94 | New Scientist | 21/28 December 2019
The back pages Puzzle answers
#34 Ant on a tetrahedron
First spider patrols this wireSecond spider patrols
this wireThird spider patrols
a cycle of the other
4 sidesQuick Crossword #47
ACROSS 8 Velcro, 9 Eta, 10 Ibex, 11 Geneticist,
12 Haar, 13 Glitch, 16 Asio otus, 17 Czerski,
18 Squares, 22 Obsidian, 25 Acetic, 26 Inga,
27 Oncologist, 30 Biro, 31 Eye, 32 Déjà vuDOWN 1 Meme, 2 Acne, 3 Novichok,
4 Webinar, 5 Canthi, 6 Dichromate,
7 Déjà vu, 14/23 Liz Bonnin, 15 Terminator,
19 Quaalude, 20 Epi, 21 Unscrew, 24 Isomer,
28 Goji, 29 SaveTwo spiders patrol up and down a wire each,
removing them from the possible routes of the
ant. The four remaining wires form a connected
path that the final spider can keep going round
to eventually catch the slightly slower ant. To
prevent the ant quickly darting onto their wires
to get behind the chasing spider, the first two
spiders should reach the end of their edges to
meet the third spider as it goes past.Celestial crossword
I have received 42 geese-a-laying and the same
number of swans-a-swimming. The pattern
goes 12 x 1 (partridges), 11 x 2 (turtle doves),
10 x 3 (French hens) and so on, reaching a
maximum at 6 x 7 and 7 x 6.23 December 2020. The total number of gifts
I received was 1 + (1+2) + (1+2+3) +... +
(1+2+3+4+5+6+7+8+9+10+11+12).
Add that lot up and you get 364. If I give away
the first gift on 26 December, I give away the
last gift 363 days later. In most years, that
would be Christmas Eve, but because 2020
is a leap year, it will be a day earlier.RADIAL
1 Erasure, 2 Salivate, 3 Sniper, 4 Landmass,
5 Else, 6 Debark, 7 Overseas, 8 Torsion, 10 Roe,
11 Armpit, 12 Maui, 13 Genteel, 15 Nacre,
16 Ethic, 20 Prius, 24 Try this, 25 Unicode,
26 Satyr, 27 Aperçu, 28 Tidal, 29 Urine,
31 Who’d’ve, 32 Apnoea, 33 Duke,
35 Maroon, 39 On Cue, 40 Jets, 42 Kinds,
44 Ache, 45 Ohio, 50 Tr iRING
6 Doubt, 9 Dream, 14 Inept, 17 Unessential,
18 Anus, 19 Pupa, 21 Lever, 22 Odour,
23 Watt-Hour, 28 Turns, 30 Be warned,
34 Munich, 35 Mona Lisa, 36 Sip, 37 Ride,
38 Soju, 41 Teriyaki, 43 Tedium, 44 Arson,
46 Electric, 47 Ransacked, 48 Octet, 49 Heart,
51 Honorary, 52 Clews, 53 Heaven, 54 Spoil,
55 Period, 56 Deter, 57 Mercury, 58 Tsetse,
59 Apex, 60 IroquoisSecret message: “De revolutionibus”.
Nicolaus Copernicus’s 1543 De Revolutionibus
Orbium Coelestium proposed that Earth orbits
the sun, rather than the other way around.#35 Christmas gifts part 1
Christmas gifts part 2
We are looking for a year that is in the fairly near
future and is a square number. The square root of
the current year, 2019, is a little under 45, so the
next square year will be 452 = 2025, meaning
Natalie was born in 2025 - 45 = 1980.The difference between two squares,
a2 – b2, is the same as (a + b)(a – b).
68 + 32 = 100, and 68 – 32 = 36,
so 682 – 322 = 100 x 36.
Similarly, 592 – 412 = 100 x 8.
So (682 – 322 )/(592 – 412 ) = 36/18 = 2.A solution:#36 All squares
#37
#38 Meaningful matches
#39
1 C The practice mimics how mothers in
the wild feed joeys “pap”, a watery mixture
of partly digested food and bacteria
2 D People who claim to have heard
the northern lights variously say they
sound like flocking birds, the rustle of
a silken skirt and bacon sizzling in a pan
3 B In July, the figure stood at 58 out
of a total of 562
4 D Researchers are investigating using
slimmer materials such as carbon nanotubes
5 A The crabs remembered their way
through the maze two weeks later
6 D It is also highly probable that
gravitational forces would string you
out into spaghetti before you found
out which answer is true
7 C The dark biosphere could contain
a staggering 10^30 microbial cells
8 B The survey of 55,000 European
over-50s confirmed that kids are a
delight, but only when you don’t have
to look after them
9 C 11.6 billion, to be precise
10 C or D Contrary to popular wisdom, the
researchers found that the order of drinking
them didn’t matter. However, “subjective
signs of progressive intoxication were
confirmed as accurate predictors of hangover
severity”, so maybe answer D is safest
11 A The lava tubes are natural cylindrical
caves created by ancient lava flows.
They could be more than 200 metres
wide and stretch for kilometres
12 B The conclusion was broadly valid
regardless of discipline. Tell your boss.
13 D Comb jellies don’t have A, B or C
anyway. Uniquely, this comb jelly’s anus
appears to be transient, appearing only
when the animal needs to defecate
14 B We can’t actually do the experiment
to see if it’s true yet, though
15 C, although A and B also happened
16 D Among the classic moves mastered
by Snowball were the down-shake,
the foot-lift down swing, the headbang
and the headbang with lifted foot
17 B They could buy a sack of the
Sunshine State’s finest on arrival
at their destination for $3
18 A What variety was not reportedHow did you do?
14-18 correct answers Is that
a stack of New Scientists we see
beside you? Congratulations – you are
a winner in the game of remembering
important science stuff
9-13 50 per cent of success is down to luck,
right? Well done for entering the realm of skill
4-8 The existence of contradictory realities
obviously led you astray. Better luck
working out what is real next time
0-3 Were you sucked down a black hole
on 1 January and only just emerged again?
Get yourself a New Scientist subscription
for 2020 and keep up to speed with what
really matters!Quiz of the year