"Life We Find Will be Much Older and More Evolved than Life on Earth" --Harvard-Smithsonian cFa

 

          

 

“We thought we would have to search vast distances to find an Earth-like planet. Now we realize another Earth is probably in our own backyard, waiting to be spotted,” said Courtney Dressing of the Harvard-Smithsonian Center for Astrophysics (CfA). Six percent of red-dwarf stars have habitable, Earth-sized planets, astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) have found. Red dwarfs are the most common stars in our galaxy; about 75 percent of the closest stars are red dwarfs. The closest Earth-like planet could be just 13 light-years away, Harvard astronomer and lead author Courtney Dressing calculated.

Red dwarf stars are smaller, cooler, and fainter than our Sun. An average red dwarf is only one-third as large and one-thousandth as bright as the Sun. The cFa team culled the Kepler catalog of 158,000 target stars to identify all the red dwarfs, then reanalyzed those stars to calculate more accurate sizes and temperatures. They found that almost all of those stars were smaller and cooler than previously thought.

 

                          

Locating nearby Earth-like worlds may require a dedicated small space telescope, or a large network of ground-based telescopes. Follow-up studies with instruments like the Giant Magellan Telescope and James Webb Space Telescope could tell us whether any warm, transiting planets have an atmosphere and further probe its chemistry. Since red dwarf stars live much longer than Sun-like stars, this discovery raises the interesting possibility that life on such a planet would be much older and more evolved than life on Earth.

Courtney D. Dressing, David Charbonneau, The occurrence rate of small planets around small stars, The Astrophysical Journal, 2013, in press

Daily Galaxy via Harvard-Smithsonian Center for Astrophysics

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Comments

[Stainless Steel Rat]

There is no such thing as more evolved. Evolution,natural selection, has no direction. A trait is either beneficial or it is not,and it allows the survival of an organism to pass that trait on.

[ross]

Exactly. Intelligence might be a particularly rare trait to evolve

[Iqbal Latif]

Sentient life is not easy, a 'Red Dwarf' and earth like planet alone are just not enough, even if life exists to graduate to the level of self awareness is a huge bet. But once self awareness evolves the road to super connectivity for us was only few thousand years of civilisation, after 14 billion years of wait. We 'composite elements' from the throes of death have found deep expression. Imagine a sentient civilisation that was on this path of growth a billion or two years ahead of us, it would be a different path and they would be different version of beings, but is it so easy for sentient life to develop, this is the question. If they will be a billion or few more years advance, they would be be civilised enough to put us on the fast track. A cultured billions of years ahead civilisation will hate to see we sentient beings to suffer from our own man made famine and horrors of war and scriptural backwardness dictated by dogma, they would have come and lend us a helping hand; they would take us back in time to show that there were no people like Jesus and Moses who were born without a sperm and ovum and went up the hill to meet the creator. They would not allow localhost to happen, they would help us form ravages of our own minds.Would we humans allow a Dolphin Hitler to kill every other Dolphin on a mass scale, as higher sentient beings we will stop such a massacre.

As a species, H. Sapiens has only been around for somewhere in the range 70,000-200,000 years; the surface formed roughly 4.6 billion years ago. And we can expect the Earth to persist for about another 3-5 billion years, until the sun leaves the main sequence of the Hertzsprung-Russell diagram and becomes a red giant, presumably swallowing the Earth.

Of the 4.6 billion years of Earth's known history, there's only been enough oxygen in the atmosphere for us to survive for about 500m years. Homo sapiens on the Earth's surface had something like a 15% chance of finding it survivable. A random sampling over the historical epoch would return a survivability probability of around 1%. 7 billion of us live on this less 50% of this 15% habitable surface of earth that isn't lethal without life support equipment.

We don't know when life got started on Earth. However, we do know that the early history of life relied on anaerobic processes for a surprisingly long time. It wasn't until roughly 580 million years ago (at the end of the Proterozoic era) that free oxygen came to dominate our planet's atmospheric chemistry.

Prokaryotes show up 3.8 billion years ago. Oxygen doesn't build up in the atmosphere until about 580 million years ago. That's 3.2 billion years that life was around in a reducing atmosphere, free to evolve into multicellular life if the energy conditions would support it, whether by taking appropriate organelle-precursors hostage or by other methods. 580-500 million years ago photosynthetic bacteria's oxygen production finally overwhelms the ability of dissolved iron to precipitate it out as rust in the banded iron formations. This is also when the first complex multicellular life appears--and the latter part of it coincides with the Cambrian Explosion.

And, not incidentally, this is about when life starts scuttling and growing out onto land. 580 million years ago oxygen starts to build up in the atmosphere. Multicellular life shows up a fairly short time (by geological standards, granted) later.

Even the most chemically capable life bacteria/archaea, on this world needs two things--a carbon source to replenish its substance and an electron acceptor, for energy. Prokaryotes can use a lot of different things as electron acceptors. Multicellular life uses oxygen. Oxygen is a great choice because hanging electrons on it gets you lots of energy, and because there's lots of it (now) in the atmosphere. The Pre-GOE atmosphere was what they call "reducing' which is a way of saying there wasn't anything that, like oxygen, gives you lots of energy when you hand it electrons.

We know the sun is steadily brightening by about 6% per billion year. It's postulated that within a couple of billion year, solar output is going to have some unpleasant effects. Ultraviolet radiation can split the covalent bonds that hold water molecules together, high in the atmosphere: and hydrogen ions (or, more likely, hydrogen molecules) can be blasted right out of the ionosphere by the same mechanism. The slow, steady loss of Earth's water is a one-way process, but exacerbated by warming (more water vapour in the upper atmosphere means more hydrogen is lost). As hydrogen loss proceeds, we end up with a carbon-dioxide dominated atmosphere and a runaway greenhouse effect like that of Venus.

There are other mechanisms that might render the Earth uninhabitable by our kind of life. Over geological time, the partial pressure of oxygen in the atmosphere has risen. With more solar energy inputs, it may be that oxygen levels continue to soar. Above about 28%, even waterlogged biomass will burn handily: and there are indications that atmospheric oxygen (currently down around 16%) has been well over 20% in the past. If oceanic photoautotrophs pump out too much of the stuff, the continents may well be burned back to bedrock by the resulting lightning-triggered fires.

All of this leaves aside the prospects for either an anthropogenic catastrophe, or the evolution (or creation) of new types of chemoautotrophs that have a drastic effect on the Earth's atmospheric chemistry. Or something else. Phase of the moon, perhaps.

The upshot is, we may well be most of the way through the Earth's inhabitable epoch. In which case, of the 4 billion years remaining, we may have 300 million - 1 billion years to go with an oxygen-dominated atmosphere and water close to its triple point — the minimum necessary criteria for human survival on a planetary surface.Much before that time we will time travellers and off to other planets. Who knows we are the most perfect evolution and The Universe awaits to be de-ciphered by us?

[Sad King Billy]

Intelligence is inevitable once a method of encoding biologically significant process (DNA = algorithm = programming) is available. These processes will eventually expand in number and diversify through evolutionary forces in a manner dictated by their environment. Note the exact nature of the environment is irrelevant. It is useless to say water is required or oxygen is required at a certain percentage. These figures would apply only to us and intelligence is much greater than us.

[ET Gamer]

"life on such a planet would be much older and more evolved than life on Earth."

Where the heck are they? exclaimed Enrico Fermi. Where are all this much older civilizations? A few hundred space civilizations could colonize the Galaxy in 100.000 years.

[Jack Butler]

Just a thanks to stainless steel rat for pointing out the egregious error of "more evolved." Egregious as far as current evolutionary theory assumes, certainly. In order to speak of the "more evolved," we must assume a direction implicit in evolution, which, we are repeatedly told, evolution does not show.

I would agree, incidentally. The operations of evolution seem to me to resemble play more than directed effort.

[DVine]

Evolution does have a direction, it evolves towards the direction of time and chaos increase, so if the life on those planets is older it will indeed have evolved more.
To think more evolved means more intelligent however that's total bs, in fact not even sure if it's true for us apes :D

[James Duff]

(The operations of evolution seem to me to be more like play than directed effort). Play requires a player and directed effort requires a director. It is more than probable that it is nothing more than the circumstances of the environment allowing blind chance and the passage of thousands of millennium to effect the myriad incremental changes required for intelligence. With the proper environment and enough time intelligence will eventually arise in the life forms through the processes of evolution.