What’s the fundamental reason why the speed of light cannot be broken?

Answer by Ethan Hein:

The speed of light can't be broken because in a sense, it's the only speed there is. Brian Greene explained this well in The Fabric Of The Cosmos. You can interpret relativity to mean that everything always moves through spacetime at the speed of light. Some of that movement is through space, and some of it is through time. They add like the sides of a right triangle, so the sum of the squares of the two velocities is always c^2, the speed of light squared. Your and my velocity through space is very slow, so most of our motion is through time. A spaceship moving through space at half the speed of light will be moving through time only \frac{\sqrt{3}}{2} times as fast as you and me. And a photon moves through space at the speed of light, so it has no movement through time at all — time doesn't pass for a photon.

What's the fundamental reason why the speed of light cannot be broken?

Advertisements

What is the coolest psychological trick?

Answer by Gokul Nair:

  1. Ask  someone for small favors first. This is will make a bond in their head. Now it's more likely they will do bigger favors for you.
  2. When in a meeting or other gatherings, crack a joke and observe the people  around you who are laughing. People who feel close to each other will be  looking at each other. This is useful for discerning out friendships and  other relationships.
  3. If  you know someone has it out for you in a particular meeting. Sit next  to them during the actual event, this will reduce the confrontation  level.
  4. To know if someone is interested in a conversation look at their feet if  they are pointing towards you they are. Feet don't lie.
  5. Offer  someone a choice instead of a command. For example instead of saying  drink your milk to a toddler ask him which mug would he like to drink  milk from. This gives the person a sense of control hence produces a higher chance of a better outcome.
  6. When in a conversation keep your silence even after they have finished speaking more often than not they will start talking again to avoid the awkward silence. This usually makes people trip up.

DISCLAIMER: Read all these facts online.

What is the coolest psychological trick?

Why is Mukesh Ambani the richest person of India and not Ratan Tata?

Answer by Arvind Devaraj:

I was student of IISc, affectionately called Tata Institute.  I was surprised that a government institute like IISc should be named after private individual.

These are the lesser known facts about Tata I came to know only after spending years in the institute. So the general public might know lesser. I wrote this note as I was pained to see some people linking all wealthy people with corruption. While facts about other great people are widely available on web, facts about Tata aren't known much. Some information is present on books. Maybe Tatas deliberately haven't focussed much on marketing their own goodness. Compared to the magnum opus of their work, their publicity pales in comparison.

1)  Tata Institute 

Even as a young kid, I have heard Tata's name. "Tata Birla" is a term synonymous with exorbitant rich . I knew about Tata as another business man who sought to become rich and succeeded. But there is much more….
Before coming to IISc , I knew Tata only as a businessman. In IISc, the name of Tata was omnipresent – Tata Auditorium, Tata Library. Tata is the chairman of the IISc trustees.  IISc itself is known only as Tata institute in bangalore. I first thought why should a government institute like IISc have to associate so much with Tata, I also thought such associations might affect the autonomy of the institute.
 
2) PROFILES
 
(Jamshetji) J.N.Tata  ( 1839 – 1904 )
Dorab Tata / Ratan Tata ( early 1900s )
JRD Tata ( 1930s till 1990s)
Ratan Tata ( 1990s – present )
 

 
3) LEGACY 
 
“Tatas represent the spirit of adventure,”  – Mahatma Gandhi
 
J.N.Tata is the founder of the Tata empire . In the book '100 Great Modern Lives' by John Canning only two Indians feature – Mohandas Karamchand Gandhi and  Jamsetji Tata. The chapter on Jamsetji Tata concludes with the paragraph: ‘Probably no other family have ever contributed as much in the way of wise  guidance, industrial development and advancing philanthropy to any country as the Tatas have to India, both before and since independence (1947).’
 
 
J.N.Tata's sons Dorab and Ratan Tata would carry the legacy of J.N.Tata.  Ratan Tata financially supported a then unknown lawyer in South Africa protesting against British. The lawyer said during a meeting "We have got so much contributions from Tata and we have to work hard to justify that".
 
That lawyer was Gandhiji.  When Godrej asked for blessing from Gandhi to start a new product – Gandhi light heartedly replied – "If you are going to compete against my good brother Tata I wont be able to bless that"
 Sir Ratan Tata and Mahatma Gandhi
 
After Dorab/Ratan , JRD Tata becomes chairman. JRD Tata was instrumental in giving wings to India by building Tata Airlines, which ultimately became Air India .Kalpana Chawla, the Indian-born astronaut  cited JRD and his pioneering airmail flights as her inspiration for taking up aeronautics.  In 1992, because of his selfless humanitarian endeavors, JRD Tata was awarded India’s highest civilian honor, the Bharat Ratna – rare for a businessman to get in the License Raj.
 
 
After JRD Tata,  Ratan Tata becomes chairman in 1992.
 
 
4) HISTORY
 
COTTON MILLS
 
It was around 1870s. JN Tata purchases a small cotton mill. Over the next 20 years he made it successful one. He was a running a successful business in India. The most significant thing is the way he treated his employees – sick leaves / hospital facilities / school for children / Provident Fund / Life Insurance/ Room conditioners to prevent dust. All these seems trivial in today's world. But in the industrial age, even workers in England worked in very inhuman conditions and facilities like insurance were unheard of. ( the condition of workers in that era is captured well in many of Charles Dicken's novels ).
 
It was 1890 – JN Tata was fifty years of age and a reputed businessman employing thousands of people . The story till now alone would suffice to have his mark in India's history. But still more to come…
 
Tata was on a sea voyage where he met Swami Vivekananda. Swami tells him that the future of India is in young people – especially young people working in science and research have to ability to rewrite the history of nation. The term  'Science' for many businessmen may not mean much… but Tata was not a mere businessman. This meeting with Swami Vivekananda would turn important and establish basis for scientific research in India.

 
 
5) TAJ HOTEL
 
when British ruled us, Indians were not allowed to enter star hotels. Tata was determined to build a fine hotel where Indians wouldn't be treated as an outcaste and thus Taj Hotel was born
 

6) TATA STEEL
 
"The nation that has the steel has the gold" – these were the last words in a talk attended by Tata in England given by an eminent scholar. These words were ringing in Tata's mind for next decade of his life. JN Tata would lay the foundation of steel empire. He died in 1904, but his dream would be carried forward by his sons Dorab and Ratan. He had left detailed instructions about the steel plant. "We are not just building factories…we are building cities around a factory….we are enriching lives…in the factory complex – make sure you allocate space for schools / day care centres / hosptials / places of worship – temples, mosques, churches "

 
 
 The British were skeptical of Tata's ability to produce steel. "The Indians are making steel?  The Indians can't run a shop properly"  The Governor said "Why I offer to eat every pound  of steel Tatas produce" Later the Tata steel plant began to produce successfully . Dorab Tata said if the Governor had kept his words , he would have a slight indigestion. The British would later order steel from Tata during the World war as Tata steel was more robust in making bullet proof shields in  vehicles. That time the steel was produced in a small village in Bihar called Sakshi. Later the city would be renamed in honor of Jamshedji Tata as Jamshedpur

Jnt presentation
 
 

At Tata Steel, not only steel but also men were forged in Jamshedpur. That’s why it’s a place where India is still shining, it’s a place where the nation of India was transformed and it’s a place that was selected as a UN Global Compact City because of the quality of life, conditions of sanitation,roads and welfare that were offered by Tata Steel
 

 
7) INDIAN INSTITUTE OF SCIENCE
 
Swami Vivekananda's meeting was still on the mind of Tata. Tata wanted to establish an institute of higher learning focussed on research. Unlike setting up hotels or industry, he needed Governments permission for setting up educational institute. The man in power and who had to give permission was Lord Curzon ( the man who partitioned Bengal )  . When he told Curzon of his plan , Curzon replied- You mean the Indian students have the ability to undertake scientific research – Where will you find teachers for such advanced courses and where will you find students who can grasp such concepts…And what will students do with such advanced degrees if they are anyway going to work as a clerk after completion . In short "Surely, You are joking Mr.Tata". After the meeting with Curzon, every one in Tata's team was heart broken. They were cursing Curzon .. Tata replied to them "Lets wait for Curzon's mind to change – there must be some good in him somewhere"
 
The permission to setup the institute came years after JN Tatas death. JN Tata had instructed his sons to carry on the struggle of establishing the institute after his death.. A newspaper in US wrote "The amount <X> millions is more than enough to establish an university in US and in a country like India it is a great amount". 

J.N.Tata gave one third of his wealth to establish IISc. He had 2 sons Dorab and Ratan, so many consider that he considered IISc to be his another child. Originally the institute was to be setup in Bombay. The nobel prize winning scientist Ramsey was asked to tour India to find the best place conducive to research. He suggested Bangalore, but Tata favored Bombay.  Finally,  the Maharaja of Mysore offered vast amount of lands and persuaded Tata to setup the institute at Bangalore.
 

Statue of the founder J N Tata in front of IISc Main Building. He is holding a replica of the main building in his left hand.

JRD Tata Memorial Library
 
8) AVIATION
 
JRD Tata was the first Indian to have flying license.His license reads #1. His interest in aviation caused him to start Air India and Indian Airlines. The Maharaja symbol of these airlines was his conception. Air India was providing the finest service in aviation at moderate rates until its take over by Government.
 

continuing the tradition

 
9) SCHOLARSHIPS
Tatas provide scholarship for people who have potential , but economic condition prevent them continuing their studies. One such candidate applied to Tata for scholarship.  Though his love was political science, he chose to enroll in English literatue due to financial constraints . After analyzing the applicant, the Tatas persuaded him to study political science offering to pay the entire tuition fees and provide stipend for expenses also. This incident was later narrated by K.R.Narayanan who became President of India. If not for the scholarship, K.R.Narayanan might have become professor in English literature.

Ratan Tata and K.R.Narayanan

 
Every year thousands  of people  apply for Tata scholarship, even among wealthy people. There is a pride in being a Tata Scholar. There are people like Raja Ramanna ( space scientists) and many more who benefited from it.
 
In 1912, the London School of Economics established the Ratan Tata Department. The following year it advertised for a position of a lecturer in that department for which two people applied. One was a young man called Clement Atlee, who after careful consideration was selected for this position. About 32-years later Atlee became the Prime Minister of Britain. Interesting enough that it was under his government that India was granted independence in 1947. 
 
 
10)  INSTITUTES
 
Tata Memorial hospital – Focuses on Cancer research . Tatas lost few of their family members to cancer and they are supporting research
 
TIFR ( Tata institute of fundamental research ) – from wikipedia
 
"In 1944, Dr. Homi J. Bhabha, known for his role in the development of the Indian atomic energy program, wrote to Sir Dorabji Tata Trust requesting financial assistance to set up a scientific research institute.[2] With support from J. R. D. Tata, then chairman of the Tata Group, TIFR was founded on 1 June 1945, and Homi Bhabha was appointed its first director"
 
NCPA- National center for performing arts
 
TISS – Tata institute of social sciences
 
 

Homi Bhabha and Nehru

11) CSR (Corporate Social Responsibility)
 
from wikipedia
 
"In general, about 66% of the profits of Tata Group go to charity and executives made it clear that they have no intention of leaving control to Wall Street.[21] The charitable trusts of Tata Group fund a variety of projects, for example the Tata Swach and the TCS project. They founded and still support such cherished institutions as the Indian Institute of Science, Tata Institute of Fundamental Research, the National Centre for the Performing Arts and the Tata Memorial Hospital. Each Tata Group company channels more than 4 percent of its operating income to the trusts and every generation of Tata family members has left a larger portion of its profit to them. This makes the Tata family evidently less wealthy as individuals than other Indian family-owned companies.[19]"
 
 
12) FRIENDS
 
Sudha was studying in IISc and it was placement season. There was a notice 'Tata group is hiring'. Unfortunately there was a P.S stating "Only male candidates can apply' . Sudha was very angry on seeing this – what qualification preclude me from applying to this job. She wrote an angry letter to JRD Tata venting out her anger – though she never expected any reply.  The next day, she was called to meet JRD Tata and he explained that the job required physical endurance and thats why women were dissuaded from that job. However Tata offered  Sudha that position
 
Later Sudha would leave Tata group to start Infosys with her husband Narayana Murthy. she said to Tata "Let me try how things work out in Infosys", Tata replied "There is no try…I know you and Murthy very well, you will definitely succeed "
 

13) GROUPS
 
TCS with 200,000 employees is one of largest private sector employers. TRDDC  was the research wing of TCS. One of its products 'Tata swach' aim to provide low cost water purifier. They diversified into many more areas
and have become brands in their own right like Voltas, Tanishq , Titan, Star bazaar, Tetley. Lakme was established when Nehru banned import of cosmetics and suggested to Tata that we need Indian products.
 
 
13) WALL
 
"Acquired Jaguar LandRover"
 "Acquired Corus " 
 
The acquired companies  are great European companies. Only few decades back, getting employed in an European company was a dream come true . Owning an European company  was far from our dreams.
 
 
14) POKES
 
Air India and Indian Airlines were taken over by the Government when they nationalized Airlines. JRD Tata was stripped of his chairman position and this was not even informed to him. Only the succeeding chairman called him on phone and informed that he is taking over. Many other constraints during the license raj as the general philosophy of the govt was that businessmen are evil people.
 
 
15) NETWORK
 
The Tatas are of Parsi origin –  descend from a group of Zoroastrians of Iran who immigrated to India during an invasion in 10th century. The then Gujarat king offered home for them.   The Parsis would become prominent – Pherozeshah Mehta, Dadabhai Naoroji, Bhikaiji Cama, Homi Bhaba, Homi Sethna, Godrej, Wadia, Shapoorji Pallonji, Zubin Metha, Field Marshal Manekshaw.  Thanks to that King for allowing the Parsis.  The parsi belief is 'HUMATA HUKTA HAVARASHTA'- meaning good thoughts, words, deeds.
 
 
15) REFERENCES
 
R.M.Lala's books on Tata especially "For the love of India".  Rare old  books in IISc Library . Not much is available on the internet. (once was excited to find a  promising youtube video – later it was on Tata Young singing Dhoom Dhoom….)

Why is Mukesh Ambani the richest person of India and not Ratan Tata?

What can kill us so quickly that we wouldn’t even know?

Answer by Dhakshitha Rao:

Source: 9 ways the universe is conspiring to kill us all

I am only sharing this information here. Obviously, NASA gets the credit for these points! I didn't discover them.

1. Rogue Black Holes





The universe is full of wonderful things. It’s also full of things that are pretty terrifying. A black hole is described as “a region of space having a gravitational field so intense that no matter or radiation can escape.” Basically that means you’ll be crushed in a black abyss.
Thousands of rogue black holes could surround our galaxy alone. They form when two black holes rotating at different speeds, or of different sizes, combine, giving the newly merged black hole a “big kick” and sending them hurtling in a random direction at up to 2,485 miles per second.
One could be heading right for you. The worst part? We’re not likely to get a warning until very late on… Not that there’s much we could do anyway.

2. Galactic cannibalism





Perhaps the scariest sounding of the lot, galactic cannibalism is when a smaller galaxy gives in to a bigger galaxy’s gravity, slowly being sucked into it until it just becomes a part of its mass. The added mass just makes it hungrier for more galaxies, and the cycle continues.
Our galaxy has been known to do this, but more worryingly for us is that Andromeda, our closest galaxy, a galaxy that is pretty much double our size, has previous for devouring those closest to it. It’s almost definitely sizing us up too.

3. Gamma Ray Bursts





Wanna know something cool about a gamma ray burst? They emit as much energy in a few seconds as our sun will during its entire 10-billion-year life.
If one were to happen in our galaxy, our ozone layer would basically be boiled off, leaving us to deal with all that harmful UV radiation that will rain down. Fear not though, these happen very rarely in the universe – if you can call once a day rare.
They happen when a particularly huge star collapses into a black hole, initiating a supernova explosion which then emits twin energy flares in opposite directions. At least it’s pretty though, right?

4. Asteroid impact





This is probably the most talked about and most common way life on Earth could be ended. After all, it’s happened before.
A small one wouldn’t end life on Earth, but could put an end to modern life in whatever country it hits. A medium one would have effects similar to that of a nuclear winter, killing all – except things like cockroaches. A large one would turn the Earth’s crust into magma, killing everything.
A big asteroid came close to us last year, and will come back around in 2032. At the time, people were saying that next time it would hit us. But Nasa moved quickly to calm people. They said the most dangerous known asteroids don’t really pose much of a threat – and there are very few of them.
This basically means that the one that’s going to kill us all will take us completely by surprise.

5. Supernovae





A supernova is the explosion of a dying star. But they’re selfish, so they’d ideally like to take someone else out with them.
They happen about every 100 years, but luckily for us, there’s not many too close. Despite this though, those far away could still strip our ozone layer, much like a gamma ray, and send that radiation pouring down on our heads all over again.
There was a lot of panic that Betelgeuse in the Orion constellation was going to explode in 2012 and kill us all. It didn’t, but that doesn’t mean it’s not going to.

6. Mercury





Nobody likes Mercury. Nobody even thinks about Mercury, and that’s why it’s going to kill us.
There’s a theory that the planet’s orbits can elongate, and computer simulations have shown that this can happen over a period of time. In our solar system, Mercury is the one this is most likely to happen to, and it will take out our sister planet Venus before it gets us.
We’ve always known Venus doesn’t like us though, and there’s a chance that the collision with Venus could alter Mercury’s orbit even further, sending it right for us. It is a very, very, very small chance, but it’s still a chance. So be prepared. Or just go about your day as usual, whatever.

7. Cosmic Strings





What’s one dimensional, extremely dense and is just cruising through the universe? Justin Bieber will not be accepted as an answer.
It’s a cosmic string – basically the ripples still travelling the universe from the Big Bang.
There’s a question over whether they exist, but honestly, we don’t ever want to find out. We’d probably be dead before we realised what happened. If one of these was travelling towards us at the speed of light, and passed through our equator, (it would literally travel through our atoms and out the other side as if we were air), the North Pole would actually crash into the South Pole in less than a second.
It’s because these strings are so dense that if there was one even just a kilometre long, it would weigh as much as the Earth.

8. Mini Black Holes
Not applicable for question context





So you thought a kilometre long string that weighed as much as the Earth was scary? How about a black hole the size of a ping pong ball that weighs as much as the Earth?
If one of these got caught in our gravitational field and came crashing down to Earth until it lodged itself right in our centre, things would actually be quite fun before our demise (we imagine).
We’d weight twice as much. In fact, everything would. Imagine the confusion if you were playing a game of golf at that moment in time, or the awkward scenes in gyms across the world. We wouldn’t be laughing at others’ misfortune for long before karma came to get us though, as the black hole would literally start eating us from the inside, until there was nothing left but a slightly larger black hole orbiting our sun.

9. Cosmic space dust
Not applicable for question context





Life wouldn’t exist without nebulae, the clouds of gas and dust that formed all the planets in existence. So you think they’d have some affection for us right? Wrong. So horribly wrong.
None of these exist particularly close to us, but we do travel past a lot when we orbit the galaxy. How would we know if one of these was about to kill us? It would be beautiful. There would be shooting stars and bright colours. But it would also be cold.
The dust would block the light, and heat, from the sun. We would become a giant snowball floating through infinite space, and, while that’s a nice image, you wouldn’t be around to enjoy it. What’s worse is that as the ice grows on the polar caps, more heat and light would be reflected back up away from the Earth, making the planet even colder.

What can kill us so quickly that we wouldn't even know?

What can I learn right now in 10 minutes that will be useful for the rest of my life?

Answer by Shondhi Singhal:

Create your own wifi hotspot on Windows 7 or 8 –

You don't need connectify or any other software for it. Also, you can save yourself from that 90 minutes counter in connectify.

All you need to do is run the following two commands in cmd –

Open cmd with Run as Administrator.

1) netsh wlan set hostednetwork mode=allow ssid=wifiname key=wifipassword

2) netsh wlan start hostednetwork

Best solution – Make a batch file of it and just run the file every time when you start the pc.

To make a batch file –

First write the commands on a notepad

Then save it with the extension bat.  e.g. wifi.bat

Your batch file is made and now execute the file with Admin Privileges.

Important – For this to work, your sharing should be on in network properties for the network/ethernet connection that you want to share through your wifi:

Go to Open Network and Sharing Centre ->Change Adapter Settings(On left panel)

Your wifi hotspot would be Microsoft Hosted Network Virtual Adaptor in the Network Connections.

Go to the properties of the LAN/ethernet/WiFi connection and make the changes accordingly.

Your wifi hotspot would be ready. 🙂

Edit :

To stop the wifi hotspot –
Write the following in command prompt : netsh wlan stop hostednetwork

What can I learn right now in 10 minutes that will be useful for the rest of my life?

What are the most innovative, unique and crazy civil engineering projects ever done?

Answer by Kshitij Salgunan:

I will mention some of the most crazy civil engineering works which have always inspired me.

1) Rotating 17000+ton bridge

A challenging project was put forward by the Chinese government to make a 250 meter long 6 lane flyover above the high-speed railway without stopping the railway service for even a minute! With the country’s high speed rail network being the largest in the world, it was considered not feasible to even halt it temporarily.

Ofcourse it was very challenging project and surprisingly one firm with a group of brilliant engineers took the challenge and build it successfully!

Here are the photos.

They first build the complete bridge on the side of the railway line.

Then they rotated the 17000 ton structure at 106 degrees to connect it to the rest of the section!

It took only 90 minutes to connect the section to the rest of the bridge, turning it 106 degrees on a 15metre high axis.
 

They completed their task without even stopping the train service for a minute! Infact they didn't even inform the train company!

Whoever was the lead engineer, I should say that it takes lot of guts to do something extraordinary like this.

2. Gateshead Millennium Bridge

The Gateshead Millennium Bridge is a pedestrian and cyclist bridge spanning River Tyne in England. The bridge is essentially two graceful curves, one forming the deck and the other supporting it, spanning between the two islands running parallel to the quaysides. To allow ships to pass underneath, this whole assembly rotates as a single, rigid structure. As the arch tilts lower, the pathway rises, each counterbalancing the other, and a pathway over the river is formed. The parabolic curves of the deck extend the 105m crossing distance to around 120m, giving enough extra length to provide the required clearance above the water. The appearance of the bridge when in motion leads to it sometimes being called the 'Blinking Eye Bridge'

Source:- Gateshead Millennium Bridge: World’s Only Tilting Bridge

At night, the lighting makes it beautiful.

3. Trampoline Bridge, Paris

The most amazing bridge in the world? Yes! I believe it is! This awesome structure is basically a giant trampoline that encourages people to embrace their inner child by hopping across the water! This is a bridge concept proposed by a design firm in Paris.

There is one small problem with the Parisian Bouncy Bridge though: the lawsuits would flow in like the butter over a plate of escargot.  Trampoline injuries are one of the cornerstones of personal injury liability these days.  Unfortunately, it is insanely easy to injure yourself on a trampoline, and even easier to bring a lawsuit against the owner if you haven’t signed a liability waiver.  Most commercial places have you sign one before being able to use their trampolines, but I cannot imagine the Parisian government being able to gather a signature from everyone crossing the river.

Source: The Greatest Bridge That Never Was – Paris' Trampoline Bridge

I hate it when 'fear of lawsuit' brings down awesome ideas.

4. The Tianjin Eye , Tianjin

Tianjin Eye is a 120-meter tall giant Ferris wheel built on the Yongle Bridge over the Hai River in Tianjin, China. It is claimed to be the only such wheel to have been constructed over a bridge.

It is one of the world's biggest ferris wheels with a capacity of 384 passengers at a time! I like it when something extra-ordinary like this are made.

5. The Kurilpa Bridge, Brisbane, Australia

Doesn't that structure look crazy?

The Kurilpa Bridge utilizes Buckminster Fuller's principle of tensegrity producing a synergy between balanced tension and compression components to create a light structure that is incredibly strong.

It features a LED lighting system powered almost completely by 84 integrated solar panels which produce and average of 100KWh a day. This is connected to the grid & hence the bridge can get power when needed or give power back to the grid when a surplus is generated.

6. Falkirk Wheel

The Falkirk Wheel is the world's first and only rotating boatlift and was created to link two canals between the east and west of Scotland. The wheel was designed to carry two boats up and two boats down the 35-metre drop in level between two canals in just 15 minutes.
source: The Falkirk Wheel and Visitor Centre, Scotland

This is really an amazing piece of engineering.

It looks beautiful at night.


Wow. You just crossed the average attention-span of most humans! Read on, you super-human 🙂


7) Gotthard Base Tunnel: 57 Kms of Pure Engineering Marvel

The Gotthard Base Tunnel  is a railway tunnel in the heart of the Swiss Alps expected to open on June 2, 2016.With a route length of 57 km (35.4 mi) and a total of 151.84 km (94.3 mi) of tunnels, shafts and passages, it is the world's longest rail tunnel.

source: Gotthard Base Tunnel

It was constructed by continuously boring for 15 years using multiple tunnel boring machines as shown above. It is also one of the safest tunnels in the world with multiple emergency exits.

8) Millau viaduct Bridge,France

Now, what's extraordinary about this bridge?

It's height! The height of the pillars supporting this bridge is higher than the height of Eiffel tower!

The Millau Viaduct is a cable-stayed road-bridge that spans the valley of the river Tarn near Millau in southern France. Designed by the French structural engineer Michel Virlogeux and British architect Norman Foster, it is the tallest bridge in the world with one mast's summit at 343.0 meters above the base of the structure. It is also the 12th highest bridge in the world, with a 270 meters drop from the bridge road to the valley below. The 2460 meters long bridge is a stunning architectural and design feat. And it is beautiful to look at as well.

The bridge was opened in 2004 to close the "missing link" on the A75 autoroute that connects Paris in the north to Perpignan in the south; the Millau Viaduct was the result of 17 years of ideas, proposals, and design that resulted in shaving 37 miles off the former route through the region. But rather than choose a mundane design that simply did the job, the French went big.

source: Millau Viaduct, France: the Tallest Bridge in the World 

9) Large Hadron Collider (This is the craziest one)

The Large Hadron Collider is a massive and powerful machine. It consists of eight sectors. Each sector is an arc bounded on each end by a section called aninsertion. The LHC's circumference measures 27 kilometers (16.8 miles) around. The accelerator tubes and collision chambers are 100 meters (328 feet) underground.

The LHC uses magnets to steer beams of protons as they travel at 99.99 percent the speed of light. The magnets are very large, many weighing several tons. There are about 9,600 magnets in the LHC. The magnets are cooled to a chilly 1.9 degrees Kelvin (-271.25 Celsius or -456.25 Fahrenheit). That's colder than the vacuum of outer space.
source: LHC By The Numbers – HowStuffWorks

This is one place where mechanical engineers, electronic engineers, computer science engineers, civil engineers, electrical engineers, plumbers, electricians, chemists, physicists, and every expert you can think of, works together as a team. This project pushes every engineering to its limits. I hope  they will soon find the answers of life, universe and everything. :p

It will require an answer bigger than this one to explain about what it does.
I may write it as another answer soon. 🙂

-by Kshitij Salgunan ( If you liked this answer, you may want to check out my other detailed answers. You may be surprised to know that I am a computer science engineering student and not a civil engineer! I just happens to have diverse interests.)

What are the most innovative, unique and crazy civil engineering projects ever done?

How do I become a data scientist?

Answer by William Chen:

There are amazing (and free!) resources online that you can use to teach yourself data science.

Please bookmark this page so you can refer to it later! Also check out Quora's data science FAQ at What is the Data Science topic FAQ?


Fulfill your prerequisites

Before you begin, you need Multivariable Calculus, Linear Algebra, and Python.

If your math background is up to multivariable calculus and linear algebra, you'll  have enough background to understand almost all of the probability / statistics / machine learning for the job.

Multivariate Calculus: https://www.quora.com/What-are-the-best-resources-for-mastering-multivariable-calculus
Numerical Linear Algebra / Computational Linear Algebra / Matrix Algebra: Linear Algebra

Multivariate calculus is useful for some parts of machine learning and a lot of probability. Linear / Matrix algebra is absolutely necessary for a lot of concepts in machine learning.

You also need some programming background to begin, preferably in Python. Most other things on this guide can be learned on the job (like random forests, pandas, A/B testing), but you can't get away without knowing how to program!

Python is the most important language for a data scientist to learn. Check out

For some reasoning behind that.

To learn Python, check out How can I learn to program in Python?

Plug Yourself Into the Community

Check out Meetup to find some that interest you! Attend an interesting talk, learn about data science live, and meet data scientists and other aspirational data scientists!

Start reading data science blogs and following influential data scientists!

Setup your tools

  • Install Python, iPython, and related libraries (guide)
  • Install R and RStudio (I would say that R is the second most important language. It's good to know both Python and R)
  • Install Sublime Text

Learn to use your tools

Learn Probability and Statistics

Be sure to go through a course that involves heavy application in R or Python.

Complete Harvard's Data Science Course

This course is developed in part by a fellow Quora user, Professor Joe Blitzstein.

Intro to the class

Lectures and Slides

2013 Assignments

2014 Assignments

2013 Labs

Do most of Kaggle's Getting Started and Playground Competitions

I would NOT recommend doing any of the prize-money competitions. They usually have datasets that are too large, complicated, or annoying, and are not good for learning (Kaggle.com)

Start by learning scikit-learn, playing around, reading through tutorials and forums at Data Science London + Scikit-learn for a simple, synthetic, binary classification task.

Next, play around some more and check out the tutorials for Titanic: Machine Learning from Disaster with a slightly more complicated binary classification task (with categorical variables, missing values, etc.)

Afterwards, try some multi-class classification with Forest Cover Type Prediction.

Now, try a regression task Bike Sharing Demand that involves incorporating timestamps.

Try out some natural language processing with Sentiment Analysis on Movie Reviews

Finally, try out any of the other knowledge-based competitions that interest you!

Learn More

A/B Testing is just a rebranded version of what pharmaceutical companies have been doing for decades. Learn more about A/B testing here: The Ultimate Guide To A/B Testing – Smashing Magazine

Visualization – I would recommend picking up ggplot2 in R to make simple yet beautiful graphics, checking out The Visual Display of Quantitative Information ($), and just browsing DataIsBeautiful • /r/dataisbeautiful and FlowingData for ideas and inspiration.

User Behavior – This set of blogs posts looks useful and interesting – This Explains Everything " User Behavior

Feature Engineering – Check out

Big Data Technologies – Check out Page on quora.com

Do Side Projects

Code in Public

Create public github respositories, make a blog, and post your work, side projects, Kaggle solutions, insights, and thoughts! This helps you gain visibility, build a portfolio for your resume, and connect with other people working on the same tasks


Check out more specific versions of this question:


Think like a Data Scientist

In addition to the concrete steps I listed above to develop the skillset of a data scientist, I include seven challenges below so you can learn to think like a data scientist and develop the right attitude to become one.

(1) Satiate your curiosity through data

As a data scientist you write your own questions and answers. Data scientists are naturally curious about the data that they're looking at, and are creative with ways to approach and solve whatever problem needs to be solved.

Much of data science is not the analysis itself, but discovering an interesting question and figuring out how to answer it.

Here are two great examples:

Challenge: Think of a problem or topic you're interested in and answer it with data!

(2) Read news with a skeptical eye

Much of the contribution of a data scientist (and why it's really hard to replace a data scientist with a machine), is that a data scientist will tell you what's important and what's spurious. This persistent skepticism is healthy in all sciences, and is especially necessarily in a fast-paced environment where it's too easy to let a spurious result be misinterpreted.

You can adopt this mindset yourself by reading news with a critical eye. Many news articles have inherently flawed main premises. Try these two articles. Sample answers are available in the comments.

Easier: You Love Your iPhone. Literally.
Harder: Who predicted Russia’s military intervention?

Challenge: Do this every day when you encounter a news article. Comment on the article and point out the flaws.

(3) See data as a tool to improve consumer products

Visit a consumer internet product (probably that you know doesn't do extensive A/B testing already), and then think about their main funnel. Do they have a checkout funnel? Do they have a signup funnel? Do they have a virility mechanism? Do they have an engagement funnel?

Go through the funnel multiple times and hypothesize about different ways it could do better to increase a core metric (conversion rate, shares, signups, etc.). Design an experiment to verify if your suggested change can actually change the core metric.

Challenge: Share it with the feedback email for the consumer internet site!

(4) Think like a Bayesian

To think like a Bayesian, avoid the Base rate fallacy. This means to form new beliefs you must incorporate both newly observed information AND prior information formed through intuition and experience.

Checking your dashboard, user engagement numbers are significantly down today. Which of the following is most likely?

1. Users are suddenly less engaged
2. Feature of site broke
3. Logging feature broke

Even though explanation #1 completely explains the drop, #2 and #3 should be more likely because they have a much higher prior probability.

You're in senior management at Tesla, and five of Tesla's Model S's have caught fire in the last five months. Which is more likely?

1. Manufacturing quality has decreased and Teslas should now be deemed unsafe.
2. Safety has not changed and fires in Tesla Model S's are still much rarer than their counterparts in gasoline cars.

While #1 is an easy explanation (and great for media coverage), your prior should be strong on #2 because of your regular quality testing. However, you should still be seeking information that can update your beliefs on #1 versus #2 (and still find ways to improve safety). Question for thought: what information should you seek?

Challenge: Identify the last time you committed the Base rate fallacy. Avoid committing the fallacy from now on.

(5) Know the limitations of your tools

“Knowledge is knowing that a tomato is a fruit, wisdom is not putting it in a fruit salad.” – Miles Kington

Knowledge is knowing how to perform a ordinary linear regression, wisdom is realizing how rare it applies cleanly in practice.

Knowledge is knowing five different variations of K-means clustering, wisdom is realizing how rarely actual data can be cleanly clustered, and how poorly K-means clustering can work with too many features.

Knowledge is knowing a vast range of sophisticated techniques, but wisdom is being able to choose the one that will provide the most amount of impact for the company in a reasonable amount of time.

You may develop a vast range of tools while you go through your Coursera or EdX courses, but your toolbox is not useful until you know which tools to use.

Challenge: Apply several tools to a real dataset and discover the tradeoffs and limitations of each tools. Which tools worked best, and can you figure out why?

(6) Teach a complicated concept

How does Richard Feynman distinguish which concepts he understands and which concepts he doesn't?

Feynman was a truly great teacher. He prided himself on being able to devise ways to explain even the most profound ideas to beginning students. Once, I said to him, "Dick, explain to me, so that I can understand it, why spin one-half particles obey Fermi-Dirac statistics." Sizing up his audience perfectly, Feynman said, "I'll prepare a freshman lecture on it." But he came back a few days later to say, "I couldn't do it. I couldn't reduce it to the freshman level. That means we don't really understand it." – David L. Goodstein, Feynman's Lost Lecture: The Motion of Planets Around the Sun

What distinguished Richard Feynman was his ability to distill complex concepts into comprehendible ideas. Similarly, what distinguishes top data scientists is their ability to cogently share their ideas and explain their analyses.

Check out Edwin Chen's answers to these questions for examples of cogently-explained technical concepts:

Challenge: Teach a technical concept to a friend or on a public forum, like Quora or YouTube.

(7) Convince others about what's important

Perhaps even more important than a data scientist's ability to explain their analysis is their ability to communicate the value and potential impact of the actionable insights.

Certain tasks of data science will be commoditized as data science tools become better and better. New tools will make obsolete certain tasks such as writing dashboards, unnecessary data wrangling, and even specific kinds of predictive modeling.

However, the need for a data scientist to extract out and communicate what's important will never be made obsolete. With increasing amounts of data and potential insights, companies will always need data scientists (or people in data science-like roles), to triage all that can be done and prioritize tasks based on impact.

The data scientist's role in the company is the serve as the ambassador between the data and the company. The success of a data scientist is measured by how well he/she can tell a story and make an impact. Every other skill is amplified by this ability.

Challenge: Tell a story with statistics. Communicate the important findings in a dataset. Make a convincing presentation that your audience cares about.



Any feedback on this post is appreciated – in the comments, as a suggested edit, or in a private message.

If you liked this material, please consider following:

1) What is the Data Science topic FAQ?
2) This question!
3) Me! William Chen
4) My personal blog, Storytelling with Statistics
5) Learn Data Science, where I am curating material on Quora that is relevant for anyone seeking to become a data scientist!

How do I become a data scientist?

How Google Used Motorola To Smack Down Samsung — Twice

Samsung is giant. It employs 427,000 staff, has an annual turnover in excess of $270bn and assets of $600bn spread across over 80 business units. And Google just floored it twice using Motorola as a baseball bat.

Why?
On the surface having 81 per cent of Android marketshare would seem to make Google and Samsung best buddies. Samsung has been the driving force behind Android’s meteoric growth and put Google mobile devices in pole position.

The problem is Samsung wanted too much credit. It wasn’t enough for Samsung to make the most popular Android phones and tablets, it had to hide Android – and consequently Google’s role in its achievement. It did this using ‘TouchWiz’, the company’s proprietary skin which painted over all aspects of Android leaving it unrecognizable. To the casual consumer they were buying ‘a Samsung’, Google’s role was largely unrecognized.

Then things got worse. Samsung began degrading Android performance by switching out vast parts of the software – phone dialer, calendar, email client, contacts, notification center, music and video player, voice control and much more – for its own apps. Reviews were largely negative with TouchWiz and its bloatware slowing down Android, wasting storage space and the replacement apps were seen as inferior or, worse still, needless gimmicks.

Samsung then exploited this further. It put TouchWiz on its smart TVs, another market it dominates, and began building its own Android rival – Tizen – which, thanks to its TouchWiz interface, looks identical to the casual observer. The long term strategy was clear: switch over to Tizen and take the majority of the handset market with it. Google had to act.

How?
The ‘how’ was Motorola. On 15 August 2011 Google announced it had bought Motorola Mobility for $12.5bn in cash. With it Google acquired more than 20,000 mobile patents and publicly declared the purchase of the phone maker would not in any way compromise relationships with its handset partners… honestly, really, pinky swear.

Of course Google didn’t expect handset partners to fully believe this and platitudes issued from them in reaction to the deal confirmed it. Should Google use Motorola to ramp up its own major handset business the market would be theirs. The phones would have stock Android and no-one, not even Samsung, could afford to subsidise their cost as Google can leveraging its mammoth advertising revenue.

The bait was set: obliteration by Google stock Android handsets unless manufacturers (read: Samsung) stopped messing with Android. Google quietly showed it could walk the walk as well as it ramped up Nexus production and introduced the well-received Motorola X and Motorola G which stripped away almost all customisation from stock Android.

Samsung bit. On 27 January 2014 Google and Samsung signed a wide-ranging global patent deal which will last a decade. Buried within it was an agreement that Samsung would tone down TouchWiz, refocus on core Android apps over its own customisations and cancel more radical customisations such as its ‘Magazine UX’ interface. Two days later Google announced the sale of Motorola Mobility to Lenovo showing both agreements had been working in parallel.

The consequences
The smack down for Samsung is twofold.

Firstly, despite its size and dominance of the Android market, Samsung has been brought back into line. No longer will Samsung run roughshod over Android’s design, kick out its apps in favour of Samsung alternatives and hide Google’s hard work underneath. Indications of a low key Galaxy S5 launch suggest it will stand by its word.

Secondly, the jump off point for Samsung from Android to Tizen is no longer straightforward. With Android shining through more strongly in future Samsung handsets it won’t be a seamless switch from one to the other. If Samsung wants Tizen to succeed it will now have to be earned rather than snuck in under the radar.

All of which should be good news for Android users who will find it easier to move between handset makers when they upgrade while a stock Android experience (particularly with Android 4.4 KitKat’s optimisations) will make for faster, more responsive budget devices. Whether it gives smaller handset makers a greater chance to compete with the all-conquering Samsung, however, remains to be seen.

And what of Google’s supposed $10bn loss? It’s a misreported myth calculated by subtracting Motorola’s $2.91bn sale price from its $12.5bn purchase. What it misses are the $3.2bn Motorola had in cash, $2.4bn saved in deferred tax assets and two separate Motorola unit sales totalling $2.5bn in 2013. Factor in Lenovo’s purchase and Google has paid $1bn for what it retained: $5.5bn worth of Motorola patents and the company’s cutting edge research lab.

Well played Google!

Posted from WordPress for Android