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Today's Headlines - 02 August 2023
Climate change is altering the colour of the oceans
GS Paper - 3 (Environment)

The colour of the Earth’s oceans has significantly altered over the past two decades, most likely due to human-induced climate change, according to a new study. Over 56 per cent of the oceans, more than the total land area on the planet, has experienced the shift in colour, it added. The study, ‘Global climate-change trends detected in indicators of ocean ecology’, was published in the journal Nature.

What makes the oceans colourful in the first place?

In most regions across the world, the oceans appear blue or navy blue for a reason. This happens due to “the absorption and scattering of light”.
When the sunlight falls on deep and clear water, colours with longer wavelengths, such as red, yellow and green, are absorbed by the water molecules but blue and violet, which have a much shorter wavelength, are reflected back.
When sunlight hits the ocean, some of the light is reflected back directly but most of it penetrates the ocean surface and interacts with the water molecules that it encounters.
The red, orange, yellow, and green wavelengths of light are absorbed so that the remaining light we see is composed of the shorter wavelength blues and violets.
But when the water isn’t deep or clean, an ocean can appear to be of a different colour.
For instance, along Argentina’s coastline, where major rivers merge into the Atlantic Ocean, the ocean exudes a brown tint because of dead leaves and sediments spewing from the rivers.
In other parts of the world, the oceans appear green, which happens due to the existence of phytoplankton on the upper surface of the water.
Phytoplanktons are microscopic marine algae that contain the green-coloured pigment chlorophyll.
The pigment helps them absorb sunlight, which they use to capture carbon dioxide from the atmosphere and convert it into sugars. Moreover, chlorophyll absorbs the red and blue portions of the light spectrum — or photosynthesis — and reflects green light.

What methods were used to carry out the study?

To conduct the study, Cael and his team first analysed data from Moderate Resolution Imaging Spectroradiometer (MODIS), aboard NASA’s Aqua satellite, which has been monitoring ocean colour since 2002 — the measurements are taken in terms of the amount of light coming off the surface of the oceans, at all seven of the different wavelengths of light, from violet to red.
The examination of 20 years worth of data indicated that in more than 50 per cent of the world’s oceans, the colour has changed.
Then, to check if the phenomenon has occurred due to climate change, researchers used a climate model – a computer representation of the Earth.
This model simulated the planet’s oceans under two scenarios: one with the addition of greenhouse gases, and the other without it.
The greenhouse-gas model predicted that a significant trend should show up within 20 years and that this trend should cause changes to ocean colour in about 50 percent of the world’s surface oceans — almost exactly what Cael found in his analysis of real-world satellite data.

#upsc #news #headline #climate #colour #oceans #pigment #phytoplankton #chlorophyll #sediments #spewing #rivers #spectrum #methods #MODIS #NASA #Aqua #satellite #world #earth #wavelength #gases #greenhouse #data #planet

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Today's Headlines - 09 August 2023
The legacy of the Voyager mission
GS Paper - 3 (Space Technology)

The National Aeronautics and Space Administration (NASA) lost communication with Earth’s longest-running space probe, Voyager 2, the space agency detected a “heartbeat” signal from the spacecraft. Although too faint for extraction of data, the detected signal confirms that Voyager 2, which is about 19.9 billion kilometres away from Earth, is still operating.

Why were the Voyager spacecraft sent into space?

In 1972, NASA cancelled its plans of exploring the five outer planets (Mars, Jupiter, Saturn, Uranus and Neptune) with four highly complex spacecraft — the proposal, estimated to cost $ 1 billion, was scrapped due to budgetary constraints.
Instead, it proposed to send the Voyager probes, initially slated to explore only Jupiter and Saturn. In 1974, however, it was decided that if one spacecraft completes the mission, the other one would be redirected towards Uranus and then Neptune.
Interestingly, the spacecraft were scheduled for a take-off towards the end of the 1970s for a reason.
NASA chose the particular launch window to take advantage of a rare alignment of Jupiter, Saturn, Uranus and Neptune that occurs once every 175 years.
The alignment allowed the spacecraft to harness the gravity of each planet and swing from one to the next using relatively minimal amounts of fuel. NASA first demonstrated the technique with its Mariner 10 mission to Venus and Mercury from 1973 to 1975.
Voyager 2 was launched on 20 August 1977, two weeks before the 5 September Voyager 1 takeoff.
This reversal of order took place as the two spacecraft were put on different trajectories — Voyager 1 was set on a path to reach Jupiter and Saturn, ahead of Voyager 2.

What are the most notable achievements of the Voyager spacecraft?

Fifteen months after its launch, Voyager 1 reached its first target planet, Jupiter, on 5 March 1979, and was soon followed by Voyager 2, which arrived there on 9 July.
The most interesting discoveries made by Voyager 1 included the finding that Io, one of Jupiter’s moons, was geologically active.
After the Saturn expedition, as Voyager 1 headed on a trajectory to escape the solar system, Voyager 2 was redirected towards Uranus — both probes had fulfilled their primary mission goals but scientists kept them operational for further exploration.
Voyager 2 arrived at Uranus in 1986, becoming the first human-made object to fly past the aquamarine planet.
The spacecraft took stunning photographs and confirmed that the main constituents of Uranus are hydrogen and helium.
Then, the probe went to Neptune. Becoming the first human-made object to fly by the planet in 1989, Voyager 2 made some more notable discoveries there.
Apart from finding new moons and rings, it discovered that Neptune is more active than previously thought — winds on the planet blow at the speed of 1,100 kph.
After the Neptune encounter, Voyager 2, like Voyager 1, was put on the path to head out of the solar system. While Voyager 1 officially entered interstellar space in August 2012, Voyager 2 made its entry in November 2018.

#upsc #news #headline #voyager #mission #legacy #space #technology #national #aeronautics #spacecraft #data #NASA #planets #jupiter #saturn #uranus #neptune #mars #mercury #solar #moons

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Today's Headlines - 16 August 2023
Isro’s space probe to study the Sun
GS Paper - 3 (Space Technology)

The Indian Space Research Organisation (Isro) released images of the Aditya-L1 mission — the space agency’s first attempt to study the Sun. The satellite has reached the Satish Dhawan Space Center (SDSC) in Sriharikota, Andhra Pradesh, for its integration with the launch vehicle, PSLV.

What is the Aditya-L1 mission?

The Aditya-L1 will observe the Sun from a close distance, and try to obtain information about its atmosphere and magnetic field.
It’s equipped with seven payloads (instruments) on board to study the Sun’s corona, solar emissions, solar winds and flares, and Coronal Mass Ejections (CMEs), and will carry out round-the-clock imaging of the Sun.

Why is studying the Sun important?

Every planet, including Earth and the exoplanets beyond the Solar System, evolves — and this evolution is governed by its parent star.
The solar weather and environment affect the weather of the entire system. Variations in this weather can change the orbits of satellites or shorten their lives, interfere with or damage onboard electronics, and cause power blackouts and other disturbances on Earth. Knowledge of solar events is key to understanding space weather.
To learn about and track Earth-directed storms, and to predict their impact, continuous solar observations are needed.
Every storm that emerges from the Sun and heads towards Earth passes through L1, and a satellite placed in the halo orbit around L1 of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/eclipses.
L1 refers to Lagrangian/Lagrange Point 1, one of five points in the orbital plane of the Earth-Sun system. Lagrange Points, named after Italian-French mathematician Josephy-Louis Lagrange, are positions in space where the gravitational forces of a two-body system (like the Sun and the Earth) produce enhanced regions of attraction and repulsion.
These can be used by spacecraft to reduce fuel consumption needed to remain in position. The L1 point is home to the Solar and Heliospheric Observatory Satellite (SOHO), an international collaboration project of NASA and the European Space Agency (ESA).
The L1 point is about 1.5 million km from Earth, or about one-hundredth of the way to the Sun. Aditya L1 will perform continuous observations looking directly at the Sun.
NASA’s Parker Solar Probe, launched in 2018, has already gone far closer — but it will be looking away from the Sun.
The earlier Helios 2 solar probe, a joint venture between NASA and the space agency of erstwhile West Germany, went within 43 million km of the Sun’s surface in 1976.

#upsc #news #headline #ISRO #study #sun #space #technology #india #space #research #technology #aditya #mission #SDSC #satishdhawanspacecenter #srihorikota #andhrapradesh #PSLV #distance #magnetic #corona #solar #planet #weather #earth #repulsion #gravitational #forces #fuel #SOHO #NASA #germany #surface

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#upsc #news #headline #private #rockets #3D #printed #engines #emerging #technology #chennai #spacetech #agnikul #cosmos #rocket #developed #launchpad #flight #suborbital #company #hyderabad #skyroot #indian #commence #integration #aerospace #vikram #privatespace #industry #vehicle #agnilet #agnibaan #LEO #payloads #earth #orbit #diameter #mass #cryogenic #supercold #kerosene #dhawan #superalloy #globally #economy #indiannationalspacepromation #authorisationcenter #satellite #market #research #ISRO #NASA #scientificmisssion

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Today's Headlines - 25 August 2023
Experiments after Chandrayaan-3’s landing
GS Paper - 3 (Space Technology)

After rolling down a ramp from the Chandrayaan-3 lander, the six-wheel, 26-kg rover, which is capable of slowly moving up to 500 metres, began its job of lunar exploration. The landing happened at lunar dawn, and the six payloads on board the lander and rover was started collecting data soon after to get as much science as possible in the single lunar day or 14 Earth days for which they will remain operable.

Mission experiments

The lander has four experiments on board.

The Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA) will study the electrons and ions near the surface of the moon and how they change over time.
The Chandra’s Surface Thermo physical Experiment (ChaSTE) will study the thermal properties of the lunar surface near the polar region. Chandrayaan-3 has landed around 70 degree south latitude, the closest that any spacecraft has reached to the lunar South Pole.
The Instrument for Lunar Seismic Activity (ILSA) will measure the lunar quakes near the landing site and study the composition of the Moon’s crust and mantle.
The LASER Retroreflector Array (LRA) is a passive experiment sent by NASA that acts as a target for lasers for very accurate measurements for future missions.
There are two scientific experiments on the rover

The LASER Induced Breakdown Spectroscope (LIBS) will determine the chemical and mineral composition of the lunar surface.
The Alpha Particle X-ray Spectrometer (APXS) will determine the composition of elements such as magnesium, aluminium, silicon, potassium, calcium, titanium, and iron in the lunar soil and rocks.
Discovery of water

The southern polar region of the Moon is known to have deep craters that remain in permanent darkness, with a high likelihood of having water-ice.
Perhaps the most important discovery made by instruments on board Chandrayaan-1 was the discovery of water and hydroxyl (OH) molecules in the Moon’s thin atmosphere (exosphere) as well as on the lunar surface.
India’s Moon Impact Probe (MIP) — a payload that was deliberately crashed on the lunar surface near the South Pole — helped study the concentration of water and hydroxyl molecules in the lunar atmosphere.
Another payload called mini-SAR helped detect the subsurface deposits of water-ice in the permanently shadowed regions within the craters near the South Pole.
A third payload developed by NASA called Moon Mineralogy Mapper or M3 also helped detect these molecules on the surface of the Moon.
Chandrayaan-2, which was designed to further study the water on the Moon, helped in separately identifying the water and the hydroxyl molecules, and mapping water features across the Moon for the first time.

#upsc #news #headline #experiments #chandrayaan #landing #spacetechnology #exploration #lunardawn #missionexperiments #board #radio #anatomy #hypersensitive #atmosphere #RAMBHA #electrons #ChaSTE #latitude #southpole #ILSA #landingsite #LRA #NASA #LIBS #magnesium #aluminium #silicon #potassium #calcium #titanium #iron #lunarsoil #OH #MIP #miniSAR

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Today's Headlines - 29 August 2023
Crew-7 mission to space station
GS Paper - 3 (Space Technology)

Four astronauts from four countries, including the US, Denmark, Japan, and Russia, launched aboard a SpaceX rocket towards the International Space Station (ISS) from NASA’s Kennedy Space Center in Florida. This was the first US take-off in which all the astronauts atop the spacecraft belonged to a different country — until now, NASA had always included two or three of its own on its SpaceX flights. The mission has been known as Crew-7.

Why has such a diverse group of astronauts gone to the ISS?

The Crew-7 mission is a result of the ongoing cooperation among different countries in space, especially since the launch of the space station in 1998.
The International Space Station Program involves the US, Russia, Canada, Japan, and the participating countries of the European Space Agency, and is one of the most ambitious international collaborations ever attempted.
The program “brings together international flight crews, multiple launch vehicles, globally distributed launch, operations, training, engineering, and development facilities; communications networks, and the international scientific research community”.
What is the mission?

The Crew-7 is the eighth flight operated by NASA and Elon Musk-owned SpaceX as part of the agency’s commercial crew program, which has been taking astronauts to the ISS since SpaceX’s first crewed mission in 2020.
During their stay at the space station, the Crew-7 astronauts will conduct more than 200 science experiments and technology demonstrations to prepare for missions to the Moon, Mars, and beyond.
The research will include a collection of microbial samples from the exterior of the space station.
The team will also analyse how sleeping in the microgravity environment differs from Earth by examining astronauts’ brain waves while they sleep.
Yet another experiment will look at the formation of biofilms in wastewater on the space station, which could be key to finding better ways to recycle water for drinking and hygiene while in space (Yes, astronauts have long used recycled sweat and urine to drink and shower on the station).

#upsc #headline #crew #mission #spacestation #spacetechnology #astronauts #internationalspacestation #NASA #denmark #japan #russia #takeoff #earth #brain #microgravity #hygiene #recycle #waves #commercialcrew #biofilms #wastewater #moom #mars #microbial #samples #program #station #cooperation #denmark #rocket

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Today's Headlines - 01 September 2023
Super Blue Moon of Raksha Bandhan
GS Paper - 3 (Science and Technology)

The Raksha Bandhan full moon on 30-31 August was unusual: it was both a “blue moon” and a “super moon” and therefore, a “Super Blue Moon”, a rare trifecta of astronomical events.

What is a supermoon?

The orbit of the moon around the earth is not circular; it is elliptical, that is, an elongated or stretched-out circle. It takes the moon 27.3 days to orbit the earth.
It is 29.5 days from new moon to new moon, though. This is because while the moon is orbiting the earth, both the earth and the moon are also moving around the sun — and it takes additional time for the sun to light up the moon in the same way as it does at the beginning of every revolution around the earth.
The new moon is the opposite of the full moon — it is the darkest part of the moon’s invisible phase, when its illuminated side is facing away from the earth.
The point closest to earth in the moon’s elliptical orbit is called perigee, and the point that is farthest is called apogee.
A super moon happens when the moon is passing through or is close to its perigee, and is also a full moon. (This happens with a new moon as well, just that it is not visible.
A full moon occurs when the moon is directly opposite the sun (as seen from earth), and therefore, has its entire day side lit up. The full moon appears as a brilliant circle in the sky that rises around sunset and sets around sunrise. The moon appears ‘full’ not just on Purnima, but also on the night before and after the full moon night.
What is a blue moon?

Though the expression “once in a blue moon” implies a rare or unusual occurrence, a blue moon is not that rare an astronomical phenomenon.
There are a couple of definitions of a blue moon, but the one that is most commonly understood — and is endorsed by NASA — describes the situation when a full moon is seen twice in a single month.
Because the new moon to new moon cycle lasts 29.5 days, a time comes when the full moon occurs at the beginning of a month, and there are days left still for another full cycle to be completed.
Such a month, in which the full moon is seen on the 1st or 2nd, will have a second full moon on the 30th or 31st. According to NASA, this happens every two or three years.
The first full moon of August 2023 occurred on 1 August. That was also a super moon, but the super moon of 30-31 August will be bigger because the moon is now closer to the perigee.
Will the moon actually appear blue?

No. Sometimes, smoke or dust in the air can scatter red wavelengths of light, as a result of which the moon may, in certain places, appear more blue than usual. But this has nothing to do with the name “blue” moon.
Speaking of colours, you may have noticed that the moon appears more yellow/ orange when it is lower in the sky (closer to the horizon).
This is because moonlight travels for longer through the atmosphere at this stage, and along the way, more of the shorter, bluer wavelengths of light are scattered, leaving more of the longer, redder wavelengths.
NASA points out that dust or pollution can end up deepening the reddish colour of the moon.

#upsc #news #headline #superbluemoon #rakshabandhan #science #technology #fullmoon #supermoon #trifecta #astronomicalevents #orbit #earth #newmoon #ellipticalorbit #apogee #purnima #phenomenon #air #wavelength #yellow #orange #atmosphere #NASA #dust #pollution #reddishcolour

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Today's Headlines - 05 September 2023
A sunrace of significant global missions
GS Paper - 3 (Space Technology)

In the wake of the Indian Space Research Organisation's successful launch of its inaugural solar mission, Aditya-L1,, let's embark on a journey through key missions from space agencies worldwide, all dedicated to unravelling the enigmatic secrets of the Sun.
A Sunrace
USA
US: National Aeronautics and Space Administration (NASA), the US space agency, launched the Parker Solar Probe in August 2018. In December 2021, Parker flew through the Sun's upper atmosphere, the corona, and sampled particles and magnetic fields there. This was the first time ever that a spacecraft touched the Sun, according to NASA.
In February 2020, NASA joined hands with the European Space Agency (ESA) and launched The Solar Orbiter to collect data to find out how the Sun created and controlled the constantly changing space environment throughout the solar system.
Other active solar missions by NASA are Advanced Composition Explorer launched in August, 1997; Solar Terrestrial Relations Observatory in October, 2006; Solar Dynamics Observatory in February, 2010; and Interface Region Imaging Spectrograph launched in June, 2013.
Also, in December, 1995, NASA, ESA and JAXA (Japan Aerospace Exploration Agency) jointly launched the Solar and Heliospheric Observatory (SOHO).
Japan
JAXA, Japan's space agency, launched its first solar observation satellite, Hinotori (ASTRO-A), in 1981. The objective was to study solar flares using hard X-rays, according to JAXA. JAXA's other solar exploratory missions are Yohkoh (SOLAR-A) launched in 1991; SOHO (along with NASA and ESA) in 1995; and Transient Region and Coronal Explorer (TRACE), along with NASA, in 1998.
In 2006, Hinode (SOLAR-B) was launched, which was the successor to Yohkoh (SOLAR-A), the orbiting solar observatory. Japan launched it in collaboration with the US and the UK. The objective of Hinode, an observatory satellite, is to study the impact of the Sun on the Earth.
Yohkoh's objective was to observe solar flares and the solar corona. It was the first satellite to track almost an entire 11-year solar activity cycle.
Europe
In October, 1990, the ESA launched Ulysses to study the environment of space above and below the poles of the Sun, giving scientists information about the variable effect the Sun has on the space surrounding it. Other than solar missions launched in collaboration with NASA and the JAXA, the ESA launched Proba-2 in October, 2001.
Proba-2 is the second of the Proba series, building on nearly eight years of successful Proba-1 experience, even as Proba-1 was not a solar exploratory mission. On-board Proba-2 were four experiments, two of them were solar observation experiments.
Proba stands for Project for On-Board Autonomy. Upcoming solar missions of the ESA include Proba-3, scheduled for 2024 and Smile, scheduled for 2025.
China
The Advanced Space-based Solar Observatory (ASO-S) was successfully launched by the National Space Science Center, Chinese Academy of Sciences (CAS), in October, 2022. The ASO-S mission is designed to reveal connections among the solar magnetic field, solar flares, and coronal mass ejections (CMEs).
Solar flares and CMEs are eruptive solar phenomena, thought to be driven by changes in the Sun's magnetic field.

#upsc #news #headline #sunrace #significant #global #missions #spacetechnology #indian #space #organisation #AdityaL1 #NASA #Solar #magnetic #fields #spacecraft #firsttime #orbiter #ESA #enviroments #spectrograph #JAXA #SOHO #japan #USA #EUROPE #CHINA #ASO #CMEs #autonomy #mission

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