hey guys, welcome to space train.
2018 was a big year for dark matter.
As usual, astronomers didn't actually find
any of the stuff, which is invisible to all
our telescopes but appears to make up at least
80 percent of the universe by mass.
There were reports of a dark matter hurricane,
but we can't actually see it. A galaxy was
discovered that seemed not to have any dark
matter, which oddly would have proved dark
matter existed. But then it turned out that
the galaxy may have dark matter after all
— leaving the existence of dark matter in
doubt for some physicists. Multiple experiments
that were supposed to directly detect dark
matter here on Earth turned up nothing.
So, where does that leave scientists hunting
for dark matter as we head into 2019? Pretty
optimistic, all things considered. The hunt
for dark matter presses forward on all fronts.
From massive underground detectors to huge
sky surveys, here are the four major steps
in the hunt for dark matter to look forward
to in 2019.
#1. LIGO comes back online.
The Laser Interferometer Gravitational-Wave
Observatory (LIGO), the American detector
that directly observed the first gravitational
waves in 2015, will begin its third observation
run in early 2019, collecting more data than
ever before after a series of upgrades to
its equipment.
So what's a gravitational-wave detector doing
in an article about dark matter? It turns
out that there are a lot of tantalizing possibilities
for uncovering hints of dark matter using
gravitational-wave data — though none of
them have yet been realized.
Researchers in 2018 proposed that if a "dark
photon" with a very slight mass lurks somewhere
in the universe, its signal might turn up
in LIGO data, causing very specific irregularities
in the signatures of gravitational waves.
“We show that both ground-based and future
space-based gravitational wave detectors have
the capability to make a [conclusive dark
matter] discovery,” the researchers wrote.
With LIGO back online, turning up evidence
for dark matter in gravitational-wave data
is very much a live possibility.
#2. Physicists will try to figure out whether
MiniBooNE gave up the ghost of a neutrino.
Throughout 2018, scientists chattered excitedly
about intriguing results from an experiment
at Fermilab National Accelerator Laboratory,
called MiniBooNE, suggesting the presence
of particles that shouldn't exist. The best
explanation so far is that there's a fourth,
as-yet-undiscovered neutrino out there, called
the sterile neutrino, that interacts with
the rest of the universe even less than its
other neutrino cousins.
Some researchers believe that the sterile
neutrino could be a candidate particle for
dark matter, and as 2018 comes to a close,
physicists are firming up their perspectives
on this anomaly. Look for scientists thinking
in new ways about that data and sterile neutrinos
in general in 2019.
#3. First light at the Large Synoptic Survey
Telescope (LSST).
There's a telescope being built in Chile that
will make detailed images of vast regions
of the sky every 15 seconds, completing a
full scan of the sky every three days. Over
the course of 10 years, it will compare those
images to one another again and again to track
how the sky shifts and changes, providing
the most in-depth-ever resource for understanding
how dark matter pushes and pulls on the cosmos.
Scientists know, broadly, that dark matter
shapes the way galaxies and their stars move
and interact with one another. LSST's goal
is to fill out that picture, offering an unprecedented
level of detail on how the cosmos functions.
That should offer astrophysicists a wealth
of data on the nature of dark matter and the
role it plays in the universe.
And in 2019, for the first time, researchers
will open the 6,200-lb.(2,800 kilograms) eye
of that telescope and take in light. Science
operations begin in 2022.
#4. The race to build a next-generation detector
will heat up.
Particle physicists have speculated for a
long time that the first direct sign of dark
matter might be a sparkle. Here's how it might
work: As dark matter collides with inert substances
in very dark rooms, those substances would
emit faint specks of light. For decades, scientists
have built detectors according to this principle,
but so far, none have produced a conclusive
result.
In 2019, scientists in China will be hard
at work on the PandaX platform, which stares
at xenon all day and night looking for a twinkle.
Those scientists are rapidly upgrading the
detector to accommodate a 4-ton (3.6 tonnes)
xenon target, reporting that they expect to
complete most of that work over the course
of 2019 and 2020. The new detector will be
called PandaX-xt.
Not to be outdone, researchers in South Dakota
will be completing the most important phases
of construction on LUX-ZEPLIN, which will
observe a full 10 tons (9 tonnes) of xenon
nearly a mile under the town of Lead, South
Dakota. Like PandaX-xt, the project will likely
not wrap up until 2020.
Italy will also move forward on upgrading
its detector, appropriately named XENON, to
an 8-ton (7.2 tonne) scale. The upgrade, called
XENON-nt, should be wrapped up in 2019.
It's always possible that some experiment
somewhere will turn up incontrovertible, specific
evidence that a particular kind of possible
dark matter particle really exists. But in
the short term, in almost every area, physicists
are focused on using the lessons of the past
to inform bigger, better dark matter hunts
in the future. Will an incontrovertible dark
matter finding turn up in 2019? That might
be a bit optimistic. But the physicists chasing
that goal are heading into the new year arming
themselves to hunt with more precision and
power than ever before.
That's all today, see you next time, don’t
forget to free up your brain, and stay with
us. there are lots of new subjects we should
talk about.
if you are still her grab your knowledge and
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