Can a Living Creature Be as Big as a Galaxy? • Hacker News Board

Re: Can a Living Creature Be as Big as a Galaxy?

#61

Post by Cozumel » Sat, Aug 05, 2017, 8:20 PM UTC

olegkikin wrote: post #48

banachtarski wrote: post #7

Earlier quoted context omitted.

We do. If you bothered to read the article, it makes a point that the communication speed between the components would be slow enough (even at light speed signaling) that the age of the universe would not have permitted sufficient time for such an organism to evolve and do anything.

You're presuming the speed of light is the hard limit. Whereas we know for a fact faster movement is possible - the space-time itself was expanding faster.

^This. The universe expanded faster than light, that's why we still can't see everything, so saying things like 'the communication speed is too slow to permit evolution' is just wrong, it also doesn't take into account things like time doesn't actually exist, it's just a biological construct.

The whole article is predicated upon a bunch of faulty assumptions, it's like it was written by a simple minded child.

Re: Can a Living Creature Be as Big as a Galaxy?

#62

Post by Koshkin » Sat, Aug 05, 2017, 8:20 PM UTC

Since proteins cannot exist in space, then, using the currently accepted definition of "life" at the basic level as the complex of processes that allow protein molecules to exist, then the answer must be 'no'.

On the other hand, it is an interesting mental exercise to also consider other reasons why such creature might be impossible. One reason could be because the time needed for such creature to grow from something much, much smaller (as it usually happens in biology) would be longer than the age of the universe.

Another one is that nerve impulses travel slower than the speed of light, and so, again, it would take forever for a signal to reach the central nervous system. One could argue that the creature can be "decentralized", i.e. look more like a large colony of smaller organisms, but then the question arises as to what makes it a single creature in the first place.

Yet another issue concerns what drives the evolution of this particular species, and, again, the time it takes.

So far, all these considerations unavoidably lead to the answer 'no'.

Re: Can a Living Creature Be as Big as a Galaxy?

#63

Post by andars » Sat, Aug 05, 2017, 8:22 PM UTC

olegkikin wrote: post #48

banachtarski wrote: post #7

Earlier quoted context omitted.

We do. If you bothered to read the article, it makes a point that the communication speed between the components would be slow enough (even at light speed signaling) that the age of the universe would not have permitted sufficient time for such an organism to evolve and do anything.

You're presuming the speed of light is the hard limit. Whereas we know for a fact faster movement is possible - the space-time itself was expanding faster.

You have some misunderstandings about the expansion of the universe. I would recommend reading http://www.preposterousuniverse.com/blog/2015/10/13/the-univ...

Re: Can a Living Creature Be as Big as a Galaxy?

#64

Post by 21 » Sat, Aug 05, 2017, 8:24 PM UTC

Koshkin wrote: post #62

Since proteins cannot exist in space, then, using the currently accepted definition of "life" at the basic level as the complex of processes that allow protein molecules to exist, then the answer must be 'no'. On the other hand, it is an interesting mental exercise to also consider other reasons why such creature might be impossible. One reason could be because the time needed for such creature to grow from something…

Maybe you should expand your definition of life to not require proteins.

From Wikipedia:

> From a physics perspective, living beings are thermodynamic systems with an organized molecular structure that can reproduce itself and evolve as survival dictates. ... A major strength of this definition is that it distinguishes life by the evolutionary process rather than its chemical composition.

Re: Can a Living Creature Be as Big as a Galaxy?

#65

Post by Cozumel » Sat, Aug 05, 2017, 8:25 PM UTC

danharaj wrote: post #5

devoply wrote: post #4

This article does not take into account quantum phenomenon. It's possible that instead of being limited by the speed of light transmissions, such a system uses quantum phenomenon for communication. Which then would make the whole argument that this article makes invalid. It's based on the premise that life would be based on the same sort of physics as life on Earth... which does not make sense as such life if it exis…

There are no quantum effects that allow superluminal communication of information.

Sure there is. You've just not seen it on HN yet.

Re: Can a Living Creature Be as Big as a Galaxy?

#66

Post by Swizec » Sat, Aug 05, 2017, 8:28 PM UTC

olegkikin wrote: post #46

Swizec wrote: post #41

Earlier quoted context omitted.

> There is also no way to disprove that without observing beyond the universe, which may get a bit dicey. My high school physics prof had the best answer to "What is beyond the universe?" --> "Surely if we ever find something outside of the universe, we will be smart enough to call that the universe too" He was referencing the idea that universe contains everything by definition.

In terms of definitions, generally cosmos contains everything. Universe is our local observable space-time with the earliest event we can detect being the big bang.

> Universe is our local observable space-time

So if we observe something beyond what is currently observable, would that not become observable and thus part of the universe?

Re: Can a Living Creature Be as Big as a Galaxy?

#67

Post by komali2 » Sat, Aug 05, 2017, 8:28 PM UTC

eljimmy wrote: post #50

tsunamifury wrote: post #39

It's answer of "No" is predicated on two assumptions: that the lifeform is not colonial in nature and that time is not a localized phenomenon. While on the surface that later assumption might sound absurd, our universe could very well be a Local Bubble of time. Time could even be a biological function of a higher dimensional being that is the size of the universe. There is also no way to disprove that without observi…

Thinking about what exists outside the universe always makes my brain feel weird. It seems impossible for your thoughts to imagine anything because your thoughts themselves are bound by the universe itself.

Well even worse, our thoughts are bound by some maximum distance of comprehension. We can abstract the stellar scale but we can't understand it like we understand the distance across the street or whatever. I find this frustrating :(

Re: Can a Living Creature Be as Big as a Galaxy?

#68

Post by laumars » Sat, Aug 05, 2017, 8:30 PM UTC

Koshkin wrote: post #62

Since proteins cannot exist in space, then, using the currently accepted definition of "life" at the basic level as the complex of processes that allow protein molecules to exist, then the answer must be 'no'. On the other hand, it is an interesting mental exercise to also consider other reasons why such creature might be impossible. One reason could be because the time needed for such creature to grow from something…

There are animals on Earth with a decentralised nervous systems (most famously the octopus) and there isn't any confusion about whether they're classed as one animal or multiple ones.

Re: Can a Living Creature Be as Big as a Galaxy?

#69

Post by alansammarone » Sat, Aug 05, 2017, 8:34 PM UTC

Swizec wrote: post #66

olegkikin wrote: post #46

Earlier quoted context omitted.

In terms of definitions, generally cosmos contains everything. Universe is our local observable space-time with the earliest event we can detect being the big bang.

> Universe is our local observable space-time So if we observe something beyond what is currently observable, would that not become observable and thus part of the universe?

Yes, but it might also be the case that we don't observe something outside of it, but rather infer the existence of something outside of it through some other phenomenon (which is much more probable - observing something outside of the visible universe as we know it would violate relativity). In that sense, it would be there, but would never be visible.

Re: Can a Living Creature Be as Big as a Galaxy?

#70

Post by alextheparrot » Sat, Aug 05, 2017, 8:34 PM UTC

Koshkin wrote: post #62

Since proteins cannot exist in space, then, using the currently accepted definition of "life" at the basic level as the complex of processes that allow protein molecules to exist, then the answer must be 'no'. On the other hand, it is an interesting mental exercise to also consider other reasons why such creature might be impossible. One reason could be because the time needed for such creature to grow from something…

Proteins (Or the ability to make them) is not requisite for life, nor are nerve impulses, nor is evolution. If we encountered an immortal (Does not evolve), sterile (Does not reproduce), silicon-based alien (No proteins), that would most certainly be heralded as finding extraterrestrial life.

Reasoning about much large systems than our own is difficult. Imagine a bacteria attempting to reason about a human - the existence of fluid transport and centralized heating may seem a bit odd, as bacteria have developed to solve an entirely different class of problems at the organism level.