Qs on science and my replies to them - Part 106

Opinions can have two faces - right and wrong, the right ones based on facts and data and the wrong ones based on emotions, beliefs and ideologies.

Both have no place in science!

But when the right opinions are formed based on evidence which is not anecdotal, and fact based consensus, science might accept them.

Q: What made life possible on Earth?

Krishna: 1. Goldilocks zone of Earth which has tolerable temperature for life.

2. Stabilization of wobble of Earth because of moon and the resultant seasons.

3. Water brought by asteroids and comets.

4. Oxygen production in the earlier times of Earth's history by tiny organisms known as cyanobacteria, or blue-green algae. These microbes conducted photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen.

5. Ozone layer that protect life  from Sun's harmful radiation.  Earth's magnetic field also protects us from solar radiation.

Extinction of dinosaurs made mammals -which include human beings - evolve robustly.

Q: Can human beings co-exist with dinosaurs if they are brought back to life?

Krishna: It is difficult for men to live with terrifying huge creatures. They try to kill them like we are killing lions, tigers, Cheetahs, wolves etc. now. But we can live with the smaller ones if they are tamable.

Q: Recently I read an article which told about scientists who are racist, misogynist and those who had several flaws as human beings. Should we overlook their negativity or forgive them because they are geniuses?

Krishna: Being a genius doesn't give you immunity from punishment. Everybody should be equal before law. Brilliance doesn't buy you a free pass for bad behaviour.

You should separate their academic life from their personal ones. While you appreciate their grey matter, you should also condemn their bad behaviour. You need not put up with anybody's bad behaviour just because they are geniuses. 

Q: I am 70. I feel very tired and cannot do much work like I used to do when I was young. Why is this so? 

Q: Why do old people get tired easily?

Krishna: As you age your energy levels won't be the same as when you 're young. This is because

1. Medical issues like restricted blood flow - as the body ages, fatty deposits build up along the inside of blood vessel walls, which causes them to lose their elasticity and become thicker and stiffer. These changes mean that the blood vessels take longer to relax, which increases pressure and results in common problems such as angina, atherosclerosis, and high blood pressure. The heart has less capacity for physical exertion when we age and may feel fatigued more easily. As a result, we feel a gradual decline in our energy and endurance levels. 

Old age illnesses can cause fatigue, ranging from the flu to rheumatoid arthritis and infections to cancer. If you have anemia, you will likely notice a drop in energy when your blood has too few red blood cells or those cells have too little hemoglobin. Heart disease is another cause of fatigue because, as blood is pumped less efficiently, fluid accumulates in the lungs, which can lead to shortness of breath. This, in turn, lowers the oxygen levels going to your heart and lungs, potentially causing fatigue. Yet another medical cause is hypothyroidism.

Medications (antidepressants, antihistamines, blood pressure medications and more) can be a source of fatigue too. Chemotherapy and radiation therapy too can cause fatigue.

2. Less sleep. As you age, you sleep less because of your altered biochemical changes in your brain. If you aren’t getting enough sleep, it’s natural to feel tired. Causes of sleep problems include apnea, in which the affected person has paused or shallow breathing while sleeping; this isn’t unusual with older adults. People with overactive bladders and enlarged prostates can wake multiple times a night to use the bathroom, which also disturbs sleep.

3.  Emotional Issues. Spending a significant amount of time worrying can contribute to fatigue. So can anxiety or depression because of old age , and grief . 

4. Mitochondria. The body produces energy in the mitochondria, where it combines food and oxygen to generate the energy molecule adenosine triphosphate (ATP). To a certain extent, mtDNA copy number, mitochondrial content and mitochondrial function are correlated. In aging, skeletal muscle mass decreases from mid-life onwards. The annual rate of loss is said to be almost 1%, although the trajectory probably gradually increases with advancing age. Along with this loss of mass, is a reduction in mitochondrial functional capacity, but the decrease in mitochondrial capacity is out of proportion, such that the mitochondrial density also decreases . In a similar way muscle strength per given muscle mass is also seen to fall with age. However, it is unclear to what extent such changes are due to aging per se, as opposed to inactivity. It is now accepted that many studies showing apparent deterioration in mitochondrial function or content with age may be heavily confounded by decline in activity with age. In studies where subjects have been stratified by activity levels it is interesting to note that the age-related declines are seen in the sedentary group. The active group shows a very mild decline only.

5. Muscle mass decline. Muscle mass declines steadily with age and may be replaced with fatty tissue - muscle tone declines by around 22% by the age of 70. As muscles shrink, they lose strength and flexibility and become fatigued more easily, and you may find you are less coordinated or have trouble balancing. The more sedentary you are, the quicker these changes take place so it’s important to keep active as you age. Focus on strength training exercises that can help to reduce the rate of muscle loss and improve endurance. Exercising in the morning will also help to keep energy levels higher throughout the rest of the day. Energy drainers can include what you eat (with fried foods and sweets being common culprits) and what you drink (caffeine found in coffee, tea and some sodas) and alcohol.

6. Irregular digestion and decreased absorption of nutrition . As you age your digestion slows down because the speed of contractions moving food through the digestive system slows. Production of gastric juices and enzymes too gets reduced.  Artery blockages in older people are also very common. Blockages in arteries can affect blood flow to the bowels, a condition called intestinal ischemia, during which blood flow to the intestines decreases and this in turn leads to less sucking up of nutrients.

7. The metabolic rate drop- Hormonal changes cause your metabolic rate to drop, which results in more body fat and less muscle mass. Fat also tends to move deeper inside the body as we age, which increases the risk of heart disease and diabetes. To combat a slow metabolism, it is important to stay active using a variety of different activities that include cardio and strength training.

Updates:

Why energy fades with age: Missing membrane lipid may destabilize mitochondria

Why do cells age—and why do we lose our energy and vitality as we get older? This question is one of the central challenges of modern biomedicine. The focus is particularly on mitochondria—tiny cellular organelles long known as the cell's powerhouses but now understood as dynamic control centers that not only produce energy, but also coordinate cellular communication, adaptation, and many of the processes essential for life.
They supply us with the energy that our body needs for movement, growth, and repair processes. But as we age, these powerhouses begin to slow down. It has long been known that their function declines with age.
Age-related decline in cellular energy is linked to reduced phosphatidylcholine synthesis, leading to destabilized mitochondrial membranes and impaired mitochondrial network function. Supplementation with phosphatidylcholine or its precursor choline restores mitochondrial structure and energy production in aged cells, indicating that aspects of mitochondrial and systemic aging are modifiable through targeted metabolic interventions.
For a long time, it was assumed that genetic damage within the mitochondria themselves was primarily responsible. A study now published in Nature Communications by an international research team.
provides a surprising answer to this question: A key factor appears to be the imbalance in the structure of the mitochondrial network, which is caused by the absence of a major lipid in the membrane composition.

The focus is on phosphatidylcholine—a fundamental lipid that is a major component of biological membranes. It ensures that membranes remain flexible and can dynamically reorganize themselves. Precisely this property is crucial for so-called "mitochondrial fusion"—a process in which individual mitochondria merge into networks. These networks are necessary for cells to distribute key molecules—such as cellular energy equivalents, metabolic products, DNA, and signaling molecules—and facilitate their exchange, thereby preventing imbalances and replacing damaged components.

The study shows that the body's production of phosphatidylcholine declines with age, leading to increased fragmentation and dysfunction of mitochondrial membranes. When genes involved in phosphatidylcholine synthesis were deactivated in young worms, their mitochondria in the cells quickly began to look "aged."

The researchers were particularly fascinated by how closely these changes resembled the mitochondria typically observed in chronologically old organisms. Even more striking was the observation that the mitochondria regained a more youthful structure within just two days when the worms were fed phosphatidylcholine or its precursor, choline.

The most important finding of the study, however, lies in the reversibility of aging-associated failures: through a targeted increase in phosphatidylcholine levels—for example, via diet.

Tetiana Poliezhaieva et al, Aging-associated decline of phosphatidylcholine synthesis is a malleable trigger of natural mitochondrial aging, Nature Communications (2026). DOI: 10.1038/s41467-026-71508-7

Q: Heavy metals are present in both non-vegetarian as well as vegetarian foods. So we get toxic substances from both. What can we do then? 

Krishna: Yes, it is true we have toxic heavy metals like lead,mercury and cadmium  in both vegetarian and non-vegetarian foods. However, absorption of these heavy metals by a human body will be low with vegetarian diets. Therefore, vegetarian diets are less risky in this regard.

Q: Can people like Ravana with ten heads really exist?

Krishna: Ravana with 10 heads is just a figment of imagination as it is not possible for living beings to have so many heads.

Two-headed animals (called bicephalic or dicephalic) and three-headed (tricephalic) animals are the only type of multi-headed creatures seen in the real world, and form by the same process as conjoined twins from monozygotic twin embryos.

Q: Is the recent discovery of methane on Mars being oversold to the public as a discovery of life to encourage more funding for future projects? If so, how do scientists feel about this? 

The hunt for life on Mars—new findings on rock 'chimneys' could hol...

Krishna: Journalists always try to find a way to keep science ‘interesting’ to the general public. They attempt to make even small findings sensational by using ‘eye-ball-catching’ language. But we know most of the time, it means nothing for people in the labs.

Ground based calculations have found methane in Martian atmosphere long back, but none have been able to conclude if they definitely indicated any life. This is because methane could be of geological as well as biological origin. Methane is interesting because most of it in our atmosphere is produced by methanogenic Archaea (or microbes); in other words, it is a signal of life. So if we find out the source, we might have detected life on Mars if it is biological in origin.

Until the source is found … we just read, smile and go back to our all important work. We have better things to do than fall prey to journalistic gimmicks.

We love lab science, not journalistic science. 

Q: How can you justify the statement, "laughter increases life span"? Will laughter really increase life span?