54 | New Scientist | 2 November 2019
Star quality
With the enormous pressure and
temperatures within Jupiter, what
is the chance that one day it could
ignite and turn itself into a star?Hillary Shaw
Newport, Shropshire, UK
Jupiter’s diameter is in fact larger
than that of the smallest star, at
140,000 kilometres against
121,000 km for the tiniest star.
However it is mass, not size,
that counts. This determines
the internal pressure that, if
sufficiently high, can overcome
the mutual repulsion of hydrogen
nuclei and convert these to helium
through nuclear fusion. This
releases the huge amount of
energy that makes stars shine.
If a large cloud of interstellar gas
came Jupiter’s way, maybe the
planet could gain enough extra
mass to start fusion. Fusion would
be short lived if it became a brown
dwarf, an object midway between
star and planet. If it accreted even
more mass, just enough to become
a true star, it would be a dim red
dwarf. Its radiation would barely
affect us and it wouldn’t look very
different to now. A bigger worry
would be Jupiter’s increased mass
disrupting the solar system, not to
mention the raised temperature of
the sun, as a result of it capturing
most of the gas cloud.Mike Follows
Sutton Coldfield, West Midlands, UK
The smallest known stars are red
dwarfs. EBLM J0555-57Ab, which is
about 600 light years away, is the
current record holder for the star
with the least mass. It is slightly
smaller than Saturn and has about
6.4 per cent the mass of the sun or
about 70 times the mass of Jupiter.Richard Swifte
Darmstadt, Germany
This subject was a theme in Arthur
C. Clarke’s novel 2010: Odyssey
Two in which Jupiter turns into a
star, albeit with help from alien
monoliths that increase the
planet’s density past a critical
point. This is the key factor ingoing from giant planet to star.
Exact figures are uncertain, but
calculations suggest Jupiter would
need to be 80 times as massive as
it is to turn into a small red dwarf
star. Another possibility, though,
is a brown dwarf, which is a kind
of half-star. This isn’t massive
enough for ordinary hydrogen to
fuse into helium as in most stars.
Instead it uses the rarer hydrogen
isotope deuterium. First predicted
by theory in the 1960s, several
brown dwarfs have been found,
faint objects emitting mostly
infrared radiation. It is estimated
a brown dwarf needs to be about
13 times the mass of Jupiter.Once upon a time
Why does my brain like
fictional stories?Graham Lawton
London, UK
In two words: survival value.
Stories are part of our evolved
nature, and are regarded as thefundamental unit of human
communication for the simple
reason that they increase our
reproductive fitness. They package
up complex and potentially
life-saving information into a
digestible, relatable and, crucially,
memorable format. This was vital
for disseminating information
orally, the only means for passing
on knowledge for most of our
evolutionary history.
Stories raise and resolve moral
ambiguities, give us heroes to root
for and villains to hate. They are
often formulaic and predictable,
which we also like. The “inciting
incident” is a well-known story
element that gives the protagonist
a goal that they strive for while
being thwarted by forces beyond
their control. Such stories allow us
to marshal our messy real lives.Of course all of these formulas are
there to be subverted, inverted
and played with, but all good
communication can ultimately
be likened to a story structure.Izzy Hanson
Bishopbriggs, Glasgow, UK
I would recommend reading any
decent introduction to writing
screenplays, which say that story
is everything and the primary job
of the writer is to create a story
that “grabs the brain by the ears”.
The brain seems to be a narrative
junkie: that’s how it makes sense
of the world, even in science. This
might be a survival trait, helping
us to know what to expect from the
world. The only problem is that
once the brain has grabbed hold
of a story, it hangs on. Even if it is
wrong... which is another story.David Muir
Edinburgh, UK
Our ancestors would have
cemented relationships with
storytelling. Stories enhance
cohesion and cooperation, giving
an evolutionary advantage.
We are neurologically adapted
to enjoy stories. The brain
chemistry of early people would
have evolved through natural
selection to that which we possess
today, and they would have
responded to a story much like us.
We empathise with fictional
heroes and emotionally live their
predicaments and struggles, all
accompanied by a cascade of
neurotransmitters in our brain.
When a hero comes good or a
baddie gets their comeuppance,
we experience a chemical hit in the
brain’s pleasure centre, and we like
it. We want more, so we buy the
next book in the series. Enjoying
stories is addictive. ❚This week’s new questions
Twit or true? Owls have become a symbol of wisdom. Are
they really so intelligent compared with other birds?
Subramaniam Divakaran, Euless, Texas, USDead before his time I have just read Poor Little Warrior, a
story about a man who time travels to the dinosaur era, dies
there and is fossilised. Can we be sure hominin fossils haven’t
met a similar fate? Edward Mynors, Walderton, West Sussex, UKWant to send us a question or answer?
Email us at [email protected]
Questions should be about everyday science phenomena
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IMAGEBROKER.COM/ARDEAAre owls brainy enough to
justify their role as a symbol
for mental prowess?