Elusive Dark Matter

[ronians1]

Considering the fact that the Universe is principally made up of Dark Matter, how is it that the spacecraft Voyager that started its journey about forty years ago and has travelled a billion or so miles in space has not hit/encountered Dark Matter?

[swansont]

Considering the fact that the Universe is principally made up of Dark Matter, how is it that the spacecraft Voyager that started its journey about forty years ago and has travelled a billion or so miles in space has not hit/encountered Dark Matter?

 

Who is to say it hasn't encountered any dark matter? DM manifests itself on the scale of galaxies, where its effects are obvious. That tens of thousands of light-years. A billion or so miles is somewhere around 2 light-hours.

 

Voyager 1 is actually about 11 billion miles, or 17 light-hours, away from us. 17,500 years from getting to 1 light year.

http://en.wikipedia.org/wiki/Voyager_1#Current_status (See Sep 2012 entry)

[Airbrush]

Dark matter is so subtle that even our best detection devices are hard pressed to find any evidence of it. Voyager was not designed to find it. Interesting about Voyager's current distance.

Edited February 19, 2013 by Airbrush

[Enthalpy]

Normal and dark matter are very dilute, at the scale of a galaxy; in addition, dark matter interferes very little with normal one, as a hypothesis. Put both together, one doesn't expect an observable effect.

[ACG52]

But these guys seem excited. Note that they're particle physicsts, not astronomers or cosmologists.

 

http://www.space.com/19845-dark-matter-found-nasa-experiment.html

 

 

BOSTON — Big news in the search for dark matter may be coming in about two weeks, the leader of a space-based particle physics experiment said today (Feb. 17) here at the annual meeting of the American Association for the Advancement of Science.

 

That's when the first paper of results from the Alpha Magnetic Spectrometer, a particle collector mounted on the outside of the International Space Station, will be submitted to a scientific journal, said MIT physicist Samuel Ting, AMS principal investigator.

Though Ting was coy about just what, exactly, the experiment has found, he said the results bear on the mystery of dark matter, the invisible stuff thought to outnumber regular matter in the universe by a factor of about six to one.

 

"It will not be a minor paper," Ting said, hinting that the findings were important enough that the scientists rewrote the paper 30 times before they were satisfied with it.

 

 

I don't think they'd have gone through 30 rewrites to announce there is no dark matter. WIMPS anyone?

Edited February 20, 2013 by ACG52

[imatfaal]

Can you detect a WIMP in a magnetic spectrometer? Maybe they found stranglets?

 

 

Edit Just noticed on AMS home page that they believe they can (they hope) spot Neutralinos via cascade patterns upon collision - and stranglets by very high mass/charge ratio.