Why should we sit far from the TV?

Why should we sit far from the TV?

Televisions really do give off radiation. But having said that, it’s only a little bit of radiation and it’s not that dangerous. What happens is that anything with a cathode ray tube, a tube where you shoot high-energy electrons at some sort of screen, when those electrons hit the screen, they give off very low energy x-ray radiation. This is the same way that x-rays are produced in regular x-ray tubes. So, if you're sitting close to a cathode ray tube, whether a computer monitor, a television screen, a radar set or anything else with that type of technology, you're going to be getting low doses of x-ray radiation.

1950's televisionNow having said that, I’ve got to emphasize, they're low doses of radiation. It’s not enough to be dangerous and in fact, if you watch your television for several hours a day all year, you're getting less radiation than you would from a single medical x-ray and less radiation than you get from the radioactivity that’s just naturally within your body. So, it’s something that we can measure, but it’s not something that’s harmful.

LCD and plasma screens don't give off any radiation at all. They don't use high-energy electrons. It’s a different type of technology. I could not say that they're safer because I don't consider the radiation from cathode ray tubes to be a risk, but I can say that they give off less radiation. As far as sitting too close to the television goes, the further back you are, the lower the radiation dose will be. But having said that, I don't consider the radiation dose even at a distance of just one metre to be dangerous.

Would a helium balloon float on the moon?

Would a helium balloon float on the moon?

As far as the balloon’s concerned you need two things to make a balloon float. First you need an atmosphere for it to float in. The second thing you need is gravity. That’s because the reason why a balloon floats is that the balloon itself is less dense than the air around it so gravity pulls on the air around it more than the balloon. The air around it actually tries to push underneath the balloon. That forces the balloon up and makes it float. Unfortunately the moon hasn’t got an atmosphere at all. Therefore you’re missing one of the two things that you need to make a balloon float. In that case a balloon on the moon wouldn’t float at all. It would just land on the floor. However, that doesn’t mean you can’t have balloons or other bodies in space at all. Actually the Russians launched a space mission in the 80s called Vega. That involves putting a balloon in the atmosphere of Venus which is the second-closest planet to the sun. Balloons in space are possible and have been done in the past. Looking to the future there’s a possibility we might be looking at putting balloons on titan which is one of Saturn’s moons. Titan has got an atmosphere and it’s really cold there. There’s obviously gravity there. Therefore you’ve got all the things you might need to have a balloon on Titan. The reason to do that would be to have atmospheric instruments that you would hang from the bottom of the balloon and they would measure Titan’s atmosphere. That’s exactly what we’ve done on Venus with the Vega mission. So unfortunately no balloons on the moon but they do have uses elsewhere in the solar system. Not just on the Earth.

Would a compass work on Mars?

Would a compass work on Mars?

No, it would not. Unfortunately Mars does not have a magnetic field anymore. The magnetic field on Earth is generated by the core rotating inside the Earth and Mars has just cooled down too much and that whole process has just been frozen. So it has lost its magnetic field. Some rocks are still magnetised but the planet itself has no overall field.

Why do we laugh when we find something funny?

Why do we laugh when we find something funny?

Why do we laugh at something that’s funny? Something that’s funny is by definition something that makes us laugh. I’ll talk about why we laugh. Laughter is really a social phenomenon. If we look back to its origins, laughter, the ‘ha ha’ originated in the ‘pant pant’ of rough and tumble play such as you would find in tickle or the rough and tumble play of children. ‘Pant pant’ became the human ‘ha ha.’ With adults, however the arena of laughter has shifted from tickle and rough and tumble to a more linguistic and cognitive arena whereby, for example, the play of adults has to do with wordplay during conversations. You don’t have to tickle one of your colleagues to get them to laugh. You can tell them the joke. Even within conversation the key to laughter is the presence of another person. Laughter almost totally disappears when we’re alone. The key element for producing laughter is another person and not a joke. In fact we have followed people around and recorded what was said before people laugh. In only 10 or 15% is it anything remotely joke-like. Most laughter follows comments like ‘hey, where have you been? Ha ha!’ or ‘I’ve gotta go now, haha!’ These aren’t jokes so it basically is about developing bonds and relationships with other people.

What is the smell of old books?

What is the smell of old books?

A smell or odour is caused by volatile compounds which we perceive by the sense of olfaction. An odour of a book is a complex mixture of odorous volatiles, emitted from different materials from which books are made. Due to the different materials used to make books throughout history, there is no one characteristic odour of old books. A professional perfumer has evaluated seventy odorous volatiles emitted from books and described their smells as dusty, musty, mouldy, paper-like or dry.

The pleasant aromatic smell is due to aromatic compounds emitted mainly from papers made from ground wood which are characterised by their yellowish-brown colour. They emit vanilla-like, sweetly fragrant vanillin, aromatic anisol and benzaldehyde, with fruity almond-like odor. On the other hand, terpene compounds, deriving from rosin, which is used to make paper more impermeable to inks, contribute to the camphorous, oily and woody smell of books. A mushroom odour is caused by some other, intensely fragrant aliphatic alcohols.

A typical odour of ‘old book’ is thus determined mixture of fragrant volatiles and is not dominated by any single compound. Not all books smell the same.

What makes planes leave vapour trails?

What makes planes leave vapour trails?

The reason planes leave vapour trails is because they’re burning hydrocarbons, chains of carbon atoms linked together with hydrogen round it. When this mixes with oxygen you make water and some carbon dioxide. The vapour trail is the water and because the plane’s very high up in the air actually what you’re getting is ice. Vapour trails are water vapour that often form ice crystals. They leave those nice miniature clouds behind in the wake of the plane.

It is also possible to make much weaker vapour trails form without the plane's engines running. As the plane flies, the wings create a vortex of lower air pressure. This low pressure can lead to lower temperatures, where water vapour condenses forming vapour trails starting at the tips of the wings.

How will faster computer processors be made in the future?

How will faster computer processors be made in the future?

Computer processors have been doubling in speed every two years for the last fifty years or so and it’s been driven by something called Moore’s Law which says the number of transistors on a processor keeps doubling every two years. As the transistors have got smaller and smaller we’ve fitted more on the chip. We’ve started to run into some problems. One of the problems we’re hitting already is to do with the heat density that’s produced by all these transistors in a tiny space switching on and off. Right now the heat density on a chip is equal to that on a hotplate on a cooker. If we carry on the way we’ve been going then in ten years’ time that heat density will A computerequal that of the surface of the sun. We have to find a new way forward. The main approach that we’re adopting is to do what we call parallel computing. Instead of trying to make each individual processor run faster we have several processor s side-by-side, all working on the problem together. Using that technique of parallel processing we should be able to continue to get processors collectively to run faster and faster and to continue this doubling every two years for a good many years if not decades to come.

Why is it that food that was once red or green or yellow, et cetera, comes out one color when it comes out of the human body?

Why is it that food that was once red or green or yellow, et cetera, comes out one color when it comes out of the human body?

And we know what color she is referring to and the answer actually is that the food itself doesn’t necessarily contribute very much to the color of what comes out the back end. The reason being that the dominant determinant of the color of what comes out the back end is bile and bile salts, what your liver squirts into your small intestine to help you to absorb fat. And the reason for that is that there is a chemical which is called bilirubin which is a breakdown product of hemoglobin, the stuff that makes your red blood cells red, that goes into your intestines and it gets modified by a bacteria in the small bowel and as a result of that modification, it gets oxidized into a chemical first called urobilinogen which is what gets reabsorbed into your blood stream and makes your wee go yellow but then it also ends up back in your gut and gets turned into an even browner chemical called stercobilin and stercobilin is the brown stuff that it makes pooh a brown color. And if you have a blockage in the supply of bile into your intestines from the liver, what that does is actually prevent you from getting any of this stercobilin being made and you actually do very pale colored poohs and so, you can use that as a way to diagnose people who have gall stones or liver problems.

Why is the demand for meat going to increase in the future?

Why is the demand for meat going to increase in the future?

Well, many would say, quite reasonably, that we shouldn’t increase the meat demand, but the fact is that we will. It’s clear that China’s appetite for meat in their diet in particular is going up and up. These are people who, from having rice seven days a week, now want have rice plus meat in one day out of seven and maybe even two days out of seven. And so, as affluence goes up, demand for meat will go up, and I think it’s unfortunate because we could reduce our impact on the environment if we ate less meat, especially in the West. But anyway, I think that’s what’s going to happen and a major trade pipeline is soy beans from Brazil to China to grow pigs.

Can copper bracelets relieve the pain of arthritis, and do magnets have healing properties?

Can copper bracelets relieve the pain of arthritis, and do magnets have healing properties?

The answer to the magnet question is, no. There’s absolutely no evidence that magnets have healing properties. It’s all a scam. In terms of copper bracelets, there’s a lot of old wives’ tales about copper bracelets and when they’ve been investigated for arthritis, again, the scientific studies don’t actually show any significant benefit. There may be psychological benefit. The placebo effect as we know is extremely powerful, but no. There’s no real scientific evidence.

Are female humans are the only mammals that suffer from post-natal depression?

Are female humans are the only mammals that suffer from post-natal depression?

there is some evidence that some animals can have post-natal depression. The main animals that have been looked at are rats and mice because they've mainly been used as laboratory models for humans and they do find that rats can show depressive symptoms, things like poor nursing, signs of stress and anxiety after birth and they were also quite useful, you can manipulate the hormone levels in rats to bring on post-natal depression type symptoms and there’s some labs that are doing this and are trying to test interventions and ways to help reduce this because it’s definitely thought that changing hormone levels, increases in cortisol, drops in females sex hormones help to bring on this kind of problem. There are some interesting mice models as well; particularly mice who have faults in their GABA receptors in their brain on their brain cells and the nerve cells are much more likely to show these kind of depressive symptoms after birth and a terrible experiment has been in done rats they find that if they take their puppies away for short lengths of time, well not like you know days, if they take their pups away it does induce depression like symptoms. I can’t find any evidence about larger animals but there are certainly some anecdotes out there about dogs and cats. Some of them showing post-natal depression types symptoms like not nursing properly and not really being themselves.

Why does the body needs salt and what happens if you have low salt levels?

Why does the body needs salt and what happens if you have low salt levels?

The reason the body needs salt is because every single one of our cells contains large amounts of salt and, salt is the generic term for ions, charged particles, and most of the cells in our body in fact, all of the cells in our body are electrical. In other words they pump these ions from one side of their cell membrane which is a lipid or oily substance and therefore an insulator so they pump ions from one side of that membrane to the other and this means there is an electrical potential difference across the membrane of a cell and this means that this gradient this electrical difference can be used by the cell to do other sorts of work. So cells for instance do have channels that sodium can flow in to the cell and it comes down its potential difference in concentration gradient and the result is that it can be used to pull in glucose at the same time. So sugars can get into cells.

So we need salts in our cells - that’s how they regulate their size by bringing water in by osmosis. That’s how they regulate electrical activity. Nerve cells for instance couldn’t carry information without actually having this electrical gradient across the membrane because all that’s happening when a nerve cells fires off an impulse is that you get a sudden flood of sodium in to one patch of a nerve cell. This brings in lots of plus in to that part of the cell and therefore an electrical signal goes whizzing goes down the nerve and gets built up and regenerated as it goes down the nerve and it travels at about 50 to a 100 meters a second so very rapid transmission of information.

So we need salts in our body, we take in salt in our diet, we absorb salts and those salts are also include important things like calcium to make your bone strong but you’re also losing salts all the time when you go to the toilet for example you lose calcium, you lose phosphates. This is both in urine and faeces so you have to continuously top up the number of salts that you have in your body because you have obligate or insensible losses.
The body is very good at scavenging salt from what you eat and what you drink so it’s very rare for people to get too lower levels of salt in the body based on diet alone. Usually there’s something pathological going on. Sometimes what happens is that people have a problem called syndrome of inappropriate ADH. This is anti-diuretic hormone and the body saves too much water so it scavenges back water and as a result your blood can become too dilute and you have very low sodium levels and this can cause problems with your brain swelling. It can also cause the accumulation of water elsewhere around the body and it can cause heart failure so a bad thing to have. But that can cause low salt levels that can make people feel dizzy.

What are benefits of life-long mates if you're a bird?

What are benefits of life-long mates if you're a bird?

I don’t think there’s a consensus in the scientific literature on this, but there are a couple of good ideas and the general theme is that if it takes two to rear babies effectively then you stick together with the one that you already know. So, that might be the case for example if nest sites are in short supply and it takes two of you to defend the site, then it’s better to stick with the team-mate that you’ve got than to change for the next season. Similarly, if you’re feeding your chicks on complex food that’s hard to forage for, it’s better to stick with an experienced bird than to try your luck with a potentially naive individual.

How does an artificial pacemaker know how fast the heart should beat?

How does an artificial pacemaker know how fast the heart should beat?

The role of an artificial pacemaker is to monitor and control the heart’s natural rhythm. They’re implanted for many reasons and the way they work will vary according to the reasons for which they’re implanted. In the case of the slow heart rate, for example, a certain number of beats per minute will be programmed into the pacemaker according to the needs of the patient. The pacemaker would then sense through a number of wires the number of beats being delivered naturally by the heart’s own pacemaker, which is called the sino-atrial node.

And it will only interject to deliver another beat if there is a shortfall. So the pacemaker is there only for the reason for which it has been implanted. So if it’s a slow heart rate and you go running for a bus then the pacemaker will only interject if your heart rate falls below the required minimum level. Sometimes, doctors will put a maximum level on a pacemaker. So for some abnormal heart rhythms (if the heart rate went too fast) it could cause fainting or black-outs or possibly even a life-threatening rhythm and then maybe in an overriding upper level that the pacemaker will be set at but that’s quite complex.

They tend to be implanted with internal defibrillators so they will be the ones that are sensing for life-threatening rhythms so that the person can receive a shock if they require it.

How does an artificial pacemaker know how fast the heart should beat?

How does an artificial pacemaker know how fast the heart should beat?

The role of an artificial pacemaker is to monitor and control the heart’s natural rhythm. They’re implanted for many reasons and the way they work will vary according to the reasons for which they’re implanted. In the case of the slow heart rate, for example, a certain number of beats per minute will be programmed into the pacemaker according to the needs of the patient. The pacemaker would then sense through a number of wires the number of beats being delivered naturally by the heart’s own pacemaker, which is called the sino-atrial node.

And it will only interject to deliver another beat if there is a shortfall. So the pacemaker is there only for the reason for which it has been implanted. So if it’s a slow heart rate and you go running for a bus then the pacemaker will only interject if your heart rate falls below the required minimum level. Sometimes, doctors will put a maximum level on a pacemaker. So for some abnormal heart rhythms (if the heart rate went too fast) it could cause fainting or black-outs or possibly even a life-threatening rhythm and then maybe in an overriding upper level that the pacemaker will be set at but that’s quite complex.

They tend to be implanted with internal defibrillators so they will be the ones that are sensing for life-threatening rhythms so that the person can receive a shock if they require it.

Is this earth getting heavier due to plant growth on it with photosynthesis converting energy into mass.

Is this earth getting heavier due to plant growth on it with photosynthesis converting energy into mass. And if so, does this affect the earth’s spin?

We have actually looked at this in the past and the answer is actually, yes. Because E=mc2 Einstein’s famous equation, (E) energy equals (m) mass times (c) the speed of light squared. So, if you increase the energy in the system then the mass must also increase. The sun is adding energy to the earth’s system in the form of chemical, -comes in this light and is converted into chemical energy by photosynthesis. Therefore, the earth is gaining a little bit of weight in the form of the entrapment of that energy as plant chemistry. But, compared with the 40,000 tons of dust and stuff that rains in on earth from space every year, it’s probably quite literally a drop in the ocean. It’s all a balance because the earth’s temperature isn’t going up or down dramatically, a little bit. But I think on the whole, the earth is gaining a bit of weight in plants in the biosphere because of the energy coming from the sun, I would say.

Why does television signal improve when you hold the aerial?

Why does television signal improve when you hold the aerial?

Essentially when you grab the aerial, you’re typically increasing the size of the aerial and then to take your body sort of conducting electrolytes. And a good example of this would be in a laboratory if you have an oscilloscope and you look at the pick up from the main frequency, you can see a 50-Hertz signal which is to pick up from the resonance (circus) in the room. And if you hold the probe in your hand, the amplitude of the pickup increases dramatically and the same thing happens when you grab the TV aerial, you’re improving the pickup and it’s then using you to resonate within the circuit to produce the signal within the televisions. And the TV has to tune quite closely to the right frequency but when you touch the aerial it will improve the signal dramatically. The other thing is when you grab on to the aerial the connectivity between your fingers and aerial and tightly squeeze on the aerial or if your fingers are wet and the conductivity between you and the aerial will be improved. So it often depends on how hard you squeeze the aerial.

Why does it smell so nice after it rains?

Why does it smell so nice after it rains?

The answer to this was quite slow coming and no one really knew for sure, perhaps we still don’t know for certain, but there was certainly some work done on this in the 1960s and the paper got published in 1966 where scientists actually, they think got the answer.

The theories where that this could either be something coming out of the soil, something reacting with water in the soil to produce the smell, or perhaps something organic, something living and it turns out, it’s probably the latter. A group of scientists analyzed the air and they found that when you took soil, you find a very common soil bacterium called actinomycetes. This is a filamentous bacteria and it grows lots of little filaments that ramify through the soil, picking up nutrients. But it also has another form which it uses to protect itself when the soil is very, very dry. So, when there’s severe arid, dry conditions, it recedes into a spore and this is a dormant form of the bacterium from which it can reactivate when water comes back and the soil is fresh and there’s lots of good environment for it to exploit again.

So what scientists think happens when you get a rain shower and it produces that beautiful earthly smell in the air, is that the rain comes down, it hits dry soil where all these bacteria have formed this little spores, the spores then get ejected up into the air, and they drift around in a cloud. Because they’re so tiny, they stay drifting around in the cloud for quite sometime. You then breathe them in and they smell the way they smell. That’s their smell. But it’s also a form of, sort of, dispersal for the bacterium because it then descends on another patch of ground, out of the air and can germinate and grow. So, I suppose that’s one point. Another thing to bare in mind is of course, there’s the other possibility that was also raised by scientists historically and that is that there are various chemical reactions that can occur when water hits soil or dry soil or a rock. And so, it might be that some of these smells, because of particular rocks getting wetted, then chemical reactions are being elaborated and then they produce various chemicals that go up in to the air. But we think it’s mainly the actinomycetes, that’s the main cause.

sharks are cartilaginous fish, how do they make blood?

sharks are cartilaginous fish, how do they make blood?

In vertebrates, a major component of the blood is the red blood cell or erythrocytes and this can make up the half volume of the blood and it’s these cells that contain haemoglobin and do the job of transporting oxygen around the circulatory system. Oceanic Whitetip SharkNow in adult humans, and other mammals these red blood cells are made in the red bone marrow and this is the soft tissue found inside the hollow bones of tetrapods or four-limbed vertebrates which as well as the mammals include amphibians, reptiles and birds. But red bone marrow isn’t the only site where red blood cells are produced and in bony fish and cartilaginous fish that don’t have bones like sharks and rays, the main places where red blood cells are made are in the spleen and in the front section of the kidneys. And some sharks also have the unique organ called Leydig's organ which is actually absent in the other vertebrates, and this is a large organ that’s wrapped around the oesophagus. And although it was discovered way back in 1857, very little is known about exactly what it does, but it’s thought that it might play some additional role in producing red blood cells and also in the immune system. So, although bone marrow is important for making red blood cells in humans; in fish, the most important site seems to be the spleen.

Can the heart develop cancer?

Can the heart develop cancer?

It’s very rare to get cancer of the heart. And if you do get it, it’s usually cancer of the blood vessels in the heart angiosarcoma rather than the muscle cells of the heart itself. And in a sense, cancer and heart disease are two ends of the spectrum with cancer being very fast-growing cells whereas; heart disease is because the heart can’t regenerate itself very much. And one of the things that we have to be really careful about in stem cell research for heart disease is not doing things to trigger cancers. If there were things that we might want to do for the heart like growing more blood vessels or stimulating stem cells, or reducing the amount of natural cell death are all the opposite things to what the cancer people want to do to kill off the cancers. So we have to be really careful in treading that line.
There’s a bit of a myth that the heart is something that doesn’t get cancer but it can happen, and as Sian says incredibly rare and it is because the heart doesn’t regenerate. It doesn’t turnover its cells whereas tissues like breast, bowel, skin, they tend to make new cells a lot so you just increase your chances of getting cancer in those tissues. But it can happen though it is phenomenally rare.

Why is urine yellow? Is it usually yellow in most species, just mammals? It’s mostly water so why is it yellow?

Why is urine yellow? Is it usually yellow in most species, just mammals? It’s mostly water so why is it yellow?

The yellow colour is because of the stuff that makes your blood red. When we break down red blood cells which last about 120 days the haemoglobin makes a protein which has a iron atom at the centre. That protein gets broken down into something called bilirubin. Bilirubin is dumped out of the body by the liver. The liver metabolises the bilirubin bit by adding sugar to make it dissolve in water, puts in bile and your bile then gets squirted into your small intestine to help it reabsorbs fats. The bilirubin, because it has sugars stuck on it becomes broken down by bacteria. The bacteria metabolise the molecule and they turn it into something which is called urobilinogen. Urobilinogen gets reabsorbed further down the small intestine. Unlike bilirubin, which is not very soluble in water urobilinogen is very soluble but it’s a brown colour. The urobilinogen goes round the blood stream again but when it goes round in your blood stream again but when it goes through you kidney, because it’s soluble in water, it moves out through the kidney in the same way as the other things that go into urine do and it goes into your urine. Because your urine is a concentrate of plasma you take water back but leave the products that have got filtered behind and it builds up in the urine and adds this brown colour. So urine goes darker and darker. The more dehydrated you are the darker it is because the concentration is higher.
It may be a bit of it’s riboflavin as well because if you take a lot of B vitamins you just wee them out. I think, riboflavin, when it’s dissolved in water is very yellow as well

Why does lemon make green tea go clear?

Why does lemon make green tea go clear?

There’s probably two reasons for this. The first one is that the lemon is acidic and so it’s affecting the pH of your tea and it may be that it’s causing changes in the chemicals that are in your tea and making them change to a different colour. So, like you can make indicator paper and change colour with different acids or bases and I think also, certainly down the south, we have a lot of limescale which is calcium carbonate in our water and it can make your tea cloudy. So, if you put in an acid, it will help to dissolve the calcium carbonate in it so it makes it go clearer.

Why does water expand when it freezes?

Why does water expand when it freezes?

Basically, the default thing for things to do is to shrink because normally, if you make something hotter, it’s vibrating more. It vibrates. It tends to take up more space. It tends to expand. Ice is very unusual that as it gets colder, it’s essentially vibrating less, it does expand. And the reason for that is due to the strange shape of water. If you’ve ever seen the picture of a water molecule, it looks like a Mickey Mouse head with a sort of oxygen molecule where Mickey Mouse’s face is and then two hydrogen atoms where his ears are and it’s bent basically. The oxygen atom is slightly negative and the hydrogens are slightly positive. And because of that bend, the way they tend to link together is actually a very open structure with big holes in it and that means, there’s quite a lot of extra, sort of basically vacuumspace in that structure. So when it freezes it, it releases a load of energy because it means lots of more extra strong bonds can be made. But it does take up more space. And so, ice expands when it freezes.

Jelly fish swim in groups. How do they communicate to stay together or do they communicate?

Jelly fish swim in groups. How do they communicate to stay together or do they communicate?

Jellyfish are in some ways extremely simple creatures. They don’t have a brain, so they don’t really have the ability to process inputs and sensory inputs like that. So, I think usually when you see large numbers of jellyfish together, it’s probably more likely to be, the fact that the currents and the ocean currents are actually moving them together and keeping them in similar places. Or also, they can respond to things like the availability of food in the water and chemicals and things like that. So possibly, they're all following food sources, and that’s why they're all ending up together. But I don’t think we yet have an idea that jellyfish can actually communicate to each other. Although some of them do have quite complex eyes, which is quite exciting and box jellyfish have eyes. They're actually quite...
They have eyes quite a lot like humans and in fact, some of the genes they have are very similar to human genes for creating parts of the eye, but we think that happens in parallel and wasn’t from a common ancestor, but we arrived at the same solution to having eyes and what do they see? We know they certainly respond to daylight, light and dark. They need to know basically, what time of day it is because they tend to come up the water column at nighttime when they're less easily seen by predators and when it’s light, they actually go further down the water column. So, they respond to light and dark. And even though they have quite complex eyes, it’s actually a very good eye at detecting things like diffuse light to figure out

How are gases separated for bottling?

How are gases separated for bottling?

So this is how you separate oxygen from nitrogen in the air or helium. The way that it’s done commercially is by cooling air down and all the different gases in air have different points at which they condense so carbon dioxide will come out first, then oxygen, nitrogen and argon. If you slowly cool it down at different temperatures you take out different gases, different liquid gases. Helium isn’t found in the atmosphere. You can only find it in the top of oil wells. It’s caused by radioactive decay.

Do rockets punch holes in the ozone layer?

Do rockets punch holes in the ozone layer?

we know that the major culprit for making holes in the ozone layer are chemicals called CFCs — chloro-fluoro carbons. These are things that were used in aerosols, even in aspirin inhalers, but also in fridges as refrigerants, and they were used in huge amounts until the Montreal Treaty came in, in the late 80s to try and ban them. What provoked that was that a group of scientists including Brian Gardner (who appeared here on The Naked Scientists a few years back) had actually noticed this massive hole opening up over Antarctica in the mid-to-late 80s and this hole actually grew to be the size of Australia at its peak. It stopped growing; it’s actually beginning to shrink a little bit now and that’s because we have stopped using these chemicals. The reason that they concentrate down in the Antarctic is because the Antarctic is an isolated continent. It’s completely surrounded by ocean and this creates something called a circumpolar current, and this has a sort of whirlpool-like effect in terms of air; and it draws in and concentrates these molecules over the Antarctic over winter when it’s very dark. They then accumulate in high clouds over the Antarctic and when the sun comes out the following spring the sun breaks down the CFCs and they get turned into reactive chemicals that would then react with the ozone and deplete it. They are, by far, in a way the worst culprit. We don’t send enough rockets and spaceships up into space to make a huge difference, I wouldn’t have thought, in grand scheme of things. So I think although we have to be environmentally conscious, I think the benefit of sending rockets into space in terms of what they can do for satellites and furthering research is far greater than the small bit of damage they might make to the ozone layer. So I think on the whole, probably not, it’s probably more a manmade, anthropogenic problem. But great question, thank you for that.

Can Plants get Cancer?

Can Plants get Cancer?

Cancer in the context of a human has got a specialist disorder. What we mean by cancer, our cells that have lost the ability to obey the normal signals that control and dictate how things grow and move and obey signals that tell them not to go to other places in the body and not to grow through boundaries of tissues and not to disobey ‘kill yourself’ signals. Because every cell in the body is programmed to die unless it’s told otherwise.

Cancer cells ignore that signal and so, they are immortal as Richard Van Noorden was saying, and they also disobey all those normal regulatory signals that can spread to other bits of the body and cause secondary tumours. And it’s usually those secondary tumours that cause problems. Now, plants don’t have a disease like that. They don’t get secondary spread through their system of disease which starts in one part of the plant and goes elsewhere, at least in the form of the cells from the plant itself. But they can get localized growths, a cancer-like phenomenon and just like some human cancers which can be triggered by microorganisms, cervical cancer for example is caused by infection with a virus, human papilloma virus. Also, gastric cancer in the stomach is caused by bacterial infection, Helicobacter pylori, is strongly associated with gastric cancers.

In plants, there is an environmental organism, it’s called Agrobacterium tumefaciens, this is a soil dwelling bacterium and it has something called a transposon. This is a piece of genetic material which the bacterium injects into the plant’s own genetic material and that transposon carries genes which code for growth factors. And it causes the plant cells to begin to grow out of control. And the idea is to produce a big growth locally on the plant that then gives a home and provides protection to bacteria and that’s a Gall. And it’s very, very common, it’s called Crown Gall disease when the plants actually have it, but it doesn’t spread predictly to other bits of the plant. So there are some similarities between human cancers and animal cancers and plant tumours like Crown Gall disease, but it’s not the same disease. There’s nothing systemic as far as I know that does the same thing but it’s a very good question.

How far would electricity carry in the sea?

How far would electricity carry in the sea? If a toaster, connected to the mains at 240 volts was accidentally dropped into the ocean, let’s say the North Atlantic, would the sea life be electrocuted? And if so, how far and how deep from the toaster would these electrical shockwaves travel?

Seawater conducts electricity reasonably well, but not very well. It’s about a 10 millionth as good as copper. So, you will get electricity flowing through it, but it will also depend on where the other cable is because electricity always moves from one place to another place. And if the other connection to the circuit is an awful long way away, then you get very, very small currents and it’s not going to do a lot of damage. If you’ve got two contacts a foot apart and a fish swims between them then it’s almost certainly going to get electrocuted. So, I think it depends an awful lot about how you set up this test.

Do animals speak regional languages?

Do animals speak regional languages? If I emigrated from South Africa to South America and I took my family dog with me, would his bark be understood by South American dogs?

Animals do indeed. Some of them do have regional accents, if you like, or dialects. And whether or not your dog would understand another dog might come down to breeds, rather than necessarily where it’s living in the world. But yes, animals do. We know that some birds have regional accents, some amphibians do, and if you jump into the oceans, there are creatures there that definitely have different languages and accents of their own. And that is the whales and dolphins, the cetaceans. And various studies have shown that if you listen to the sounds that some of these great whales are making, you can actually work out pretty well where it came from. Blue whales are one example and scientists have worked out that there are about nine regional populations of blue whales that seem to have their own distinct languages. And so, that might be something that has implications for things like conservation. Maybe we have to think about those nine populations as being slightly separate and different.
Is that because the baby whales learn to speak by imitation from parents and that’s how this regionality arises?

Probably, we know so little really about these amazing creatures, given the huge area of ocean that they live in, things like that. So these sorts of questions, we don’t yet know. For example, we also don’t know if they could understand each other between these regions. We don’t know that yet. Killer whales are another example of fantastic regional dialects. Along the eastern pacific coast of North America, there’s been a lot of study of killer whales living around Vancouver and Alaska. And these guys also have regional dialects. In fact, you can tell whether or not the individual killer whale belongs to a residential population, whether it’s a transient individual that’s coming through or whether it’s one from offshore because all these different killer whales basically speak with different accents, a little bit like different accents throughout the UK. We could tell where someone comes from, from the way they sound. I think this is fantastic.

They've also shown that there's a genetic link which is fantastic which shows that there seems to be some way that killer whales can tell how related they are to each other. And therefore, try and avoid problem with things like inbreeding, just by the way that they're talking to each other. So I think that’s just really fantastic

Is it true that vitamin C helps to cure cancer or perhaps even prevent it? And if so, how’s that possible?

Is it true that vitamin C helps to cure cancer or perhaps even prevent it? And if so, how’s that possible?

No, it isn’t. This is something that Linus Pauling put around - the idea that you take massive doses of vitamin C and it can stop you getting cancer or treat cancer. And basically, there’s no scientific evidence that this works. However, about a year or so ago, there was a paper that showed that injections of vitamin C may help some treatment. I can’t remember all the details, but we certainly blogged about it on the Cancer Research UK Science blog. But it’s important to stress that obviously, vitamin Cs are anti-oxidants and taking high doses of anti-oxidants may well interfere with some kinds of cancer treatment in ways that we don’t really know and again, it’s something that we have blogged about and it’s an area that’s really quite interesting because people do love to take vitamin pills. Indeed. There was also a Meta analysis by Goran Bjelakovic who’s at the University of Copenhagen in Denmark. I remember this coming out last year and they looked at many, many thousands of people who’d all been in little trials on giving anti-oxidant vitamins like vitamin A, vitamin D, vitamin E, vitamin K, selenium, and that kind of thing, vitamin C, and compared that with people’s outcomes if they didn’t take vitamins. And in fact, in many cases, they found that some chronic vitamin treatments actually resulted in people having a higher mortality rate and morbidity rate than people who didn’t take any of these supplements. A modest increase in risk, but at the same time, vitamin A and vitamin E did increase the risks. So, the chances are, yes, it’s based on sound physiological principles, trying to take anti-oxidant but the outcomes don’t necessarily fit the facts at the moment. So, needs more work I guess is the bottom line.

Can stem cells treat brain diseases?

Can stem cells treat brain diseases?

There’s a lot of promise in stem cells, but we’re probably several years away from being able to see the benefits of the research that’s going on. You mentioned at the beginning of the program that brain cells, once they're dead, they're gone and they can't be replaced from within the brain because brain cells don't divide. And the hope of stem cell research in neurodegenerative diseases is that you can take these stem cells which are capable still of dividing and becoming any kind of cell they like, put them into the brain and they’ll then re-grow, and replace the cells that have died. But as you also mentioned earlier on, the brain is a phenomenally complex thing and performing its functions normally, depends not just on the cells being there but on the connections, the billions and billions of connections that there are between the brain cells. And even if you could get the brain cells, the stem cells to differentiate into neurons that behave completely normally, you’d probably never be able to get them to make all the right connections. So there’s certainly be a lot of work, training the stem cells to make the right connections and behave the same way as the cells around them.

What are the floaters we see in the eyeball?

What are the floaters we see in the eyeball? And would it be possible to have a coil of thin wire in ones spectacle frames which would attract floaters to the extremities of the eye so that they would not float across the eye and be a distraction?

Well, floaters are actually very common. It is an age related phenomenon for the most part especially as we get in to the 40s and older. And what it is, is a clear gel in the back of the eye starts to condense and coil less and cloud over. Hence, that what the person sees will be spots and threads and shadowy clouds or cobweb type shadows which move around in the vision. Most of these floaters are considered benign, but it is worth getting a good eye examination to make sure that it’s not part of something more serious such as a retinal tear or a retinal detachment. The common advice that most people are given is to just learn to live with it and hope that it will go away. Now, the traditional treatment as I said is just to learn to live with it. There is actually a surgical intervention, a surgical procedure called the vitrectomy and it involves putting small instruments inside the eye to essentially suck out the gel in its entirety and replace it with salt water. As you can imagine, it’s invasive, it has complications, commonly cataract and sometimes even retinal detachment. And as far as your reader’s question about putting a coil of wire, it reminds me of a Steve Martin movie called The Jerk where he did put a little handle, a little wire on some glasses and in the movie, everybody got cross-eyed. Well, that wouldn’t happen, but there’s nothing you can really do to distract yourself from those floaters because they are inside the eye and they're constantly there. I have an unusual situation where I have a practice entirely devoted to treating floaters and I use a laser. So I use a highly focused laser on the floater material itself and vaporize it, convert it to a gas, the gas goes away and the floaters are gone.

How many LCROSS NASA missions would it take to change the orbit of the moon by 1%?

How many LCROSS NASA missions would it take to change the orbit of the moon by 1%?

What they were doing was firing the top stage of a centaur rocket and crashing it into the moon. They’ve been trying to watch the plume of stuff that comes up from that to see if there is water in that plume.

Now the centaur rocket weights about 2.3 tons and it’s going at about 10,000 kilometres per hour, that’s 2,800 metres per second, which means it’s got 6.4 million (6.4 x 106) kilogram metres per second of momentum. That’s an awful lot of momentum. For anything on Earth, that’s a scary amount of momentum. However, the moon has got awful lot more momentum than that. It’s moving at a kilometre per second and it weighs 7.3 x1022 kilograms.

That means the moon has got 7.3 x 1025 kilogram metres per second of momentum.

So, how many LCROSS’s crashing into it would change it’s momentum by 1%?

7.3x1025 minus 6.4x106 is roughly 1x1019

So about 1019 collisions. So that’s 1 with 19 zeros after it (10,000,000,000,000,000,000!).

And actually, an LCROSS’s momentum compared to the moon is about the same as 1 millilitre of water compared to all the water in all the earth’s oceans.

Why are background radiation levels so much higher in Germany than the UK?

Why are background radiation levels so much higher in Germany than the UK?

We spent some time looking at geological maps of Germany in the UK and our conclusion is that a lot of Germany is made of granite and granite releases a radioactive gas called radon. But the UK isn’t completely bereft of radioactive rocks. A lot of Cornwall, a lot of Wales, quite a lot of the Pennines and some of the Peak district and of course, Edinburgh is made of granite and does release radon. And there was some research I think a couple of years ago that showed that people Cornwall are actually getting quite a significant dose of radioactivity that does increase the risk of lung cancer in these areas. And in fact, if you smoke and live in places like Cornwall that are very granity, that’s actually a much more significant impact on your cancer risk than if you just live there and didn’t smoke. So, if you live in Cornwall or anywhere that looks a bit granity, then don’t smoke. But as to whether the background radiation is higher in Germany versus the UK, it really depends where you live. If you live in a very granity bit of Germany, yes it will be higher, but if you live in a very granity bit of the UK compared to a non-granity bit of Germany then obviously, it will be higher in the UK.

Is the blood-brain barrier real?

Is the blood-brain barrier real?

Absolutely. People talk about this blood-brain barrier. This notional structure which in some way keeps the brain isolated, cocooned inside you biochemically and physically-away from what's happenign in you blood stream and it;s absolutely true. The history of the blood brain barrier goes back a hundred and something years to a guy called Paul Ehrlich, who was a German scientist, he was interested in dyes initially. He used to inject dyes inot animals and then see which bits of the body got stained. andhe was intrigued to see that when he put dyes into the blood stream, much of the time the dye did not get into the brain. And so he realised there must be some kind of barrier separating what goes round in the blood stream from the delicate issue inside the brain. We not understand more about what this blood-brain barrier is. It's a bit contrived, what what's going on is that you basically have special junctions between ceels that line the surfaces of the brain, that separate the brain tissue from blood vessels and these cells make very tight junctions, that's what they're called, and this effecttively means that there's a barrier which is the membranes of those cells separating what's in the blood stream from what's in the blood tissue.

And what this means is that certain substances can move very easily into the brain, especially if they're substances that can dissolve well in fat, because of course the membranes of cells are made of fat. So lipid-solube drugs like heroin, cigarettes-nictone, cocaine, they're very oily molecules. they go into the brain beautifully and that's why they tend to be addictive. Because they move preferentially into fatty tissue like the brain. Other substances which don't dissolve in fat very well, don't get into the brain very well. But there are some exceptions. Those exceptions are things that the brain needs. So sometimes if it needs a certain chemical that wouldn't be able to diffuse in very easily, it has special transporters which can scrutinise what is going past in the blood, grab goodies that it wants and move those into the brain. This is what people found when they were giving the drug L-Dopa for Parkinson's Disease. -Dop is an amino acid, dissolves in water, doesn't dissolve in brain tissue very well but it gets into the brain much betetr than it should do and the reaon is theer are these special transporters that get hold of it and shove it into the brain.

If you cut your skin, it can regenerate, but after a stroke or brain injury, you can't replace neurons. Why is that?

If you cut your skin, it can regenerate, but after a stroke or brain injury, you can't replace neurons. Why is that?

Well, the answer is that the brain has an architecture which is what’s called post- mitotic. There are only a few restricted areas in the brain and central nervous system where there are new nerve cells being born. For the most part, you rely on the compliment of nerve cells you are born with and which continue to divide for a very short window after you were born and then stopped. So basically, what you're born with is what you have to make last a lifetime. And there’s a reason for that because if brain cells were dividing all over the place, remember that brain cells have long connections that they make from one cell to the other. And those connections are crucial to you being able to do the right thing, say the right thing have memories and for your brain to be able to work properly. If those cells were dividing all over the place and making aberrant connections, then it will be very, very difficult to preserve that architecture. So there’s kind of method in the madness.

The problem is that as that is a fixed structure, it’s very hard to repair it by getting the cells to re-divide because basically, if you have an injury, evolutionary speaking, that’s bad enough to destroy a part of your brain or your nervous system. The chances are you’d be dead anyway. So, we haven’t really evolved the ability to repair the brain and spinal cord. In some animals though, that can happen and things like gold fish, lampreys, and also even salamanders can restore whole limbs, bits of their nervous system. If you take the eye out of a frog, turn it around and put it back in again, it will rewire itself back into the brain, only because the eyes now are upside down. The animal see upside down and it does the wrong thing. If you hold a fly in front of it, instead of jumping forward at the fly, it jumps backwards and takes a bite out of the deck and that won a Nobel Prize for Roger Sperry a few years ago and proves that some animals can regenerate their nervous system, but certainly, not us unfortunately.