13 ms·

Observable Universe contains 10x more galaxies than previously thought (2016)

178 points by mkempe 9y ago

arghwhat 9y ago
... isn't our error margin much larger than this?
Razengan 9y ago
And some people still aren’t sure if there is other life beyond Earth. :) That's entire galaxies. Not just stars, and that's just the observable universe. We are still being surprised by the lifeforms we observe here on Earth, and the environments and conditions they can thrive in (including the outer hulls of our spacecraft), and we still have yet to discover and catalog all the life on our planet. Life may even come in the form of "artificial" constructs that build, learn, teach and reproduce on their own, created by "natural" life somewhere then set free into the cosmos. How, when given the evidence of practically infinite planets out there (considering that almost every star may have at least one planet, and there are even rogue planets [0] that don't orbit any star, and that asteroids and comets or even dense nebulas could also harbor life), can we even consider the possibility that this is the only planet with life? This game is Big, folks: Even if 90% of all planets had life there would still be billions if not trillions of them without any life, and the incomprehensibly vast distances (including voids, like the one our own galaxy is near or inside of [1]) between them may mean millions of years before life from one planet encounters life from another (which is good I suppose; every species would have some room to expand into at their own pace.) And of course, not all intelligent civilizations will be "successful." We will either die out on our home planet or expand. We may not encounter other life for hundreds or even thousands of year after we develop interstellar travel, or the life that we encounter may turn out to be mundane and eventually unexciting (I mean, imagine being an spacefaring species discovering us; planetlocked and still collectively figuring many basic things out.) [0] https://en.wikipedia.org/wiki/Rogue_planet https://en.wikipedia.org/wiki/Rogue_planet [1] https://en.wikipedia.org/wiki/Milky_Way#Environment https://en.wikipedia.org/wiki/Milky_Way#Environment
- coldtea 9y ago
  >How, when given the evidence of practically infinite planets out there (considering that every star has at least one planet, and there are even rogue planets [0] that don't orbit any star), can we even consider the possibility that this is the only planet with life? For the "rogue" planets, it's easy -- we can be pretty sure they don't have any life. For the others, we'll believe it when we see it.
  - Razengan 9y ago
    > For the "rogue" planets, it's easy -- we can be pretty sure they don't have any life. Why? Even if you assume all life requires heat and/or light, a rogue planet could produce heat/light from geothermal or other chemical activity. A rogue planet drifting through certain nebulas might have more surrounding material for the processes of life to work with. The life on a rogue planet may even be "artificial", say a colony of self-sufficient, self-replicating AI machines that originated elsewhere, but otherwise in-differentiable from "naturally-evolving" life.
    - TeMPOraL 9y ago
      > A rogue planet drifting through certain nebulas might have more surrounding material for the processes of life to work with. Keep in mind that nebulae are in reality less dense than industrial-grade vacuum. From the point of view of a rouge planet passing through one, it's pretty much still empty space.
      - Razengan 9y ago
        What about the regions of nebulas that are about to coalesce into stars? Wouldn’t they have some kind of protostellar “stuff” at point that makes the region more active than the rest of the average nebula? https://en.wikipedia.org/wiki/Molecular_cloud https://en.wikipedia.org/wiki/Molecular_cloud
- jobigoud 9y ago
  We don't know the probability of life arising from matter. We haven't replicated that emergence yet. If that p is something like 1/10^100 due to some compounding factors, we are alone in the observable universe.
mrarjen 9y ago
Just imagine all the stuff that's not giving off light or anything observable by us at this time. Rogue planets and what not should be everywhere no?
ngcc_hk 9y ago
Need less dark mass and dark energy then. ...
- SEMW 9y ago
  No? The data for the makeup of energy in the universe is mostly from CMB anisotropy (plus various measures of how fast the universe is accelerating, like how much supernovae have been redshifted). Finding out that galaxies in the early universe used to be smaller and more numerous than previously thought doesn't much affect any of that. (there's quite a lot of different data sources now all pointing towards an omega_lambda of 0.7). To be clear, per the article, the new discovery isn't about the early universe being a significantly different density (i.e. anything other than 'approximately flat', total omega ≈ 1) than the current one. Like, it's not that there was more mass-energy in it that's somehow vanished, rather that it's just distributed between more & smaller galaxies
almavi 9y ago
I don't understand. They say the observable universe contains 10x more galaxies than previously thought, and the reason for that is the concentration of galaxies being greater in the part of the universe that our telescopes can't see?
- bergoid 9y ago
  What they mean is that these unseen galaxies are within the radius of the observable universe, but too faint to be detected with current telescopes.
- im3w1l 9y ago
  "observable universe" is a technical term for the part of the universe from which light has had enough time to travel to us. It doesn't mean we can literally observe it using current tech.
  - almavi 9y ago
    Ok, I was missing the technical definition. Thank you very much!
- andyjohnson0 9y ago
  The Observable Universe is the part of the total universe that we can theoretically observe because electromagnetic radiation from it has had time to reach us. In practice, some of this radiation will be detectable with current technology and some of it will be too faint. The article is about work, using models of galaxy formation, that tries to better estimate the number of galaxies we can't detect due to limits on telescope sensitivity, but which are nevertheless theoretically observable. It might be useful to describe the detectable part of the observable universe as the "visible universe", but astronomers have a different meaning for that. See https://en.wikipedia.org/wiki/Observable_universe https://en.wikipedia.org/wiki/Observable_universe.
  - almavi 9y ago
    Yeah, I understand this now, thanks.
ttoinou 9y ago
I think other lifeforms exist in the universe, but the probability that they live in the same timeframe or that the two lifeforms meet each others is ridiculous
- olegkikin 9y ago
  Vlad the Astrophysicist https://www.youtube.com/watch?v=o9kbcGfX35M https://www.youtube.com/watch?v=o9kbcGfX35M
kulu2002 9y ago
Like Carl Sagan rightly said - "Cosmos is also within us. We're made of star stuff. We are a way for the cosmos to know itself.” We need to study ourselves more to comprehend this vastness.. [1] https://www.sciencealert.com/physicists-show-that-our-brains-s-learning-is-controlled-by-entropy https://www.sciencealert.com/physicists-show-that-our-brains...
- luxcem 9y ago
  "Given enough time hydrogen starts to wonder where it came from and where it is going."
- deleted 9y ago
  [deleted]
0xBA5ED 9y ago
Staring into those deep field images sometimes gives me an out-of-body sensation. The vastness of it is so over-the-top.
- mtgx 9y ago
  If looking at a few images gives you that sensation, then you should try out the Space Engine (traveling through space in 3D): http://spaceengine.org/ http://spaceengine.org/ A demo: https://www.youtube.com/watch?v=ve0Bpmx8Fk0 https://www.youtube.com/watch?v=ve0Bpmx8Fk0
  - 0xBA5ED 9y ago
    Thanks. I've already played with this and it's awesome.
dahart 9y ago
From 2012: "But even the XDF is not optimized for finding these galaxies; we’d need an infrared space telescope for that, which is what James Webb is going to be. When that comes around, I wouldn’t be surprised to find that there are maybe even close to a trillion galaxies in the observable Universe; we just don’t have the tools to find them all yet. In the meantime, our best tool—the Hubble Space Telescope—is showing us that the deeper we look, the more we’ll continue to be rewarded with new, faint, and distant galaxies, as well as richer details in the already discovered ones. "It makes me so impatient for a more powerful telescope with the ability to see far into the infrared, because I can’t help but wonder what’s still invisible to even the XDF. Twice as many galaxies? Four times? Fainter ones, redder ones, more distant ones, or all of them? There’s at least 176 billion of them in our Universe, but I can’t help wonder, “how many more?”" http://blogs.discovermagazine.com/crux/2012/10/10/how-many-galaxies-are-there-in-the-universe-the-redder-we-look-the-more-we-see/ http://blogs.discovermagazine.com/crux/2012/10/10/how-many-g... "It boggles the mind that over 90% of the galaxies in the Universe have yet to be studied." Maybe this one's different, but when discussing astronomical terms, a factor of 10 doesn't ever surprise me. What does surprise me, continuously, is how many unimaginably large numbers of factors of 10 are involved in anything related to the size of the universe. There are so many estimated stars in the universe, it would make little difference to my already boggling mind if our estimates were off by a factor of a million.
pedro_hab 9y ago
I wonder if this has some impact in our (mis)understarding of dark-matter/dark-energy, and how the universe expands.
rdruxn 9y ago
I’ve seen a lot of posts recently discussing humanity’s concept of the size of the cosmos throughout history, but never a timeline of discoveries and the prevailing estimate du jour. I would love to see something like that and Wikipedia doesn’t do it justice.
taloft 9y ago
"The Universe is a pretty big place. If it's just us, seems like an awful waste of space."

178 points by mkempe 9y ago

... isn't our error margin much larger than this?

And some people still aren’t sure if there is other life beyond Earth. :) That's entire galaxies. Not just stars, and that's just the observable universe. We are still being surprised by the lifeforms we observe here on Earth, and the environments and conditions they can thrive in (including the outer hulls of our spacecraft), and we still have yet to discover and catalog all the life on our planet. Life may even come in the form of "artificial" constructs that build, learn, teach and reproduce on their own, created by "natural" life somewhere then set free into the cosmos. How, when given the evidence of practically infinite planets out there (considering that almost every star may have at least one planet, and there are even rogue planets [0] that don't orbit any star, and that asteroids and comets or even dense nebulas could also harbor life), can we even consider the possibility that this is the only planet with life? This game is Big, folks: Even if 90% of all planets had life there would still be billions if not trillions of them without any life, and the incomprehensibly vast distances (including voids, like the one our own galaxy is near or inside of [1]) between them may mean millions of years before life from one planet encounters life from another (which is good I suppose; every species would have some room to expand into at their own pace.) And of course, not all intelligent civilizations will be "successful." We will either die out on our home planet or expand. We may not encounter other life for hundreds or even thousands of year after we develop interstellar travel, or the life that we encounter may turn out to be mundane and eventually unexciting (I mean, imagine being an spacefaring species discovering us; planetlocked and still collectively figuring many basic things out.) [0] https://en.wikipedia.org/wiki/Rogue_planet https://en.wikipedia.org/wiki/Rogue_planet [1] https://en.wikipedia.org/wiki/Milky_Way#Environment https://en.wikipedia.org/wiki/Milky_Way#Environment

coldtea 9y ago
>How, when given the evidence of practically infinite planets out there (considering that every star has at least one planet, and there are even rogue planets [0] that don't orbit any star), can we even consider the possibility that this is the only planet with life? For the "rogue" planets, it's easy -- we can be pretty sure they don't have any life. For the others, we'll believe it when we see it.
- Razengan 9y ago
  > For the "rogue" planets, it's easy -- we can be pretty sure they don't have any life. Why? Even if you assume all life requires heat and/or light, a rogue planet could produce heat/light from geothermal or other chemical activity. A rogue planet drifting through certain nebulas might have more surrounding material for the processes of life to work with. The life on a rogue planet may even be "artificial", say a colony of self-sufficient, self-replicating AI machines that originated elsewhere, but otherwise in-differentiable from "naturally-evolving" life.
  - TeMPOraL 9y ago
    > A rogue planet drifting through certain nebulas might have more surrounding material for the processes of life to work with. Keep in mind that nebulae are in reality less dense than industrial-grade vacuum. From the point of view of a rouge planet passing through one, it's pretty much still empty space.
    - Razengan 9y ago
      What about the regions of nebulas that are about to coalesce into stars? Wouldn’t they have some kind of protostellar “stuff” at point that makes the region more active than the rest of the average nebula? https://en.wikipedia.org/wiki/Molecular_cloud https://en.wikipedia.org/wiki/Molecular_cloud
jobigoud 9y ago
We don't know the probability of life arising from matter. We haven't replicated that emergence yet. If that p is something like 1/10^100 due to some compounding factors, we are alone in the observable universe.

mrarjen 9y ago

Just imagine all the stuff that's not giving off light or anything observable by us at this time. Rogue planets and what not should be everywhere no?

ngcc_hk 9y ago

Need less dark mass and dark energy then. ...

SEMW 9y ago
No? The data for the makeup of energy in the universe is mostly from CMB anisotropy (plus various measures of how fast the universe is accelerating, like how much supernovae have been redshifted). Finding out that galaxies in the early universe used to be smaller and more numerous than previously thought doesn't much affect any of that. (there's quite a lot of different data sources now all pointing towards an omega_lambda of 0.7). To be clear, per the article, the new discovery isn't about the early universe being a significantly different density (i.e. anything other than 'approximately flat', total omega ≈ 1) than the current one. Like, it's not that there was more mass-energy in it that's somehow vanished, rather that it's just distributed between more & smaller galaxies

almavi 9y ago

I don't understand. They say the observable universe contains 10x more galaxies than previously thought, and the reason for that is the concentration of galaxies being greater in the part of the universe that our telescopes can't see?

bergoid 9y ago
What they mean is that these unseen galaxies are within the radius of the observable universe, but too faint to be detected with current telescopes.
im3w1l 9y ago
"observable universe" is a technical term for the part of the universe from which light has had enough time to travel to us. It doesn't mean we can literally observe it using current tech.
- almavi 9y ago
  Ok, I was missing the technical definition. Thank you very much!
andyjohnson0 9y ago
The Observable Universe is the part of the total universe that we can theoretically observe because electromagnetic radiation from it has had time to reach us. In practice, some of this radiation will be detectable with current technology and some of it will be too faint. The article is about work, using models of galaxy formation, that tries to better estimate the number of galaxies we can't detect due to limits on telescope sensitivity, but which are nevertheless theoretically observable. It might be useful to describe the detectable part of the observable universe as the "visible universe", but astronomers have a different meaning for that. See https://en.wikipedia.org/wiki/Observable_universe https://en.wikipedia.org/wiki/Observable_universe.
- almavi 9y ago
  Yeah, I understand this now, thanks.

ttoinou 9y ago

I think other lifeforms exist in the universe, but the probability that they live in the same timeframe or that the two lifeforms meet each others is ridiculous

olegkikin 9y ago
Vlad the Astrophysicist https://www.youtube.com/watch?v=o9kbcGfX35M https://www.youtube.com/watch?v=o9kbcGfX35M

kulu2002 9y ago

Like Carl Sagan rightly said - "Cosmos is also within us. We're made of star stuff. We are a way for the cosmos to know itself.” We need to study ourselves more to comprehend this vastness.. [1] https://www.sciencealert.com/physicists-show-that-our-brains-s-learning-is-controlled-by-entropy https://www.sciencealert.com/physicists-show-that-our-brains...

luxcem 9y ago
"Given enough time hydrogen starts to wonder where it came from and where it is going."
deleted 9y ago
[deleted]

0xBA5ED 9y ago

Staring into those deep field images sometimes gives me an out-of-body sensation. The vastness of it is so over-the-top.

mtgx 9y ago
If looking at a few images gives you that sensation, then you should try out the Space Engine (traveling through space in 3D): http://spaceengine.org/ http://spaceengine.org/ A demo: https://www.youtube.com/watch?v=ve0Bpmx8Fk0 https://www.youtube.com/watch?v=ve0Bpmx8Fk0
- 0xBA5ED 9y ago
  Thanks. I've already played with this and it's awesome.

dahart 9y ago

From 2012: "But even the XDF is not optimized for finding these galaxies; we’d need an infrared space telescope for that, which is what James Webb is going to be. When that comes around, I wouldn’t be surprised to find that there are maybe even close to a trillion galaxies in the observable Universe; we just don’t have the tools to find them all yet. In the meantime, our best tool—the Hubble Space Telescope—is showing us that the deeper we look, the more we’ll continue to be rewarded with new, faint, and distant galaxies, as well as richer details in the already discovered ones. "It makes me so impatient for a more powerful telescope with the ability to see far into the infrared, because I can’t help but wonder what’s still invisible to even the XDF. Twice as many galaxies? Four times? Fainter ones, redder ones, more distant ones, or all of them? There’s at least 176 billion of them in our Universe, but I can’t help wonder, “how many more?”" http://blogs.discovermagazine.com/crux/2012/10/10/how-many-galaxies-are-there-in-the-universe-the-redder-we-look-the-more-we-see/ http://blogs.discovermagazine.com/crux/2012/10/10/how-many-g... "It boggles the mind that over 90% of the galaxies in the Universe have yet to be studied." Maybe this one's different, but when discussing astronomical terms, a factor of 10 doesn't ever surprise me. What does surprise me, continuously, is how many unimaginably large numbers of factors of 10 are involved in anything related to the size of the universe. There are so many estimated stars in the universe, it would make little difference to my already boggling mind if our estimates were off by a factor of a million.

pedro_hab 9y ago

I wonder if this has some impact in our (mis)understarding of dark-matter/dark-energy, and how the universe expands.

rdruxn 9y ago

I’ve seen a lot of posts recently discussing humanity’s concept of the size of the cosmos throughout history, but never a timeline of discoveries and the prevailing estimate du jour. I would love to see something like that and Wikipedia doesn’t do it justice.

taloft 9y ago

"The Universe is a pretty big place. If it's just us, seems like an awful waste of space."