Science, Art, Litt, Science based Art & Science Communication
Interactive science series
Q: Why can't science be proved wrong?
Krishna: :) Ironically, if you can actually prove convincingly that science or something in science is wrong - it will become part of science, and as such science simply cannot be wrong (at least not for long).
Confused? You can use only science to prove something in science 's wrong. Then your method of science or science becomes right! So 'science' or 'whole of science' can never be proved wrong!
Get that right!
Q: Is scientific education and critical thinking the same thing?
Krishna: If the education is ‘scientific’ , critical thinking is a part of scientific training. But most people treat it like training in car driving. Use it on the road and forget it when you go home.
Once trained in the true sense scientific education should remain with you 24X365X70. It has to guide you in everything you do both inside and outside of your labs. So critical thinking which comes to you as part of scientific training and education should be a guiding force through out the life of a scientifically minded person.
Q: What is the simplest answer to the Q, ' Why do you love science'?
Krishna: Because science gives me a never-ending thrill and realistic answers to several of my questions.
Q: Why nature can be studied scientifically but not human behaviour?
Krishna: Human behaviour is highly complex. It is conditioned by things like culture, religion, politics, emotions, groups, age, education, up-bringing and genes. That is why most of the ‘scientific studies’ of human psychology are not reproducible and faulty.
Q: A person standing nearby sometimes says the same thing one is thinking. Is there a scientific explanation for that?
Krishna: You might be discussing the same subject. Or you might be viewing the same object or people in front of you. The person who said the same thing you were thinking might be your friend or relative and could have the same line of thinking as you go through guided by the same conditions and forces.
Even if he is a stranger, he might have the same thought process as you had and conditioned by the same elements as you are governed.
We call that co-incidence. A statistical fluke.
Q: Is plastic-bottled water good for consumption?
Krishna: Whenever you have used plastic-bottled water you must have smelt some chemicals and felt some bitter taste - this is because of leaching of chemicals from packaging which is a health concern here in India as quality is not maintained properly like in Western countries, and the heat here makes the toxins leach more - but as far as toxic chemicals go, you can get exposure to most of those chemicals from freshly bottled water as well as bottled water that has been on the shelf a while. A 'plastic' taste is not necessarily an indicator that the water is bad and absence of an unpleasant flavour does not mean the water is free from contaminants.
While a single refill in a freshly drained bottle probably will cause less problems if the quality of plastic is maintained properly, there can be some issues when it is done repeatedly. First, these bottles are difficult to wash and are thus likely to carry the bacteria that have started colonizing it the minute you first unsealed it.
While algae and bacteria will not grow in sealed bottled water, the situation changes once the seal has been broken. You have to deal with microbes.
So, no, plastic bottled water is not good for consumption. I usually take my own water in a steel bottle whenever I go out.
Q: How are planets and their atmospheres are found by scientists?
Krishna: Scientists study the planet by watching how it blocked some of the light of its host star as it passed in front of it. It makes the star look a little bit fainter - and it's actually a very good way of finding transiting planets. Moreover, the gravity of both the star and planet effect each other's movement in space. By studying the deviation, you can tell about planets and their stars.
But different molecules in a planet's atmosphere - if it has one - absorb light in different ways, allowing scientists to look for their chemical signatures when the world transits its star.
You can find more details here: http://kkartlab.in/group/some-science/forum/topics/how-exo-planets-...
Q: What is the significance of a human being in the universe?
Krishna: According to wise men, it is nothing! Why? Watch this video:
When Earth itself is nothing when compared to the universe, what significance can a humble human being have? That is why we are being advised to shun egos, superiority complexes, pride and prejudices by people who can think well. Great counsel to follow - according to science!
Q: If sunlight takes eight minutes to reach Earth, how is it I can see Sun immediately after I open my eyes in the morning?
Krishna: :) You are seeing the Sun now how it actually appeared eight minutes back!
Q: What training should a student get before joining Ph.D.?
Krishna: If a student gets comprehensive training in research literature search, designing experiments, interpreting results and writing manuscripts for publications, scientific presentations, communication/presentation skills it would become very easy to conduct research, publish/present papers and get a Ph.D. in the shortest possible time.
However, I never received any training, most of my colleagues too never received any formal training, we found our own ways and completed our work with our own experiences learnt along the way.
Q: Why are smaller sample sizes not good for research?
Krishna: Consider this example: You take 9 samples. 5 samples give one result and 4 give the opposite one. Based on this observation if you say the majority (5) is correct, that would become erroneous because if you take 10 samples and if the 10th one shows the the second set results, that becomes half- half. So smaller samples show more errors. You cannot come to correct conclusions based on them.
As you increase the sample size ( like 9000), the errors become less significant and show more appropriate results. The use of small sample sizes could contain a skewed sample that shows stronger effects. Good results depend on seeing large-scale patterns across thousands of studies and meta-analyses.
Q: How can research results made reliable and scientists accountable?
Krishna: Experts say these things make research more valid - better trained scientists, more funding, more supervision and regulatory oversight, better control or transparency on conflicts of interest.
Q:Why do people publish their papers in international conferences? What is the significance and importance of doing this?
Krishna: You will get more coverage and recognition when you present papers in international conferences. It also denotes that your paper is of high standard because only very good papers are selected for international conferences.
You will receive instant critical feed back from experts in the field which makes you improve yourself.
You will upgrade your presentation skills and discussion dialogues.
More significantly, you are standing up for your science before the international media.
Q: What are predatory journals?
Krishna: The predatory journals are not genuine. They charge the researchers, accept manuscripts without reviewing them, print them without editing them, and otherwise make a mockery of the scientific literature by pumping out low-quality work.
You will find the list here: http://beallslist.weebly.com/
Q: Can one cite a blog post in a Ph.D. thesis?
Krishna: You may do that in art subjects, but in science a blog post is not treated as a reliable source of information because blogs are not peer reviewed, things mentioned in them need not be verified and you can’t tell for sure whether they are based on authentic data or not unless the authors give good citations. People can publish anything they want in them - even their opinions.
If I am reviewing a Ph.D. thesis in my subject, I would definitely object to blog post citations if they are used in it.
Q: Can scientific research be a hobby? I am fascinated by black holes and the theory of wormholes, but have no interest in pursuing theoretical physics as a career. Can I make any significant contributions to science if I am doing it as a hobby?
Krishna: Even if you start it as a hobby, it becomes a passion after some time. The more deep you go into it, the more it sucks you to its bottom. There is no escape if your interest and curiosity are genuine. It will have you in its grip all the time.
Well, that is my experience!
Q: Can one finish Ph.D. in 2 years?
Krishna: Extremely difficult especially in science subjects. You or your supervisor or the circumstances must be extraordinary to complete your research work in just two years in today’s world.
Q: Can a fresher with no research papers get admission to an MS in CS?
Krishna: Yes. Most of the students - at least from India - who join MS in Computer Science don’t have any research papers.
Q: Is peer-review perfect?
Krishna: No! Peer-review is only as valuable as the expertise of the “peers” doing the “review”. That is why people still publish peer-reviewed papers in alternative medicine and boast their papers are of good quality and insist that they be trusted.
Q: How can a student of B.Sc. Physics write a research paper?
Krishna: You can write a research paper if you conducted original research and got results that are significant. If you think you have enough knowledge and confidence to do that go ahead by taking the help of your professors.
You can get some training in scientific research by joining a research group and doing some voluntary work. Also read all the available literature in the field to know how to proceed.
Q: Should the motivational letter for pursuing a PhD be written by the students or the professors?
Krishna: Unless you yourself are not motivated fully, other people can’t help you much. It should come from within first. The letters written by others can only augment your own motivation.
Q: Why does one want to do PhD?
Krishna: In my case… it is to gain more knowledge. To pursue the subject I love more vigorously. To get trained as a scientist.
It became easy for me to go ahead when I got top ranks in the University and a CSIR fellowship.
Q: How do you know the people who do the peer-review of your paper are competent for the position? I once knew a first-year PhD student was asked to do peer-review for papers of a conference hosted by her adviser. I think first-year PhD is totally new, still have lots to learn…
Krishna: There is no way to learn unless the publishers tell you about it and they usually won’t!
You can’t escape some things not only in peer-reviewing but also in allocating projects, funds and in judging awards, prizes etc. Biases and incompetence are real and you need not feel sorry if you miss something despite having merit.
Lesson that should be learnt: Don’t lose your confidence because of somebody else’s bias and incompetence.
Q: How do I kick my PhD adviser from my papers' author list? Long story short, I published a paper alone recently, and my PhD adviser came to me and said: you have to put my name on all your papers, otherwise you can leave. The problem is that he never payed attention to my research, never gave me ONE single idea, never asked me "how are things going SR?", never ever. But he says: I worked to get the money that is funding your PhD, which is true, but this is a proposal for a research project that I wrote. He basically reviewed the text and we sent it out. I wouldn't mind to keep him in the author list, but not only he helps me 0 with my PhD, as he also started to humiliate me in front of more people, saying that I am disorganized and incompetent, about 1 year ago.
I am thinking about publishing two other papers till I graduate, and he freaked out when I mentioned the possibility he wouldn't be in the author list. I am afraid he stops me from graduating or gives me a bad grade.
Krishna: Oh, My! This shows how bad things can get.
To tell you the truth, my adviser too never advised me to do anything. I did everything myself. In the beginning itself I was told I would have to depend entirely on my grey matter. I took it as a challenge and strictly followed what I was told to do.
But I think whatever had happened was for my good only. When you learn how to go about things on your own, you gain confidence, knowledge and get more creative.
I added my supervisor’s name to all my papers despite the help I didn’t get. I never complained but maintained a very cordial relationship throughout my Ph.D. with my ‘guide’. In the end I got a very good recommendation letter from my supervisor praising me and my capabilities to no end!
It is easy to get bitter but I think you too should follow what I did. Kicking your adviser out of your papers gives a very bad impression about you to other people in your academic circle and it doesn’t bring you any good.
Q: Are identical strains necessary in the Biological research?
Krishna: Yes, to make uniform research conditions identical strains are very important. By allowing access to identical strains, cultivars and cell lines, the collections allow published research to be directly reproduced. This is of special value because – along with addressing concerns about the reproducibility of scientific data – it also makes individual organisms, clones, populations or tools that have been used successfully in research studies available to other investigators, bypassing the need for repeated optimization studies.
Q: Can we trust research findings all the time?
Krishna: There is a research paper that discusses this problem. It says: There is increasing concern that most current published research findings are false. The probability that a research claim is true may depend on study power and bias, the number of other studies on the same question, and, importantly, the ratio of true to no relationships among the relationships probed in each scientific field. In this framework, a research finding is less likely to be true when the studies conducted in a field are smaller; when effect sizes are smaller; when there is a greater number and lesser preselection of tested relationships; where there is greater flexibility in designs, definitions, outcomes, and analytical modes; when there is greater financial and other interest and prejudice; and when more teams are involved in a scientific field in chase of statistical significance. Simulations show that for most study designs and settings, it is more likely for a research claim to be false than true. Moreover, for many current scientific fields, claimed research findings may often be simply accurate measures of the prevailing bias.
( Why Most Published Research Findings Are False : http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pm... )
Q: Is having a relationship during grad school a distraction?
Krishna: The opinions differ from person to person. I used to think it’s a distraction and ran away from men who pursued me. And my opinion was proved right in my case.
Q: Are prophylactic antibiotics necessary?
Krishna: Antibiotic prophylaxis is the use of antibiotics before surgery or a dental procedure to prevent a bacterial infection. This practice isn’t as widespread now as it was 10 years ago. This is due to the increase in the resistance of bacteria to antibiotics, the change in bacteria that cause infections, improvements in technology that can detect infections early.
However, antibiotic prophylaxis is still used in people who have certain risk factors for bacterial infection.
People who may need antibiotic prophylaxis usually have factors that put them at higher risk of infection during surgery than the general population. These factors include vulnerability with compromised immune systems like very young or very old age of the patient, poor nutrition, obesity, diabetes, smoking, including a history of smoking, existing infection, even at a different site from where the surgery will be done, recent surgery, extended hospital stay before the procedure, certain congenital heart conditions, meaning ones that have existed since birth.
Antibiotic prophylaxis for dental procedures may be appropriate for people who have compromised immune systems, artificial heart valves, histories of infection in the heart valves or the lining of the heart, known as infective endocarditis, heart transplants that have led to problems with one of the heart valves.
In ordinary circumstances use of prophylactic antibiotics are not necessary . Moreover using them would increase the drug resistance in microbes.
Q: After reading your article this-is-what-a-liver-transplant-surgeon-told-me-recently
I really got scared. Because we use ayurvedic medicines in our home. Are they really that bad? Is any research going on them to find out the truth?
Krishna: I will not say all of the ayurvedic medicines are bad. Some might have good qualities too. Until you test them scientifically you will never know about their qualities - good or bad.
Yes, some people in the West have tested these medicines and found some bad qualities like my article states. But some Indian scientists and doctors too are studying the qualities of these medicines.
I have been given this list:
1). Padma Vibushan and Chitra Cardiac valve inventor and World renowned cardiologist Dr. M.S.Valiathan [, , , , , , ] who is into serious research in Ayurveda for the past 12 years.
2). Padma Bhushan Dr. B M Hegde [M.B.B.S from(Madras), a M.D. from (Lucknow), FRCP from , London, Glasgow, Edinburgh, and Dublin. He also has a FACC and FAMS. He also received training in cardiology from under , a Nobel Laureate.,} world renowned Cardiologist and researcher of Ayurveda - member editorial board of J-AIM (Ayurveda Journal), Ex-Vice Chancellor, Manipal Academy of Higher Education.
3). Dr. Bhushan Patavardhan - Director - Interdisciplinary School of Health Sciences, Pune University and the Chief editor of the Journal of Ayurveda and Integrated medicine (J-AIM) - published by Elsevier - link - You may look at the prestigious and distinguished Doctors and Medical science researchers (who review Ayurveda articles and research papers /reports) in the Editorial board of
4). Dr. G Gangadharan (Ayurvedacharya, FAIP(USA), PhD, MoM (McGill, Canada), Director, Ramaiah Indic SpecialityAyurveda - See more at:- who as part of 22 member Sr. research team proved and published a research on Ayurvedic Prakriti based on Genome-wide Analysis (paper here: )
5). Dr. Thelma B.K, who a Human Geneticist and HoD - Dept. of Genetics at University of Delhi and published papers on Ayurgenomics (one paper here)
6). NCBI /PubMed (of US Govt) which contains peer reviewed 6000+ research papers and clinical trial reports on Ayurveda system /herbs /formulations (In addition to over 190,000 papers on Complimentary and Alternative medicine)… some links on scientific validations of Ayurvedic formulations and Herbs here (a). Guduchi -, (b). Ashwagandha - ., (c). Brahmi - , (d) Various Ayurvedic formulations for Innate anti-oxidant activity (oxidative stress is a main cause of Cancer): , (e). Traditional Ayurvedic Medicines: Pathway to develop anti-cancer drugs:
7). Nobel Laureate Dr. Tu You You, who won Nobel prize in 2015 for TCM (Traditional Chinese Medicine) - who is now an inspirations to all Alternative medicine researchers - I’m sure the day is not far away where Ayurveda finds total cure for a stain of Cancer or any other life threatening disease without the side effects & costs of the so called modern medicine system and associated widespread international recognition.
8). ICMR-NIMS-Clinical Trials Registry has over 400 clinical trials reports of various Ayurvedic formulations and Drugs - link:- This is for those who say there is no scientific basis for Ayurveda !.
9). Clinical trials in Ayurvedic Drugs /Reverse Pharmacology method: This is about why we shouldn’t be harping only on Clinical trials for Ayurveda
10). NIMHANS (National Institute of Mental Health and Neurosciences) Ayurvedic center:
11). Manipal University A multi-centric project supported by the AYUSH Foundation and DST, Govt. of India, this program deals with understanding the underlying scientific principles of Ayurveda, an Indian traditional medicine. Work carried out in our labs is focused on deciphering possible molecular (genetic and epigenetic), metabolic and biochemical clues to the various Prakriti classifications of Ayurveda, as well as its treatment modalities for quality ageing, improving mental abilities etc.
12). What Doctors Don't Get to Study in Medical School - by Dr. B. M. Hegde, This is not a textbook as the author says but, in my opinion, this is a "Holy Text" of medicine and is a must read for everyone who deals with sickness. Richard Smith, MD, FRCP Former Editor, British Medical Journal, London. Here, laid out clearly and concisely, are all the well-established potholes and pitfalls in current medical thinking and practice. It is a thought provoking challenge to modern medical practice and research. Dr Hegde confronts the issue, and proposes an alternative humanistic attitude to education and treatment. Drawing on a huge range of resources from Sanskrit texts, Green and European philosophers, ancient and modern healers, to the most up-to-date Western research and publications. He has written a book that is both scholarly yet easy to read, and which will appeal to everyone involved in medicine whether students, practitioners or patients
This book provides part of the important and formative reading a medical student must do outside the prescribed requirements for a degree, and is also equally valuable to qualified practitioners and medical professionals. Here, laid out clearly and concisely, are all the well-established potholes and pitfalls in current medical thinking and practice. It is a thought provoking challenge to modern medical practice and research and is intended to encourage us to consider the way medicine is taught. Modern medical practices are driven by science, technology and consumerism, with the cost of treatment weighted in favour of the doctor rather than to the benefit of the patient.
Ayurveda does work. I am a living example of its efficacy. I trust my experiences.
Most allopathic medicines have side effects. Why do you ask people to be cautious?
Krishna: Some Ayurvedic medicines work because of sheer chance. Who says Ayurvedic medicines don’t have side effects? My mother developed severe diabetes when she took Ayurvedic medicines for her knee problems and doctors told her to discontinue them immediately as they contain steroids and would enhance the diabetic conditions if you are genetically predisposed to the condition.
Atleast we know what the side effects are for allopathic medicines. So we can take remedial measures. We don’t know much about side effects of Ayurvedic medicines as most of them are not studied scientifically.
A study by Harvard researchers ( researchers-estimate-lives-lost-delay-arv-drug-use-hivaids-south-af... and https://www.ncbi.nlm.nih.gov/pubmed/19186354 )
estimates that the South African government would have prevented the premature deaths of 365,000 people earlier this decade if it had provided antiretroviral drugs to AIDS patients and widely administered drugs to help prevent pregnant women from infecting their babies.
The Harvard study concluded that the policies grew out of President Thabo Mbeki's denial of the well-established scientific consensus about the viral cause of AIDS and the essential role of antiretroviral drugs in treating it.
Similarly the growing “anti-vaxxer” movement is extremely harmful to innocent children who are falling pray to various diseases despite the availability of vaccines to prevent them.
You have your right to disagree with scientific consensus only up to a point. If your disagreement is causing harm to the society, that right should be taken away from you.
Q: Why do scientists like you also seem to have general knowledge in the humanities?
Krishna: I am interested in several things and want to learn about them as much as possible.
So I am an artist, a writer, a poet, a designer, a network creator, a social activist and deal with several things apart from science.
I use humanities to communicate science effectively.
Well scientists are human beings first and they would naturally be interested in human cultures they were born into. And everything associated with humanity interests them too. If they can use these things for the advancement of their subject as well as bringing together various subjects for mutual benefits that is the peak of human intelligence.
Q: Why does the public like to favour heroes instead of scientists?
Krishna: Film heroes are easy to understand than scientists for the general public.
Majority of the people don’t want to burden their brains with complex maths, statistics and scientific theories, when they can easily enjoy life by getting into a dream world, feel happy about heroics, super dialogues, songs and dances of a hero.
People cannot relate to science and scientists the way they can relate to films and heroes.
The media plays favourites too. It promotes movies more than science and film heroes more than scientists.
The enchanting charms of sublime science reveal only to those who have the courage to go deeply into it - Carl Friedrich Gauss
Unfortunately several people are missing the beauty and thrills of science by avoiding it and seeking the easy way out to go through life.
Q: Were you superstitious earlier? What was the most superstitious thing you ever believed?
Krishna: Oh, yes! When I was very young, I used to believe in lot of superstitions people around me followed - like wearing a particular lucky dress whenever I was about to do some important work.
All that has changed with my scientific training and critical thinking. All those beliefs got thorough analyses and thrown out of the window. No more superstitions for me now. In fact things I followed when I was young make me laugh now. How stupid I was then?!
Q: Scientists are the most intelligent people on our planet. They are capable of thinking clearly and taking good decisions. Yet, why do some people want to impose restrictions on their work in the name of ethics?
Krishna: Good question.
But scientists are human beings too. They can come under religious, political and emotional pressures. And there is no international body to keep an eye on their work. Public fear this aspect.
In such situations general public and the media have greater roles to play to guide politicians and religious leaders. But can a person outside the scientific arena understand fully the implications of a research work like a scientist does? NO!
For example consider the field of Synthetic Biology - you can use the knowledge to make both designer babies and cure diseases. While fear about the first one is making politicians, religious and some members of general public (like activists) to oppose it, scientists say it is necessary to conduct research that goes beyond a limit in the field to find answers to human suffering.
Who has the right to decide here? Obviously the people who fund such research i.e., those that are outside science - like politicians (Governments and business people that are influenced by religious leaders) can make a huge impact by cutting the money flow. Who suffers? The General public themselves.
You might fear about a bad outcome. But that shouldn't make you stop good progress. Partial Picture Paralysis of the people outside of scientific research is the reason for all this mess.
Like several scientists are accepting now, we need a revamp of these ethical guidelines and it must come from the scientific community itself.
Q: What is the importance of different types of science?
Krishna: Although there are different subjects in science, in today’s world, they are all being interlinked by scientists to creatively solve the problems humanity is facing.
So in basic science, we have several subjects that deal with basics of each subject. This is important in understanding the subject properly.
In applied sciences, the boundaries somewhat blur and creative-connecting of the knowledge acquired in various areas becomes vital.
Q: Do scientists and doctors view living beings merely as a complex system of chemicals and DNA and that is why they don't care much about ethics and suffering?
Q: What if ethics was removed from scientific research?
I believe there's a famous scientist who disregards ethics and views humans merely as a complex system of chemicals and DNA. I forgot his name, unfortunately.
What if scientists adapted this mindset. What would happen? How much more advanced would we be?
Krishna: Even if scientists and doctors view living beings merely as a complex system of chemicals and DNA like you suggested, they know how when some of these chemicals are brought together they form neural systems that cause pain and agony to that being. So most of them take ethics seriously.
Q: What is the role of belief in science? Do scientists believe in science?
Krishna: I trust in science and don’t blindly believe in it.
Belief is acceptance that something exists or is true, especially one without proof which is against scientific methodology but followed by people who pursue some religions.
My trust in science is based on my experiences. Science gave me several answers to my critical questions, helped me solve several problems. Religious belief failed to do what science did in my life. That is how trust in science has been built.
But still I will have to keep my skepticism alive about science because science itself demands it. It says always have an open mind about falsifiability
Q: Why does ISRO keep spending lots of money to explore other planets rather than spend it to solve problems like starvation and deadly diseases?
Krishna: Space research is important in solving some of the problems you mentioned. How? Read here:
Q: Why do you love science so much?
Krishna: Because of its universality (it has no boundaries, no partitions) , dealing with truth based on evidence, right reasoning and methodology, thrilling encounters in unknown lands and knowledge seeking and gaining capacity.
You don't find any other field that is based on so perfect characters! Science is unparalleled!
Q: Where does lead contamination come from?
Krishna: Potential sources of lead contamination include crumbling old paint, contaminated soil, tainted drinking water or other lead hazards.
Q: How do people of religion, politics etc. manipulate things to make people make bad decisions?
Krishna: A scientist told me an interesting story recently.
A student wanted to test how people's opinion can be manipulated.
In 1997, a 14-year-old boy did a science-fair project around this. He surveyed 50 random people, and asked if dihydrogen monoxide should be banned.
He told them that this chemical:
A resounding 47/50 people said that it should.
2 people were undecided, and 1 was a strong supporter of dihydrogen monoxide.
Guess what dihydrogen monoxide is also called?
H2O. Also known as…Water.
Obviously, water should be banned, according to 94% of the population, the student surveyed.
Why did they think so? Because the student tried to trick them into believing that water is harmful.
That is what happens if you are not aware of scientific facts. People can manipulate your mind in any way they want.
We, the science communicators, are fighting a tough battle to make general public realize this.
The problem of starvation is easy to solve: give people food.
The reason why that food doesn’t get to where it’s needed is well understood: It’s called politics. There is no need for scientific research. There is need for some basic humanity on behalf of those who, for whatever reason (but it’s usually related to power or wealth) stand in the way.
As to deadly diseases, one thing does not exclude the other. Science is not a zero sum game. In fact, science flourishes best when it is pursued on all fronts. Space research does not stand in the way of medical research, and sometimes, the two fields actually contribute to one another: space research benefits from better medical understanding when it comes to humans and weightlessness, whereas weightlessness studies can lead to better understanding of certain illnesses (e.g., changes in bone density).