The Hubble telescope is looking ever deeper into space and seeing the Universe near its creation (the Big Bang). If it can do this, can it see what happened last week?

If the Hubble telescope looked at something at the right distance, so that light took a week to get from it to us, it would see what happened there then. At that distance there is little more than a rarefied cloud of very cold, inert, slow-moving comets, and what the Hubble telescope would see happening there last week is not much.

Paul Murdin, Royal Astronomical Society, Cambridge

Indeed it can. To answer this question we first need to know the speed of light in a vacuum (space). The latest and the most accurate accepted value is exactly 299,792.458 km per second. In other words, if the Hubble telescope was to focus on a region of space 299,792.458 km from its location in orbit, it would be looking one second into the past (it takes light one second to reach it).

Now, there are 604,800 seconds in a week. So the question is: how far does light travel through space in a week? By multiplying the speed of light in kilometres per second by the number of seconds in a week, we arrive at the staggering figure of 181.314 billion (roughly 5 million trips around the world). The light from a region of space 181 billion km would take a week to reach the Hubble telescope. In other words, the Hubble telescope can see what happened last week, but only in a region of space 181 billion kilometres away.

Lee Kempster, London E4

In a recently repeated episode of Dixon of Dock Green, Sergeant Flint, a rotund Londoner character, quoted the line: “I would bet Lombard Street against a china dog, that he didn’t do it.” Can anyone supply an explanation?

Brewers Dictionary of Phrase and Fable describes “All Lombard Street to a China orange” (not “dog”) as an old saying implying very long betting odds. Lombard Street is, of course, where the Italian merchants settled as the original banking and mercantile quarter of London and the contrast is between the untold wealth of the City of London and the price of a trivial item (Brewer’s adjectives).

Michael Berkson, Great Shelford

Sergeant Flint was misquoting Edward Bulwer-Lytton. In The Caxtons, a study of the aristocratic side of his family and English society in the 19th century, Edward’s uncle Jack Lytton has the comment “it is Lombard Street to a China orange”. “Are the odds in favour of fame against failure so great?” asked Edward’s father. The expression evidently caught on as it is quoted, correctly, on several occasions during the next 100 years.

Ray Long, London SW16

Why do convolvulus and related plants climb stems anticlockwise, and are there exceptions?

Your correspondent who asks about the anticlockwise progress of convolvulus clearly has led a deprived existence, and requires to be introduced without delay to Misalliance by Michael Flanders and Donald Swann: “The fragrant honeysuckle spirals clockwise to the sun/ And many other creepers do the same./ But some climb anticlockwise: the bindweed does, for one/ Or convolvulus to give its proper name.”

Neil Allan, Dumfries

Questions

Sometimes when going round a corner, a double-decker bus appears to be about to keel over. What would the angle from the vertical have to be before this would occur, and has it ever happened when passengers were on board?

Tony Knifton, Liverpool

Sunday is the day of the Sun and Monday is the day of the Moon. When and how did Moonday lose one of its “o”s?

Joe Allison, Dallas County, Texas

Why do we refer to “a square meal”?

John Idris Jones Borthwen, Ruthin, Clwyd