# How many Galaxies blocked by my fingernail **URL:** \ **Category:** Factual Questions\ **Created:** [November 11, 2019, 6:22pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297 "2019-11-11T18:22:43Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Nansbread1](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@Nansbread1](https://boards.straightdope.com/u/Nansbread1)\ **Post date:** [November 11, 2019, 6:22pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/1 "2019-11-11T18:22:43Z")
If i held up my hand to the sky how many galaxies are blocked by one fingernail. Is the number of galaxies blocked just on one plane or are there galaxies blocked behind other blocked galaxies in the plane that is right behind the finger nail part. In other words does it go to infinity behind that blocked part. If the answer is yes, it is infinite behind that blocked fingernail patch, then my question does not have an answer? In a finite numerical way. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [November 11, 2019, 6:34pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/2 "2019-11-11T18:34:39Z")
It’s definitely not an infinite number, because light from very distant galaxies can never reach us in order to be blocked in the first place. They are so far away, and the distance between us is growing so quickly, that even light cannot reach us - it will be farther away with every passing moment even if heading straight at us. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [November 11, 2019, 6:45pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/3 "2019-11-11T18:45:10Z")
A thumbnail is about 1.5 degrees in width at arm’s length. A thumbnail takes up probably about one-hundred-thousandth of the sphere around your eye at arm’s length. There are at least 2 trillion galaxies in the observable universe, so there are about 20 million galaxies covered up by your thumbnail at arm’s length from the point of view of your eye. ---
**Author:** ![glee](https://avatars.discourse-cdn.com/v4/letter/g/b5a626/32.png) [@glee](https://boards.straightdope.com/u/glee)\ **Post date:** [November 11, 2019, 6:52pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/4 "2019-11-11T18:52:04Z")
> [@Babale](#): > > It’s definitely not an infinite number, because light from very distant galaxies can never reach us in order to be blocked in the first place. They are so far away, and the distance between us is growing so quickly, that even light cannot reach us - it will be farther away with every passing moment even if heading straight at us. Are you saying the distant galaxies are receding from us at greater than the speed of light? I thought only massless objects could travel that fast… ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [November 11, 2019, 6:59pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/5 "2019-11-11T18:59:02Z")
> [@glee](#): > > Are you saying the distant galaxies are receding from us at greater than the speed of light? Yes. The further away an object in some other part of the universe is, the faster it is moving away from us. Not because the object is moving, but because the space in between us and it is expanding. ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [November 11, 2019, 7:13pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/6 "2019-11-11T19:13:38Z")
Just because the light will never reach us doesn’t mean there aren’t galaxies back there. It’s entirely possible there could be an infinite number of galaxies blocked by your fingernail, though we’ll likely never know for sure. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [November 11, 2019, 7:24pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/7 "2019-11-11T19:24:09Z")
This is why we need to limit the question to the observable universe (the part of the universe for which light has traveled less than 13,787,000,000 (plus or minus 20,000,000) miles to reach us). If we expand the question to any non-observable part of the universe, there’s no way to answer it. We have no idea how big the non-observable part of the universe is. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [November 11, 2019, 8:18pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/8 "2019-11-11T20:18:43Z")
> [@Wendell\_Wagner](#): > > A thumbnail is about 1.5 degrees in width at arm’s length. A thumbnail takes up probably about one-hundred-thousandth of the sphere around your eye at arm’s length. There are at least 2 trillion galaxies in the observable universe, so there are about 20 million galaxies covered up by your thumbnail at arm’s length from the point of view of your eye. This is an average of course. The galaxies in the observable universe are not all all evenly spread out, so it could be a lot less or a lot more. ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [November 11, 2019, 8:26pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/9 "2019-11-11T20:26:19Z")
Here’s the obligatory link to one of the [Hubble (Ultra) Deep Field](https://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field#/media/File:Hubble_ultra_deep_field_high_rez_edit1.jpg) images. Rather than your fingernail, this image spans about the size of a pencil dot marked on your fingernail, about 0.1 mm x 0.1 mm at 1 meter. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 11, 2019, 8:31pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/10 "2019-11-11T20:31:47Z")
> [@RickJay](#): > > This is an average of course. The galaxies in the observable universe are not all all evenly spread out, so it could be a lot less or a lot more. But it shouldn’t be that much more or less. Galaxies are found in dense clusters and filaments, with voids in between, so in the relative near universe, there will be a lot of variation in the numbers. But going out all the way to the edge, these will average out and the numbers will be about the same. ---
**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:** [November 11, 2019, 8:39pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/11 "2019-11-11T20:39:32Z")
To be clear, in **Pasta** ’s link, three of those dots (the ones with crosshairs on them) are faint stars in our own Galaxy that just happened to photobomb that image (they tried to get as few as possible in the frame, but it’s tough to entirely avoid all stars). Everything but those three is an entire galaxy. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 11, 2019, 9:12pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/12 "2019-11-11T21:12:09Z")
I see 4 stars with diffraction spikes (the crosshairs) on them. One near the top about halfway to the right edge, one just right of center, one below center near what looks like merging galaxies, and the fourth at the very bottom center. And just to note, even the very faintest dots that you can barely make out are mostly galaxies[sup]1[/sup]. And there’s likely some galaxies that are too small and faint to show up in that part of space. [sup]1[/sup] A few could be extremely faint red dwarf stars in our own galaxy. Those would not show diffraction spikes. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [November 11, 2019, 9:24pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/13 "2019-11-11T21:24:53Z")
> [@glee](#): > > I thought only massless objects could travel that fast… The fabric of space itself is what’s expanding. ---
**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:** [November 11, 2019, 9:43pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/14 "2019-11-11T21:43:13Z")
Ah, yes, I missed the bluish one right at the bottom. Still, the vast majority are galaxies. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [November 11, 2019, 9:48pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/15 "2019-11-11T21:48:42Z")
> [@Wendell\_Wagner](#): > > This is why we need to limit the question to the observable universe (the part of the universe for which light has traveled less than 13,787,000,000 (plus or minus 20,000,000) miles to reach us). 13.7 billion light years, not miles. And don’t forget that the most distant galaxies that we can see are now about 45 billion light years away, but were much closer when they emitted the light. Expanding space is _weird_ ---
**Author:** ![Nansbread1](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@Nansbread1](https://boards.straightdope.com/u/Nansbread1)\ **Post date:** [November 11, 2019, 10:07pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/16 "2019-11-11T22:07:59Z")
This whole Universe thing is getting far too crazy. Billions of light years away and trillions of galaxies. That photo of a pin head sized area from Hubble deep space images is mind boggling. And 1 light year is 6 trillion miles. So a billion light years…why do we even bother I think mankind should just give up trying to understand this shit. We will forever be earthbound and maybe that is what the universe is trying to tell us. The space is too vast to venture out. Stay on your planet and enjoy it. ---
**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:** [November 11, 2019, 10:28pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/17 "2019-11-11T22:28:57Z")
But that’s the beauty of it: We _can_ understand it. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [November 11, 2019, 11:22pm UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/18 "2019-11-11T23:22:03Z")
My apologies. That was a stupid mistake on my part. Yes, it should have said “(13,787,000,000 (± 20,000,000)) \* (6,000,000,000,000) miles”. ---
**Author:** ![TreacherousCretin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/treacherouscretin/32/476_2.png) [@TreacherousCretin](https://boards.straightdope.com/u/TreacherousCretin)\ **Post date:** [November 12, 2019, 12:13am UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/19 "2019-11-12T00:13:19Z")
> [@Nansbread1](#): > > This whole Universe thing is getting far too crazy. Billions of light years away and trillions of galaxies. That photo of a pin head sized area from Hubble deep space images is mind boggling… Not a pinhead. A grain of sand held at arm’s length. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [November 12, 2019, 1:02am UTC](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297/20 "2019-11-12T01:02:36Z")
> [@TreacherousCretin](#): > > Not a pinhead. A grain of sand held at arm’s length. Or about 1/10 the apparent diameter of the Moon. (So 1/100 the area of the Moon.) [Next page](https://boards.straightdope.com/t/how-many-galaxies-blocked-by-my-fingernail/843297.md?page=2)