This past 4th of July 2013, a European team of
astronomers led by Hongsheng Zhao of the SUPA
Centre of Gravity at the
University of St Andrews presented a radical new theory at the RAS National
Astronomy Meeting in St Andrews. Their theory suggested that the Milky Way and Anromeda galaxies collided
some 10 billion years ago and that our understanding of gravity is
fundamentally wrong. Remarkably, this would neatly explain the observed
structure of the two galaxies and their satellites.
In 2009, Zhao led An international team of astronomers
that found an unexpected link between 'dark matter' and the visible stars and
gas in galaxies that could revolutionize our current understanding of gravity.
Zhao suggested that an unknown force is acting on dark matter.The team believes that
the interactions between dark and ordinary matter could be more important and
more complex than previously thought, and even speculate that dark matter might
not exist and that the anomalous motions of stars in galaxies are due to a modification
of gravity on extragalactic scales.
"The dark matter seems to 'know' how the visible
matter is distributed. They seem to conspire with each other such that the
gravity of the visible matter at the characteristic radius of the dark halo is
always the same," said Dr. Benoit Famaey (Universities of Bonn and Strasbourg). "This is
extremely surprising since one would rather expect the balance between visible
and dark matter to strongly depend on the individual history of each galaxy.
"The pattern that the data reveal is extremely odd.
It's like finding a zoo of animals of all ages and sizes miraculously having
identical, say, weight in their backbones or something. It is possible that a
non-gravitational fifth force is ruling the dark matter with an invisible hand,
leaving the same fingerprints on all galaxies, irrespective of their ages,
shapes and sizes."
Such a force might solve an even bigger mystery, known
as 'dark energy', which is ruling the accelerated expansion of the Universe. A
more radical solution is a revision of the laws of gravity first developed by
Isaac Newton in 1687 and refined by Albert Einstein's theory of General
Relativity in 1916. Einstein never fully decided whether his equation should
add an omnipresent constant source, now called dark energy. Astrophyisicts Neil Degrasse Tyson has stated
that dark energy soould in fact be
renamed dark gravity.
In the image above above dark energy is represented by the purple grid above,
and gravity by the green grid below. Gravity emanates from all matter in the
universe, but its effects are localized and drop off quickly over large
distances.
Dr Famaey added, "If we account for our observations with a
modified law of gravity, it makes perfect sense to replace the effective action
of hypothetical dark matter with a force closely related to the distribution of
visible matter."
The implications of the new research could change some
of the most widely held scientific theories about the history and expansion of
the universe.
Lead researcher Dr. Gianfranco Gentile at the University
of Ghent concluded, "Understanding this puzzling conspiracy is probably
the key to unlock the formation of galaxies and their structures."
In January 2010, Erik Verlinde, professor ofTheoretical Physics and world-renowned string theorist, caused a
worldwide stir with the publication of On the Origin of Gravity and the Laws of
Newton, in which he challenged commonly held perceptions on gravity, going so
far as to state ‘for me gravity doesn’t exist’. If he is proved correct, the
consequences for our understanding of the universe and its origins in a Big
Bang will be far-reaching.
"Everyone who is working on theoretical physics is
trying to improve on Einstein," says Robbert Dijkgraaf, UvA University Professor
and current director of the Institute
for Advanced Study in
Princeton (where scientists including Turing, Oppenheimer and Einstein have
worked) In my opinion, Erik Verlinde has found an important key for the next step
forward."
Verlinde, who received the Spinoza prize (the Dutch Nobel Prize)
from the Netherlands Organisation for Science, is famous for developing this
new theory, or idea, on gravity in which he says that gravity is an illusion.
"Gravity is not an illusion in the sense that we know that things
fall," says Verline." Most people,
certainly in physics, think we can describe gravity perfectly adequately using
Einstein’s General Relativity. But it now seems that we can also start from a
microscopic formulation where there is no gravity to begin with, but you can
derive it. This is called ‘emergence’."
"We have other phenomena in Physics like
this," Verlinde continued.
"Take a concept like ‘temperature’, for instance. We experience it every
day. We can feel temperature. But, if you really think about the microscopic
molecules, there’s no notion of temperature there. It’s something that has to
do with the property of all molecules together; it’s like the average energy
per molecule."
To Verlinde, gravity is similar. It’s something that only appears
when you put many things together at a microscopic scale and then you suddenly
see that certain equations arise. "As scientists," he observes,
"we first want to understand nature and our universe. In doing so, we have
observed things that are deeply puzzling, such as phenomena related to dark
matter. We see things happening that we don’t understand. There must be more
matter out there that we don’t see. There’s also something called ‘dark
energy’. And then there’s the whole puzzle of the beginning of the universe. We
now have what is called the ‘Big Bang’ theory.
Verline belives his ideas will shed
new light on the concept of ‘dark matter’ and ‘dark energy’ and why they’re
important in relation to gravity.
"We think we understand gravity in most
situations," he says "but when we look at galaxies and, on much
larger scales, at galaxy clusters, we see things happening that we don’t
understand using our familiar equations, like Newton’s equation of gravity or
even Einstein’s gravity. So we have to assume there’s this mysterious form of
matter, which we call dark matter, which we cannot see. Now dark energy is even
weirder, in the sense that we don’t even know what it consists of. It’s
something we can put in our equations to make things work, but there’s really a
big puzzle to be solved in terms of why it’s there and what it’s made of. At
present, we have not really found the right equations to describe it. There’s
clearly progress to be made in terms of finding a bettertheory of gravity, and
understanding what’s happening in our universe."
For example, the Big Bang theory is the idea that at a
particular moment things suddenly started exploding and growing, and that our
universe got bigger, which Verlinde finds illogical to think it came from this one moment.
"It’s illogical to think there was nothing and then
it exploded. We use concepts like time and space," he adds, "but we
don’t really understand what this means microscopically. That might change. The
Big Bang has to do with our understanding of what time should be, and I think
we will have a much better understanding of this in the future. I think we will
figure out that what we thought was the Big Bang was actually a different kind
of event. Or maybe that we should not think that the universe really began at a
particular moment and that there’s another way to describe that."
Verlinde believes that the information we have today and the
equations we now use only describe a very small part of what is actually going
on. "If you think that something grows, like our universe, than something
else must become smaller," he observes."I think there’s something we
haven’t found yet and this will help us discover the origins of our universe.
In short, the universe originated from something, not from nothing. There was
something there and we have to find the equations. It has something to do with
dark energy and how that is related to dark matter. If we understand the
equations for those components of our universe, I think we’ll also have a
better understanding of how the universe began. I think it’s all about the
interplay between these different forms of energy and matter.
The Big Bang theory works well in the sense that it
gives us some understanding of how particular elements in our universe came
about and there are other things that we can observe, like the radiation that
came from the Big Bang. But the whole idea of an expanding universe that
started with a big explosion will change. "You need to think about the
equations in a bigger setting," Verlinde observes. "You need to describe more than just the
matter particles. You need to know more about what space/time is. All these
things have to come together in order to be able to explain the Big Bang."
Quantum mechanics took approximately 26 years to
develop, Verlinde concludes.
"We’ve had string theory for 40 years and nothing yet has come out of that
which can be directly tested with observations or experiments. I think my idea
has a greater chance of being tested with observations, which is an exciting
thing. I think it will take no more than 10 or 15 years."
The end result be belives will lead to a paradigm shift in how people think that
the universe was created.
Journal Reference: Gianfranco Gentile, Benoit Famaey, HongSheng Zhao, Paolo Salucci. Universality of
galactic surface densities within one dark halo scale-length. Nature, 2009; 461
(7264): 627 DOI: 10.1038/nature08437
I can respond to most of the point in above topic
ReplyDelete1. "This past 4th of July 2013, a European team of astronomers led by Hongsheng Zhao of the SUPA Centre of Gravity at the University of St Andrews presented a radical new theory at the RAS National Astronomy Meeting in St Andrews.
my comment in http://www.dailygalaxy.com/my_weblog/2013/07/is-an-unknown-force-of-the-universe-acting-on-dark-matter.html
2. "our understanding of gravity is fundamentally wrong"
3. "It is possible that a non-gravitational fifth force is ruling the dark matter with an invisible hand"
4. "Such a force might solve an even bigger mystery, known as 'dark energy', which is ruling the accelerated expansion of the Universe. A more radical solution is a revision of the laws of gravity first developed by Isaac Newton in 1687 and refined by Albert Einstein's theory of General Relativity in 1916. Einstein never fully decided whether his equation should add an omnipresent constant source, now called dark energy. Astrophyisicts Neil Degrasse Tyson has stated that dark energy soould in fact be renamed dark gravity."
5. "Verline belives his ideas will shed new light on the concept of ‘dark matter’ and ‘dark energy’ and why they’re important in relation to gravity."
my comment in http://swarajgroups.blogspot.in/2013/10/gravity-pushing-force-arising-due-to.html
http://swarajgroups.blogspot.in/2013/06/out-of-box-thinking-is-essential-in.html
6. "The team believes that the interactions between dark and ordinary matter could be more important and more complex than previously thought"
my comment in http://www.quantumdiaries.org/2013/07/01/getting-our-hands-on-dark-matter/#comment-168173
http://www.pbs.org/wgbh/nova/blogs/physics/2014/01/journey-into-the-dark-realm/
http://swarajgroups.blogspot.in/2014/02/new-space-telescope-to-map-dark-matter.html
7. ""We’ve had string theory for 40 years and nothing yet has come out of that which can be directly tested with observations or experiments. I think my idea has a greater chance of being tested with observations, which is an exciting thing. I think it will take no more than 10 or 15 years."
My work is important because I am thinking out of box, I am looking the Universe from another window (of Dark Matter & Dark Energy) while our scientific window is different but on many topic we are drawing the same picture of universe.
swarajgroups.blogspot.in