Is there a latitude at which the total number of hours of daylight in a year is a maximum?

The two places that have the maximum daylight per year are the north and south poles.

David W. Hughes, Emeritus Professor of Astronomy, University of Sheffield

If the questioner doesn’t fancy learning Norwegian, Swedish or Russian, or living in northern Canada, then northern Scotland at about 58 degrees north is quite a good bet.

Dr Hillary J. Shaw, Newport, Shropshire

Is there any evidence that lettuce contains any nutrients, without any of the dressing that makes it palatable?

An average lettuce is 94.8 per cent water, 1.3 per cent protein and 2.8 per cent carbohydrate. The carbohydrate is largely cellulose, which human beings cannot digest. It also supplies about 15kcal of energy, 140mg of potassium and 8mg of vitamin C, all per 100g. Thus it is about as nutritious as eating wet toilet paper.

Dr Peter Byles, Brackley, Northants

The Bible refers many times to 40-day periods, and to the Israelites’ 40 years in the wilderness. Could this be linked to early Babylonian knowledge of the planet Venus moving in regular 40-year cycles, and of the Pleiades star cluster disappearing for 40 days a year?

Some modern authors (notably Colin J. Humphreys in his book The Miracles of Exodus, 2003) support the argument that Hebrew, Egyptian (and some Greek) writers used a 40-year period as a round number to express the length of one generation, it being an old practice to date past events by the number of generations since the event in question.

Crispin Shorter, Suffolk

In Modern Turkish the word for 40 is “kirk”. The word for “a great many” is “kirkek”. In Hebrew the word for “a great many” is “kirkek”. I have thought for some time that this could possibly be a mistranslation that has just been perpetuated over many centuries.

Joan Langrognat, Harrow

Forty weeks is the gestation period of the human embryo, and the number 40 was considered by the ancients as a transition period of birth or rebirth; a period of cleansing and learning. So the periods stated in the Bible may have been a description of a transition or rebirth such as the Israelites’ journey from Egypt to the Promised Land.

Terry Hyde, Newport, Isle of Wight

We all know that the Earth and the planets go around the Sun, but where is the Sun going? And how fast?

The Sun is heading in the direction of the star Vega, near the border of the constellation Hercules and Lyra, at a speed of 43,000mph through the rest of the stars in our part of the galaxy.

Paul Murdin, Royal Astronomical Society

Mark Ramprakash seems to be taking ages to go from 99 to 100 first-class centuries. But has anyone been stuck on 99 hundreds for longer?

Tim Mickleburgh, Grimsby

Why do basketball players wear vests and shorts five sizes too big?

Graham Baldwin, South Croydon

Why do so many Welshmen have double-barrelled (albeit not particularly distinguished) surnames?

Ben Harte, New York

From Vivien Leigh and Leslie Howard in Gone with the Wind to Jude Law in Cold Mountain, British actors have been able to pull off US southern accents quite well. Other regional accents work, but not so convincingly. Why is this?

Joseph Logue

In tennis, if Hawk-Eye declares a point “in” by showing the ball contact mark as just touching the outside of the line, how reliable is the shape of that contact mark? Does Hawk-Eye calculate its shape each time from speed and angle?

John Pope, Tisbury, Wiltshire