Scientific American Space & Physics 2020 12.pdf

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DECEMBER 2019 /JANUARY 2020 | SCIENTIFICAMERICAN.COM
Plus:
Space
&
Physics
A QUANTUM-
COMPUTING
GOLD RUSH
GRAPHENE
ELECTRONICS
BOOM
WATER ON
EXOPLANET
124 LIGHT-
YEARS AWAY
WE’RE DUE
FOR A
GEOMAGNETIC
SUPERSTORM
Galactic
Wormholes
DOES THE MOVEMENT
OF STARS AT THE
CENTER OF THE MILKY
WAY REVEAL TUNNELS
THROUGH SPACETIME?
WITH COVERAGE FROM
FROM
THE
EDITOR
&PHYSICS
Your Opinion
Matters!
Help shape the future
of this digital magazine.
Let us know what you
think of the stories within
these pages by emailing us:
editors@sciam.com.
SPACE
Wormholes within Reach?
In the 1967 episode of
Star Trek
“The City on the Edge of Forever,” the crew of the
Enterprise
finds itself on an alien
planet and discovers a large, doughnut-shaped machine referred to as a “time portal” that can transport anyone across
spacetime to any time or place in the universe. Though not explicitly called a wormhole, it is one of the earliest appear-
ances of the theorized cosmological phenomenon in popular science fiction. And certainly not the last. The intriguing
prospect of traversing hundreds of millions of light-years in an instant is explored by numerous films, from
Thor
to
Inter-
stellar—not
to mention several more episodes of
Star Trek
in all the various iterations of the franchise over many decades.
But the existence of wormholes, while hypothesized, has never been proved and remains a controversial topic in physics.
As Jonathan O’Callaghan explains in “Hidden Passage: Could We Spy a Traversable Wormhole in the Milky Way’s
Heart?” a team of researchers now proposes that we might be able to determine the existence of a wormhole by mea-
suring gravitational pulls from stars on the other side of the portal. It’s a fascinating premise, and we won’t have to wait
until stardate 48579.6 to get the results.
In a special report in this issue, we present some of the latest news on quantum technology. Investments are pouring into
this research that promises to revolutionize encryption, medical imaging and basic computing, as Elizabeth Gibney writes
in “The Quantum Gold Rush,” the first article of this series. But will the upfront costs bear fruit? Many physicists are
betting that this new wave of technology will live long and prosper. (Sorry, I had to.)
Andrea Gawrylewski
Senior Editor, Collections
editors@sciam.com
LIZ TORMES
On the Cover
Does the movement of
stars at the center of the
Milky Way reveal tunnels
through spacetime?
MARK GARLICK
GETTY IMAGES
2
WHAT’S
INSIDE
GETTY IMAGES
Volume 2
•
Number 11
December 2019-
January 2020
GETTY IMAGES
OPINION
ALFRED PASIEKA
GETTY IMAGES
NEWS
4.
Trapping
the Tiniest Sound
Controlling the smallest
unit of sound could
have applications in
quantum information
5.
New Studies Warn
of Cataclysmic
Solar Superstorms
Data suggest the 1921
New York Railroad Storm
could have surpassed the
intensity of the famous
Carrington Event of 1859
7.
Cosmology and
Exoplanets Win 2019
Nobel Prize in Physics
James Peebles, who
helped found the field of
cosmology, shares the
prize with Michel Mayor
and Didier Queloz,
discoverers of the first
exoplanet around another
sunlike star
9.
Astronomers
Find Water on
an Exoplanet Twice
the Size of Earth
Water vapor in the skies
of the world K2-18 b
may make it “the best
candidate for habitability”
currently known beyond
our solar system
12.
Hidden Passage:
Could We Spy
a Traversable
Wormhole in the
Milky Way’s Heart?
Anomalous motions of
stars orbiting our galaxy’s
central supermassive
black hole might reveal
the existence of long-
hypothesized tunnels
through spacetime
S PE CIAL R E P ORT
14.
The Quantum Gold Rush
The science is immature, and a multipurpose quantum
computer doesn’t yet exist. But that isn’t stopping
investors from pouring cash into quantum start-ups
20.
Beyond Quantum Supremacy:
The Hunt for Useful Quantum Computers
Researchers look for ways to put today’s
small noisy quantum systems to work
24.
New Encryption System Protects
Data from Quantum Computers
As quantum computing creeps closer,
IBM successfully demonstrates a way
to secure sensitive information
27.
The Crystal Kings
Two researchers in Japan supply the world’s
physicists with a gem that has accelerated
graphene’s electronics boom
35.
How Mere Humans
Manage to
Comprehend the
Vastness of
the Universe
Peering into
the unknown requires
us to recognize our own
mental blind spots
38.
The International
Space Station Is
More Valuable Than
Many People Realize
It’s crucial to our
exploration of the solar
system, but this marvel
of innovation has not
always had the support
it deserves
40.
The Moon as a
Fishing Net for
Extraterrestrial Life
Its surface could, in
principle, preserve the
remains of organisms
or even technology from
beyond our solar system
43.
I’m Convinced
We Found Evidence
of Life on Mars
in the 1970s
The Labeled Release
experiment on the
Viking mission reported
positive results, although
most have dismissed
them as inorganic
chemical reactions
46.
String Theory Does
Not Win a Nobel,
and I Win a Bet
Science writer John
Horgan wins a 2002
bet with physicist Michio
Kaku that by 2020 no
unified theory of physics
will win a Nobel Prize
49.
Celestial Movement
The sky is always
changing. To appreciate
this ever changing view,
grab these sky maps,
go outside at night and
look up!
Sky maps: December,
p. 52; and January, p. 53
3
NEWS
Controlling the smallest unit
of sound could have applications
in quantum information
GETTY IMAGES
Trapping
the Tiniest
Sound
RESEARCHERS HAVE GAINED
control of the elusive “particle” of
sound, the phonon. Although
phonons—the smallest units of the
vibrational energy that makes up
sound waves—are not matter, they
can be considered particles the way
photons are particles of light.
Photons commonly store informa-
tion in prototype quantum comput-
ers, which aim to harness quantum
effects to achieve unprecedented
processing power. Using sound
instead may have advantages, al-
though it would require manipulating
phonons on very fine scales.
Until recently, scientists lacked this
ability; just detecting an individual
phonon destroyed it. Early methods
involved converting phonons to
electricity in quantum circuits called
superconducting qubits. These
circuits accept energy in specific
amounts; if a phonon’s energy
4
NEWS
matches, the circuit can absorb it—
destroying the phonon but giving an
energy reading of its presence.
In a new study, scientists at JILA
(a collaboration between the Na-
tional Institute of Standards and
Technology and the University of
Colorado Boulder) tuned the energy
units of their superconducting qubit
so phonons would not be destroyed.
Instead the phonons sped up the
current in the circuit, thanks to a
special material that created an
electric field in response to vibra-
tions. Experimenters could then
detect how much change in current
each phonon caused.
“There’s been a lot of recent and
impressive successes using super-
conducting qubits to control the
quantum states of light. And we
were curious—what can you do with
sound that you can’t with light?”
says Lucas Sletten of U.C. Boulder,
lead author of the study published
in June in
Physical Review X.
One
difference is speed: sound travels
much slower than light. Sletten and
his colleagues took advantage of
this to coordinate circuit-phonon
interactions that sped up the
current. They trapped phonons
of particular wavelengths (called
modes) between two acoustic
“mirrors,” which reflect sound, and
the relatively long time sound takes
to make a round trip allowed the
precise coordination. The mirrors
were a hair’s width apart—similar
control of light would require mirrors
separated by about 12 meters.
Sound’s “slowness” also let the
experimenters identify phonons of
more than one mode. Typically,
Sletten says, quantum computers
increase their capacity through
additional superconducting qubits.
But having just one qubit process
information with multiple modes
could achieve the same result.
“This is definitely a milestone,”
says Yiwen Chu, a physicist at ETH
Zurich, who was not involved in the
study. Analogous experiments with
light were a first step toward much
of today’s work on quantum comput-
ers, she notes.
Similar applications for sound are
far off, however: among other things,
scientists must find a way to keep
phonons alive much longer than
they currently can—about 600
nanoseconds. Eventually, though,
the research could open new paths
forward in quantum computing.
—Leila Sloman
Outbursts from the sun, such as
this one captured by a NASA
satellite in June 2015, can wreak
havoc with power grids and
telecommunications on Earth.
Data suggest the 1921 New York
Railroad Storm could have
surpassed the intensity of the
famous Carrington Event of 1859
bility in the near future, likely causing
blackouts, satellite failures, and more.
Unlike other threats to our planet,
such as supervolcanoes or asteroids,
the time frame for a cataclysmic
geomagnetic storm—caused by
eruptions from our sun playing havoc
with Earth’s magnetic field—is com-
SOLAR DYNAMICS OBSERVATORY AND NASA
New Studies Warn
of Cataclysmic Solar
Superstorms
A POWERFUL DISASTER-INDUC-
ing
geomagnetic storm is an inevita-
5

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