My Science School

The sky and the flock of stars that flicker endlessly have always been an inspiration for mankind. Some 400 years ago, on a starry night, Italian astronomer Galileo Galilei aimed his telescope towards the sky. That was just the beginning of modern astronomy. Stargazing is the start of an incredible journey towards exploring the cosmos, which will help you learn more about the universe we are living in.

Look at the stars. Look how they shine for you..." sang Coldplay's lead singer Chris Martin in the song "Yellow" which was part of their debut album "Parachutes". Legend has it that the inspiration for the song came when Martin and his bandmates were asked to look at the stars. The band had just finished recording the song "Shiver" and was taking a break when the song's co-producer Ken Nelson asked them to look at the stars. A melody popped into Martin's head. And "Yellow" was born.

The sky and the gaggle of stars that flicker endlessly have always been an inspiration for mankind. It is our window to space and every cosmic body out there. The quest to explore the stellar world dates back centuries.

The start of modern astronomy

Some 400 years ago, on a starry, starry night, Italian astronomer Galileo Galilei aimed his telescope towards the sky. He was the first to use the earliest version of the telescope, his own version of the "spyglass" (a device used to see far away objects) to observe celestial bodies.

He documented what he saw and made discoveries that changed how we perceived the Cosmos. Observing the night sky, he found out that the Moon had mountains and pits, and that Jupiter had moons. That was just the start of modern astronomy.

The compelling need to watch the Moon or the many astral bodies in a star-spangled sky has no rhyme or reason. So if you like the sky and stars, read on.

The art of stargazing

Stargazing is just the start of an incredible journey towards exploring the cosmos, which will help you learn more about the universe we are living in. Every astronomer started off as an enthusiastic stargazer.

Stargazing or amateur astronomy is the practice of watching the stars and other celestial bodies. It can be a rewarding hobby that lets you disconnect from the chores of your routine life and connect with the vast universe.

The first thing to ensure is that you have a clear, dark sky. without light pollution. It is difficult to enjoy the sky and stars if you live in a well-lit area, where light is directed towards the sky. Once you get a clear, dark sky, just look up and befriend the sky.

Observing the sky

You do not need expensive telescopes to see the celestial bodies. All you need to do is look up. The naked eye can guide you well enough. What you might need though is a sky map that can help you identify the many stars and constellations (groups of stars that look like patterns).

Once you correctly identify a star or a constellation, your journey gets more exciting. As many as 88 constellations cover the sky. Try to make out easily recognisable star patterns or constellations such as the Orion, Cassiopeia, Big Dipper/Ursa Major, Ursa Minor, Pegasus and Taunus.

Did you know that some planets are visible to the naked eye? Planets thus visible are Venus, Mercury, Mars, Saturn, and Jupiter.

The brightest star in the night sky is Sirius. But how do you know if you are looking at a planet or a star? Stars have their own light, whilst planets do not. Planets only reflect the light from the Sun and do not twinkle.

Befriend the sky

What you see in the sky, depends on where you are located on Earth. As Earth orbits the Sun, the stars also shift. Once you have understood this, you will know that even as the stars shift as our planet moves, they tend to return to the same spot in the sky every year. Have a journal and make a note of everything you observe in the sky.

One way to get better at spotting the stars and learning about them is to join star parties or go to your nearest observatory. Star parties are events where stargazers join to watch the stars and the sky using telescopes. You can look at the skies using a telescope in observatories as well. You can also join local astronomy clubs. Your school might even have one. If not why don't you take an initiative to start one? Alternatively, you can download mobile applications that help you identify the stars and planets.

As you progress, you can invest in a decent pair of astronomical binoculars that will help you see the celestial bodies up close. For instance, many craters on the moon that you have seen only in pictures become crystal clear as you peer through the binoculars.

Did you know that there is even a global movement to protect the dark sky? So what are you waiting for? The sky is calling. And you must go.

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Scientists find that minerals from the asteroid were produced more than 4.5 billion years ago, even closer to the beginnings of the solar system

The age of our solar system is estimated to be around 4.57 billion years. While previous studies of ancient meteorites have revealed minerals created 4.5 billion years ago, a new study has pushed that even closer to the beginnings of the solar system.

Using mineral samples from the Ryugu asteroid collected by Japan's Hayabusa2 spacecraft, researchers from the University of California - Los Angeles are trying to better understand the chemical composition of the early solar system, closer to its infancy. Their results were published in January in Nature Astronomy.

Within 1.8 million years

 With the help of isotopic analysis, scientists discovered that carbonate minerals in the samples were crystallised through reactions with water. According to their estimates, these carbonates were formed within the first 1.8 million years after the solar system came into existence. They thus preserve a record of the temperature and composition of the asteroid as it was at that time.

Apart from being rocky and carbon-rich, Ryugu is the first C-type (carbonaceous) asteroid from which samples have been collected and studied. Unlike meteorites, which might have been chemically contaminated during their contact with Earth, these samples plucked off the asteroid are untouched.

Formed rather rapidly

Based on their research, the scientists were able to tell that Ryugu's carbonates were formed several million years earlier than previously believed.

Additionally, it also indicates that Ryugu, or the parent asteroid from which it broke off, was a relatively small object- less than 20 km in diameter. This came as a surprise as most existing models predicted the formation of bodies at least 50 km in diameter.

In essence, the study helped the researchers suggest that the Ryugu asteroid and similar objects formed in the outer solar system. They must have formed relatively rapidly and probably as small bodies.

Understanding the mineral structure of asteroids provides insights into various questions on astrobiology. Current and future research on the Ryugu samples and other materials will thus continue to help our understanding about the formation of the solar system's planets, including our own Earth.

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Space and Science: From the spectacular images dispatched by the James Webb Space Telescope and NASA’S ambitious missions to explore the moon to the breakthrough in malaria vaccine and the invention of the half-a-millimetre-wide remote controlled, walking robot, the year 2022 witnessed plenty of wow moments in Space and Science.

1. HD 1

In April 2022, we discovered the most distant galaxy to date. Christened HD 1, this galaxy is some 13.5 billion light-years away. To explain why the galaxy was unusually bright in ultraviolet light, the astronomers propose that either HD1 might be forming stars at a very high rate or may be home to a supermassive black hole. HD 1 could also be home to the Population III stars, the very first stars of the Universe. The discovery of HD 1 also breaks the record of the GN-Z11 galaxy that was discovered in 2017, lying some 13.4 billion light-years away.

The distant early galaxy HD1, object in red, is shown at the centre of this undated zoom-in handout image.

2. China's space milestones

In 2022, China took a firm foothold in space with significant additions to its own space station called "Tiangong". The space station will assist future Chinese missions and also help carry out scientific research and enable the stay of astronauts for longer periods in space. In July 2022, it launched its laboratory module called "Wentian". The final piece "Mengtian", also a laboratory module, was launched and docked, thereby completing the basic construction of its space station. It may be recalled that China began construction of its space station with the "Tianhe" module, the main living quarters for astronauts in 2021. Seen here is the Long March 5B rocket, carrying China's Mengtian science module, the final module of Tiangong space station, lifting off.

3. James Webb Space Telescope

The James Webb Space Telescope, the largest and most powerful space telescope (launched in December 2021), has been dispatching stellar images of the universe since July 2022, propelling astronomical research in new directions. It has captured the farthest and oldest galaxies seen to date; offered a detailed image of the famous Pillars of Creation; presented the clearest view of Neptune's rings, and captured the geographical phenomenon on Jupiter’s surface. It also gave us the first evidence of carbon dioxide in the atmosphere of an exoplanet - all this from its orbit around the second Lagrange point, a million miles away from Earth. Seen here is the detailed image of the Pillars of Creation shared by NASA's James Webb Space Telescope.

4. DART mission

In a first-of-its-kind mission, NASA launched its Double Asteroid Redirection Test (DART) spacecraft successfully in September 2022. The mission aimed at deflecting asteroids was a step towards preparing the world for a potential future asteroid strike like the one which killed the dinosaurs millions of years ago. The first test DART mission targeted the asteroid moonlet Dimorphos, a small body about 160 metres in diameter. NASA confirmed the mission altered the asteroid's motion in space. The one-way trip proved how a spacecraft could intentionally collide with an asteroid in order to deflect it - a planetary defence against near-Earth objects. The last image to contain a complete view of asteroid Didymos (top left) and its moonlet, Dimorphos, about 2.5 minutes before the impact of NASA'S DART spacecraft.

5. Women in space

The year 2022 was a milestone year for women astronauts. Nicole Mann became the first native American woman to go to space. She was the commander of NASA's SpaceX Crew-5 mission that blasted off in the Dragon Endurance spacecraft built by SpaceX in October 2022. Jessica Watkins became the first Black woman on a long-duration ISS mission. Nora Al Matrooshi became the first woman astronaut from the UAE. She trained at the Johnson Space Centre in Houston. She is the Arab world's first woman astronaut and has joined the second batch of the UAE Astronaut Program, training with NASA for future space missions.

6. Artemis

Half a century after astronauts walked on the moon, NASA is a few steps away from putting humankind back on the Moon. The Artemis 1 mission, launched on November 16, was an uncrewed mission designed to test the viability of the Space Launch System, NASA's next-generation rocket ship, and the Orion Space Capsule scheduled to enter lunar orbit and return to Earth after about 25 days. Artemis 1 demonstrated the capabilities of both SLS and Orion. Its success has cleared the path for Artemis II and III in 2024 and 2025, when astronauts will embark on lunar-flyby-return-to-earth test missions. Seen here is the Orion Capsule, launched on the Artemis rocket, getting drawn into the well deck of the USS Portland during recovery operations.

7. ISRO's major milestones

Indian Space Research Organisation (ISRO), the country's space agency, hit many milestones in 2022. The agency launched India's first privately developed rocket “Vikram-suborbital (VKS)" in November 2022. It also test-fired the Astronaut Safety System for India's ambitious Gaganyaan mission- the country's manned mission to space. The year 2022's last PSLV mission blasted off with one ocean research satellite and eight nanosatellites by Indian start-ups and Bhutan. The 200th consecutive launch of the multipurpose sounding rocket RH200 was also held. The agency successfully launched 36 Gen-1 satellites via the LVM3 launch vehicle as part of its commercial mission for the U.K.-based communications company OneWeb. Seen here is ISRO's first privately developed Indian rocket Vikram-S being launched from the Satish Dhawan Space Centre in Sriharikota.

8. Human Cell Atlas

In May 2022, about 2.300 researchers from 83 countries came up with a compilation called the Human Cell Atlas. The task involved mapping the positions of over a million cells across 33 different organs in the healthy human body. The aim of this international collaborative consortium is to help understand biology and diseases better. Cutting-edge single cell and spatial genomics and computational techniques were used. The compilation is seen as a major step towards analysing how illnesses can be diagnosed and treated. It is expected to eventually transform our understanding of the 37.2 trillion cells in the human body.

9. Monkeypox

In May 2022, another global health concern arose, when the viral disease Monkeypox was detected in the U.K Monkeypox is a viral zoonotic disease that has symptoms similar to those in smallpox patients. Come July and 90 percent of the cases were centered mainly around Europe. The World Health Organisation declared the monkeypox outbreak a Public Health Emergency of International Concern. Over the months, with testing, surveillance, and vaccination, cases declined. JYNNEOS, a two-dose vaccine that was developed to protect against both mpox and smallpox was used during the outbreak. Monkeypox was renamed Mpox by the WHO. Seen here is a magnifying glass focusing on a vesicle rash created by monkeypox disease.

10. World's smallest remote-controlled, walking robot

In May 2022, a team of engineers at the Northwestern University in the U.S. demonstrated the world's smallest walking robots. They measured just half-a-millimeter wide. The crab-shaped remote-controlled invention is a milestone in the field of robotics because they are capable of performing practical tasks in tight spaces. The micro robot, scientists say, could repair small machines and even offer help in performing surgical tasks such as clearing clogged arteries or eliminating cancerous tumours. They are still in developmental stage and were primarily created for academic purpose. Nevertheless, the technology used to create them has potential for scaling.

11. Earth's shortest day on record

On June 29 2022, we had the shortest day ever to be recorded since the 1960s. The Earth completed its rotation in 1.59 milliseconds less than its routine 24  hours. Scientists recorded this using atomic clocks. In recent years, Earth has been spinning faster and taking less time to complete its rotation. A study in 2016 found that in the previous 2,740 years, Earth's rotation slowed by about six hours. This truncation of day length is attributed to climate effects. The speed depends on factors such as gravity, changes in winds, ancient ice sheets, dynamics of the planet's core, and so on.

12.  Paper coating that behaves like plastic

Plastic is problematic. So, a team of researchers from the University of Japan developed a coating for the paper that makes it behave like plastic in July 2022. The coating, "Choetsu", is claimed to be a cheap and safe mixture of chemicals. It makes the paper rigid, waterproof, bacteria-repelling, and durable. The initial target is to test its efficacy in food packaging. With the technology, paper is given some of the properties of plastic and is touted to degrade safely. The process involves dipping the paper structure into the coating mixture and drying it. The coating is low-cost and biodegradable.

13. Malaria vaccine breakthrough

In a major boost to the global fight against Malaria, one of the leading causes of child mortality, a new vaccine against the disease has been found to be highly effective. The scientists at the University of Oxford's Jenner Institute who created the vaccine R21/ Matrix M published their trial results in September 2022. It is also the first malaria vaccine to meet and exceed the World Health Organisation's (WHO) vaccine target of 75% efficacy against the deadly disease. The vaccine has been found to be 77% effective in early-stage trials. Malaria kills more than 4,00,000 people each year. Seen here is a feeding female Anopheles funestus mosquito, a known vector for malaria.

14. Zombie virus

A 48,500-year-old zombie virus that was trapped under a frozen lake in Russia emerged in November 2022. The zombie virus, which was revived by scientists, emerged as a result of global warming. According to the French scientists who published the study, the thawing of the permafrost a permanently frozen layer on or under - Earth's surface-led to the release of the virus which was trapped and frozen for up to a million years. Scientists maintained that the zombie viruses are a health threat and that further studies need to be undertaken on the risk posed by ancient viral particles.

15. Nobel Prize for Science and Medicine 2022

Alain Aspect, John Clauser, and Anton Zeilinger were awarded the 2022 Nobel Prize for Physics in December 2022. Their work established the quantum property of entanglement. The trio worked independently and were awarded for their experiments with entangled photons, establishing the violation of Bell's inequalities and pioneering quantum information science". Meanwhile, geneticist Svante Paabo was awarded the 2022 Nobel Prize in Physiology or Medicine. The award was "for his research in the field of genomes of extinct hominins and human evolution". Instituted by Swedish chemist Alfred Nobel, the Nobel Prize is presented to honour those from around the world for their remarkable achievements.

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A mission conceived as one for preventive maintenance turned out to be more urgent after four of the six gyroscopes on board the Hubble space telescope failed.

The Hubble space telescope has changed our understanding of the universe A telescope that was launched into low Earth orbit in 1990, Hubble still remains operational and continues to be a vital research tool. Following NASA's most recent review of Hubble's operations, it has been announced that NASA would support the observatory through June 2026, with estimates suggesting that it might be able to continue operations until the mid-2030s and even beyond.

Designed to be visited

While the longevity of the telescope is testament to the vision of those who conceived the mission, there's another crucial factor that has made it possible. Hubble was the first telescope that was designed to be visited in space. This meant that astronauts could not only perform repairs and replace parts, but also upgrade its tech with newer instruments. There have been five such missions that have taken place from 1993 to 2009. One such servicing mission in December 1999 turned out to be a life saver for the telescope.

After the first servicing mission in 1993 and the second one in 1997, the third to carry out preventive repairs was scheduled for June 2000. Since Servicing Mission 2 in February 1997, however, three of the six gyroscopes aboard Hubble had failed. With at least three working gyroscopes necessary for Hubble's operation, it prompted the managers to split Servicing Mission 3 (SM3) into two parts, SM3A and SM3B, with the former scheduled for December 1999.

An unexpected failure

 On November 13, 1999, a fourth gyroscope failed unexpectedly. With SM3A planned for the following month, this triggered NASA to place Hubble into safe mode. The safe mode was a sort of protective hibernation that prevented the telescope from making any observation. Hubble was in this state for over a month, waiting for the crew of SM3A to make their way.

With servicing mission veterans Steven Smith and Michael Foale at the helm, the seven-member crew aboard the Discovery Space Shuttle (STS-103) left for space on December 19. Within a couple of days, they manoeuvred close enough to Hubble such that it could be grappled with Discovery's robotic arm.

All six gyroscopes replaced

 The first of the three scheduled spacewalks took place over 8 hours and 15 minutes spanning December 22-23 (Central European Time, CET). Smith, along with fellow crew member John Grunsfeld, managed to replace all six of Hubble's gyroscopes. The entire astronomical community heaved a collective sigh of relief on receiving this news. The duo also replaced kits to prevent Hubble's batteries from overcharging.

While Hubble's main computer was changed in the second spacewalk that spanned 8 hours 10 minutes through December 23-24 (CET), the final spacewalk spanning 8 hours 8 minutes through December 24-25 (CET) saw a faulty transmitter and data tape recorder being replaced. Preliminary tests were then conducted to ensure that all of Hubble's systems, be it old or new, were performing satisfactorily.

Backs away slowly

Minutes into December 26 (CET), the Hubble telescope was released. Discovery then backed away from Hubble slowly. Having successfully performed the major objectives of the mission, the astronauts on board used the time remaining to stow away equipment, apart from making preparations for landing.

After orbiting the Earth 119 times and travelling more than 5 million km, Discovery made its way back. It performed a smooth night-time landing, touching down on the runway at the Kennedy Space Center in the U.S. on December 27. Hubble was successfully back in operation, and has been for over two decades since then.

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Discovered first on December 20, 1900, comet 21P/Giacobini-Zinner gets its name from two astronomers. From being one of the last comets to be discovered in the 19th Century, this comet is now best known for having the first encounter with a spacecraft.

Comets are popular for different reasons. There's Halley's comet, which is the most famous of them all. Regularly visible to the naked eye from the Earth, Halley's comet has been observed and recorded by astronomers for over 2,000 years. Then, there is comet Hyakutake. Discovered only in 1996, this comet's passage near the Earth in the same year was one of the closest cometary approaches in nearly 200 years. We will be turning our attention to comet 21P/Giacobini-Zinner, whose claim to fame now includes being the first comet to encounter a spacecraft. This comet was first discovered on December 20, 1900, making it one of the last comets to be discovered in the 19th Century. A discoverer of a number of comets, French astronomer Michel Giacobini found this comet while skygazing from Nice Observatory. It was followed for two months and orbital calculations revealed that the comet was a periodic object with an orbital period less than seven years.

Recovered in 1913

It wasn't recovered in 1907, when it was not placed favourably for viewing. Even though the comet was expected to be unfavourably placed in 1914 as well, German astronomer and renowned science historian Ernst Zinner accidentally rediscovered it on October 23, 1913.

Since both Giacobini and Zinner discovered and recovered this comet, it is named after them and is called comet 21P/Giacobini-Zinner. The letter "p" indicates that it is a periodic comet, which are comets with orbital periods less than 200 years. When orbital calculations were revised when the comet was recovered in 1913, its orbital period was found to be close to 6.6 years, and the comet has been observed on almost every return since then.

Draconid meteor shower

This comet had favourable returns in 1959, 1985, and 2018, when it was well observed as its perihelion (closest approach to sun) allowed it to pass close to the Earth. The nucleus of the Giacobini-Zinner sprays ice and rock into space every time it returns to the inner solar system. This makes the comet the parent comet of the Draconid meteor shower, which takes place in early October each year.

While this meteor shower is quite weak in most years, there have been Draconic meteor storms on record, meaning that over 1,000 meteors were seen per hour at the location of the observer. The 1933 and 1946 Draconid storms were particularly intense, with over 500 meteors observed per minute in Europe during the former and 50-100 per minute seen in the U.S. during the latter.

Farquhar's idea

Comet Giacobini-Zinner's current claim to fame was a result of its favourable return in 1985. When funding for a spacecraft mission to comet 1P/Halley, which was enroute to its 1986 perihelion passage, didn't materialise, planetary scientist Robert Farquhar came up with an idea. He suggested that the already existing International Sun-Earth Explorer 3 (ISEE-3) be placed on an alternate path that would take it towards Giacobini-Zinner.

Once the idea was approved, ISEE-3 was sent on a series of lunar flybys that would take it towards Giacobini-Zinner. Following the final lunar flyby in December 1983, ISEE-3 was renamed the International Cometary Explorer (ICE).

On September 11, 1985, ICE passed through the ion tail of Giacobini-Zinner, thereby completing the first encounter between a comet and a spacecraft. While ICE lacked cameras, it did carry scientific instruments that enabled it to record measurements of the electric environment around the comet and also as to how the comet interacted with the solar wind.

Even though an international fleet of spacecraft, including ICE, met Halley in 1986 from a number of vantage points for a study like never before, Giacobini-Zinner will forever hold the title of being the first comet to encounter a spacecraft. While its most recent return in 2018 might be comet 21P's most favourable return in the 21st Century, you can still look forward to its approach once in less than seven years, and maybe even try and track it.

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Sunspots are regions on the sun that appear dark. They occur in regions where the magnetic field of sun is strong. The temperature of a sunspot is super hot-something around 6,500 degrees Fahrenheit

The Sun, the centre of our solar system and our closest star, is 4.5 billion years old. This fiery glowing orb of hydrogen and helium sustains life as we know it

Sunspots

Sunspots are regions on the sun appear dark. These parts appear darker as they are cooler when compared to other parts of the sun. They occur in regions where the sun's magnetic field is highly concentrated or strong.

The centre of the sunspot is dark and this is called the umbra while the outer and lighter ring is called the penumbra. Spots vary in sizes. They could be larger than the Earth, or so tiny that it will be difficult to pick them up in telescopic observation. The sunspots could stay on for months. Most of the sunspots can be seen in pairs or groups but single spots also do occur. When they occur in pairs, they have opposite magnetic polarity.

Why are sunspots cooler

Sunspots form in areas on the sun where the magnetic field is very strong and powerful. These magnetic fields will prevent the heat within the Sun from reaching its surface. Even when we say that the sunspots are cooler, this is just in comparison to the other regions of the Sun. The temperature of a sunspot is super hot something around 6.500 degrees Fahrenheit.

Why do sunspots matter

 In most cases, sunspots precede the occurrence of a solar flare. Solar flares are sudden bursts or explosions of energy from the sun's surface. This occurs when the magnetic field lines near the sunspots reorganise or cross. These solar flares will release huge amounts of radiation into space. The more intense the solar flare, the more intense will be its radiation. This can affect radio communication on Earth. Studying and monitoring the sunspots are required to understand the reason behind the occurrence of solar flares.

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Many years ago, in 1610, Italian astronomer Galileo Galilei discovered the first moons beyond Earth. Those were the moons of the planet Jupiter, the largest planet in the solar system.

Planet Jupiter has 80 moons. There are many interesting moons orbiting the planet, but the ones of great interest to us on a scientific level are the first four moons discovered called the Galilean satellites. They are lo, Europa, Ganymede, and Callisto. Here we look at the four largest moons of Jupiter.

What is a Moon?

Moons are those celestial bodies that orbit planets and asteroids in the solar system. They are also called natural satellites. The Earth has one moon, whilst the solar system has more than 200 moons. Most of the major planets except Mercury and Venus have moons.

Jupiter and Saturn have the most moons. Four of Jupiter's moons are named after Galileo Galilei who first discovered them.

And how were the Galilean moons formed? According to scientists, the moons were formed out of the dusty disc left after Jupiter was formed.

lo

The most volcanically active body in the solar system, lo has its surface enveloped by sulfur. Jupiter's gravity causes "tides" that rise some 100 metres high on lo and lead to the generation of heat for volcanic activity.

Europa

Europa's surface is covered mostly by water ice. This moon is considered to have twice as much water as Earth.

Ganymede

The largest moon in the solar system, Ganymede is the only moon that has its own internally generated magnetic field. Did you know that this moon is even larger than the planet Mercury?

Callisto

The second largest moon of Jupiter, Callisto's surface is highly cratered and ancient. This moon is about half rock and half ice.

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On December 11, 1972, Apollo 17 achieved lunar landing. The sixth mission in the Apollo program to explore the lunar surface, Apollo 17, for now, is the last human expedition to the moon.

Apollo 11 will forever be remembered as the mission which enabled human beings to set foot on the moon, our natural satellite, for the first time. While the first will always remain the the same cannot be said for what is the last such mission, as future missions might take that place. But for the time being, Apollo 17 remains the last human expedition to the moon.

After the success of Apollo 11 in 1969, there were six more Apollo missions to the moon, five of which were successful. As U.S. President John F. Kennedy's objective of landing humans on the moon had been achieved, NASA faced funding cuts. Technology and research-based missions weren't seen as important as the landing itself, forcing NASA to cancel some of the planned missions in 1970. As a result, the Apollo 17 mission of 1972 became the last manned mission to the moon.

Firsts and records

Apollo 17 was a 12-day mission that spanned from December 7-19. Apart from the distinction of being the last human expedition to the moon for now, Apollo 17 also achieved a number of firsts and broke some records. It had the then longest space walk and enabled the collection of the largest lunar samples brought back to Earth. It was the first Apollo mission to be launched at night and allowed a scientist to walk on the moon for the first time.

The scientist in question was Harrison H. Schmitt, a geologist who had been part of the backup crew for Apollo 15. Schmitt was originally scheduled to go on Apollo 18, which was cancelled. The scientific community lobbied for Schmitt's inclusion in Apollo 17. While Schmitt served as the pilot of the lunar module "Challenger", Eugene A. Cernan was commander and Ronald E. Evans was the pilot of "America", the command module.

Following a successful night launch on 7, Apollo 17 achieved lunar orbit insertion on December 10. Then, with Evans orbiting the moon, Cernan and Schmitt flew Challenger and landed on the moon's surface on December 11, touching down within 200 m of the targeted landing point.

Two primary objectives

Apollo 17's two primary objectives were to obtain a specific sample and to explore geologically recent, explosive volcanism. The former was achieved as they retrieved the oldest known unshocked (unaltered by meteoric impact) rock from the moon. This sample, called Troctolite 76535, is believed to be at least 4.2 billion years old.

The second objective was met as Schmitt discovered orange soil near Shorty crater. This colour was the result of orange and black volcanic glass that had formed in the type of volcanic eruption that is referred to as "fire fountain" on Earth.

Cernan and Schmitt were on the lunar surface for 75 hours, the longest till now. They clocked 22 hours of extravehicular activity (EVA) with the help of their rover and travelled about 36 km. They went as far as 7.4 km away from the Challenger, close to the limit of what was considered the walk-back distance possible, should the rover have failed. Apart from conducting various experiments, they took over 2,000 photographs and collected 110 kg worth of soil and rock samples from 22 different sites.

Last man on the moon

Following the third and final EVA, the duo televised the unveiling of a plaque with a message, which they left on the moon. On December 14, Cernan took humankind's final step, to date, off the moon.

After lifting off from the moon, the Challenger was docked with America on December 15. Four days later, on December 19, the Apollo 17 capsule splashed down in the Pacific Ocean at a distance of 6.5 km from the recovery ship, after a mission elapsed time of 301 hours.

For 50 years, Cernan has often been referred to as the last man on the moon. With NASA's Artemis program aiming to return to the moon and even set up a sustained human presence, it might not be long before the next human being sets foot on the moon.

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A protogalaxy is in simpler words a primeval galaxy. It refers to a galaxy that is undergoing the first generation of star formation. It is also defined as a cloud of gas that is forming into a galaxy. This particular celestial mass would just comprise hydrogen gas trapped in some dark matter prior to the initial stages of star formation. The stars are formed from the smaller clumps of gas in the protogalaxy.

Types of Galaxies

 There are two types of galaxies viz. elliptical galaxies and spiral galaxies. The majority of the galaxies that you come across are elliptical galaxies and they are called so because they have an even, ellipsoidal shape. They also are comprised with a greater population of older stars when compared to spiral galaxies.

A spiral galaxy normally has a rotating disc replete with spiral 'arms. The stellar orbits are circular in shape and they have a flattened disk system. Most spiral galaxies also contain in their centre a mini-elliptical galaxy. Our galaxy, the Milky Way, is a spiral galaxy.

So what determines the shape of a galaxy? The rate of star formation during galactic evolution determines whether it turns out into a spiral or elliptical galaxy. If the star formation is at a slower pace, then it turns into a spiral galaxy.

Milky Way

About 12.5 billion years ago, the Milky Way started to form. Several huge clusters of stars and clumps of gas fused together to form a protogalaxy. This was the building basis of our home!

It then collided with many galaxies, and after a lot of mergers, it acquired its present form.

Recently, scientists discovered a population of millions of stars at the center of our galaxy. Those were the remains of the ancient protogalaxy! These oldest stars that were found in the core area of our galaxy were analysed and the scientists found out that they were part of a protogalaxy.

The diameter of which extended to 18 thousand light-years, and with a mass that was 50-200 million times that of the Sun!

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This new black hole is 1.600 light-years away in the constellation Ophiuchus So far scientists have discovered 20 black holes in the Milky Way. About 100 million more are estimated to be present in our galaxy.

A new black hole has been discovered very near to Earth, closer than any other previously found. Christened Gaia BH1, this dormant blackhole is 1.600 light-years away in the constellation Ophiuchus.

This new black hole is ten times as massive as our sun. To date, scientists have found 20 black holes in the Milky Way galaxy whilst 100 million more are estimated to be present in our galaxy. The newly discovered one is three times closer than the earlier black hole which sat about 3,000 light-years away in the constellation Monoceros.

Since there are more undetected black holes, even this newly discovered one wouldn't hold its spot of "closest to Earth" for too long.

The discovery was mentioned in a paper in the peer-reviewed Monthly Notices of the Royal Astronomical Society. The black hole was discovered by "Kareem El-Badry, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and his colleagues.

They found evidence of the existence of this dormant black hole using the data from the European Space Agency's GAIA (Global Astrometric Interferometer for Astrophysics) spacecraft. After they noticed a star in the constellation Ophiuchus moving in unexpected ways, they understood that it was a result of the gravity of an unknown, massive object. Using the observation from other telescopes, they confirmed that the object causing this was a black hole.

What is a Black Hole

A black hole is a celestial body that has an immensely huge gravitational pull, so huge that nothing escapes it. Not even light can escape i it!

The black hole grows by accumulating matter that falls in it. Black holes are formed at the end of the life of a big star. When a massive star collapses after its nuclear fuel depletes, it will collapse onto itself and become a black hole.

 It was in 2019 that an image of a black hole was captured for the first time. It was an international collaboration and the astronomers used the Event Horizon Telescope (EHT), networking eight ground-based radio telescopes.

Picture Credit : Google 

Now known to host at least 83 moons, researchers propose that Saturn at one point must have had at least one more satellite, which they call Chrysalis

While all four gas giants - Jupiter, Saturn, Uranus, and Neptune - have rings, Saturn is the most popular ringed-planet. Swirling around Saturn's equator, these rings indicate clearly that the planet is spinning at a tilt relative to the plane in which it orbits the sun.

For a long time, astronomers have suspected that this tilt is the result of Saturn's interactions with neighbouring Neptune. A new modelling study by astronomers at Massachusetts Institute of Technology (MIT). however, suggests that while the two planets may have been in sync before, Saturn has since escaped Neptune's pull.

Call it Chrysalis

 In a study appearing in Science in September, the MIT team

posits that a missing moon might be responsible for this planetary realignment. Now known to host at least 83 moons, Saturn at one point must have had at least one more satellite that the researchers call Chrysalis.

The team estimates that after orbiting Saturn for several billion years, Chrysalis became unstable about 160 million years ago, coming too close to Saturn in the process. As the proposed satellite was long dormant before suddenly becoming active - just like a butterfly's chrysalis - the researchers gave it the name Chrysalis.

The resulting encounter pulled the satellite apart and the loss of the moon was enough for Saturn to escape

Neptune's grasp and leave it with its current tilt. Additionally, the researchers suggest that while most of Chrysalis' shattered body may have impacted Saturn, a fraction of its fragments could have remained suspended in orbit. These could then have broken into small icy chunks to form the planet's standout rings.

Explains two mysteries

The missing moon hypothesis, the researchers believe, could thus explain two mysteries pertaining to Saturn's system. While one of these is Saturn's present-day tilt, the other one is the age of its rings.

The rings are estimated to be about 100 million years old. very much younger than the planet itself. If the rings were indeed formed from fragments of Chrysalis, then the story fits perfectly.

Cassini's inputs

The team of researchers arrived at this hypothesis by modelling the interior of Saturn. They identified a distribution of mass that matched the gravitational field that was observed by the Cassini spacecraft in its final phases. What they found indicated that Saturn is no longer in sync with Neptune, paving the way for researching various hypotheses, before arriving at their final result. The lead author of the study says that it is "a pretty good story, but like any other result, it will have to be examined by others".

Picture Credit : Google