We now have
even more strong evidence that our galaxy sits inside a gigantic void, and it
could help resolve a disagreement over the speed at which the Universe is intensifying.
even more strong evidence that our galaxy sits inside a gigantic void, and it
could help resolve a disagreement over the speed at which the Universe is intensifying.
The new
study denies a basic assumption about how unusual our place is in the cosmos,
and submits that we are sitting in what could be the largest known void in the
Universe.
study denies a basic assumption about how unusual our place is in the cosmos,
and submits that we are sitting in what could be the largest known void in the
Universe.
Not that
science targets to be a giant buzzkill, but cosmologists tend to turn on the straightforward
idea that there’s nothing special about our time and place in nature until we
have some reason to contemplate otherwise.
This
assumption, founded on the cosmological principle – the spreading of matter
across space is quite even when seen from a huge enough distance – means that
when we search, our viewpoint on the Universe shouldn’t be measured
particularly unique. On scales greater than about 250 million light-years, this naturally holds true, but at certain
point, the Universe surprises to look a little like, well, Swiss cheese.
assumption, founded on the cosmological principle – the spreading of matter
across space is quite even when seen from a huge enough distance – means that
when we search, our viewpoint on the Universe shouldn’t be measured
particularly unique. On scales greater than about 250 million light-years, this naturally holds true, but at certain
point, the Universe surprises to look a little like, well, Swiss cheese.
Holes (or
voids) in the scattering of matter can occur on numerous scales, from gaps in where we’d assume stars in the middle of a galaxy to complete collections of
voids that give the presence of a 1.8 billion light year wide-ranging
“cold spot” in the Universe’s background radiation. With the idea
of dark matter, the photograph of the Universe is now one of collections of
galaxies connected by long, unseen filaments, with bubbles holding less stuff
in between.
voids) in the scattering of matter can occur on numerous scales, from gaps in where we’d assume stars in the middle of a galaxy to complete collections of
voids that give the presence of a 1.8 billion light year wide-ranging
“cold spot” in the Universe’s background radiation. With the idea
of dark matter, the photograph of the Universe is now one of collections of
galaxies connected by long, unseen filaments, with bubbles holding less stuff
in between.
The hint
that the Milky Way Galaxy sits in a backwater rather than a interstellar urban center
was suggested in 2012 by astronomers Amy Barger ,Ryan Keenan and Lennox Cowie,
who published their study on what is now mentioned to as the KBC void. Their
calculations predicted that the void could be a giant one, too. At about 1
billion light-years across, it would be 7 times larger than the average void, placing
it in the running for the leading known void in the Universe. One of
Amy Barger’s students, Ben
Hoscheit from the University of Wisconsin-Madison (UWM), has now evaluated her
previous work; presenting variations in the arrangement of the early Universe
still matches with their observations.
that the Milky Way Galaxy sits in a backwater rather than a interstellar urban center
was suggested in 2012 by astronomers Amy Barger ,Ryan Keenan and Lennox Cowie,
who published their study on what is now mentioned to as the KBC void. Their
calculations predicted that the void could be a giant one, too. At about 1
billion light-years across, it would be 7 times larger than the average void, placing
it in the running for the leading known void in the Universe. One of
Amy Barger’s students, Ben
Hoscheit from the University of Wisconsin-Madison (UWM), has now evaluated her
previous work; presenting variations in the arrangement of the early Universe
still matches with their observations.
“What
Ben has revealed is that the density shape that Keenan measured is steady with
cosmological observables,” said Amy Barger from the University of Hawaii’s
Department of Physics and Astronomy (DPA).
Ben has revealed is that the density shape that Keenan measured is steady with
cosmological observables,” said Amy Barger from the University of Hawaii’s
Department of Physics and Astronomy (DPA).
This steadiness
is important – the fact we possibly sit in a void isn’t just a piece of exciting
trivia, it disturbs how we define an important cosmological factor. The Hubble Constant (HC) is a number that defines how the Universe is expanding, evaluated
by measuring the manner light from distant objects stretches as they travel,
and then working out how far they are. While we’ve identified
for almost a century that the Universe is expanding, but in recent years, many
calculations on the constant have put forward that the rate of expansion was
much slower in the early Universe.
is important – the fact we possibly sit in a void isn’t just a piece of exciting
trivia, it disturbs how we define an important cosmological factor. The Hubble Constant (HC) is a number that defines how the Universe is expanding, evaluated
by measuring the manner light from distant objects stretches as they travel,
and then working out how far they are. While we’ve identified
for almost a century that the Universe is expanding, but in recent years, many
calculations on the constant have put forward that the rate of expansion was
much slower in the early Universe.
“No
matter what method you use, you should get the identical value for the
expansion speed of the Universe today,” says Hoscheit.
matter what method you use, you should get the identical value for the
expansion speed of the Universe today,” says Hoscheit.
These
numbers are according to the cosmological principle, so if there is something a
slight different about our place in the Universe, we might need to take that
difference into account. For instance,
one constant as restrained by the Hubble Space Telescope depends on supernovae
that shatter in galaxies nearby (and thus nearby in time) with a expected
amount of energy.
numbers are according to the cosmological principle, so if there is something a
slight different about our place in the Universe, we might need to take that
difference into account. For instance,
one constant as restrained by the Hubble Space Telescope depends on supernovae
that shatter in galaxies nearby (and thus nearby in time) with a expected
amount of energy.
Measurements
using information taken by the Planck observatory instead use the CMB (Cosmic Microwave Background).
using information taken by the Planck observatory instead use the CMB (Cosmic Microwave Background).
One understanding
for the difference is the Universe was growing slower when the radiation from
the Cosmic Microwave Background (CMB) was produced back when the Universe was beginning,
and is now expanding faster. Tiny
differences in the CMB are supposed to turn out as large-scale arrangements in
the Universe, as well as the clusters of galaxies nearby relatively empty
voids. It’s those tiny baby bubbles that Ben Hoscheit looked at.
for the difference is the Universe was growing slower when the radiation from
the Cosmic Microwave Background (CMB) was produced back when the Universe was beginning,
and is now expanding faster. Tiny
differences in the CMB are supposed to turn out as large-scale arrangements in
the Universe, as well as the clusters of galaxies nearby relatively empty
voids. It’s those tiny baby bubbles that Ben Hoscheit looked at.
Hoscheit
says, “Photons from the Cosmic Microwave Background encode a baby photo of
the very early Universe. But, actually those tiny temperature differences are precisely
what let us to conclude the Hubble Constant through this cosmic method.”
says, “Photons from the Cosmic Microwave Background encode a baby photo of
the very early Universe. But, actually those tiny temperature differences are precisely
what let us to conclude the Hubble Constant through this cosmic method.”
Hoscheit offered
his findings at a recent conference of the American Astronomical Society, so
they are yet to go through the peer-review procedure. Keeping all of that in
mind, the KBC void and its part in the Hubble Constant is still far from proven. It also
doesn’t rule out a speeding up Universe, even if it does present questions on
how we should be calculating it. In any case,
Hoscheit’s work demonstrates there are not any observations we can at this time
make to indicate the void theory is empty.
his findings at a recent conference of the American Astronomical Society, so
they are yet to go through the peer-review procedure. Keeping all of that in
mind, the KBC void and its part in the Hubble Constant is still far from proven. It also
doesn’t rule out a speeding up Universe, even if it does present questions on
how we should be calculating it. In any case,
Hoscheit’s work demonstrates there are not any observations we can at this time
make to indicate the void theory is empty.
“One
always wants to discover consistency, or else there is a difficult problem
somewhere that needs to be fixed,” says Barger.
always wants to discover consistency, or else there is a difficult problem
somewhere that needs to be fixed,” says Barger.
The study
has been presented at the 2017 American Astronomical Society conference.
has been presented at the 2017 American Astronomical Society conference.
