Some Qs people asked me on science and my replies to them - Part X

                                                                      Interactive science series

Q: I did my PhD in Physics and just joined as a scientist in a research organization. But ashamed to admit that I am not scientifically literate too. When I read your article  literate-people-living-in-urban-areas-are-scientifically-illiterate too , I was shocked to realize this. Your quote 'Being a scientist is a state of mind, not a profession' rings true. More than three thousand people read your article . Did anybody tell you that he or she is scientifically literate? I am sure even majority of scientists wouldn't be scientifically literate. What can we do to rectify this problem?

MR: No, nobody contacted me till now, even the scientists who read it!  That is the problem. But don't get disheartened. Identifying the problem is the first step to rectify it. But we are not policy makers. We can only bring it to the notice of everybody around. It is the people who must decide whether they want to be scientifically literate or not. It is the responsibility of science communicators to make people think that scientific literacy really benefits them. We will do everything possible to make them  scientifically literate, if they co-operate with us. 

By the way, I admire your honesty and courage to confess that being a scientist you too are not scientifically literate :)

 Q: How do self driving cars work?

MR: Amazing how science and technology are going places! Ummm... I want to have one now!

Driver error is the most common cause of traffic accidents, and with cell phones, in-car entertainment systems, more traffic and more complicated road systems, it isn't likely to go away. But if drivers aren't going to concentrate on the road, who is? If technology continues on its current course, your car will do the concentrating for you. 

Autonomous cars - rather taxis - could ultimately reduce the number of cars on the roads...You can create smaller roads, you can create much smaller car parks. Plus machines are much better at following rules than humans, reducing accidents and fatalities.

People who tested it  were nervous when they got into the car the first time, and then surprised as they watched the steering wheel turn by itself.  Some described the feeling like this ... "It felt like there was a ghost or something".  But when they saw the magic with their own eyes... the feeling turned to awe...as they quickly grew more comfortable. The rides were smooth and controlled and they were relieved to see that the car recognized even small obstacles like birds and motorcycles parked in the distance and negotiated them safely. They couldn't see them with their  human eyes, but the car could, so they realized that they could trust the car .

The software fitted makes these decisions. Robots are taking over the controls. Automakers are developing complex systems that allow cars to drive themselves. They're also furthering existing technologies such as self-parking and pre-safe systems. The systems differ depending on the car, but what all have in common is that they can anticipate crashes and prepare the car to keep the occupants safe.

Most self-driving cars work in this way...

There are several systems that work in conjunction with each other to control a driverless car.

Radar sensors placed around the car monitor the position of vehicles nearby. Video cameras detect traffic lights, read road signs and keep track of other vehicles, while also looking out for pedestrians and other obstacles.

The Chauffeur system, as they call it, uses lidar, which stands for light detection and ranging and is not related to the liger, which is a lion and a tiger. Lidar works like radar including one that constantly spins on the roof and sonar, but it's far more accurate. Lidar sensors help to detect the edges of roads and identify lane markings by bouncing pulses of light off the car’s surroundings. It maps points in space using 64 rotating laser beams taking more than a million measurements per second to form a 3D model in its computer brain that's accurate to the centimeter. Preloaded maps tell the system where the stationary stuff is -- traffic lights, crosswalks, telephone poles -- and the lidar fills in the landscape with moving objects like people. It also has regular ol' radar, a camera and GPS to help out.  There are also two cameras on the dashboard to scan for obstacles and detect changes in traffic lights. Ultrasonic sensors in the wheels can detect the position of curbs and other vehicles when parking. A central computer analyses all of the data from the various sensors to manipulate the steering, acceleration and braking.

But still, as the technology hasn't been perfected yet, a driver needs to stay in the seat ... just in case...

Q: Your article on "Sport Science" is very informative.  Had we utilized the scientific benefits more efficiently, we would have won more medals in the recently held Olympics. 

I have a very specific Q . I want to know how Usain Bolt achieved so much success. Can science explain this?

MR: According to sport scientists the athletes are getting more taller and skinnier giving them a competitive edge over others who don't have these qualities. Sport persons like Bolt are built to perform perfectly!

Scientists have found that speeds for running the 100 metres have increased as champion sprinters have become taller and leaner, giving them a competitive edge over other athletes. This helps to explain why Usain Bolt, the 6ft 5in tall, 12-stone Olympic gold medallist and 100 metre world record holder, has been able to achieve race times far quicker than his rivals. Carl Lewis, who is 6ft 2in and weighed almost 13 stone, also managed to set world sprinting records during the 1990s, but his body shape is less well adapted than Usain Bolt's, according to the researchers.

Tall, thin athletes may have an edge because they are better at dissipating heat from their bodies due to greater skin surface area, which allows their muscles to work harder for longer. They also have greater stride length. Professor Neville, whose research is published in the Journal of Sports Sciences, examined the body composition and sprint times for the top 10 men and women in 100 meter sprinting over the past ten decades. Athletes with a leanness ratio, known as a reciprocal ponderal index, of greater than 44 seemed to be the most successful.

Another set of studies indicate that symmetrical knee structures are beneficial to sprinting. Jamaican children have remarkably symmetrical knees compared to others, Bolt is no exception. Additionally, Jamaicans are more likely to have higher ratios of fast-twitch muscle fibers essential for generating power quickly. Bolt is one of a gifted few who likely have close to 90% fast twitch muscle fibers in his legs.

Bolt is fast because he can run fast longer. Winning a sprint is all about reaching your top speed quickest while maintaining the top speed longest. In the recently held Olympics in Brazil, Bolt ran 100m in 9.58 s, this means his speed was 10.438 meters/second. That’s the average speed, which doesn’t give the complete picture. When any runner sprints, the sprinter accelerates from 0 to his/her top speed, maintains that speed and then decelerates at the end of the run. The top speed for any sprinter is obviously higher than the average speed. In Bolt’s case, his top speed was 12.195 meters/second. This itself is not extraordinary for Olympic level sprinters. What’s extraordinary about Bolt is that he maintained it for a full 30 meters. Most sprinters cannot maintain their top speed for more that 10 meters. Bolt is not extraordinary faster than other Olympic level sprinters. He is fast for a longer duration.

That’s why you see in most of his races it seems like he accelerates in the last 40 m and then does like a victory dance in the last 20m. His accleration is an illusion. He isn’t accelerating; the others are decelerating. Right around the 50m mark, everyone reaches their top speed, including Bolt. Around the 60m mark, everyone else slows down while Bolt keeps going. Right around the 80m mark, Bolt realizes that everyone else has dropped behind and he starts slowing down. It is possible that he can continue at the same pace for longer than 80m, but he doesn’t really need to.

None of his genetic prowess takes away from his training. He works his legs with intensity in the weight room and does a lot of sport-specific training off the track to strengthen his legs and posterior chain.

Usain St. Leo Bolt’s achievement of athletic excellence while living with scoliosis is a testament of his mental strength and ability to overcome obstacles.

Bolt is a lethal combination of several things to kill all his rivals!

Q: Can planes fly into outer space like rockets do?

MR: No! There is a difference between jet engines and rocket engines. All jet engines are 'breathing engines'. The plane carries fuel and the oxidizer is oxygen from the air. The fuel and the oxidizer are combusted to provide thrust. Once above about 50,000 feet (9 miles) the atmosphere is very, very thin and there is not enough oxygen and the planes motor flames out. 

As we go up and up and up and up, through the atmosphere, it just becomes less and less dense and the oxygen content in it becomes very very low. 

The most commonly accepted boundary of space,  as defined by the World Air Sports Federation (Fédération Aéronautique Internationale), is something called the 'Kármán line', 100 kilometres above Earth's mean sea level. This line is where the atmosphere becomes too thin for aeronautical flight to happen.

Rockets on the other hand carry tanks with both fuel and oxidizer. They burn and produce thrust way higher above the atmosphere, build up a lot of speed (16,000 to 20,000 mph vs 1300 mph for a jet) as they approach  space boundary and go beyond it. While boosting, the engines have steerable nozzles to control direction and roll.

Considering they have to boost their own fuel and oxidizers to a speed 10 times faster than the jet, they have very little payload capacity left for the huge weight of the rocket - this is why it costs so much to get to space.

Other reasons why jets cannot fly into outer space are... only if thrust is greater than the aircraft weight will it fly straight up - this is limited to a very few high performance jet fighters. And if it did get to space, jets don't have steerable thrust nozzles, and its wings, elevators and ailerons will not work on a vacuum so it can't be navigated in any useful way.

Q: ISRO recently tested a scramjet. What are its advantages and in what way it is different from other rocket engines?

MR: The scramjet engines can be used only during the atmospheric phase of the rocket's flight (when atmospheric oxygen is available for use, read the explanation above to know why). So, the technology needs to be combined with the conventional chemical rockets, for meeting the final orbital velocity requirements.

Oxygen is as essential for the process of combustion. Therefore a rocket, during its launch, needs to combine a combustion fuel with liquid oxygen to create the thrust needed for the take-off and flight. However, if the need for liquid oxygen is taken away, the space craft can be much lighter, hence cheaper to launch. The technology also has the potential to be adapted to commercial planes and it can substantially reduce the travelling time as well.

This is what essentially SCRAMJET or  Super Sonic combustion Ramjet achieves, by reducing the amount of oxidiser to be carried along with the fuel. While conventional rocket engines need to carry both fuel and oxidiser on board for combustion to produce thrust, air-breathing rocket systems on the other hand uses the atmospheric oxygen from their surroundings and burn it with the stored on- board fuel. Scramjet engines obtain oxygen from the atmosphere by compressing the incoming air before combustion at hypersonic speed. It uses hydrogen as fuel and the oxygen from the atmospheric air as the oxidiser.

When the rocket reaches a height of 11 km, the scramjet engines would start breathing air directly from the atmosphere, therefore the spacecraft can be smaller or carry more payloads, making it a commercially viable option. Isro's main concern was igniting the air-breathing engine in the air and then sustaining the flame at supersonic speed. If the engine can sustain it for five seconds, then it can last for even 1000 seconds.

The engine when fully developed, will eventually be used in Reusable Launch Vehicles or RLV's. The engine can be used both in ascent and descent phase of the vehicle.

Scientists say that the scramjet technology effectively cuts down the cost of launching rockets by reducing its weight by more than half.

Q: Why do some waves hurt while others don't?

MR: The reason why some waves hurt us and others don’t has to do with the specifics of each wave. Gravitaitonal waves don’t hurt us because they pass through; similarly for neutrino waves; green light waves bounce off, but gamma rays (also particles of light) have enough energy per photon to break molecules, so they hurt.

Q: Your articles on brain are very informative.  I want to know why human brains consume so much energy. Can you expalin?

MR:  It is well established that the brain uses more energy than any other human organ, accounting for up to 20 percent of the body's total consumption. Most scientists till now thought that it used the bulk of that energy to fuel electrical impulses that neurons employ to communicate with one another.

A study in 2008 showed that two thirds of the brain's energy budget is used to help neurons or nerve cells "fire'' or send signals. The remaining third, however, is used for  "housekeeping," or cell-health maintenance. There must be enough energy to maintain a proper ionic balance inside and outside cells; if too many get stuck inside, it can cause swelling, which can damage cells and lead to strokes and other conditions.

Q: According to science how did the universe originate without a creator?

MR: We cannot give a perfect answer to this question. Scientists put forth these assumptions  ... 

Coming into existence of this Universe is a  logical and mathematical necessity. The equations and laws of the universe are so compelling that they forced the formation of a universe for them to describe.

Quantum fluctuation* ( don't know fully why, this is my favourite one, most probably because it makes some sense ) -  we see quantum fluctuations in the universe. Virtual particles are a result of quantum fluctuations.  Events at the quantum level are uncaused. The universe is a huge quantum event.

* In quantum physics, a quantum fluctuation (or quantum vacuum fluctuation or vacuum fluctuation) is the temporary change in the amount of energy in a point in space, as explained in Werner Heisenberg's uncertainty principle.

The Uncertainty Principle states that for a pair of conjugate variables such as position/momentum and energy/time, it is impossible to have a precisely determined value of each member of the pair at the same time. For example, a particle pair can pop out of the vacuum during a very short time interval.

The uncertainty principle is illustrated with a schematic representation on the left. An extension is applicable to the "uncertainty in time" and "uncertainty in energy" (including the rest mass energy mc2). When the mass is very large (such as a macroscopic object), the uncertainties and thus the quantum effect become very samll, classical physics is applicable once more.

In the inflationary theory, matter, antimatter, and photons were produced by the energy of the false vacuum, which was released following the phase transition. All of these particles consist of positive energy. This energy, however, is exactly balanced by the negative gravitational energy of everything pulling on everything else. In other words, the total energy of the universe is zero! It is remarkable that the universe consists of essentially nothing, but (fortunately for us) in positive and negative parts. You can easily see that gravity is associated with negative energy: If you drop a ball from rest (defined to be a state of zero energy), it gains energy of motion (kinetic energy) as it falls. But this gain is exactly balanced by a larger negative gravitational energy as it comes closer to Earth’s center, so the sum of the two energies remains zero.

The idea of a zero-energy universe, together with inflation, suggests that all one needs is just a tiny bit of energy to get the whole thing started (that is, a tiny volume of energy in which inflation can begin). The universe then experiences inflationary expansion, but without creating net energy.

A proposal by Stephen Hawking and updated with Turok: If all the dimensions of the universe were the same shortly after the Big Bang, you get a universe that doesn't have a beginning and therefore was never "created". It just IS.

 Ekpyrotic. The universe is the result of a random collision between two quantum membranes in 11 dimensions. The 11 dimension membrane has always existed.

It is a classic case of multiple competing hypotheses with insufficient data to choose between them. None have been falsified, so all are still on the table as far as science is concerned.

Q: Why don't most scientists believe in God and don't accept the 'creation theory'?

MR: Because, according to the scientist friends of mine, God concept doesn't fit into data properly and creation stories have no evidence that can stand up to the logic of intellectuals ! 

Science is not out to disprove or prove the existence of any God. Science attempts to find answers to questions with regard to nature and our universe.  Yes, there have been accepted truths of the various faiths that science has refuted: Science proved that Apollo does not pull the Sun across the sky, but the goal was not to disprove Apollo but to prove why the Sun rises and sets.

Likewise disproving creation theory was not the idea of scientists when they  went about finding the evolution process.

Religious stories get automatically proved wrong when you find facts about the universe and people interpret the results of scientific experiments in whichever way they want and some think science's goal is to demolish religion.

Q : Your reply to the two Qs above this sounds similar but still scientists have no objection to entertain the one above and not the creation theory. Why is this so?
M R: Because at least you can have some plausible and logical explanations with regard to scientific origins of universe like we see in quantum fluctuations in the universe. Virtual particles are a result of quantum fluctuations. We can also formulate mathematical equations to explain them that can be tested in the future when the science is more advanced. We don't have that possibility with regard to 'creation theory'. There is absolutely no evidence, no data, no logic that can satisfy intellectuals. So scientists try to keep away from it.

Q: Who are more intelligent among the scientific communities? Mathematicians and Physicists?

MR: Ho, ho, not biologists eh,, who could save people from deadly diseases using all their gray matter?!

Anyway, you cannot define intelligence properly in the first place. In my view every field has its own importance and each and every person contributing in some way to the knowledge bank is intelligent.

Q: How do you know so much about  so many things?

MR: By learning about them! :) 

Q: Why don't women scientists get credit for what they do in science. Why do men take all the praises?

MR: It is a fact that women can work as efficiently in science as men do. And it is also true that they don't get  as much credit as the men do.  I think the situation is similar to other fields. Till recently we lived in patriarchal societies that refused to accept women as equals.  But science, as a field recognized as an area where intelligent people work, you would expect  more ready acceptance from men.  Unfortunately that is not the case and this field too reflected the societies in which they are embedded. 

Hmmm... isn't  intelligence different from intellectualism?

This video shows the same is true...

When would the situation change? The answer is blowing in the wind. 

But anyway, this shouldn't dishearten us. We know what we are. We don't need anybody else's certificate to tell us what we are capable of.