## What is the shortest day ever recorded?

A day has 24 hours, right? That's 1,440 minutes. Or 86,400 seconds. That's to say, a day is 8,64,00,000 milliseconds. Only that, at that scale, hardly any of our days hits exactly that number. As the Earth's rotation speeds up or slows down, fractions of a millisecond are often added or subtracted, making our days a teensy bit longer or shorter on record.

June 29, 2022

On June 29, 2022, we had the shortest day ever recorded since scientists started measuring the length of each day with the precision of atomic clocks in the 1960s. June 29, 2022 was 1.59 milliseconds shorter than 24 hours.

In December 2020, the website Time and Date reported that that year alone had experienced the 28 shortest days since records were maintained. This included July 19, 2020, which was previously the shortest day on record at 1.47 milliseconds under 24 hours.

Speeding up or slowing down the rotation of any object comes down to its angular momentum, which has three components: mass of the rotating object, speed at which it moves, and the distance from the point it is rotating about. To help your understanding, imagine swivelling around in a chair. While your rotation will slow when you have your arms outstretched, you will spin faster when you pull your arms back in.

Remains a challenge

As Earth constantly redistributes its mass and angular momentum, its rotation rate and the length of the day keep changing. Scientists have a number of ideas as to why the Earth speeds up and slows down, but predicting the length of a day remains a challenge, even in the future.

This is because a number of factors are involved and there could even be a mix of several factors acting together. These include the wind, the gradual movements of mass within the Earth, the interactions where the Earth's core meets its mantle, and the fact that the Earth isn't exactly spherical, to name a few.

While understanding the planet's long-term changes that influence its rotation might put us on the path towards predicting the next shortest day, scientists believe that the most recent one could likely be the result of a brief climate phenomenon such as wind speed change high in the atmosphere. As for the next shortest day, we will just have to wait and see for the moment.

## Can reforestation alone save the Earth?

Trees are huge carbon sinks. They saok up the carbon. Planting trees will help mitigate the climate change and cool the planet to some extent. But that has to be combined with a dedicated effort to reduce carbon emission. Reforestation combined with the reduction of greenhouse gases, especially carbon dioxide (CO2), is the need of the hour. It is these gases that warm the earth, leading to climate change which we have been witnessing in many forms such as the melting of ice sheets, rising of sea levels, wildfires, floods, droughts and other natural calamities. So the carbon emissions need to be reduced by nations, on an industrial scale as well as individual level.

## WHAT IS THE FARTHEST WE HAVE GONE INTO THE EARTH?

What is the furthest down humans have gone? What is the Kola superdeep Borehole? Read on to find the answers.

In Jules Verne's science fiction novel, Journey to the Centre of the Earth (1864), three men reach the centre of the Earth. Is this ever possible? Our planet is made up of three main layers- the crust, the mantle and the core. The continents and oceans are situated on the crust which is about 8 km thick under the oceans and between 35 and 40 km deep under the continents. Below the crust is the mantle which is about 2,900 km thick. Next comes the core. The outer core, about 2.250 km thick, is made up of melted iron and nickel, and contained within it, is a ball-shaped inner core believed to be made up of solid iron and nickel.

The centre of the innermost core is the centre of the Earth. So there are thousands of kilometres to descend to reach the centre of the Earth, and what is the furthest down we've gone? When the Russians and the Americans were engaged in a race to the moon several decades ago, they also embarked on a race to inner space to see how far down they could go. While the Americans did not make much headway in this race downwards (Project Mohole'), the Russians went at it, hammer and tongs, in the Kola Peninsula and dug a hole 12.262 km deep over a period of 24 years from 1965 to 1989. They wanted to go at least 15 km down,  but just could not. This is the closest we've been able to go to the centre of the Earth. The Kola Superdeep Borehole, as it is now called, attracts curious visitors from around the world.

## BOLD AND OUTRAGEOUS ENERGY IDEAS

With World Environment Day falling in this month, it's time to see how we are faring. More importantly, we need to learn about the audacious ideas people have come up with to give Earth a chance to recuperate. How good are these eco-friendly strategies? You decide!

A grand plan for the skies

Just when we are all set to harvest energy from solar panels, the cloudy skies play spoilsport. So what's the solution? Japanese scientists have come up with an ingenious idea: send satellites into orbit carrying solar arrays up high where there are no clouds to block the sun's rays. Transmitters in the satellite will also convert the solar energy into microwave energy that can potentially provide power to millions of homes. Is it possible that the microwave beams miss the transmitter and fry up something on Earth? Let's hope that never happens.

A tornado is a powerful beast, capable of producing the same energy as a power plant... provided it is large enough. A Canadian engineer realized that taming such a beast would be the solution to our energy problems. All that was needed was an area bigger than two football fields and enough space above for manufacturing a spinning column. Some turbines here, and a generator nearby - bingo! You get loads of energy as long as the tornado does not go rogue and escapes its confines!

Hairy plants to the rescue! Who would have thought that hairy plants could one day save the planet? And no, they don't have to be brought down by aliens. There are quite a few on our planet itself. According to a team at the University of California, hairy plants absorb more light but less heat. Apparently, if there were more such plants across the world, the global temperature could go down. That would mean selecting and developing hairy versions. As long as they don't make us eat hairy spinach, this is worth a try!

Biogas to drive vehicle

Human waste can, in the future, seamlessly power cars and bikes when petrol is probably all gone. Under the right conditions, bio waste, crop stubble and leftovers from hotels can pool in to make commutes more eco-friendly. Think it's far-fetched? In Sweden. an entire fleet of buses run on biogas generated from manure and leftovers. The future isn't so bleak, after all!

The energy of hustling commuters

Rushing to catch a train or even simply sitting in the train can be precious in the future. Swedish scientists are investigating how the air made warm by commuters at Stockholm Railway Station can be harvested through heat exchangers. And just like that, it would be possible to provide heating for a building nearby. Will cities across the world be able to make their citizens feel like superheroes - or at least power generators? Time will tell.

The energy of hustling commuters

Rushing to catch a train or even simply sitting in the train can be precious in the future. Swedish scientists are investigating how the air made warm by commuters at Stockholm Railway Station can be harvested through heat exchangers. And just like that, it would be possible to provide heating for a building nearby. Will cities across the world be able to make their citizens feel like superheroes - or at least power generators? Time will tell.

Store carbon dioxide underwater

What if we could suck up carbon dioxide emitted from power plants and store them in large flexible polymer bags deep under the sea instead of releasing it into the air? As stunning as it sounds, scientists argue that the idea isn't crazy. Pipes will feed the gas into these bags and they will remain for thousands of years undisturbed. Or at least, that's what we hope (and also pray that sharks don't sink their teeth into them!).

## HOW CYCLING IS GOOD FOR HEALTH AND EARTH?

Among the numerous days celebrated the world over, the one that profoundly impacts the present as well as future generations is World Bicycle Day. Well, on 3 June every year, since 2018, the U.N. General Assembly dedicated this day to celebrate the joy of riding bicycles. The simple structure of a bicycle requires only air and a bit of energy to function, however, it has proved itself to be both environmentally-friendly and a friend to all mankind. Prof Leszek Sibilski, a Polish-American sociologist, along with his sociology students, was the inspirer of this cause.

Apart from being an eco-friendly and economic means of transport, bicycling also promotes good physical as well as mental health. Cycling decreases the possibility of falling prey to cardiovascular diseases, aids in building body muscle, and reduces overall fat. It strengthens bones, improves joint mobility and relieves stress. In addition, it also facilitates the regulation and maintenance of healthy blood sugar levels in our system. Thus, cycling reduces the risk of depression, obesity, arthritis, diabetes, certain cancers, strokes and heart attacks.

The bicycle symbolizes adaptability and sustainability. Governments around the world are adopting and promoting eco-friendly conveyance systems. Many countries have dedicated bicycle tracks which make commuting by bicycle safe. India, too, has introduced bicycle tracks in cities like Delhi and Bangalore.

Though daily riding to work may be an inconvenience, taking into consideration climatic conditions, either having to face the scorching sun or heavy rain, however, despite these conditions, enthusiastic riders change their cycling gear once they reach their destination. It's a trend already prevalent in Europe.

Types of bicycles

If you are new to buying a bicycle, these guidelines will help you choose the right one.

Mountain bikes: Suited for hilly terrains.

Hybrid/commuter bikes: Combination of road bikes and mountain bikes.

Folding bikes: Commuting, leisure or touring for the short-on-space.

Electric bikes: A hybrid, mountain or road bike with a battery and a motor.

Touring bikes: Designed for carrying loads over longer distances while remaining comfortable for the rider.

Taking into consideration the multiple benefits that cycling has to offer, using a bicycle whenever possible, if not regularly, will be advantageous to both our earth and ourselves. Look for ways in which cycling can be introduced into your daily routine; maybe riding to nearby places while carrying out daily tasks, to school, work or a friend's house. Let's try and adopt the culture of cycling and be the change our environment and our health needs.

Fun Facts

• The longest tandem' bicycle seated 35 people; it was more than 20 metres long.
• Every year, around a 100 million bicycles are manufactured worldwide.
• The use of bicycles has conserved more than 238 gallons of gas yearly.
• The Netherlands is the most bicycle friendly country in the world. 30 per cent of all transport is via bicycle. Seven out of eight of its residents over the age of 15 own bicycles.
• The Tour de France, established in 1903, is the most famous bicycle race in the world. Bicycle track racing has been a sport in the Olympic Games since 1896.