" ... The two biggest mysteries in cosmology may be one. A new theory says
that dark matter and dark energy could arise from a single dark fluid
that permeates the whole universe. And this could mean Earth-based
dark matter searches will come up empty.
Dark matter, as originally hypothesized, is extra hidden mass that
astrophysicists calculate is necessary for holding together fast-
turning galaxies. The most popular notion is that this matter is made
of some yet-to-be-identified particle that has almost no interactions
with light or ordinary matter. Yet it seems to be everywhere, acting
as a scaffolding for galaxy clusters and the whole structure of the
universe.
On the other hand, dark energy is needed to explain the more recently-
discovered acceleration of the universe's expansion. It supposedly
exists all throughout space, delivering a pressure that counteracts
gravity.
It's counterintuitive that one substance could be both a gravitational
anchor for galaxies and anti-gravity force for the universe. However,
HongSheng Zhao of the University of St Andrews in Scotland claims that
a fluid-like dark energy can act like dark matter when its density
becomes high enough.
"Dark energy is a property of the vacuum -- of fields that we do not
easily see," Zhao told Space.com. "From it, we can derive the dark
matter effect."
Zhao compares this dark fluid to Earth's atmosphere. Atmospheric
pressure causes air to expand, but part of the air can collapse to
form clouds. In the same way, the dark fluid might generally expand,
but it also could collect around galaxies to help hold them together. ... "
that dark matter and dark energy could arise from a single dark fluid
that permeates the whole universe. And this could mean Earth-based
dark matter searches will come up empty.
Dark matter, as originally hypothesized, is extra hidden mass that
astrophysicists calculate is necessary for holding together fast-
turning galaxies. The most popular notion is that this matter is made
of some yet-to-be-identified particle that has almost no interactions
with light or ordinary matter. Yet it seems to be everywhere, acting
as a scaffolding for galaxy clusters and the whole structure of the
universe.
On the other hand, dark energy is needed to explain the more recently-
discovered acceleration of the universe's expansion. It supposedly
exists all throughout space, delivering a pressure that counteracts
gravity.
It's counterintuitive that one substance could be both a gravitational
anchor for galaxies and anti-gravity force for the universe. However,
HongSheng Zhao of the University of St Andrews in Scotland claims that
a fluid-like dark energy can act like dark matter when its density
becomes high enough.
"Dark energy is a property of the vacuum -- of fields that we do not
easily see," Zhao told Space.com. "From it, we can derive the dark
matter effect."
Zhao compares this dark fluid to Earth's atmosphere. Atmospheric
pressure causes air to expand, but part of the air can collapse to
form clouds. In the same way, the dark fluid might generally expand,
but it also could collect around galaxies to help hold them together. ... "
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