Dark matter could meet its nemesis on Earth

www.newscientist.com...

Quote from source:
A SPINNING disc may be all that is needed to overturn Newton's second law of motion - and potentially remove the need for dark matter.

The second law states that a force is proportional to an object's mass and its acceleration. But since the 1980s, some physicists have eyed the law with suspicion, arguing that subtle changes to it at extremely small accelerations could explain the observed motion of stars in galaxies.

Stars move at speeds that suggest that galaxies have far more mass than is visible, which astronomers attribute to dark matter. But if Newton's second law could be modified ever so slightly, it would obviate the need for dark matter. The hypothesis, known as modified Newtonian dynamics (MOND), was proposed in 1981 by Mordehai Milgrom, then at Princeton University.

Ground-based tests of MOND had been thought impossible because of the confounding motions of the Earth. But now, Vitorio De Lorenci of the Federal University of Itajubá, Brazil, and colleagues have devised an experiment to do just that (arxiv.org/abs/1002.2766).

The key is to cancel out the acceleration of Earth's rotation, its orbit round the sun, and the orbit of the sun round the galactic centre. The basic idea was first proposed in 2007, when Alex Ignatiev calculated that the accelerations all cancel out for a millisecond at two particular points on Earth's surface, twice a year. That makes the experiment possible in theory, but not feasible.

This is a great article and I thought I should share it.

I think all old scientific theories should be looked over as they should be constantly changing. When we learn new things the old ideas should change to accommodate the new ideas. If we hold onto older theories and take them as concrete we will not advance as fast.

I personally think that nothing is concrete, Einstein changed Newtons idea's, who's to say that Einstein's ideas will not be modified?

Great idea and great science!!

Any thoughts?

Pred..

To bad it's been deemed infeasible. An accurate measure to confirm MOND would be extraordinary. There are problems with the theory though. The bullet galaxy for example is a big problem.

The matter in galaxy cluster 1E 0657-56, fondly known as the "bullet cluster", is shown in this composite image. A mere 3.4 billion light-years away, the bullet cluster's individual galaxies are seen in the optical image data, but their total mass adds up to far less than the mass of the cluster's two clouds of hot x-ray emitting gas shown in red. Representing even more mass than the optical galaxies and x-ray gas combined, the blue hues show the distribution of dark matter in the cluster. Otherwise invisible to telescopic views, the dark matter was mapped by observations of gravitational lensing of background galaxies. In a text book example of a shock front, the bullet-shaped cloud of gas at the right was distorted during the titanic collision between two galaxy clusters that created the larger bullet cluster itself. But the dark matter present has not interacted with the cluster gas except by gravity. The clear separation of dark matter and gas clouds is considered direct evidence that dark matter exists.

apod.nasa.gov...

An empirical criticism of MOND, released in August 2006, involves the Bullet cluster, a system of two colliding galaxy clusters. In most instances where phenomena associated with either MOND or dark matter are present, they appear to flow from physical locations with similar centers of gravity. But, the dark matter-like effects in this colliding galactic cluster system appears to emanate from different points in space than the center of mass of the visible matter in the system, which is unusually easy to discern due to the high energy collisions of the gas in the vicinity of the colliding galactic clusters. MOND proponents admit that a purely baryonic MOND is not able to explain this observation.

en.wikipedia.org...