But it reminds me of an irony of science communication. Landis is right that "Life is not made of protoplasm" but it is nonetheless true that modern science has found the Élan vital (vital impetus) that naturalistic writers often claim doesn't exist.
That impetus is free energy -- what Schrödinger called "negative entropy". The melancholy is that life is not made of the Élan vital, but consumes it. And it seems there is only a finite amount.
Geoffrey Landis , the writer of the subject article, may be known to some HN readers as a science fiction author. One of his SF stories, and one of my favorites in recent times, is available for free on the web. See "The Long Chase", available here:
His first novel is Mars Landing (I have not read it myself). He lists his SF bibliography on his website [1]. It consists mostly of short stories which appeared in various magazines, but a couple of stories are available free on the web [2], [3].
I am little peeved by the maneuver at the beginning of the story though. You cannot use a slingshot maneuver around the sun to gain speed relative to the sun - that's simple conservation of energy. I know Geoffrey Landis is NASA scientist, so hard to understand how he could get that wrong, but it seems he did.
It is interesting that Mr. Landis mentions entropy (in Thermodynamical sense I hope). I have always wondered what it means here, in this solar system. Assuming the solar system has negligible energy flowing in, what does it mean when life on earth is reducing entropy in this system? We are tipping the balance by assimilating atoms in a more orderly fashion with each birth. This means something bad is happening somewhere close-by. ;-(
The amount of entropy within the solar system, or on the earth is fairly constant. Also, amount of information represented biological order is pretty trivial compared to the whole.
But yes lots of entropy is going somewhere else anyway. The sun is flinging a lot of entropy-bearing photons out into the universe. Its internal heat source then makes more entropy to replace it. For now.
What 'balance' are we tipping? There is no balance. Entropy increases globally over time. You do not cause bad things to happen by locally decreasing entropy temporarily. You might interpret this as indicating that life is meaningless over cosmic time scales, but it doesn't mean something 'bad' is happening anywhere.
Our star is slowly dying, and we feed on its remains. Our feeding is not the cause of its death, however. It will die anyway.
Please note that this was written before it was discovered that the expansion of the universe is accelerating. Now that that is known, it is possible that things could end much, much more quickly as that expansion accelerates to the point that galaxies, stars, and eventually atoms are ripped apart.
Nah, the second derivative of the scale factor in the second Friedmann equation (https://en.wikipedia.org/wiki/Friedmann_equations?oldformat=...) is still determined by energy-density (rho) and pressure (p). "p", pressure, is equal to w \rho c^2, where w is a small negative number close to 0 (about -1/3 is a good fit for observation).
Galaxies stars and atoms won't be ripped apart; instead you'll get these and structures mostly collapsing into supermassive black holes which occupy their own Hubble volumes (stray ejected stars and gas molecules will also eventually occupy their own Hubble volumes too); the difference is in the features of the cosmological horizon as observed by someone at a large distance from such a black hole and stationary with respect to it. The different horizon recession from the accelerating expansion vs the previous non-accelerating expansion produces a different (higher) temperature in the thermal bath from the cosmological horizon, and has implications for the ultimate fate of these future supermassive (and very cold) black holes.
The paper your link points to is at http://arxiv.org/abs/1409.4918 and at equation (13) recovers p = wc^2\rho above (note that they set c to unity deliberately, which is common in physical cosmology) and on the next page they discuss their solutions for w = -1 and w = -2/3, both of which are far from the evidence we have for the density/pressure conversion constant and are only further from zero because their viscous fluid model requires that (unlike the perfect fluid in the Friedman-Lemaitre-Robertson-Walker model of the standard cosmology).
(Their motivation is to unify the dark sector by reducing it to dark matter with bulk viscosity, on the logic that bulk viscosity implies negative pressure. This has been tried by others before and since, and usually results in inconsistencies that their paper hopes to avoid. The standard cosmology keeps dark matter and dark energy separate, with dark matter likely having positive pressure and it definitely dilutes away with the expansion of the universe like other matter and radiation, while dark energy is a small negative pressure everywhere that does not dilute away with the expansion of the universe.)
In addition to all of what the other poster replying to you correctly pointed out, I'd just point out that the accelerating expansion of the universe, being somewhat mysterious, is also not predictable. Should such a force end, or reverse, the future becomes very uncertain.
In general though, if cosmic recession continues, it's only an issue for structures on the scale of galactic cluster and larger, when the isotropic and homogeneous nature of the universe dominate.
"The Earth has no memory for the dead-ends of evolution. In a few hundred thousand years glaciers would grind our works and our bones into gravel, would grind the gravel into sand, and in a few hundred million years the movement of continents erase the last of any trace of our brief existence, save perhaps for a handful of deeply-buried and enigmatic fossils."
This brings up a question I have often wondered about: do we really know we are the first intelligent conceptual life to do things like use tools and language on this planet?
If let's say a dinosaur reached the level of stone or bronze age civilization would anything be left other than... well... a couple enigmatic fossils that are easy to dismiss?
I doubt a massive high tech civilization like ours could come and go and leave no trace, but what about something much smaller scale?
We can be sure dinosaurs didn't have nukes and rockets, at least.
You are probably right about a Bronze Age civilization not leaving much that would survive a couple million years. 50 million years is a very long time. In not much more time than that, Hawaii will be part of Japan.
Sometimes I think that, sure, the universe it's huge and it's very possible (in my mind, almost certain) that there are other planets with advanced life forms like we can find here on Earth. If we accept this then it's safe to assume that not all life in the universe evolved at the same time. Most of the time we implicitly assume (probably because of sci-fi) that there must be a more advanced species somewhere but what if we actually are the more advanced species? From what we know right now it's just as likely for us to be the more advanced as it is for, say, the habitants of Kepler-22b. And somehow that feels more disappointing than if we were completely alone in the universe.
If the amount of computation that can be done is finite, then subjective time is also finite. (And vice-versa if the amount of computation is infinite.)
What does infinite time mean in a universe where nothing happens?
I hope I live to see a grand unified theory of physics which explains how space-time emerges from the quantum scale, but also how consciousness emerges from computation. Maybe in the future, when these theories are developed, we can have infinite consciousness, infinite subjective time.
I also acknowledge that I may be confused entirely and the previous paragraph has no meaning.
We fall into some precarious befuddlement when we start thinking about computation and our universe.
Is our universe an analog one or a digital one? (Or a mix where space is discrete but time isnt, etc, see plancks constant..)
Now, if our universe is analog. But powered by a digital conputer. The only way to simulate analog is by using an extra dimension....time. in fact, one possible hypothesis for quantum waveform collapse is that since are affecting an analog, the pertubation is infinitely hard to compute, so just nip it in the bud and return a digital value.
My intuition says that if life was possible in the infinite tail of time that has yet to come, then the probability of finding ourselves in a period close to the beginning of the universe would be zero. But then again, we are dealing with infinity here, so intuition is probably wrong.
Intuition cannot possibly work in this situation. What is the probability that an observer can observe? 100%. What is the probability that the observer is in the early universe? 100% (all other time sections are inhospitable.)
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[ 3.0 ms ] story [ 70.0 ms ] threadBut it reminds me of an irony of science communication. Landis is right that "Life is not made of protoplasm" but it is nonetheless true that modern science has found the Élan vital (vital impetus) that naturalistic writers often claim doesn't exist.
That impetus is free energy -- what Schrödinger called "negative entropy". The melancholy is that life is not made of the Élan vital, but consumes it. And it seems there is only a finite amount.
Source?
http://www.lightspeedmagazine.com/fiction/the-long-chase/
What else has he written?
[1] http://www.geoffreylandis.com/G_Bibliography.html
[2] http://www.geoffreylandis.com/time_prime.htp
[3] http://www.geoffreylandis.com/interlude.htp
I am little peeved by the maneuver at the beginning of the story though. You cannot use a slingshot maneuver around the sun to gain speed relative to the sun - that's simple conservation of energy. I know Geoffrey Landis is NASA scientist, so hard to understand how he could get that wrong, but it seems he did.
But yes lots of entropy is going somewhere else anyway. The sun is flinging a lot of entropy-bearing photons out into the universe. Its internal heat source then makes more entropy to replace it. For now.
Our star is slowly dying, and we feed on its remains. Our feeding is not the cause of its death, however. It will die anyway.
See http://news.vanderbilt.edu/2015/06/new-model-of-cosmic-stick... for more.
Galaxies stars and atoms won't be ripped apart; instead you'll get these and structures mostly collapsing into supermassive black holes which occupy their own Hubble volumes (stray ejected stars and gas molecules will also eventually occupy their own Hubble volumes too); the difference is in the features of the cosmological horizon as observed by someone at a large distance from such a black hole and stationary with respect to it. The different horizon recession from the accelerating expansion vs the previous non-accelerating expansion produces a different (higher) temperature in the thermal bath from the cosmological horizon, and has implications for the ultimate fate of these future supermassive (and very cold) black holes.
The paper your link points to is at http://arxiv.org/abs/1409.4918 and at equation (13) recovers p = wc^2\rho above (note that they set c to unity deliberately, which is common in physical cosmology) and on the next page they discuss their solutions for w = -1 and w = -2/3, both of which are far from the evidence we have for the density/pressure conversion constant and are only further from zero because their viscous fluid model requires that (unlike the perfect fluid in the Friedman-Lemaitre-Robertson-Walker model of the standard cosmology).
(Their motivation is to unify the dark sector by reducing it to dark matter with bulk viscosity, on the logic that bulk viscosity implies negative pressure. This has been tried by others before and since, and usually results in inconsistencies that their paper hopes to avoid. The standard cosmology keeps dark matter and dark energy separate, with dark matter likely having positive pressure and it definitely dilutes away with the expansion of the universe like other matter and radiation, while dark energy is a small negative pressure everywhere that does not dilute away with the expansion of the universe.)
In general though, if cosmic recession continues, it's only an issue for structures on the scale of galactic cluster and larger, when the isotropic and homogeneous nature of the universe dominate.
This brings up a question I have often wondered about: do we really know we are the first intelligent conceptual life to do things like use tools and language on this planet?
If let's say a dinosaur reached the level of stone or bronze age civilization would anything be left other than... well... a couple enigmatic fossils that are easy to dismiss?
I doubt a massive high tech civilization like ours could come and go and leave no trace, but what about something much smaller scale?
You are probably right about a Bronze Age civilization not leaving much that would survive a couple million years. 50 million years is a very long time. In not much more time than that, Hawaii will be part of Japan.
And in another 50 million Japan will be part of China! Isn't it easy to make stuff up?
What does infinite time mean in a universe where nothing happens?
I hope I live to see a grand unified theory of physics which explains how space-time emerges from the quantum scale, but also how consciousness emerges from computation. Maybe in the future, when these theories are developed, we can have infinite consciousness, infinite subjective time.
I also acknowledge that I may be confused entirely and the previous paragraph has no meaning.
Is our universe an analog one or a digital one? (Or a mix where space is discrete but time isnt, etc, see plancks constant..)
Now, if our universe is analog. But powered by a digital conputer. The only way to simulate analog is by using an extra dimension....time. in fact, one possible hypothesis for quantum waveform collapse is that since are affecting an analog, the pertubation is infinitely hard to compute, so just nip it in the bud and return a digital value.
Anyho..think about that for a while.. :-)