Scientists say they are now ‘99% certain’ the Sun is surrounded by dark matter, a phenomenon first proposed in the 1930s by a Swiss astronomer.
Fritz Zwicky, who came up with the theory decades ago, believes that clusters of galaxies were filled with a mysterious dark matter that kept them from flying apart.
At nearly the same time, Jan Oort in the Netherlands discovered that the density of matter near the Sun was nearly twice what could be explained by the presence of stars and gas alone.
Yet even today, mystery surrounds whether dark matter actually exists at all, let alone where it is.
The team in Zurich created a high resolution simulation of the milky way to test their theory, and found that large quantities of dark matter existed around the sun.
However, an international team led by researchers of the University of Zürich have developed a new theory – and built a state-of-the-art simulation of the Milky Way to test their mass-measuring method before applying it to real data.
They found that techniques used over the past twenty years were biased, always tending to underestimate the amount of dark matter in the universe.
The researchers then developed a new unbiased technique that recovered the correct answer from the simulated data.
Applying their technique to the positions and velocities of thousands of orange K dwarf stars near the Sun, they obtained a new measure of the local dark matter density.
The high resolution simulation measured the amount of mass in the galaxy to predict where dark matter was
‘We are 99% confident that there is dark matter near the Sun,” says the lead author Silvia Garbari.
In fact, if anything, the authors’ favoured dark matter density is a little high: they find more dark matter than expected at 90% confidence.
There is a 10% chance that this is merely a statistical fluke, but if future data confirms this high value the implications are exciting as Silvia explains:
‘This could be the first evidence for a “disc” of dark matter in our Galaxy, as recently predicted by theory and numerical simulations of galaxy formation, or it could mean that the dark matter halo of our galaxy is squashed, boosting the local dark matter density.’
Co-author Prof. George Lake said: ‘If dark matter is a fundamental particle, billions of these particles will have passed through your body by the time your finish reading this article
‘Experimental physicists hope to capture just a few of these particles each year in experiments like XENON and CDMS currently in operation.
‘Knowing the local properties of dark matter is the key to revealing just what kind of particle it consists of.’