The sun may be scooping up dark matter, changing the way it releases energy. This could have a profound effect on life on Earth.  (Source: Yohkoh satellite [Jaxa])
Sun may be acting as a scoop, picking up dark matter

Is life on Earth possible thanks to a bizarre solar effect of dark matter?

A mystery that has puzzled scientists for some time now is the solar composition problem.  The sun appears to have a much easier time transporting energy to the surface than standard models would predict based on traditional theories of its composition.  While the exact reason why this happens has been unclear, what has been clear is that it likely has profound implications on the radiation received by Earth and hence life on our planet.

Now physicists at the University of Oxford have come up with a wild new theory to explain what's going on and to better characterize our solar system's star.  Astroparticle physicist Subir Sarkar of the University of Oxford and his colleague Mads Frandsen claim in a new study that the sun acts as a vacuum cleaner, sucking up dark matter.  This dark matter could be to blame for the energy transfer effects.

Dark matter is thought to consist of WIMPs -- weakly interacting massive particles.  These particles are predicted to be 100 times more massive than a proton.  However, they're hard to observe as they only interact through the weak nuclear force and gravity.  Also, current theory states that when WIMPs come in contact with each other, they annihilate each other, spitting out particles like neutrinos.

Professor Sarkar believes in a slightly different theory.  He points out that if there were equal amounts of matter and antimatter in the original universe, they would have annihilated each other.  Rather, something seems to be favoring matter.  He believes that similarly that whatever is favoring the survival of matter could be favoring the survival of WIMPs.

He also believes that dark matter is much lighter than previously theorized -- a mere 5 times the mass of a proton.  He states, "If it were five times heavier, it would get five times the abundance. That’s what dark matter is.  That’s the simplest explanation for dark matter in my view."

If he's right, he's created a headache for the particle physics community; lighter particles are harder to detect.  Fortunately, he's also offered them a solution.  He suggests that the sun is sucking up dark matter and that by observing it, dark matter can be formally detected.  He states, "The sun has been whizzing around the galaxy for 5 billion years, sweeping up all the dark matter as it goes."

Indirect observation of the dark matter could come in the form of the unusual energy transfer to the solar surface.  While normal particles like photons would strongly interact with matter in the sun and have a much slower rate of energy transfer, dark matter mostly just interacts with itself (barring weak interactions), thus could transfer energy much faster to the surface.

According to Professor Sarkar, the numbers add up perfectly.  He states, "When we do the calculation, to our amazement, it turns out this is true.  They can transport enough heat to solve the solar composition problem."

The next step in verification will be to check the sun's neutrino output.  Two new detectors --Borexino and one in Canada called SNO+ -- will soon be fired up and Sarkar is requesting that they check to see if the solar emission rate is equivalent to what his theory predicted.

If he's right that could mean that life as we know it on Earth may be thanks in part to the solar effects of dark matter.

The study was published in the July 2 edition of the journal 
Physical Review Letters.

The work, while unproven, has already gained some high profile praise from academics in the field.  American physicist Dan Hooper of Fermilab in Illinois comments, "[The study is] not too much of a stretch, in my opinion.  I look at their numbers, and they’re very plausible to me.  There’s an increasingly compelling body of evidence accumulating [of less massive dark matter].  The jury is still out, but if this is really what’s going on, we should be able to know it with some confidence in the next year or so."

