Feedback is our weekly column of bizarre stories, implausible advertising claims, confusing instructions and more
Runaway expansion
A FLURRY of puzzlement greeted reports last month about the observation of the oldest galaxy spotted so far. The snappily titled z8_GND_5296 formed 700 million years after the origin of the universe 13.8 billion years ago and is . Eh? Perry Bebbington asked Feedback: how can the light we see from this galaxy be 鈥渕ore than twice the age of the Universe鈥�?
We wondered whether we ought to sharpen our pencil and work out the transformation of space-time in an expanding universe. Instead we decided to ask Steven Finkelstein, an author of the paper reporting the find ().
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Steven graciously replies that 鈥渨e are seeing this galaxy as it was 13.1 billion years ago.鈥� This means, he explains, 鈥渢hat the light we see has been travelling for 13.1 billion years. The universe has been expanding this whole time. So, if you were to 鈥榝reeze鈥� the expansion of the universe right now, and extend a very long tape measure to this galaxy, you would find that it is about 30 billion light years away.鈥�
Several readers noted a that 鈥溞影稍磗 have already calculated that it would take an elephant balancing on a pencil to break through a sheet of graphene鈥�
No orca in Dorking
BLACKFISH is a documentary film that 鈥�. It is now concluding a European tour of openings in Madrid, Luxembourg, Brussels, Amsterdam, Munich, Milan 鈥� and Dorking. Unfortunately, even if you happen to live within easy reach of the last-named semi-suburban jewel of the Surrey Hills in the UK, you can鈥檛 go because it is sold out. You can, however, buy the DVD.
Legally blonde genes
IRISH police have accidentally alerted Feedback to an urgent need for action on the public understanding of science. Last month they seized two children from Roma families, reportedly on the grounds, among others, that they were 鈥渢oo blonde鈥� to be the offspring of the people who were, as DNA tests soon confirmed, .
Clearly, all public officials should take a refresher course on the operation of recessive genetic traits, of which blondeness is a canonical example.
It seems that forensic psychiatry will be the next discipline to be engaged. The actions of the Irish police appear to have been based on the belief that Roma people are essentially liable to steal children 鈥� a version of the 鈥溾�� that in the past led to all kinds of persecution.
A gram of software鈥�
READER Dean Conrad recently had to send software to south-east Asia on a CD through the post. That meant completing a number of details on a 鈥淐ertificate of Origin鈥� form for customs. The 鈥済ross weight鈥� was easy: CD plus packaging = 150 grams.
The 鈥渘et weight鈥� presented Dean with more of a challenge. Surely the CD is also 鈥減ackaging鈥� for the software? So what is the weight, or the mass, of the data that encodes the software?
Dean is led to some further questions. Can software exist without hardware 鈥減ackaging鈥�? Can even this packaged software be said to exist without a 鈥渞eader鈥�?
鈥nd a bloated program
THINKING afresh, then, about the question raised above regarding the mass of software, a colleague asks: what is the difference between a blank CD and one with data? That software is a special case of data is the insight that allowed .
One measure of data is the 鈥溾��, which is the length of the shortest program written in an ideal, ultimately terse, computer language that could output the contents of the disc. It measures the entropy of the data, loosely its 鈥渋mprobability鈥�, which has units of energy divided by temperature. So Einstein鈥檚 well-known equation, E = mc2, gives us a route to estimating a mass 鈥� too small to weigh on a scale, it seems.
The colleague got distracted, however, by the implication that the mass depends on the quality of the software. Today鈥檚 bloated programs fail to meet mathematician ideal of compactness, to say the least.
Cabbage spacehopper
BBC Radio 4 airs a programme called , and its writers, including David Mitchell and Graeme Garden, have in time for the festive season. Brian Robinson observes that they have 鈥済rasped the nettle of new measurements鈥�: even if the theme of the programme is, er, lying.
Their discussion of cabbages claims that the largest cabbage ever recorded was 鈥渙ver three times the size of a spacehopper and weighed as much as Beyonc茅鈥�. Brian now wonders 鈥渉ow many elephants it will take to measure how far the writers鈥� tongues are in their cheeks鈥�.
Converting Wales
FINALLY, unusual units have a new champion at 鈥� which will handily convert any mass in metric or imperial units into, for example, blue whales. Feedback is not sure they鈥檝e quite grasped the concept, though, as we find no facility to convert directly between the standard units of area: the Rhode Island and the Wales.