Tuesday, November 17, 2009

Exoplanet Characterization and the Search for Life

" Introduction

A few times in human history, astronomers have made discoveries that changed people’s view of the universe and of themselves. The most renowned of these was Copernicus’ suggestion, and Galileo’s subsequent proof, that the Earth orbited the Sun, rather than vice versa. This list should also include the discovery that stars are other Suns, that some nebulae are galaxies like our own, and that the universe began with a Big Bang some 13 billion years ago. We now stand at the brink of answering two other paradigm-changing questions: Do other planets like Earth exist, and do any of them harbor life? The tools for answering these questions either exist already or can be developed within the next 10-20 years.

The stellar energy flux incident on a planet drives its atmospheric chemistry to a disequilibrium state. But the degree of disequilibrium can be profoundly increased by the presence of life on a planet’s surface. As a prime example, the simultaneous presence of O2 and reduced gases such as CH4 or N2O in a planet’s atmosphere is considered the best available remote evidence for Earth-like life.9

Marine plants and algae do this as well, although the effect is muted by overlying water. This red edge is easy to pick out if one looks directly at a leaf, or down from space at a patch of densely vegetated land.14

Nearly all of Earth’s O2 comes from photosynthesis, which is carried out by plants, algae, and cyanobacteria. Predicted atmospheric O2 concentrations prior to the origin of photosynthesis are too low to detect spectroscopically.15


References:
9. Lovelock JE. 1965. Nature 207: 568-70.
14. Sagan C, et al.,1993. Nature 365: 715-21.
15. Segura A, et al. 2007.Astrobiology 7: 494-5.


Taken from:
ArXive

13 comments:

Unknown said...

Lovelock was picked by NASA to determine the best way to look for life on our nearby planets. He based his predictions on the stuff that was described here, and determined that any planet with life would have an active atmosphere like ours that was created by the earliest life forms.

If you condider the discoveries of Lovelock, Margulis, Dorion* Sagan, (Carl Sagan's and Lynn Margulis son), and the anthropic principle in conjunction with Einstein's cosmological model... then you get the bigger picture that we are not here by accident, because we are extremely adept at **efficiently** increasing the entropy of the universe.

The "self-regulating" nature of the process of matter generation from vacuum energy, also makes clear that the extreme small value of the cosmological constant is the result of a very simple energy conservation law that enables the universe to maximize work by increasing entropy more efficiently than the naive quantum theoretical expectation for a wide-open universe would allow for. A "maximum action principle", or a maximum possible entropy principle, if you will.

There is no life on Mars or Venus because they exist outside of the habitable zone, and are subject to the dramatic runaway effects that prohibit life on all of the anthropic balance points *together*, enable.

This is a good example of what I'm talking about, and the falsifiable prediction that falls from this is that we will NEVER find other life forms in our solar system, but we will find it on similarly developed planets in similarly developed galaxies... because the right TIME in the history of the universe is also a relevant balance point of the Goldilocks Enigma.

http://www.astronomynotes.com/solarsys/s9.htm

Unknown said...

PS: I have been looking at Dirac's original Hole theory, and I think that it can be fixed by this new physics so that the modern Quantum reinterpretation isn't necessary.

I think that some of Dirac's other ideas make sense now in this new light, as well. His large numbers hypothesis works, for example except gravity doesn't get weaker, the electric charge grows instead via particle creation. Dirac himself said that it had to be one way or the other, (either the electric charge increases or gravity gets weaker), but he chose to let gravity fall off with time.

http://www.fdavidpeat.com/interviews/dirac.htm

I'm telling you, Eduardo... you're gonna need to make a reservation to Copenhagen... ;)

Eduardo Cantoral said...

Island:
I'm ready man.

I knew about Gaia, and Dirac's large number hypothesis; what I didn't know is that you think one can now put together several of those ideas, and start calculating the size of the cosmological constant, like Weinberg did several years ago for the size of galaxies.

I'll keep thinking.

Unknown said...

Let me give you some more food for confusion then, because I'm not sure that you can without the drastic throwback in understanding that the physics demands, because there is a huge difference in the effect that matter generation from vacuum energy has on the universe if the universe is not infinite. I mean, yes, you can look at the brute facts and come to the conclusion that the is an energy conserving "constraint" on the forces of the universe, because a near static, yet expanding universe quite obviously wastes less energy to heat-death, (maximizes the available energy), than a wide-open expanding universe would. This configuration also disseminates energy more uniformly, again, an obvious energy conservation law at work.

Bear this in mind as you read what follows:
Eddington observed that the cosmological constant version of the general-relativistic field equation expressed the property that the universe was "self-gauging".

Homeorhesis and Gaia Theory

http://en.wikipedia.org/wiki/Homeorhetic
In ecology the concept is important as an element of the Gaia theory, where the system under consideration is the ecological balance of different forms of life on the planet. It was Lynn Margulis, the coauthor of Gaia hypotheses, who wrote in particular that only homeorhetic and not homeostatic balances are involved in the theory. That is, the composition of Earth's atmosphere, hydrosphere, and lithosphere are regulated around "set points" as in homeostasis, but those set points change with time.

This is exactly what we observe when we look directly at the near-static expanding universe without assuming that accelerating expansion means that dark energy is increasing while gravity is not.

And it's also what happens when you make real, massive particles from vacuum energy, because the increase in gravity that you get from particle creation is regulated or offset by the increase in negative pressure that occurs when you rip a big void in the finite vacuum structure to make a particle pair.

It is "self-gauging" and homeorhetic.

This screams-out that Einstein was right all along.

Then there is the effect that this has on the quantum oscillator...

Unknown said...

The phenomena that define the habitable zones of the Goldilocks Enigma are always *near* perfectly balanced between diametrically opposing runaway tendencies, just like the universe is.

Like the Earth is homeorhetically balanced between the life-prohibiting diametrically oppoisng runaway tendencies that Venus and Mars suffer from.

This commonality is no coincidence.

Eduardo Cantoral said...

It sounds true. No coincidence. I just thought that acceleration is absolute, Prof. Leonard Parker many years ago studied production of quantum particles due to acceleration.

I guess you are up to something here.
http://www.jsonline.com/news/wisconsin/32419634.html

Unknown said...

No, I didn't say that acceleration isn't true, and this is also explained by the described physics, because it takes a greater volume of vacuum energy every time that you create a particle pair from the increasing rarefied vacuum, so expansion accelerates each time that a pair is created, even though dark energy remains nearly balanced by gravity.

That looks like a great video. I'm watching it now.

Unknown said...

Thank you, Eduardo, the video was very helpful as I have been trying to understand how you can get a oppositely charged pair from a **finite** sea of particles possessing only negative energy.

I think that the trick to fixing Dirac's hole theory is that you can have both negative energy "holes" and positrons.

Eduardo Cantoral said...

Sorry:
I was thinking to myself. After reading your comment I remembered that acceleration is absolute, and I remebered Parker's proposal. I am not saying that you don't think so. Since Mach at least, physicists have been thinking about relative and absolute motion.
Production of particles from the vacuum is real, because acceleration is real.

Unknown said...

I made a typo:
increasing rarefied vacuum

I meant to say, "increasingLY rarefied vacuum".

So it requires a greater volume of vacuum energy each time that you make a particle pair in order to attain enough mass-energy to make a particle pair. This causes expansion to accelerate even though the increase in negative pressure that the void creates is proportionally offset by gravity. The only thing that is increasingly disproportional is the volume of vacuum energy vs the volume of the newly created particle, whose energy has to be condensed rather than rarefied in order to attain the matter density.

As a result, dark energy dominates by volume, not effect.

Unknown said...

Sorry:
I was thinking to myself. After reading your comment I remembered that acceleration is absolute, and I remebered Parker's proposal. I am not saying that you don't think so. Since Mach at least, physicists have been thinking about relative and absolute motion.
Production of particles from the vacuum is real, because acceleration is real.


This physics requires that we re-think a lot of things, like uncertainty, but if the finite universe has a center of gravity and a preferred direction of motion, then what is that motion relative to?

Unknown said...

Anyway, before I ramble too far off track, let me give you a little more food for thought, as it might help to understand the whole process:

The described mechanism for particle creation utilizes Asymmetrical Transtions to increase tension between the vacuum and ordinary matter, as both gravity and negative pressure increase.

You can see at the bottom of the linked page that somebody has made the connection to the process as it applies to vacuum energy.

The observed, low entropy configuration of the universe enables energy to be uniformly distributed as tension between the vacuum and matter grows, so the system will "evolve" to a higher ordering of the same basic configuration when growing tension finally breaches the integrity of the forces that bind the universe and we have another big bang. The next universe will be as "flat" as the energy is uniformly disseminated, in other words, so the forces are configured toward absolute balanced symmetry between matter and antimatter as the ultimate unattainable goal of an inherently imbalanced universe.

This is a Multi-objective Optimization Problem that pits diametrically opposing ideals against each other to attain the most energy-efficient structural configuration possible, given the the inherently imperfect nature of the system.

Eduardo Cantoral said...

There is a new article by Makhlin:

http://lanl.arxiv.org/abs/0911.3671

Gravity comes after Dirac particles. The presence of Dirac matter curves space and there are no singularities.

This is different than yours, but he also has a proposal for the vacuum.

I do not know with respect to what is the Universe accelerating.

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