Researchers reveal Earth's habitable lifetime and investigate potential for alien life

Sep 18, 2013
Stars

Habitable conditions on Earth will be possible for at least another 1.75 billion years – according to astrobiologists at the University of East Anglia.

Findings published today in the journal Astrobiology reveal the habitable lifetime of planet Earth – based on our distance from the sun and temperatures at which it is possible for the planet to have liquid water.

The research team looked to the stars for inspiration. Using recently discovered planets outside our solar system () as examples, they investigated the potential for these planets to host life.

The research was led by Andrew Rushby, from UEA's school of Environmental Sciences. He said: "We used the '' concept to make these estimates – this is the distance from a planet's star at which temperatures are conducive to having on the surface."

"We used stellar evolution models to estimate the end of a planet's habitable lifetime by determining when it will no longer be in the habitable zone. We estimate that Earth will cease to be habitable somewhere between 1.75 and 3.25 billion years from now. After this point, Earth will be in the 'hot zone' of the sun, with temperatures so high that the seas would evaporate. We would see a catastrophic and terminal for all life.

"Of course conditions for humans and other complex life will become impossible much sooner – and this is being accelerated by anthropogenic climate change. Humans would be in trouble with even a small increase in temperature, and near the end only in niche environments would be able to endure the heat.

"Looking back a similar amount of time, we know that there was on earth. We had insects 400 million years ago, dinosaurs 300 million years ago and 130 million years ago. Anatomically modern humans have only been around for the last 200,000 years – so you can see it takes a really long time for to develop.

"The amount of habitable time on a planet is very important because it tells us about the potential for the evolution of complex life – which is likely to require a longer period of habitable conditions.

"Looking at habitability metrics is useful because it allows us to investigate the potential for other planets to host life, and understand the stage that life may be at elsewhere in the galaxy.

"Of course, much of evolution is down to luck, so this isn't concrete, but we know that complex, intelligent species like humans could not emerge after only a few million years because it took us 75 per cent of the entire habitable lifetime of this planet to evolve. We think it will probably be a similar story elsewhere."

Almost 1,000 have been identified by astronomers. The research team looked at some of these as examples, and studied the evolving nature of planetary habitability over astronomical and geological time.

"Interestingly, not many other predictions based on the habitable zone alone were available, which is why we decided to work on a method for this. Other scientists have used complex models to make estimates for the Earth alone, but these are not suitable for applying to other planets.

"We compared Earth to eight planets which are currently in their habitable phase, including Mars. We found that planets orbiting smaller mass stars tend to have longer habitable zone lifetimes.

"One of the planets that we applied our model to is Kepler 22b, which has a habitable lifetime of 4.3 to 6.1 billion years. Even more surprising is Gliese 581d which has a massive habitable lifetime of between 42.4 to 54.7 billion years. This planet may be warm and pleasant for 10 times the entire time that our has existed!

"To date, no true Earth analogue planet has been detected. But it is possible that there will be a habitable, Earth-like planet within 10 light-years, which is very close in astronomical terms. However reaching it would take hundreds of thousands of years with our current technology.

"If we ever needed to move to another planet, Mars is probably our best bet. It's very close and will remain in the habitable zone until the end of the Sun's lifetime - six billion years from now."

'Habitable Zone Lifetimes of Exoplanets around Main Sequence Stars' by Andrew Rushby, Mark Claire, Hugh Osborn and Andrew Watson is published in the journal Astrobiology on Thursday, September 19, 2013.

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Lurker2358
1.4 / 5 (21) Sep 18, 2013
lol.

Love how they try to work in a jab about AGW and the insignificant amount of CO2 humans have added to the atmosphere compared even to natural fluctuations in the past.
Andrew Palfreyman
1.2 / 5 (20) Sep 18, 2013
There's a ton of bollocks in that article. For one thing, in a lot less than a million years from now we'll be able to incrementally bump out Earth's orbit as far as we like. That resets the clock to 6 billion years. Everyone relax :)

But there's something else. Neglecting other catastrophes, an entire fucking galaxy is headed our way at breakneck speed - Andromeda. ETA estimated at around 4 billion years
http://en.wikiped...ollision

Lastly, go check out Icarus Interstellar for power beaming proposals to nearby stars. It will not "take 100,000 years", but then again you have to do the research, don't you?
Telekinetic
1.6 / 5 (14) Sep 18, 2013
Human civilization will move underground in a climate-controlled, pharmaceutically induced comatose existence. George Lucas' best work, THX1138, was not just a film. It was a blueprint of the future.
Birger
3.8 / 5 (4) Sep 19, 2013
Once intelligence evolves, all bets are off. While AIs might be comfortable in hot environments, they might help their organic uncles to incrementally bump the Earth orbit out (by asteroid swingbys) as Andrew Palfreyman suggests.
Gmr
1.6 / 5 (9) Sep 19, 2013
re:Earth's orbit - Aww, and here I was thinking robot exhaust would do the trick.
I'm not so sure on the lifetime to intelligent life - at least from multicellularity to man - I think that clock got reset a few times with major extinction events. You do need complex brains, but I'm wondering if it isn't a lot shorter with no mass extinctions.
EnricM
1.3 / 5 (13) Sep 19, 2013
OMG!! The Astophysicians are now also in conspiracy with the Illuminaty Power Control Coalitin (IPCC).
I am amazed about the extreme power of these dreaded climate scientists. I bet they are already experimenting with Mind Control !!! OMG!!!
Quick! Get your alu-foil hats, we newed to protect ourselves from Evil!
alfie_null
4.5 / 5 (8) Sep 19, 2013
But there's something else. Neglecting other catastrophes, an entire fucking galaxy is headed our way at breakneck speed - Andromeda. ETA estimated at around 4 billion years
http://en.wikiped...ollision

Not much of a catastrophe. Galaxies don't so much collide as they pass through each other, as the link you provided points out.
Urgelt
1.8 / 5 (12) Sep 19, 2013
When I read this statement, I rolled my eyes.

""Of course conditions for humans and other complex life will become impossible much sooner – and this is being accelerated by anthropogenic climate change."

They're talking about a time scale of over a billion years...

Yeesh.

I'm not a climate change denier, far from it. But let's be reasonable here. We'd have to continue pumping greenhouse gases, not for centuries, not for millennia, but for millions of years to have any effect on that time scale. We're likely to go extinct long before then, and the excess carbon we released will, through the carbon cycle, end up where we found it.

Looks to me like the authors are over-exuberant with their findings.
Fleetfoot
5 / 5 (3) Sep 19, 2013
Lastly, go check out Icarus Interstellar for power beaming proposals to nearby stars. It will not "take 100,000 years", but then again you have to do the research, don't you?


You missed the bit that says "... with our current technology." Interstellar power beaming has too meany political problems (potential weapon use) but a simple sail based on a high temperature version of Ikaros could in theory travel at ~1% of the speed of light, or less than 1000 years for 10 light years. That is essentially "current technology".

In-flight maintenance and repair using local material at the destination would allow a self-replicating probe system to travel any distance within the galaxy, that part is yet to be developed.

http://en.wikiped...i/IKAROS
Fleetfoot
5 / 5 (3) Sep 19, 2013
re:Earth's orbit - Aww, and here I was thinking robot exhaust would do the trick.
I'm not so sure on the lifetime to intelligent life - at least from multicellularity to man - I think that clock got reset a few times with major extinction events. You do need complex brains, but I'm wondering if it isn't a lot shorter with no mass extinctions.


On the other hand, the dinosaurs were around for many millions of years but never built a radio telescope. Mass extinctions may be necessary to give new species a chance. The simple fact is that we haven't a clue as to how to identify the conditions for intelligence to arise.
Lurker2358
1 / 5 (14) Sep 19, 2013
Not much of a catastrophe. Galaxies don't so much collide as they pass through each other, as the link you provided points out.


While that is a common response from scientists, you are mis-informed, as that claim is false, and clearly in contradiction to their own models.

http://www.youtub...cBlvfjow

What slows the galaxies down is hte mechanical collision of stars, planets, dust, and other objects.

If there were no collisions, the galaxies would go into a pogo between their maximum distances and keep oscillating back and forth, but because there are collisions on each and every pass, the galaxies' relative momentum is decreased with each pass, until they merge, with most of the matter eventually falling into the SMBH, and the remnant orbiting it in a very, very tight core.
tadchem
1.8 / 5 (8) Sep 19, 2013
The assumptions upon which the hypothesis presented here is based include stochastic evolution - evolution driven by random events from single DNA mutations to major meteor impacts.
Once intelligence has evolved, adaptation and evolution are no longer random. I suggest that long before earth become 'uninhabitable' by current standards, for whatever reason, *directed evolution* will have occurred to preserve life.
Anda
5 / 5 (2) Sep 19, 2013
"We estimate that Earth will cease to be habitable somewhere between 1.75 and 3.25 billion years from now. After this point, Earth will be in the 'hot zone' of the sun"

I could say the same without any study, and... That's not new(s)
Fisty_McBeefpunch
1.4 / 5 (15) Sep 19, 2013
I propose that the inhabitants of Planet X will once again unleash Monster Zero (King Ghidorah) upon the Earth and then they will take our water. They have learned from their first mistake and the next time it will be by a direct attack rather than an attempt at deception. They will remove Godzilla and Rodan (Monsters 1 and 2) without permission and leave them on Planet X thus allowing Ghidorah full destructive power against the Earth. There is nothing we can do once Godzilla and Rodan are gone.
GSwift7
2.3 / 5 (6) Sep 19, 2013
What slows the galaxies down is hte mechanical collision of stars, planets, dust, and other objects


Yes, that's correct. While direct collisions between stars and planets might not happen to most stars and planets, there would be countless collisions between larger objects and small objects. For example, if our sun passed through the Oort cloud of another star, both systems would trade a significant amount of ice and dust and gas and rocky debris. If we pass through a large gassy nebula we would accumulate a significant amount of mass from the nebula.

You also end up with a significant amount of mass being ejected into intergalactic space though gravitational exchange of momentum without collisions.

Galaxy mergers are no joke. Chances of a habitable planet remaining viable throughout a merger probably aren't that good. You'd have a shooting gallery of small objects moving at fantastic speeds in all directions. Comets and meteors would hit with zero warning from anywhere.
Lurker2358
1.2 / 5 (13) Sep 19, 2013
I propose that the inhabitants of Planet X will once again unleash Monster Zero (King Ghidorah) upon the Earth and then they will take our water. They have learned from their first mistake and the next time it will be by a direct attack rather than an attempt at deception. They will remove Godzilla and Rodan (Monsters 1 and 2) without permission and leave them on Planet X thus allowing Ghidorah full destructive power against the Earth. There is nothing we can do once Godzilla and Rodan are gone.


This reminds me of that television mini-series "V" (for victory) in which the aliens from Sirius were looking for water to use as fuel, and thus attacked the Earth. In one episode, they had this new super weapon which they were going to use to hold Earth hostage, and they destroyed one of the Ice Moons while test firing the weapon.

If only the aliens knew that ice was water, and there was more water on that moon than on Earth...
Fleetfoot
5 / 5 (4) Sep 19, 2013
What slows down the galaxies is in part the impact of the diffuse hydrogen between the stars, not solid objects. We can see that from the x-ray emissions resulting from the heating of the gas and star formation caused by local density increases due to shock waves. The other major factor is called "gravitational drag". If you ever watched the film Galaxy Quest, consider the loss of momentum of the ship as it passed through the minefield collecting mines as it went.
Torbjorn_Larsson_OM
5 / 5 (1) Sep 19, 2013
The larger problem with Mars is that a terraformed atmosphere will last only ~ 1 billion years because of the lack of magnetic field.

Better to inhabit Oort cloud bodies, a hollowed body will last indefinitely.

@Lurker:

Well, it _is_ an exponential process. And we have already made ~ 1/50 of the way to runaway.

But moreover it isn't any longer historically "insignificant", the GW effect depends on irradiation, plate tectonics, et cetera.

@Andrew: Bollocks you say, but given the observations it is a result. Your futurism is more likely bollocks, we can't test it anytime soon.

A galaxy merger isn't a habitability problem. Earth has been through earlier mergers unscathed. (IIRC, something like 100 mergers during Milky Way evolution. So perhaps ~ 30 for Earth.)

@tadchem: Evolution is both random (mutations) and deterministic (selection). It is driven by both.

@Anda: No, earlier estimates have mostly been from 0.7 - 1.5 Ga. This is huge.
Q-Star
2.3 / 5 (6) Sep 19, 2013
What slows down the galaxies is in part the impact of the diffuse hydrogen between the stars, not solid objects. We can see that from the x-ray emissions resulting from the heating of the gas and star formation caused by local density increases due to shock waves. The other major factor is called "gravitational drag". If you ever watched the film Galaxy Quest, consider the loss of momentum of the ship as it passed through the minefield collecting mines as it went.


Fleet, good to see posting regularly again.

@ Everyone. Does anyone have any idea why physorg is not reporting the big news from University Sheffield? They are claiming to have recovered a living organism by scooping it up with high altitude balloon & that is not of Earthly origin, it probably came from a comet.

They're reporting in the Journal of Cosmology next month. They are waiting for results from isotope measurements, & will follow up with Halley meteor shower later this year.

Extraordinary claims require,,
Q-Star
2.7 / 5 (7) Sep 19, 2013
Cont:

,,,, extraordinary evidence. What's interesting is these are very conservitive researchers, from a very well respected institution, and considering the Martian bacteria debacle with NASA several years ago,, they sure went out on a limb by saying so "CERTAINLY" that they were convinced that this "organism" was extraterrestrial,,,, I'm conservative when it comes to such a big science "milestone", but they are saying they are certain, and I'm sure they well remember NASA's big "scoop".
yyz
5 / 5 (1) Sep 19, 2013
Q-Star, I'm not familiar with the story, got a link?

However, I'm underwhelmed at hearing it will be published in the "peer-reviewed" Journal of Cosmology (fer real?): http://rationalwi...osmology

Especially when other journals of equal (questionable) standing like Aperion Press or Bethany Open Science (or even vixra) are available.
Q-Star
2.3 / 5 (6) Sep 19, 2013
Q-Star, I'm not familiar with the story, got a link?

However, I'm underwhelmed at hearing it will be published in the "peer-reviewed" Journal of Cosmology (fer real?): http://rationalwi...osmology

Especially when other journals of equal (questionable) standing like Aperion Press or Bethany Open Science (or even vixra) are available.


I'm not sure about the Journal of Cosmology part, but here a link to story I heard on the radio.

http://www.telegr...ist.html
Q-Star
2.7 / 5 (7) Sep 19, 2013
Q-Star, I'm not familiar with the story, got a link?

However, I'm underwhelmed at hearing it will be published in the "peer-reviewed" Journal of Cosmology (fer real?): http://rationalwi...osmology

Especially when other journals of equal (questionable) standing like Aperion Press or Bethany Open Science (or even vixra) are available.


Having just been laughed at,,,, scolded,,,,, and then ridiculed by one of my colleagues, I must admit to all and sundry,,,, I've been PUNKED by the mainstream media.

This is not science, it is presented by a crank with an agenda, AND I do humbly apologize for wasting anyone who might have read these posts time.
yyz
5 / 5 (3) Sep 19, 2013
Thanks for the link Q-Star. To its credit The Telegraph article did point out some reasons to be skeptical of this paper:

"The findings are published in the Journal of Cosmology, a scientific journal that often publishes papers on astrobiology but is highly controversial among scientists."

and

"It has often been criticised by the scientific establishment for publishing papers of a more fringe variety."

I had to giggle a bit though when I saw that two of the authors on the paper were Wickramasinghe and Wainright: http://journalofc...atom.pdf

Wick's earlier work published in JOC has been roundly criticized by PZ Meyers and Phil Plait, among others:

http://www.slate....ite.html

http://www.slate....ong.html

Perhaps T Larsson could chime in on this new work.
Fleetfoot
5 / 5 (1) Sep 20, 2013
This is the press release on the university web site:

http://www.sheffi...1.309972

"Professor Wainwright said ... the group was confident that the biological organisms could only have come from the stratosphere.

Most people will assume that these biological particles must have just drifted up to the stratosphere from Earth, but it is generally accepted that a particle of the size found cannot be lifted from Earth to heights of, for example, 27km. The only known exception is by a violent volcanic eruption, none of which occurred within three years of the sampling trip.

In the absence of a mechanism by which large particles like these can be transported to the stratosphere we can only conclude that the biological entities originated from space.

The absolutely crucial experiment will come when we do what is called 'isotope fractionation'.

The tension will obviously be almost impossible to live with!"
Claudius
1 / 5 (12) Sep 20, 2013
In "The Night Land" by William Hope Hodgson, humans survive on Earth long after the death of the Sun by utilizing geothermal energy. Much longer than the life of the Sun. Of course, there were lots of monsters.
Captain Stumpy
2 / 5 (16) Sep 21, 2013
Having just been laughed at,,,, scolded,,,,, and then ridiculed by one of my colleagues, I must admit to all and sundry,,,, I've been PUNKED by the mainstream media.

This is not science, it is presented by a crank with an agenda, AND I do humbly apologize for wasting anyone who might have read these posts time.


at least you can admit when you are wrong... that takes strength.

remember, there are those who cant admit when they are wrong... and you hear about their pet theories all the time. so keep your chin up.
beleg
1 / 5 (1) Oct 02, 2013
If what works for correlation - entanglement - works for higher 'intelligence' too, then you leave behind a universe the rest of 'life' will find void of this higher 'intelligence' of 'life'.

Permanent traces of life isn't done with planets. Planets aren't permanent.