# Are neutrinos unaffected by black holes? **URL:** \ **Category:** Factual Questions\ **Created:** [October 28, 2000, 6:50pm UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754 "2000-10-28T18:50:02Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [October 28, 2000, 6:50pm UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/1 "2000-10-28T18:50:02Z")
Would a “massless” neutrino pass right through a black holes gravity well…or not? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [October 28, 2000, 6:56pm UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/2 "2000-10-28T18:56:02Z")
I don’t know the answer for sure, but my WAG would be “no,” because though nutrinos have no rest-mass, I think they have relativistic mass (because they go so fast.) ---
**Author:** ![TheNerd](https://avatars.discourse-cdn.com/v4/letter/t/858c86/32.png) [@TheNerd](https://boards.straightdope.com/u/TheNerd)\ **Post date:** [October 28, 2000, 9:55pm UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/3 "2000-10-28T21:55:12Z")
I would say, probably it would still be affected by the black hole, but for a different reason than friedo. The concept of rest mass vs relativistic mass is just to make the momentum equations look similar. It makes much more sense to just redefine momentum. (Chronos said something similar in another post a few days ago, but I’ve lost the link). Anyway, a black hole affects the curve of space-time. a neutrino traveling along a path in the curved space time will still be affected by it, much like photons (which have no mass) are. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [October 29, 2000, 12:15am UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/4 "2000-10-29T00:15:47Z")
Neutrinos would be affected by black holes, just like photons are. A neutrino inside the event horizon wouldn’t be able to escape because neutrinos travel at the speed of light and the gavitational pull would be more than the speed of light. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [October 29, 2000, 12:31am UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/5 "2000-10-29T00:31:51Z")
> [@](#): > > \*Originally posted by TheNerd \* > \*\*I would say, probably it would still be affected by the black hole, but for a different reason than friedo. > > The concept of rest mass vs relativistic mass is just to make the momentum equations look similar. It makes much more sense to just redefine momentum. (Chronos said something similar in another post a few days ago, but I’ve lost the link). > > Anyway, a black hole affects the curve of space-time. a neutrino traveling along a path in the curved space time will still be affected by it, much like photons (which have no mass) are. \*\* If photons have no mass how can their impact “push” a light sail? ---
**Author:** ![Arjuna34](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)\ **Post date:** [October 29, 2000, 2:24am UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/6 "2000-10-29T02:24:19Z")
> [@](#): > > \*Originally posted by astro \* > \*\* > > > [@](#): > > > > \*Originally posted by TheNerd \* > > \*\*I would say, probably it would still be affected by the black hole, but for a different reason than friedo. > > > > The concept of rest mass vs relativistic mass is just to make the momentum equations look similar. It makes much more sense to just redefine momentum. (Chronos said something similar in another post a few days ago, but I’ve lost the link). > > > > Anyway, a black hole affects the curve of space-time. a neutrino traveling along a path in the curved space time will still be affected by it, much like photons (which have no mass) are. \*\* > > If photons have no mass how can their impact “push” a light sail? > > \*\* Their momentum is transfered to the light sail. Arjuna34 ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [October 29, 2000, 3:38am UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/7 "2000-10-29T03:38:46Z")
In any event, whether neutrinos have mass or not, black holes are regions where (as far as we know) spacetime is curved past the point of no return. It’s not that there’s an irresistable “force” that you could “fight”; it’s that space itself is now on the Singularity Express. Once you cross the event horizon, there’s nowhere to go but down. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [October 29, 2000, 4:15am UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/8 "2000-10-29T04:15:19Z")
> [@](#): > > \*Originally posted by Arjuna34 \* > \*\* > > > [@](#): > > > > \*Originally posted by astro \* > > \*\* > > > > > [@](#): > > > > > > \*Originally posted by TheNerd \* > > > \*\*I would say, probably it would still be affected by the black hole, but for a different reason than friedo. > > > > > > The concept of rest mass vs relativistic mass is just to make the momentum equations look similar. It makes much more sense to just redefine momentum. (Chronos said something similar in another post a few days ago, but I’ve lost the link). > > > > > > Anyway, a black hole affects the curve of space-time. a neutrino traveling along a path in the curved space time will still be affected by it, much like photons (which have no mass) are. \*\* > > > > If photons have no mass how can their impact “push” a light sail? > > > > \*\* > > Their momentum is transfered to the light sail. > > Arjuna34 \*\* How can something with no mass have a transferable “momentum”? If momentum is the product of the mass of a particle and its velocity and there is no mass then how can we speak of a massless particles “momentum”. No being quarrelsome… just curious. ---
**Author:** ![Bobort](https://avatars.discourse-cdn.com/v4/letter/b/ac8455/32.png) [@Bobort](https://boards.straightdope.com/u/Bobort)\ **Post date:** [October 29, 2000, 5:30am UTC](https://boards.straightdope.com/t/are-neutrinos-unaffected-by-black-holes/38754/9 "2000-10-29T05:30:50Z")
> [@](#): > > \*Originally posted by astro \* > \*\*How can something with no mass have a transferable “momentum”? If momentum is the product of the mass of a particle and its velocity and there is no mass then how can we speak of a massless particles “momentum”. > > No being quarrelsome… just curious. > \*\* Relativistic momentum isn’t mass\*velocity. Have a look at [this](http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html#c2).