Naked Science Question and Answer

The brains of bored volunteers could be the key to unlocking the secrets of distant star systems. Scientists working on the Stardust Mission, which returned from the tail of comet Wild 2 in January, are currently analysing dust particles that could reveal the chemical composition of the early solar system. But amongst the primordial dust hide an estimated 50 particles of interstellar dust from other stars. To find these elusive hitch-hikers, Andrew Westphal from UC Berkeley has enlisted the help of 115 000 volunteers trained in the art of recognising ordinary dust particles. If a particle doesn't fit the mould, the volunteers alert Westphal to take a closer look. What's more the volunteers can browse the universe from the comfort of their front rooms as they can download over 700 000 images of the particles from the internet. But why not get a computer to do it? Unfortunately no-one knows what an interstellar dust particle looks like, and so the search can't rely on computer muscle. Westphal hopes that a little competitive spirit should keep the volunteers looking and eventually find him the proverbial needle in a haystack.

Chris - Most people will be aware that Jupiter, that giant planet in our solar system, has a giant red spot. We've known about this for 300 years or so. But what actually is it and why has another one, which has been named red spot junior, appeared more recently? Well I asked University College London's Steve Miller to tell me all about it.

Steve - Jupiter's a very large planet. It has a diameter of about 140 000 km compared with something like 13 000 km for the Earth. It also spins a great deal faster than the Earth does; roughly two and a half times as fast. Jupiter's day is less than 10 hours and our day, as we all know is 24 hours. So this is a huge rapidly spinning ball of gas something like five times as far away from the sun as we are. Now the great red spot is a very large storm system on Jupiter: you could fit the entire Earth into it. It's at a latitude of about 22 or 23 degrees south of the Jupiter equator. That has been known probably for 350 years and the storm is probably quite a bit older than that.

Chris - Steve, how do we know it's a storm though?

Steve - We can see that there are clouds at the northern and southern edges of it that are simply being swept round in a circle, and some winds go up to about 600 miles per hour, so you can tell that this thing must be spinning very rapidly.

Chris - Why is there just this one mega storm system? Is it because it's so powerful that it draws everything else into it?

Steve - Well that's indeed how it might have formed. It's very likely that it's formed up from a lot of smaller storms merging and then forming this enormous structure. We do know that it's changing. It's now something like 17 000 km in the west-east direction and 12 500 km north-south. When it was really catalogued in the 1880s, it was something like 39 000 km east-west, so we can see that in the past 125 years the storm has shrunk in size. It's changing. But it's almost certain that it formed from the merger of a lot of smaller storms.

Chris - We've got some evidence that this may be happening on Jupiter in the wake of the giant red spot junior, which has crept up in more recent years.

Steve - Yes, that's right. That's a storm that's a bit to the south of the great red spot and this is a storm that has resulted from the merger about five years ago of three smaller storms that basically caught each other up and then merged into one. It's really quite big; about 40% of the volume of the great red spot. So red spot junior may be junior may be junior but it's still pretty massive.

Chris - Do you know why it's red though?

Steve - Difficult question. The most likely theory is that when the three storms that formed red spot junior merged together, they became much more violent as one combined storm. This has had the effect of bringing material up from Jupiter's lower atmosphere higher up into the atmosphere. Now it's probable that this Jupiter air has quite high concentrations, or relatively high concentrations of phosphorus compounds or sulphur compounds or something like that, and bringing it up higher into the atmosphere has allowed sunlight to cause chemical reactions to occur that have turned the colour red. It's giving us an insight but we still have no idea what the actual chemical compound is that gives the great red spot and now red spot junior it's red colour. We just don't know what that is.

Chris - Steve, I have an email from Richard Wood in Columbus in Ohio and he'd like to ask a couple of questions about Jupiter. First of all, he says why do storms like Jupiter's great red spot not have eyes like hurricanes on the Earth do?

Steve - I think it's just a question of how big they are. The funnel of the great red spot and red spot junior are so much huger in size so that they don't give you the impression of an eye in the same way that a hurricane does. But then if you distance yourself a bit from them, you can actually imagine that you are looking at an eye. So there is sort of an eye but it's so much greater than anything that we see on Earth.

Chris - Richard goes on to ask, why is it that these Jovian storms don't migrate towards the poles, ie: away from the equator, like hurricanes on Earth seem to do?

Steve - Well this is something we call the coriolis force, and the coriolis force will tend to keep things rotating in the same latitude. We have coriolis forces on Earth but because the Earth is much smaller and rotating much slower than Jupiter is, they're not so effective so you do get winds that move north and south on the Earth. It's very difficult to get winds to move north or south on Jupiter simply because the coriolis force will always tend to bend anything moving north or south, it will tend to move it again in an east-west direction. That's why Jupiter has these very stable light coloured zones, these dark coloured belts on the Jupiter atmosphere. They remain very stable because they're held in place by these coriolis forces.

Chris - Now we're going to take our final trip to the States before the summer, where Bob Hirshon and Chelsea Wald will be looking at evolution in Darwin's finches and also why pregnant women get morning sickness.

Bob - This week for the Naked Scientists, the staff here at Science Update go out on a limb here in the States by throwing our support behind the controversial theory that life on Earth evolved by means of natural selection - a theory first proposed by foreign biologist Charles Darwin. In this episode, we'll learn about brand new insights into evolution from the finches Darwin studied. But first, scientists have long wondered why pregnant women get morning sickness. After all, they need all the sustenance they can get, so losing their breakfast doesn't seem to be the best course of action. But Chelsea tells us that there could be a good evolutionary reason for it. Chelsea - When morning sickness strikes, pregnant women often ask, Why me? Well, they'll be happy to know that scientists at the University of Liverpool are working on an answer. By comparing 56 studies from 21 countries, they found that pregnancy sickness is more common in places with diets high in sugars, stimulants, vegetables, meat, milk, and eggs. Evolutionary psychologist Gillian Pepper says this may be the body's way of protecting the foetus from harm.

Gillian - These were the foods that perhaps when man was evolving, were more likely to contain pathogens, because if you don't have refrigeration, meat, milk, eggs could very quickly could become infected or go bad.

Chelsea - Women fared better in places with diets low in these foods and high in cereals and pulses such as beans, but Pepper doesn't recommend that pregnant women change their diets. Much more research is needed on whether doing so would reduce sickness or even be healthy.

Bob - Thanks, Chelsea. Scientists have now reported seeing evolution in action in none other than Darwin's finches. Two decades ago, large ground finches moved to a Galapagos island where medium ground finches lived. The problem was, the large finches ate the same seeds as the medium finches, and they did it faster with their bigger beaks. So scientists predicted that the medium finches' beaks would evolve to take advantage of smaller seeds. Princeton University evolutionary biologist Peter Grant says that happened during a drought two years ago.

Peter - The recent immigrant species had almost eaten the supply of food for themselves, so they almost went extinct. The resident species, a species that was there before the new species arrives, underwent this large shift towards small size in beaks.

Bob - He says this adds to the evidence that competition between species can lead to evolutionary changes.

The reason is that it is genetically programmed into us while we are developing inside our parents. As little babies your body develops as a series of segments and each of those segments inherits its own genetic programme. In some areas the length or growth phase of the hair follicle is longer than in other areas. In your eyebrows for example, a hair grows for about a month and on the top of your head a hair follicle is active for anything up to three years. Hair follicles have three phases to their life cycle: they have a growth phase, and this is called the anagen and can last up to three years for a head hair, 21 days for an eyelash and 3 weeks for a pubic hair. If you go through the growth phase, the next phase is what's called a catagen phase, which is when the hair falls out, and then you have a resting or telogen phase, and then the cycle resets itself. The length of hair depends on the length of the growth phase.

It's not the actual eating of the chillies. The thing that makes chillies hot is called capsaicin. Not only does it make things taste hot but can also be used as a topical ointment on the skin if you have various pain syndromes. One of those is shingles. If you've had chickenpox in the past then you have chickenpox living in your nerve fibres in your body for the rest of your life. Periodically it can come back out and cause a patch of chickenpox vesicles or blisters on one patch of skin. After they go away, it can be tremendously painful. However researchers have found that if you apply this capsaicin to the painful area, it can actually help to relieve the pain. This could possibly be because pain is mediated in the nervous system by a class of tiny nerve fibres referred to as C-fibres. Capsaicin activated those nerve fibres and in some cases activates them to death. This turns them off and indirectly makes them less sensitive, which is why the pain goes away.

How dangerous UV light is depends on the kind of UV light. If it's got a very long wavelength quite close to visible light then it's not much worse than blue light. Once it starts getting beyond that it's getting more dangerous and closer to x-rays. The stuff in bakers and discos is called UVA and is closer to blue light and probably isn't that bad for you.

Then you have completely proved exactly what physicists say. At high speeds, such as 70 miles per hour, you're much better to use the air con and keep the windows closed. But at 40 miles per hour it's more efficient to keep the air con off and have the windows open. You get more air resistance the faster you go. The way the air conditioning works is that it's like a having a big fridge on your car. You take energy from the engine to drive this fridge, it you like, and it draws air over the fridge element and passes it into the car. So you're not getting something for nothing. It is taking energy from the engine. So if you want to be the most efficient you possibly can then you'll just sweat it out, although you won't necessarily be in the best possible state when you arrive at your destination.