Scoti Hayward, Newtown The Sun rotates counter-clockwise but being gas, it may have a different spin rate at its equator from its poles. Magnetic fields would get wrapped up like knotted fishing line accounting for sunspots. The Sun also orbits the centre of the Milky Way at about 225 km/sec, and our galaxy itself has a motion in its Local Group of galaxies of about 100 km/sec. Our Local Group, in turn, has a speed of about 220 km/sec relative to the Super Cluster it resides in, and there are further layers of motion beyond that.

Paul Roberts, Lake Cathie The Sun revolve around its axis. The best way to detect that, is to check the sunspots and the increase of cosmic radiation, coming from from this star at the end of each, 11 years rotation cycle. Fausto Mino, Schofields

Galileo discovered from the movement of sunspots that the Sun rotates on its own axis, and each revolution takes about an earth month. However, because the Sun is fluid not solid, it spins faster at its equator (27 days) than at the poles (35 days). The Sun spins in the same direction as the planets orbit around it, which is not surprising as the Sun and the planets condensed from the same rotating disc of gas.

John Paterson, Avalon The Sun spins on its axis in a way similar to the Earth revolving to give us day and night. Also, it 'wobbles' as the planets orbit it, in the same way your washing machine wobbles if the load is unbalanced. Further, the Sun (with planets in tow) is orbiting the centre of the galaxy. Finally, the galaxy is hurtling through space. All in all, the Sun moves quite a bit. Joshua Quigley, Gerringong

I remember reading that Earth rotates on several axis. I seem to recall it is either seven or fifteen. The three obvious ones give us the day, the seasons and the year. Can someone please help me with the others? I think one is over a 74 year period and another about 800 years. I believe this information could help us understand the various weather cycles a little better. David Brayshaw, Mudgee

As any amateur who has studied sunspots drift slowly across the sun from day to day though special filters would know, the Sun's rotation period is about 27 days. Eugene O'Connor, Terara The Sun, a middle age yellow dwarf star with a life span of 10 billion years, revolves on its axis like any other star. It moves slowly and takes 25 days (equator) and 35 days (poles) for the sun to complete one full revolution. Because stars are mainly made of gases (hydrogen and helium) they spin faster at the equator than at the poles. The Universe is expanding and because of that fact stars and all celestial objects are moving. Our solar system is located within a major spiral galaxy - the Milky Way - which in turn also revolves on its axis. The Milky Way takes around two million years to complete one revolution, pretty much in the same way planet Earth takes one year to revolve around the spinning Sun.

Jorge Estevao, Colyton Not only does the Sun revolve on its axis but, being a big ball of gas, it is fluid and consequently revolves at different speeds in different places. It takes 25.4 (Earth) days to rotate at its equator but an even more leisurely 35 (Earth) days to rotate near its poles. That means it rotates at an average velocity of 1.9 kilometres per second. However, one thing that the Sun doesn't do is to move 'across the sky' from east to west each day. That is an illusion caused by the Earth rotating on its own axis every 23 hours, 26 minutes and 4 seconds.

Alex Abbey, Central West Astronomical Society The Sun revolves once on its own axis roughly every 25 days. This was measured by reference to black sunspots appearing on the Sun's surface. Conversely the moon does not rotate on its axis at all but is held in stationery in its orbit around the earth. David Buley, Seaforth

Celestial bodies do not revolve on axes; they rotate. The Sun does, however, revolve about a point in the centre of our galaxy, taking the entire Solar System with it at a speed of 220 km/s. This Period of Orbit takes 225 million years. Victor Szudek, Rockdale

The Sun revolves at about once every 25 days at its equator and up to 30 days near its poles. This odd phenomena is possible because the Sun is not solid; it is essentially a fiery ball of gas, hydrogen and helium, possibly with a solid core deep inside. Regular movement of sunspots show the rotation, slower at the poles than at the equator. The Sun rotates like a top, or like the Earth, and its axis is inclined 7 and 1/4 degrees to the earth's orbit - this compares to the Earth's axis which is inclined at approx 23 degrees and gives us the seasons. The direction of rotation of the Sun is from east to west as seen from the Earth. Peter Carr-Boyd, Temora If by this one means does the sun rotate at all, then answer is yes. The Sun spins on its axis, however the rotational speed differs at different solar latitudes due to the liquid nature of the Sun's makeup. This differential rotation in fact causes the Sun's magnetic field to distort and leads to loops that are visible to solar observers. However if the question is does the Sun remain in the same position relative to all the planets, then the answer is no. The Sun actually oscillates due to the gravitational effect of Jupiter's mass. The oscillation is however very small. To further complicate matters, planetary orbits are in fact not circular. Eliptical orbits (defined by Kepler's third law) mean that the distance to each planet varies, with Pluto being the most variable (in fact passing inside the orbit of Neptune at times). Due to their relatively small masses the four inner planets can be said to orbit a point in space corresponding to the sun. However due to gravity considerations, the remaining planets (due to their mass and/or distance relative to the sun) actually orbit a point in space that is best termed the solar centre-of-gravity. The Sun takes just under 180 years to orbit the solar-centre-of-gravity, and the diameter of this solar orbit is about 1.5 million miles.

Paul Louis, Sydney Aren't assault and battery the same thing?

I am facing a tort law examination in a week's time, so I feel very prepped to explain the difference between assault and battery. While in everyday usage the terms are interchangeable, in legal usage assault refers to a direct threat to a person causing that person to apprehend the danger of contact. In other words, if I shake my fist at you and threaten to knock your brains out, I have assaulted you (as long as it is reasonable for you to apprehend that I will in fact hit you). If I then go ahead with my threat, that would be battery. As such, you can have assault and battery, assault without battery or battery without assault (if I came up behind you and knocked your brains out without you realising my intentions). Battery need not be violent in nature - any touching without consent can be considered battery, although there is a general exception for contact occurring in the "ordinary conduct of everyday life". Charmaine Jennings, Primbee In law, 'assault' is a threat or attempt to injure someone and 'battery' is an actual touching or striking of someone with the intent of causing injury.

Paul Dodd, Docklands, Victoria Assault is the threat and battery is the actual carrying out of the threat. I can call you all the @&*^%$#s under the sun, tell you I am going to break your neck etc - that's assault - when I do break your neck, that's battery.

Ron Corden, Tamworth It is a common misconception that slapping someone is assault. Often the cry 'That's assault!' can be heard on current affair programs when tv crew are being manhandled by a disgruntled 'shifty' businessman. But the legal definition of assault doesn't involve physical contact. Assault is the apprehension of imminent physical harm. Thus if I jumped out from a dark alley brandishing a knife and crying 'I'm going to cut you to pieces', that would constitute assault, for naturally any reasonable person would fear imminent physical harm. Battery on the other hand is actual physical contact, or causing physical contact, such as throwing an iron at someone's head. Jannali Jones, Abbotsford

To threaten violence or harm which you are capable of carrying out is an assault against the person and if you actually go ahead and physically attack them then this is battery. Michael Sobb, Rydalmere

No. English (and Australian) common law originally defined separate offences of 'assault' and 'battery'. Assault was the crime of putting another person in fear of an unlawful contact, that is, a threat. Battery was the actual application of unlawful contact or force. Eventually in the modern criminal law these two offences were collapsed under a single concept: assault. Laura Perusco, Gerringong No. But the distinction is largely irrelevant in criminal law today. An assault is an act that intentionally or recklessly causes another an immediate apprehension of violence. Whereas, a battery is the intentional or wreckless application of physical force upon another. In short - assault is putting a person in fear of immediate violence, and battery is actual violence. The distinction is irrelevant as Common Assault (Section 61 Crimes Act 1900 (NSW)) is committed by either an assault or a battery alone. Old indictments once read, 'did beat and ill-treat' but today an indictment for an offence under section 61 merely reads '... did assault ...' and this is the case whether it was, to use the old terms, truly an assault or a battery.

Stephen Lasker, Gosford While in everyday speech assault covers a wide range of invasive physical contact, at civil and criminal law its meaning is usually more limited.

Assault tends to consist of conduct that produces a reasonable apprehension of imminent physical harm. Battery is then the step after apprehension, ie: the physical harm itself. That said, the distinction between the two is not only generally lost on victims, defendants and the general public. It is sometimes even ignored by lawyers and legislators alike! See, further, Trevitt v NSW TAFE Commission [2001] NSWCA 363 and s 59 of Crimes Act 1900 (NSW). Oliver Jones, Oxford University, United Kingdom Assault refers to a movement or threat to illegally strike or touch a person, whereas battery refers to the hitting or touching of that person as a direct consequence of the assault. So, someone can be guilty of assault even if they did not actually make contact with anyone. We can't apportion blame to Rex Mossop for this apparent tautology!

Frank Gutierrez, Baulkham Hills There is a similarity between assault and battery. Assault is any wilful force that may cause bodily harm to another person and battery is similar in that it refers to hurting a person physically but to a more severe extent than assault. Legal practitioners say that assault is attempted battery.

The origin of the word 'battery' lies in an incident outside a football club in the 1930s when dress codes were very strict. A man tried to enter the club and was told by the doorman he would not be permitted as he was not wearing a tie. He returned to his car and wrapped the battery jumper-leads around his collar. When he came back to the club and asked if he could be readmitted, the doorman said 'OK, as long as you don't start anything.' Paul Hunt, Engadine Of course the difference between assault and battery is that a salt is what you put on a steak and a battery is what you put in a torch.

Stephen Soldatos, West Ryde To shake your fist at someone is an assault, to land a blow is battery.

Even to purse your lips for spitting is an assault for the spit to hit the other person is battery. John Harding, Eastwood After 1066 English law was written and conducted in a mixture of Norman French (the language of the ruling class) and Latin (the language of the educated). An accused person could be tried and sentenced in a language totally unknown to them, and without a translator.

Oliver Cromwell decreed that all law should be written and conducted in the languge of the common people. As laws were translated into English, however, lawyers felt the need to closely define certain terms, so a word often appeared both in English and Norman French to get the meaning clear: 'assault and battery', 'will and testament'. Cromwell was criticised by lawyers of his time who feared that they would lose their livelihood but this happy day does not seem to have yet arrived.

John Faulkner, Alexandria My legal training is limited to a short course in the UK in 1969. I still remember this common law ditty: Stick and stones will break my bones (that's Battery), but words will never hurt me! (that's Assault) S.Wedd, Orange

What is the difference between percentage points, basis points and old-fashioned per cent? A basis point generally refers to the smallest unit of measurement for a given item. For example, interest rates are generally quoted to two decimal places. Therefore, 0.01 per cent is referred to as one basis point (or more often "one point"). Similarly, diamonds are measured to two decimal places, so when you ask how much a 50-point (0.50 carat) diamond is, the response is normally "You gotta be kidding". A percentage point is generally one hundred basis points or 1 per cent. Per cent is reference to a proportion. That is, 1 per cent is 1/100th of something. The reason for the differences is that "points" (percentage and basis) are absolute terms whereas per cent is relative.

Patrick Anwandter, Crows Nest A basis point is one-hundreth of a percentage point. Old fashioned 'per cent' is a phrase translating to 'out of one hundred', while a percentage point is a thing ... one thing out of one hundred. Joshua Quigley, Gerringong

A percentage point is one in a hundred, so a change from 50 per cent to 60 per cent equals a change of ten percentage points. Basis points were introduced in finance to define a smaller quantum - there are one hundred in every percentage point. The derivation of the term is the Latin 'per centum' meaning simply one in a hundred. In America it is spelt percentage, and they even refer to percentages of percentages. Mathematically, relationship to hundreds is not considered - the aforementioned change would be referred to as 0.5 to 0.6. Neil Whiteley, Terara

The differences are less important than what they have in common: without them, life would become pointless. Norm Neill, Leichhardt When the value of an indicator (eg: the rate of increase in the CPI) increases from 10 per cent to 11 per cent it is often reported as a 1 per cent increase. This is incorrect. The correct way of describing such an increase is say there has been an increase of one percentage point. An increase from 10 per cent to 11 per cent is actually a 10 per cent increase (although it is dangerous to take percentages of percentages, but that's another story). Likewise, an increase in the growth rate from 2 per cent to 4 per cent is an increase of two percentage points, not two percent. Participants in financial markets often refer to basis points, where 100 basis points = 1 percentage point, or 1 basis point = 0.01 percentage point. For example, if an interest rate changes from 7.25 per cent to 7.50 per cent, it is described as an increase of 25 basis points (or simply 25 points).

Chris Turano, Finance Manager, Telstra Technology, Innovation & Product, Sydney Where does the expression "butter wouldn't melt in her mouth" come from, and what does it really mean?

This phrase is recorded as being in use since the 16th century and was thought to apply to women who were so prim and proper that they didn't even have the warmth to melt butter. The phrase seems to have become misunderstood over the centuries as it now tends to imply that a certain person that outwardly appears to be kind and benevolent is in reality, cunning and evil. David Buley, Seaforth Chilled butter was traditionally used as a salve or moisturiser and works well as an emergency lubricant. This ironic phrase belies the outward appearance of being someone who will figuratively butter you up with cool platitudes. The two-faced one will throw a spanner in your works.

Paul Roberts, Lake Cathie The expression 'butter wouldn't melt in his mouth' is the English translation of an old French proverb 'le beurre ne fondrait pas dans sa bouche', which is thought to have originated in the 16th century although no-one knows for certain. It was used to describe a person who had the face of an angel and the mind of a devil, the reference clearly being to the fact that their interior was so cold that not even butter would melt.

Michael Morton-Evans, Mosman The expression 'butter wouldn't melt in his mouth' means that the person referred to is a modest and sober soul; but that meaning bears little obvious connection to its origin. In the 1850s, bushranger Frank Melville (known to his cronies as 'Mel') escaped the clutches of the law by rowing across Port Phillip Bay in a boat made of tin. One of his gang, hoping he'd use a more conventional vessel, yelled out as Melville set off: 'Better wooden, Mel ... tin is myth!' Jim Dewar, North Gosford

With regard to the question where does the expression 'butter wouldn't melt in his mouth' come from, and what does it really mean? There seem to be a couple of scenarios her: butter wouldn't melt in his mouth - ie: he's so saintly, 'in his mouth' ie: cool customer. It can also refer to someone being prim and proper. The allusion is to women who are so proper that they don't even have the warmth to melt butter. It is recorded as being in use since the 16th century. Wigzell Leica, Redfern

Of what possible use is a tachymeter on a watch, and has anyone ever actually used one? Pilots and racing car drivers couldn't possibly use them at those speeds. I'm a pretty average pilot and at 215 knots (400 kmh) I find it quite simple to use the tachymeter - find two landmarks, say one mile apart, and it should take 15 seconds to transit. Longer distances give better accuracy, but I don't think I'd try it on the ground "at those speeds". Frankly, there are many watch features that seem of little use. It is quicker, more precise and often cheaper to use the GPS. Bryan Swansburg, New Farm, Qld

ANY ANSWERS? Why do people appear to care more for a famous person with an illness than the thousands of ordinary people who are diagnosed with terrible things every week?

Who was Bill Bailey and did he ever come home? Why ain't it over until the fat lady sings? Given that Australia has some ideal "hot rock" locations where, by drilling down about eight kilometres, it is possible to extract unlimited steam to drive turbines, why don't we start to use this free, clean power?

Why are wellington boots called gumboots in Australia? READERS' RESPONSES: Email your answers - or questions - to bigquestions@smh.com.au; write to Big Questions, Spectrum, SMH, GPO Box 506, Sydney 2001; or send a fax to 9282 2481. Limit questions to one short sentence and answers to a maximum of 130 words, and state your name and suburb/town.