Contrary to what was previously assumed, an explosion caused by the
collision of two neutron stars has the exact form of a spherical. Although
it is currently unclear how this is feasible, the finding could offer a new
way to understand basic physics and calculate the age of the universe.
Astrophysicists from the University of Copenhagen produced the finding,
which has now been reported in the journal Nature.
Black holes, the atoms in the gold ring on your finger, and the iodine in
our bodies were all created by kilonovae, the enormous explosions that take
place when two neutron stars circle each other and eventually collide. These
result in the universe's most severe physical circumstances, which are what
causes the universe to produce the heaviest elements of the periodic table
like gold, platinum, and uranium.
But there is still a lot about this terrible occurrence that we do not
understand. It wasn't until a kilonova was discovered in 2017 at a distance
of 140 million light-years that researchers could compile thorough
information. The data from this enormous explosion is still being
interpreted by scientists all across the world, including Albert Sneppen and
Darach Watson from the University of Copenhagen, who discovered a startling
finding.
"You have two extremely small stars that circle one another 100 times per
second before squeezing together. The explosive cloud produced by the impact
must have a flattened and somewhat asymmetrical structure, according to our
intuition and all prior models, says Albert Sneppen, a PhD student at the
Niels Bohr Institute and the study's first author. The research was
published in the journal Nature.
He and his study associates were so taken aback to see that this is in fact
not the case with the kilonova from 2017. It resembles a perfect spherical
in form and is entirely symmetrical.
"Nobody anticipated the explosion to appear this way. That it is spherical,
like a ball, defies logic. Yet it's evident from our calculations that it
is. According to Darach Watson, an associate professor at the Niels Bohr
Institute and the study's second author, this suggests that crucial physics
are missing from the theories and simulations of kilonovae that have been
under consideration over the past 25 years.
The spherical form is mysterious.
Yet the main puzzle is how the kilonova can be spherical. The researchers
conclude that there must be surprising physics at work:
"If a tremendous amount of energy blasts out from the explosion's core,
smoothing out an otherwise asymmetrical form, it is the most likely approach
to make the explosion spherical. Furthermore, the spherical form indicates
that the collision's center likely contains a significant amount of energy,
which was unexpected, according to Albert Sneppen.
The neutron stars temporarily combine into a single hypermassive neutron
star during the collision before collapsing into a black hole. The
researchers question if a significant portion of the secret is concealed in
this collapse:
"Maybe a type of'magnetic bomb' is triggered when the star falls into a
black hole, releasing energy from the hypermassive neutron star's massive
magnetic field. The distribution of materials in the explosion may become
more spherical due to the release of magnetic energy. The formation of the
black hole may then be quite energetic, according to Darach Watson.
But, another feature of the researchers' discovery is not adequately
explained by this explanation. All of the elements generated are heavier
than iron, but according to earlier theories, the really heavy elements,
like gold or uranium, should form in different locations in the kilonova
than the lesser elements, like strontium or krypton, and they should be
ejected in separate directions. Yet, only the lighter components, which are
equally scattered throughout space, are detected by the researchers.
They consequently think that the mysterious elementary particles known as
neutrinos, about which a great deal is still unknown, also have a
significant impact on the phenomena.
"An alternate hypothesis is that the hypermassive neutron star emits
extremely strongly during each millisecond of its existence, maybe
containing a large amount of neutrinos. Overall, neutrinos can lead to the
transformation of neutrons into protons and electrons, producing a greater
number of lighter elements. Although there are problems with this theory as
well, according to Albert Sneppen, neutrinos may be even more crucial than
previously imagined.
A New Cosmic Authority
The explosion's form is also intriguing for a completely other
reason:
There is a lot of debate among astrophysicists over how quickly the
universe is expanding. Among other things, the speed reveals the age of the
universe. And there are two ways to estimate it, but they differ by around a
billion years. According to Albert Sneppen, "We may have a third technique
here that may complement and be compared to the other metrics.
The technique now in use to gauge how quickly the Universe is expanding is
referred to as the "cosmic distance ladder." To achieve this, all that has
to be done is to calculate the distances between the many cosmic objects
that serve as the ladder's rungs.
Darach Watson adds, "If they are brilliant and largely spherical, and if we
know how far away they are, we can use kilonovae as a new technique to
measure the distance independently - a new form of cosmic ruler."
"Understanding the geometry of the item is important since non-spherical
objects produce light differently depending on your viewing angle. A
spherical explosion offers substantially higher measuring precision.
He underlines that further information from kilonovae is needed for this.
In the upcoming years, they anticipate that the LIGO observatories will find
a significant number more kilonovae.
The following researchers contributed to the work: Albert Sneppen and
Darach Watson from the Cosmic Dawn Center / Niels Bohr Institute,
University of Copenhagen; Andreas Bauswein and Oliver Just, GSI Helmholtzzentrum für
Schwerionenforschung, Germany; Rubina Kotak from the University of
Turku, Finland; Ehud Nakar and Dovi Poznanski from
Tel Aviv University, Israel; and Stuart Sim from
Queen’s University Belfast, UK.
