pioneer puzzle

[miriam_e]

Anybody see this before? I found out about it through the new Australian science magazine Cosmos. Space.com has a good article on the problem at http://www.space.com/scienceastronomy/mystery_monday_041018.html

The two old Pioneer spacecraft 10 and 11 have been heading out of our solar system for the last 34 years in opposite directions, but it turns out that they are not where they "should" be. The calculations are just a tiny bit out -- by about 400,000km, which sounds like a lot to us here on Earth, but out there it is a miniscule compared to the distance they've traveled.

Something is slowing their travel more than expected. What could it be? After posing many possibilities, all but 3 have been investigated and dismissed. Those 3 are:

    • dark matter
    • some other unknown force
    • our understanding of gravity is incomplete

Edit: the list of undiscounted possibilities is greater than those 3 above. See the article at http://en.wikipedia.org/wiki/Pioneer_anomaly for lots more info. Thanks to keithlard.

Comments

unholy blasphemer!

[j03j03.livejournal.com]

what!? are you suggesting there is something the human race does not yet understand!?

All three?

[exileinparadise.livejournal.com]

Dark matter exerting an unknown force that affects gravity in ways we don't understand because our understanding of gravity is incomplete?

[ratfan.livejournal.com]

Hm...lock on the tractor beam and reel it in!

Rats In Space