My Science School

The largest planet in our solar system, Jupiter, is located fifth from the Sun. It is more than two times the size of all the planets in our solar system combined. Jupiter has also been instrumental in our understanding of the universe and our place in it. In 1610, Galileo discovered Jupiter's four large moons: lo, Europa, Ganymede and Callisto. This confirmed the Copernican view that the Earth was not the centre of the universe as these newly discovered celestial objects were revolving around another planet.

It is estimated that eleven Earths could fit across Jupiter's equator. To put it in other words, if our planet is the size of a grape, then Jupiter is the size of a basket-ball. It has an iconic Great Red Spot, which is a giant storm that has been active in Jupiter's atmosphere for hundreds of years. This storm is bigger than the Earth!

Jupiter's orbit is about 778 million kilometres or 5.2 Astronomical Units (AU) from the Sun (Earth is one AU from the Sun). Jupiter is a gas giant, which lacks an Earth-like atmosphere. Even if it has a solid inner core at all, it would only be about the size of the Earth. Jupiter's atmosphere contains mainly hydrogen (H) and helium (He) and has more than 75 moons. It rotates about its axis once every 10 hours (a Jovian day), and takes about 12 Earth years to complete one revolution about its orbit around the Sun (a Jovian year).

In the year 1979, NASA's Voyager mission discovered Jupiter's faint ring system. We have discovered that all the four giant planets of our solar system have ring systems. Till date, nine spacecraft have visited Jupiter. Of them, only the most recent one landed on Jupiter. Seven of them only flew by this gas giant and the other two just orbited it. Juno, the latest spacecraft, arrived on Jupiter in 2016.

Although it is the biggest planet in our solar system, Jupiter cannot support life as we know it. But we have come to know that some of its moons have oceans beneath their crusts, which could possibly support some form of life.

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Yes, an air conditioner takes the warm air from inside a room and transfers it outside.

An AC unit takes the warm air from inside a room and transfers it outside. It also consumes electricity which generates further heat.

A Japanese scientist found in 2007 that air conditioners in Tokyo raised the temperature in the city by about 1°C. Surprisingly, the heating effect was more at night than during the day when more air conditioners were used.

This is because the planetary-boundary layer, the part of the atmosphere touching Earth's surface, is thickest during the day. The extra heat produced by ACS disperses upwards. At night, the same layer reduces from a thickness of 3 km to less than 100 metres! So the heat remains closer to the Earth's surface.

Researchers feel the excess heat could be channelled through the city's waste water pipes, since water can dissipate four times as much heat energy as air. This would reduce the heat on the street.

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Researchers find out an often overlooked key role played by the orbit of Jupiter on Earth.

Most planets have eccentric orbits. While circular orbits around a star would ensure that the distance between the star and the planet never changes, these eccentric orbits mean that the planets traverse around a star in an oval-shape. As a result, the planet would receive more heat when it goes closer to the star, affecting the planet's climate.

Alternative solar system

Based on this knowledge and using detailed data from the solar system as we know it today, researchers from the University of California Riverside created an alternative solar system. In this hypothetical theoretical system, they were able to show that if Jupiter's orbit were to become more eccentric, then it would lead to big changes in Earth's orbit, thereby making the Earth more hospitable than it is currently.

This is because Jupiter in this theoretical system would push Earth's orbit to be even more eccentric. As a result, parts of Earth would sometimes get closer to the sun. This would mean that even parts of Earth's surface that are now sub-freezing will get warmer. In effect, the habitable range on the surface of the Earth would be increased.

Assumptions proven wrong

 The findings of this research, published in September in Astronomical Journal, go against two long-held scientific beliefs with respect to our solar system. One of these is that the current avatar of Earth is the best in terms of habitability. The second one is that changes to Jupiter's orbit could only be bad for Earth.

Apart from upending these long-held assumptions, the researchers are looking to apply their findings in the search of exoplanets - habitable planets around other stars. While existing telescopes are adept at measuring a planet's orbit, the same cannot be said about measuring a planet's tilt towards or away from a star- another factor that could affect habitability.

The model developed in this research helps us better understand the impact of the biggest planet in our solar system, Jupiter, on Earth's climate through time. Additionally, it also paves the way to find out how the movement of a giant planet is crucial in making predictions about habitability of planets in other systems.

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As their name suggests, dwarf galaxies are smaller galaxies. In contrast to a normal galaxy that comprises hundreds of billions of stars, a dwarf galaxy would contain just about a few billion stars. These dwarf galaxies orbit larger galaxies after their formation.

Formation of dwarf galaxies

The dwarf galaxies are created when two galaxies collide, fromed from the material and dark matter coming out of the galaxies that collided.

Following these collisions, while a significant portion of the gas, dust and stars emitted gets reincorporated into the galaxy created after the collision, some can lead to the formation of dwarf galaxies which then orbit around the galaxy. They are also formed by the gravitational forces existing during the creation of these larger galaxies.

Why are dwarf galaxies crucial

Scientists consider the dwarf galaxies critical as they could help gain insight into the early stages of the formation of galaxies and stars. According to scientists, our galaxy has about 14 satellite dwarf galaxies orbiting it.

Studies are being carried out on these dwarf galaxies as it would give us clues regarding the evolution of the galaxies. By studying the motion of the stars in these galaxies, we would also get to know more about dark matter and how it is distributed in the galaxies.

It is difficult to spot dwarf galaxies as they are less bright when compared to larger galaxies. A large number of them can be spotted in galaxy clusters or as a companion to larger galaxies.

Shapes of dwarf galaxies

The dwarf galaxies take several shapes. The dwarf elliptical galaxies are quite similar to normal elliptical galaxies.

Then there are dwarf spheroidal galaxies which are more spherical in shape and smaller when compared to the former.

Then we have the irregular dwarf galaxies. They do not have a distinct structure and are rich in gas.

One of the closest dwarf galaxies to the Milky Way is the Sagittarius Dwarf Spheroidal Galaxy.

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When the Apple fell on Newton or when Archimedes took a bath, history as we know it changed. Those are the 'Aha' moments when scientific discoveries were made. A look at some of these breakthrough moments.

Archimedes' principle - Archimedes

This was history's first-ever 'Eureka' moment. The story of how the Greek mathematician Archimedes discovered the principle of buoyancy is a tale worth recounting. It was whilst taking a bath in a tub that the idea hit Archimedes. When Archimedes noticed the amount of water being displaced from the tub as soon as he entered it, he reasoned that the volume of the water displaced is equal to the volume of the body that was submerged. He is said to have run across the streets naked, shrieking "Eureka" at his discovery of the law of buoyancy. And that gave us the Archimedes' principle.

Periodic Table - Dmitri Mendeleev

For Russian chemist Dmitri Mendeleev, it all happened in a dream. The Periodic Table of Elements as we know it was conceptualised in a dream. For months, he was trying to arrive at a logical way to organise the chemical elements. Although he knew the atomic weight was a crucial element, he couldn't find a way to arrange it. One day, after racking his brain over the arrangement pattern, he fell asleep. And lo, the periodic table was born. The idea for the logical arrangement of the elements dawned on him during his dream. He later wrote "In a dream, I saw a table where all the elements fell into place as required."

Law of Gravity - Isaac Newton

Every child grew up listening to the tale of how an apple's fall changed science. It was when Isaac Newton noticed the apple fall that he first got the idea of gravity. He wondered what force attracted everything towards the Earth. The tree that inspired the idea of gravity in Newton still stands in the garden of Newton's old home.

Penicillin - Dr. Alexander Fleming

The discovery of penicillin, the world's first antibiotic, revolutionised the course of medicine. Dr. Alexander Fleming had just returned from a holiday and found mould growing on a petri dish of Staphylococcus bacteria. The green mould Penicillium notatum prevented the bacteria around it from growing. He isolated the mould, and understood it produced a substance that could kill the bacteria. He named the active agent penicillin and thus the world's first antibiotic was discovered.

First synthetic dye - William Perkin

The fashion industry must thank William Perkin for his discovery of the first synthetic dye. He was trying to find a cure for malaria, but he accidentally invented the first synthetic purple dye. Perkin was assisting German chemist August Wilhelm von Hofmann in the process of using coal tar to produce quinine which was an expensive anti-malarial drug. As he mixed different coal tar components with potassium dichromate and sulphuric acid, Perkin produced a purple sludge. The rest is history.

DID YOU KNOW? Newton recounted the story that inspired his theory of gravitation to scholar William Stukeley. It appeared in Stukeley's 1752 biography, "Memoirs of Sir Isaac Newton's Life." The UK's Royal Society converted the fragile manuscript into an electronic book in 2010 and made it accessible online to the public.

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Discovered on August 28, 1789, Enceladus is a natural satellite of Saturn. This moon, which remained in relative obscurity for nearly 200 years, is now one of the most scientifically interesting destinations in our solar system.

The possibility of worlds other than our own Earth where life could exist has enthralled us for a long time. Often seen in the realm of science fiction, we might be inching ever so closer to it in reality as scientists have identified a handful of worlds that have some of the ingredients needed for life. One of them is Enceladus, an icy moon that is the brightest in the solar system.

Enceladus was discovered on August 28, 1789 by British astronomer William Herschel, more popular for discovering the planet Uranus. Little is known about how William went about it and made his discovery.

A dwarf named after a giant

What we do know, however, is that it was William's son, John Herschel, who gave the moon its name Enceladus, after the giant Enceladus of Greek mythology. In his 1847 publication Results of Astronomical Observation made at the Cape of Good Hope, John suggested names for the first seven moons of Saturn that had been discovered, including Enceladus. He picked these particular names as Saturn, known in Greek mythology as Cronus, was the leader of the Titans.

For nearly two centuries, very little was known about Enceladus. That changed in the 1980s, when the U.S. spacecrafts Voyager 1 and Voyager 2 flew by the moon, capturing images. The pictures indicated that the icy surface of this small moon is very smooth in some places and bright white all over.

Enceladus, in fact, is the most reflective body in the solar system. Scientists, however, didn't know why this was the case for a few more decades. Enceladus reflective capability implies that it reflects almost all the sunlight that strikes it, leading to extremely cold surface temperatures, of the order of -200 degree Celsius.

E ring and tiger stripes

Shortly after NASA's Cassini spacecraft began studying Saturn's system in 2004, Enceladus started revealing its secrets. By spending over a decade in the vicinity of the small moon, including flybys as close as 50 km, Cassini was able to unearth a wealth of information about Enceladus.

Cassini discovered that icy water particles and gas gush from the moon's surface at about 400 metres per second. These continuous eruptions create a halo of fine dust around the moon, which supplies material for Saturn's E ring. While a small fraction of this remains in the ring, the remaining falls like snow back onto the moon's surface, thereby making it bright white. Scientists informally call the warm fractures on Enceladus' crust from which the water jets come from as "tiger stripes".

By measuring the moon's slight wobble as it orbits Saturn and from gravity measurements based on the Doppler effect, scientists were able to determine that these jets were being supplied by a global ocean inside the moon. As this ocean supplies the jet, which in turn produces Saturn's E ring, it follows that studying material from the E ring is akin to studying Enceladus' ocean.

While the E ring is mostly made of ice droplets, there is also the presence of nanograins of silica that can be generated only where liquid water and rock interact at temperatures above 90 degrees Celsius. Along with other evidence that has been gathered, this suggests the existence of hydrothermal vents deep beneath this moon's shell, similar to those on the Earth's ocean floor.

Orbital resonance

Enceladus takes 33 hours for its trip around Saturn, which is nearly half of the time taken by the more distant moon Dione. Enceladus is thus trapped in an orbital resonance with Dione, whose gravity stretches Enceladus' orbit into an elliptical shape. This means that Enceladus is sometimes closer to Saturn and at other times farther leading to tidal heating within the moon.

Running just over 500 km across, Enceladus is small enough to fit within the Indian State of Maharashtra, which runs around 700 km north-south and 800 km east-west. What it lacks in size it more than makes up for in stature, as Enceladus has a global ocean, unique chemistry, and internal heat. All this means that even though we still have plenty of data about the moon to pore over, explorers will eventually plan a return to Enceladus to learn more of its secrets.

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An important insight that fossil study could throw up is how plants and animals of different eras adapted to their changing environment. This is particularly crucial for us now as we battle climate change.

During scientific expeditions in 2017 and 2019, a team of scientists discovered something incredibly exciting - Africa's oldest known dinosaur fossil. The reptile "roamed the earth around 230 million years ago". What is even more unique about the discovery is that such "remains from the same era had previously been found only in South America and India". The findings were published recently. Do fossils have any use? Yes, actually much more than one can imagine! Come, let's delve deeper into this.

Fossils could be anything from skeletal remains to leaf impressions. Studying fossils give us a better understanding of an animal or plant that existed ages ago. That's not all. Something as tiny as a mosquito trapped in amber is likely to offer us a peek into how evolution works. Or, even a glimpse of the history of our planet. For instance, this dinosaur fossil in Africa "broadens the range that we knew the very first dinosaurs lived in". But it also does something very significant – the reptile "is remarkably similar to some dinosaurs of the same age found in Brazil and Argentina,  reinforcing that South America and Africa were part of continuous landmass during the Late Triassic. Apart from showing us that the now-separated continents were once connected, fossils also help us learn where humans came from, how life forms existed, and how our environment has changed through millions of years.

 Another insight that fossil study could throw up is how plants and animals of different eras adapted to their changing environment. This is particularly crucial for us now as we battle dimate change. Understanding revolutionary changes and survival methods may help us equip ourselves better to tackle what is threatening to be a great challenge in the not-so-distant future.

So, do fossil fuels have anything to do with fossils? Without a doubt. But that’s a story for another day!

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