"Goldilocks" Planet Found, Could Possibly Support Human Life

yeah, wasn't thinking from a prospect of getting there, but if we ever get terrestrial planet finder launched this would be a prime target.

Temperature variation is all depended on atmosphere, for all we know its a living hell like Venus.

The star is VERY dim, it only gives of 1.3% the energy as our sun does, Gliese581g is close enough from its star to get enough energy to support a liquid water atmosphere. I guess if you mean brightness photon wise sure, twice a much photos in the NIR have to hit the planet to keep it warm but that is accounted for in the habitability zone equations as it depends on bolometric luminosity not apparent luminosity.

For now lets just try to learn more about it from afar, at present that all we can do as it would take hundreds of years to get there with any long term technology let alone near term technology. Also as a transhumanist and singularitarian I believe that by the time we do send travelers out to explore and colonies interstellar space they will all be artificial, as technology will eventually allow the merger of human and machines into one seamless being. Assuming faster then light travel never becomes possible immortal software decedents of humans capable of downloading them selves into any form of their own hyper-intelligent construction will make the ultimate interstellar explores as time, lack of oxygen, heat or food, will be no concern to them.

 

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Chance of life on other planets

It begs the question: "what is required for life to exist on planets, initially, as well as to be still existing billions of years later following the emergence of that initial life?"

We have evidence as earthlings that planetary longevity requires life forms to mature into cosmic adults who can get along and preserve their planet until they develop the ability to travel into space competently.

Currently earthlings have shown that a planet can reach a stage of developement where life on it, at least civilization on it, can be destroyed utterly by the technology that the planet's inhabitants have developed (e.g. full-on nuclear war).

What is exciting about the discovery of the solar system at Gliese 581 is that it is so old the original star is now a red dwarf.

Our Sun too will become a red dwarf in the future when it is "old".

The important question, then, is "will the Earth be lifeless when our Sun grows old and becomes a red dwarf, or not, and why?"

Then it becomes much more interesting to ask: "do any of the planets orbiting the old star Gliese 581 have any life on them or not?"

 

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"Goldilocks" Planet Found. Could Possibly Support Human Life

The notion of "supports human life" is a variation of the theme "supports sentient life" isn't it?

These circumstances beg the question: "what is required for life to exist on planets, initially, as well as to be still existing billions of years later following the emergence of that initial life?"

We have evidence as earthlings that planetary longevity requires life forms to mature into cosmic adults who can get along and preserve their planet until they develop the ability to travel into space competently.

Currently earthlings have shown that a planet can reach a stage of developement where life on it, at least civilization on it, can be destroyed utterly by the technology that the planet's inhabitants have developed (e.g. full-on nuclear war).

What is exciting about the discovery of the solar system at Gliese 581 is that it is so old the original star is now a red dwarf.

Our Sun too will become a red dwarf in the future when it is "old".

The important question, then, is "will the Earth be lifeless when our Sun grows old and becomes a red dwarf, or not, and why?"

Then it becomes much more interesting to ask: "do any of the planets orbiting the old star Gliese 581 have any life on them or not?"

 

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Gliese 581 is not a red dwarf because it is old, it is old because it is a red dwarf. It started out life as a Red dwarf, it didn't age into one. Red dwarf stars, being smaller, cooler stars have longer lifetimes. Gliese 581 could stay in the main sequence for some 270 to 810 billion years, compared to the Sun's 10 billion. In these terms, our sun is middle aged and Gliese 581 is still in the blush of its youth.

Neither will our Sun ever become a red dwarf. it will swell into a red giant and then contract into a slowly cooling white dwarf.

 

can we merge the three thread together - tedious.

 

There's already this, still in the development phase, launches in the year 2014 at the earliest.

It really IS amazing to think that there's a planet that could possibly support life on a grand scale, and is bigger than the Earth, AND only 20 light years away, we expected to have to look a lot further away for anything Earthlike.

Granted the way technology keeps advancing, we might end up getting an expedition (hopefully) before the turn of the century out there. I know that they are sending a robotic expedition to one of Jupiter's moons (Europa I believe) within the next 10. Maybe we can get off our "populate Mars" rubbish and actually set our sights on something that could actually support human life.

 

The chance is slim anyone has noticed us, even if there are more than several advanced races on other planets. The difficulty is that there is so much space. Even to get one signal from a vast region would be like trying to find a needle in an infinite haystack.

Or perhaps looking for a needle in a dark infinite volumed room.

 

And some radiofrequencies simply don't have enough wavelength to reach the vast corners of space, so I wouldn't worry about that.

 

... not to mention cosmic debris which could easily soak these transmissions up.

 

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It is 3-4 times heavier than our planet, and orbital period around the star is about 37 Earth days. Estimating its weight, scientists assume that the surface of ‘581 G’ covered with rocks and stones, and the gravitational force may be favorable for the existence of atmosphere. Moreover, they have added that the presence of all these conditions does not necessarily mean that a planet is suitable for human habitation.

 

0.31 solar masses.

The star is so old because it was born as a red dwarf. It will be remain a red dwarf a long, long time until it finally gets dimmer and dimmer. No explosive, exciting end for a red dwarf. Just old age.

Our Sun will not become a red dwarf when it gets old. Red dwarfs are small main sequence star. Our Sun is a G-type main sequence star. These stars leave the main sequence when they switch from burning hydrogen to burning helium. At that point they turn into red giants, and bye bye Earth.

 

Thanks to DH for M = 0.31 value.

The acceleration of planet goes as mr/(P^2) = ~ GmM/(r^2) where M is the solar mass and P is the planet’s period and dropping the G as same for both Earth & P581 we have r^3 =~ MP^2 (one of Keppler’s laws, modified to compare planets orbiting different suns)

For Earth using AU and solar mass of 1, we have 1=~(365.25)^2
And for P581 we have r^3 =~ (0.31) (37)^2

Thus, r^3 =(0.31)(37/365.25)^2 = 0.31(0.1013)^2 = 0.003181

And compared to earth’s gravity gradient P581’s is 0.31/ 0.003181 = 97.45 or almost 100 times stronger gravity gradient acts on P581 than acts on Earth.

Thus, if I made no error, my guess as to why P581 (made in post 9) keeps one side always turned to its sun is very plausible, but there could be non-uniform distribution of the solid mass causing this also. I.e. my argument is not proof that P581 has abundant water, much of it as ice deposit on the cold side.

 

"Goldilocks" Planet Found. Could Possibly Support Human Life

It would take somewhere in the vicinity of 352,000 years to get there with our current "rocket science".

 

Assuming near term technology like fusion (ha fusions been 50 years away for the last 50 years so it might jsut be 50 years away forever!) maybe ~10% the speed of light, Based on say a Daedalus class type ship. Heck on a Orion class we could do 3.3% the speed of light, and that technology has been around for decades. So no its not reasonable to assume 352,000 years using chemical rockets, no one would assume chemical rockets form interstellar travel!

I still think spin–orbit resonance though is a possibility.

 

"Goldilocks" Planet Found. Could Possibly Support Human Life

Janus58,

Your summation is correct under the current theories, however a couple of discoveries have brought those theories into question.

"One mystery which has not been solved as of 2007 is the absence of red dwarf stars with no metals. (In astronomy, a metal is any element heavier than hydrogen or helium). The Big Bang model predicts the first generation of stars should have only hydrogen, helium, and trace amounts of lithium. If such stars included red dwarfs, they should still be observable today, but none have yet been identified. The preferred explanation is that without heavy elements only large and not yet observed population III stars can form, and these rapidly burn out leaving heavy elements which then allow for the formation of red dwarfs. Alternative explanations, such as that zero-metal red dwarfs are dim and could be few in number, are considered much less likely as they seem to conflict with stellar evolution models." (Red Dwarf Stars, emphasis added).

There is doubt as to the models concerning the large stars too: "A massive star a million times brighter than our sun exploded way too early in its life, suggesting scientists don't understand stellar evolution as well as they thought." (Star Explodes, and So Might Theory, emphasis added).

There are other concerns with the theories and the models as well.

As you can probably surmise, I favour a "smoother" theory & model were all stars age in a similar manner, except in some cases where external influences act to change the equation.

Nevetheless your point is well taken.

 

Good luck with changing the politics and imperialism that drives NASA so that more than "rocket science" is applied to space travel as national policy.

Look at the Space Shuttle politics for example.

 

I was not saying we should do it or that we should even try, merely saying what was technically possible, heck its technically possible for us to end all war and live in peace as well, does not mean its likely.

 

That says a lot.

 

Look the Orion class interstellar ship has been proposed for decades, its propulsion systems is known and straightforward, aside for it being too scary for public approval, it is technically feasible, that is all I was saying. Honestly we don't need to be looking into interstellar propulsion now.