Dar es Salaam
- Bordered by Uganda to the north; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to the south; Zambia to the southwest; and Rwanda, Burundi, and the Democratic Republic of the Congo to the west.
- Mount Kilimanjaro, Africa’s highest mountain, is in northeastern Tanzania.
Source: DTE
2. The Eta Aquariid meteor shower and how it can be spotted
Subject: Science and tech
Sec: Space
Context:
- The Eta Aquariid meteor shower, which has been active since April 15, will peak on May 5 and 6.
More on news:
- Comprising burning space debris moving at speeds of around 66 km per second (2.37 lakh kmph) into Earth’s atmosphere, these showers are seen in May every year.
- They are best visible to countries such as Indonesia and Australia in the Southern Hemisphere.
What are comets?
- Meteor showers come from comets, which are frozen leftovers from the formation of our solar system, some 4.6 billion years ago.
- Comets are composed of dust, rock and ice, and orbit around the Sun in highly elliptical orbits which can take hundreds of thousands of years to complete.
- Billions of comets are orbiting the Sun beyond Neptune, in the Kuiper Belt and even more distant Oort cloud.
- Comets come in different sizes, although most are roughly 10 km wide.
- As they come closer to the Sun, comets heat up and spew gasses and dust into a glowing head that can be larger than a planet.
- This material also forms a tail which stretches millions of miles.
How exactly are meteor showers related to comets?
- Meteors are simply grains of dust or rock that burn up as they enter the Earth’s atmosphere.
- This burning also creates a brief tail.
- Since most meteors are tiny (the size of a grain of sand) they completely burn up in Earth’s atmosphere.
- However, sometimes, a large enough meteor passes through and hits the ground (at which time it is called a meteorite), often causing significant damage.
- A meteor shower can be observed when Earth passes through the clouds of dust left behind in a comet’s orbital plane.
- The sky lights up with small and large meteor tails as the debris left behind by the comet interacts with Earth’s atmosphere.
How do Eta Aquarids meteor form?
- The Eta Aquariid meteor shower is formed when Earth passes through the orbital plane of the famous Halley’s Comet, which takes about 76 years to orbit the Sun once.
- While it was observed as early as 240 BCE, it was only in 1705 that astronomer Edmond Halley realized that the periodic appearances were re-appearances of the same comet.
- Last seen in 1986, Halley’s comet is due to enter the inner solar system again in 2061.
- Like Eta Aquariids, the Orionids meteor shower is also caused by the Halley’s Comet.
Why are Eta Aquariids unique?
- The Eta Aquariid meteor shower is known for its rapid speed.
- This makes for long, glowing tails which can last up to several minutes.
- About 30 to 40 Eta Aquarid meteors can be seen per hour during the peak of the meteor shower, if observed from the Southern Hemisphere.
- The number decreases to about 10 meteors per hour if being viewed in the Northern Hemisphere.
- This is due to the location of the “radiant” i.e. the position in the sky where the meteor shower seems to come from.
- In the Northern Hemisphere, Eta Aquarid meteors most often appear as ‘Earthgrazers’ — long meteors which appear to skim the surface of the Earth.
- In the South, however, they can be seen higher up in the sky, and hence are more visible.
How to catch the Eta Aquariid meteor shower?
- The meteor shower is likely to be visible across the sky.
- The shower seems to be originating from the Aquarius constellation — hence ‘Eta Aquariid’.
- The meteor shower is going to be visible to the naked eye on a clear night sky, provided there is minimum light pollution (from the Moon or artificial lighting from buildings, streetlights on Earth).
Other related geographical terms: