BBC Focus

PHOTOS: GETTY X2

, ISTOCK

, SCIENCE PHOTO LIBRARY

Is sea level rise accelerating?

KATIE RYAN,LONDON

Globalsealevelsrosebyabout 19cm

from1900to2010,creepingupby an

average of1.7mmayear.

Since 1993,satellite measurements

have allowedus to makemoreprecise

measurements ofsealevelchange,

showing thatbetween 1993 and 2010,

sea level increased by just over 3mm

per year, almost double the average

paceforthe20thCentury.Asglobal

temperatures continue to soar,

scientists expect that sea level will

riseatevenfaster rates in coming

decades, resulting in afurther

increase in globalsealevelofup to

80cm by the end of the century.AC

WHAT IS DARK MATTER?

Over 80 per cent of the matter in the Universe
is made up of this stuff, but despite its name it
can’t simply be made up of dead stars, gas and
dust. Dark matter has to consist of something
more exotic than standard atomic particles to
ensure the Big Bang produces a universe
chemically similar to the one we see.
Such observational constraints have
forced theorists to focus on a handful of
candidates for dark matter.
Leading the pack are so-called
weakly interacting massive particles
(‘WIMPs’) and gravitinos, whose
existence is predicted by theories aimed
at unifying all the fundamental forces and
particles of nature.
The other main contenders are axions,
predicted to exist by theories of how
atomic nuclei hold together. Experiments now
underway at the LHC could soon reveal
the truth. AC

NOEASY ANSWER

Ye s. I n about 10per cent ofcases in one

study, there was some regrowth of the

tonsils after four years. This can

happen if the surgeon accidentally

leaves some ofthetonsiltissuebehind,

but it’squite common todeliberately

performapartialtonsillectomy too.

Regrowth is more common after the

ageofsevenandinindividuals with

dietshigh in sugar. LV

Can your

tonsils grow

back?

RICHARD MERRIL,LITTLEHAMPTON

Howdidcavemen cut

their toenails?

EDWARD SEYMOUR,HOVE

Theycould theoretically have used a flint

edge to trim them, or a rough stone to file

them down. However, we don’t have any

firm evidence of ‘cavemanicure’ at all,

since no fingernails or toenails survive

from anyStone Ageburialsites.Ifyou

spendyourday walkingbarefoot and

scraping up roots withyourhands, your

nailswillweardown naturally, whichis

whytheyhave evolvedtokeep growing

throughout ourlives.LV

Wading through

floodwater: still more

pleasant than

public transport