What are gravitational waves and why are they important?

Finally, the gravitational waves have been detected and with this the last major prediction by Einstein has been confirmed. But what are these gravitational waves and why are they so important? First, you will be disappointed to know that such waves can not be used by you for surfing in space like you can surf on sea waves. But these are still very important as they open up an entire new chapter in the field of physics. Predicted by Albert Einstein on the basis of his theory of general relativity, gravitational waves are ripples caused in the spacetime fabric. Now, if some of you clever people are thinking that why don't we use them for mobile communication to get faster internet just like RF waves, you may be right, but the only problem is that to produce such waves you need a black hole or neutron star in your cellphone. For those who can't arrange a black hole, good news is that your bodies can also produce these waves but such waves are very very tiny to say the least.This is because gravity is a weak force and we need massive bodies to produce any significant gravitational waves. Binary neutron stars in-spiraling, colliding black holes and supernova explosions qualify as valid candidates.

Gravitational waves visualized- When a mass is correctly accelerated through space, these waves travel outward from the source. To visualize it, suppose there is a stretched rubber sheet and you put a billiards ball at the center. Now, the sheet would obviously depress in the middle due to the weight of the ball. If you put a marble anywhere on that sheet, it will roll down towards the ball due to depression in the sheet at center. This is gravity. Now if we put one more billiards ball near the first ball, it will also produce a depression on the sheet. If the balls are close enough, then their depressions will merge slowly and the balls will start moving towards each other. Imagine that they do not move quickly but are rather caught up in a spiral motion on the sheet, like in-spiraling stars. Such motion will produce waves on the rubber sheet and these waves can be called as gravitational waves.

Why we couldn't detect them before? Why it took us a hundred years after Einstein's prediction to detect them directly? This is because gravitational waves produced by distant sources can lengthen or shorten our space only by a factor of 10^-21 or less. This is less than a millionth billionth of the width of a human hair. Such detection can only be done with lasers.This unbelievable task was attempted by LIGO starting in 2002.

LIGO stands for  Laser Interferometer Gravitational-Wave Observatory. It used lasers to measure the changes in distance between ends of  4 km long tunnels. But from 2002 to 2010, it detected nothing. After this it was upgraded into what is known as Advanced LIGO. This was 10 times more sensitive. It started operating in September 2015 and has already achieved success. The gravitational waves detected by LIGO have come from a black hole merger about 1.3 billion light years away from earth.

So, gravitational waves can make you taller and thinner for an instant but such minuscule improvement in your appearance will impress your girl friend only if she uses lasers to measure you. In my opinion, exercise will be a much better option.

This detection has opened up an exciting new field of gravitational wave astronomy. Studying these waves will give us more information about the cosmic events which produce them. And yes, we know now that with this great feat we have found a key in the universe to open a box which is full of mysteries.

References-
http://www.ligo.org/
https://en.wikipedia.org/wiki/Gravitational_wave
https://en.wikipedia.org/wiki/LIGO
https://www.youtube.com/watch?v=gw-i_VKd6Wo
https://openclipart.org/detail/240758/Gravitational-waves-confirmed

What is your speed? -Video

I have converted the post titled "What is your speed?" into a video. Please check it out.

What is your speed?

As you are reading this post, this very moment, you are in motion. You are not only moving but doing so at a very high speed. To observe such movement, you need to look things at cosmic level.The rotation of earth on its axis, revolution of earth around sun and movement of sun in our galaxy, all contribute to this speed.  But we don't notice it because speed is something which is relative. Suppose, you and your friend are sitting in a moving car and you look at a person standing on a footpath. Then you are moving at some speed with respect to that man but you and your friend are stationary with respect to each other. So, to calculate speed, we always need to take some reference as stationary. Let us start looking at various motions that we are part of.

Rotation of earth on its axis- The circumference of earth at equator is around 40,000 kilometers and earth completes one rotation on its axis in around 24 hours. So, speed due to this rotation comes out to be around 500 m/sec. This is 47% more then the speed of sound in air. If you fly at this speed then you will reach Beijing from New Delhi in about 2 hours.

Revolution of earth around sun- Earth covers a distance of around 149.5 million kilometers around the sun in a year. Speed of earth because of this motion comes out to be around 30 km/sec. If you fly at this speed then you will reach Beijing from New Delhi in about 2 minutes.

 Movement of sun in our galaxy- Our sun and other stars in our galaxy are also not stationary. According to estimates, sun's speed is around 200 km/sec as it moves through the milky way. If you fly at this speed then you will reach Beijing from New Delhi in about 19 seconds.

Movement of our galaxy in space- According to estimates, the milky way galaxy is moving at an approximate velocity of  600 km/sec with respect to extra-galactic frames of reference. If you fly at this speed then you will reach Beijing from New Delhi in about 6.3 seconds.

Next time you watch a movie with speedy car chases and actors boasting about their car's high speeds, just remember that it is nothing when compared to the very very high speed at which you are already traveling. We know now that we all are pretty fast and furious.

Links and sources-
https://en.wikipedia.org/wiki/Milky_Way
https://medium.com/starts-with-a-bang/how-fast-are-we-moving-through-space-985bf470378d#.5wv8xef15

The heavy burden of waste

Waste is something which is not useful for us but information about waste management is getting more and more important. Human population always produced waste wherever it thrived but in earlier times the waste produced was small in quantity and mostly biodegradable.With the advent of industrialization, the human population grew rapidly in cities. This rising population combined with various scientific discoveries lead to the rise in waste production. This was obviously pumped by consumerism and lack of farsightedness of governments regarding waste management. Waste processing plants and dumping yards are operating well beyond their capacities. The situation is worse in developing and underdeveloped countries as they lack modern technology for waste treatment. For example, the Ghazipur landfill in East Delhi, spread over 70 acres, already has at least 12 million tonnes of waste. It had a limit of 15 feet of waste which was overshot in 2002 itself. Today it is at least 50 feet tall and still being fed with more waste.

Electrical waste-Around 50 million tonnes of electrical waste is dumped each year. This includes discarded TVs, computers,cellphones,kitchen appliances etc. This is not always waste and can be reused or recycled but only 12.5 % of e-waste is currently recycled. It would have been so nice if we could use that recycle bin icon on our desktops for deleting useless hardware also.

Food wastage- We throw away 7.2 million tonnes of food every year. What is even more shocking is that more than half of that food is edible. According to United Nations, about 21,000 people die every day of hunger or hunger related causes and the main victims are children. This means one person every four seconds is dying of hunger.This is happening when there is plenty of food for everyone in the world.

Supermarkets wastage- Around 20 to 40 percent of fruits and vegetables are rejected by supermarkets before they hit the shelves. The reason being these fruits and vegetables are simply not good looking enough according to their standards. This is because we as buyers also focus a lot on external appearance rather than the actual nutritional value. 

Packaging waste- Be it cardboard boxes, polythene bags, bubble wraps or wrapping papers, all of these simply end up in garbage bins after serving a purpose which can be served by less polluting materials. For example, cloth bags are now slowly replacing polythene bags but the pace of this shift is very slow. At Christmas in UK alone, 83 square kilometers of wrapping paper is used. With the rise of e-commerce also, packaging waste is becoming a huge concern.

 Water wastage- Water is also something which is wasted on a large scale. A single leaking tap can waste as much as 5,000 litres of water in a year and we have many leaking taps. Water is wasted not only through this but also by leaky pipelines. Bad water usage habits of people is also to be blamed and they forget that one in nine people in the world do not even have access to safe and clean drinking water.

 

When you throw waste out of your house, please do not think that your house is clean because this world is your actual house. We have only one earth and we are wasting it. So, next time we throw out those garbage bags, we know now that one day that garbage might throw us out of existence.

Links and Sources-
https://en.wikipedia.org/wiki/History_of_waste_management
http://indianexpress.com/article/india/india-news-india/wastelands-of-india-heres-how-metros-manage-their-trash/
https://www.ovoenergy.com/blog/green/10-shocking-facts-about-waste.html
http://www.poverty.com/