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FEEDBACK was there to hear Stephen Hawking concede his bet with fellow physicists Kip Thorne and John Preskill over whether information can escape from a black hole (17 July, p 11). This problem of the “black hole information paradox” had troubled him for 30 years. We asked at the end of the lecture what he was going to think about now that it was solved. “I don’t know,” he answered.

This is serious. Serious enough, in fact, to launch a one-off Feedback summer competition: what Stephen does now.

Any question profound enough to merit the great man’s attention must be expressed as one sentence in the plainest of English. (We follow the rule proposed by the publisher of Hawking’s Brief History of Time: each equation will halve the circulation of your idea.)

The winning entries will be chosen on the basis of their wit, originality and contribution to our understanding of the universe (and beyond). All entries must reach us by Monday 30 August. The winners will be announced in the 11 September issue. The Editor’s decision is final.

And what might the prizes be? That information is, er, locked in a black hole. When we reconstruct it we’ll let you know…

RADIO frequency identity tags (RFIDs) can help distinguish genuine from phoney goods – and for some raise civil liberties issues, such as the possibility of roadside detectors tracking whose underwear goes where by the chips embedded in it.

So we were intrigued when a reader wrote, apparently with insider knowledge, “in case you didn’t know, euro notes have had an RFID chip in them since they were first issued. To check this put the note in a microwave at full power. After about 15 to 30 seconds you will see a flash and a burnt pinhole in the note where the chip was.”

Being well travelled, we were able to fish a nice crisp €5 note out of the Feedback wallet, and put it in the microwave. Almost immediately the room filled with expensive smoke. Instead of a single telltale “burnt pinhole”, our note had large black gaping holes in it. The radiation had induced heavy currents in the embedded metal strip and metal hologram marks, which had got red hot and set the paper on fire.

The note is now unusable as currency, but has found new life pinned to the office wall as a reminder to take internet hearsay with a large pinch of salt.

BACK on Earth, the supermarket Tesco did have something to announce to reader Andy Taplin: a sign informs him that it now has 13 different types of trolley at his disposal. And a member of staff will be only too happy to help him choose the right one.

This kind of thing makes Feedback pine for Soviet-era shops and their simple offerings: soap, one kind. Toothpaste, ditto. Pickled carrots…

Andy, though, was intrigued by the technological possibilities. Do some models use GPS to help locate the 37 flavours of soap? Might others be self-propelled in some way? Or is it even possible that they have invented a trolley that doesn’t seem to a have a mind of its own?

FROM the minor annoyances of consumerism we turn to what appears to be an earth-shattering event.

“An outbreak of red tide in the Seto Inland Sea off Ehime, Kagawa and Hiroshima prefectures has killed about 300,000 fish, including red sea bream and flatfish,” the major Japanese newspaper Yomiuri Shimbun reported on 24 July. “The outbreak also,” it went on, “has upset the timing of tides in the area, local government officials said.”

The phytoplankton Chattonella ovata, which can turn the sea red, was blamed in Kagawa prefecture. That’s one powerful little beastie, it seems. Feedback reckons someone (or some superhero sea-monster) should keep a close eye on it.

PROBABLY a first for this column: some original research. Charles Sheppard presents for review his paper, Size is (inversely) everything. His data is “dodgy, but only to the extent that measurements were done by eye only, the ‘targets’ being somewhat uncooperative, and this researcher unwilling to push his luck”.

The nub of his paper is a graph, the axes of which are labelled “Size of gun pointed at the author” and “Height of guard or government minister wielding the gun”. The statistical fit to a straight line is indeed impressive. And the conclusion: “Generally, large guards tended to have tiny pistols nestling in their palms. The psychology of this is not discussed further (one can take ‘multidisciplinary’ too far).”

AND finally, after buying a carton of putty for his wife to fix a window with, reader John Henderson was puzzled by her reluctance to use it. Then he looked at the label, which said: “Remove skin before use.”

Startling news is buried in an advert for the Penguin Hutchinson Reference Suite CD-ROM, promising “human history from 500 million BC to the present day”

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