# Sterile neutrinos **URL:** \ **Category:** Factual Questions\ **Created:** [June 10, 2018, 9:42pm UTC](https://boards.straightdope.com/t/sterile-neutrinos/815843 "2018-06-10T21:42:44Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![EastUmpqua](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eastumpqua/32/6025_2.png) [@EastUmpqua](https://boards.straightdope.com/u/EastUmpqua)\ **Post date:** [June 10, 2018, 9:42pm UTC](https://boards.straightdope.com/t/sterile-neutrinos/815843/1 "2018-06-10T21:42:44Z")
If sterile neutrinos turn out to exist, can they explain the effects of dark matter? ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [June 10, 2018, 11:54pm UTC](https://boards.straightdope.com/t/sterile-neutrinos/815843/2 "2018-06-10T23:54:24Z")
Just for context, sterile neutrinos are hypothetical neutrinos that do not interact via the weak force [Sterile neutrino - Wikipedia](https://en.wikipedia.org/wiki/Sterile_neutrino) This article discusses the possibility that such particles could be “dark matter” [[1303.6912] The Phenomenology of Right Handed Neutrinos](https://arxiv.org/abs/1303.6912) and states “Sterile neutrinos are collisionless and can be very long lived, hence they are an obvious DM candidate. This scenario has been studied by a large number of authors, see e.g. [72, 74, 203, 204, 312, 358, 370, 493–514, 514–535]” ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [June 11, 2018, 12:30am UTC](https://boards.straightdope.com/t/sterile-neutrinos/815843/3 "2018-06-11T00:30:57Z")
Neutrinos, whether sterile or not, are a form of dark matter. But they aren’t the kind that forms halos around galaxies and modifies their rotation rates. What physicists and astronomers are looking is **cold** dark matter, where _cold_ means “not travelling at almost the speed of light”. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 11, 2018, 12:41am UTC](https://boards.straightdope.com/t/sterile-neutrinos/815843/4 "2018-06-11T00:41:23Z")
When sterile neutrinos are posited, they’re usually assumed to be high-mass and hence cold. There’s really no good evidence for them beyond vague handwaving, though. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [June 11, 2018, 4:23am UTC](https://boards.straightdope.com/t/sterile-neutrinos/815843/5 "2018-06-11T04:23:35Z")
But is oscillation a problem? Because the recent maybe-discovery of sterile neutrinos is based on some number of the other flavors of neutrino being expected and that number not showing up, hence some changed to the “sterile” flavor, right? But if they can oscillate to sterile it seems very likely they can oscillate back. So that would mean dark matter would oscillate to particles that can interact via the weak force, which seems like something we’d be aware of already. …or is all this just showing my lack of understanding of the topic? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 11, 2018, 1:19pm UTC](https://boards.straightdope.com/t/sterile-neutrinos/815843/6 "2018-06-11T13:19:04Z")
Weak-force interactions aren’t a big deal for dark matter particles directly: A particle can interact weakly and still do what dark matter does. The only reason we’d need to posit a sterile particle is to explain why we haven’t observed it directly.