humans with their greed and selfishness will make earth uninhabitable long before that....we are our own worse enemy
Image courtesy SDO/NASA
Published October 28, 2013
The final days of life on Earth will come some 2.8 billion years from now, suggests a sobering new study.
Currently at a comfortable temperature for life on Earth, our aging sun will slowly warm over its lifetime. Within about five billion years, the sun will exhaust its nuclear fuel and bloat into a "red giant" star that may even engulf our planet.
Things will get toasty for existing life-forms long before that red giant stage is reached. The question examined by a team led by astrobiologist Jack O'Malley-James, of the University of St. Andrews in Scotland, is: When will things get too hot for life to continue?
Using measures such as temperature and abundance of water and food to examine the future health of Earth's biosphere, the scientists have mapped out how all life may begin to die off.
They also analyzed what Earth's "biosignature" might look like to a distant alien civilization searching for life. The study has been accepted for publication by the International Journal of Astrobiology and released recently on the physics archive maintained by the Cornell University Library.
Plants Go First
The team's long-range weather forecast for the far future shows that as temperatures on Earth begin to slowly rise, more water vapor will form, resulting in the steady removal of carbon dioxide from the atmosphere.
Plants rely on carbon dioxide to generate energy through photosynthesis, so the complete removal of CO2 would be bad news for foliage. The first hints of the death of life on Earth, the study found, will come in 500 million years, when less-hardy species of plants begin to die off as global carbon dioxide levels drop.
As more plant species go extinct, so will the animals that rely on them as a source of food and oxygen.
"When plant numbers decline, these two commodities become increasingly scarce, resulting in the simultaneous end of animals over the next billion years alongside the end of plants," the study says.
Only Microbes Left
By about 2.8 billion years from now, only hardy communities of microbes will be left behind to inherit the Earth.
But as the Earth continues to relentlessly warm, oceans will evaporate, triggering a runaway greenhouse effect, which will lead to rapid further heating of the planet and a very scarce supply of liquid water.
"Only the hardiest microbes will be able to cope with this, until even they can no longer survive when temperatures cross the threshold at which DNA breaks down—around 140°C [284°F]," added O'Malley-James.
Signs of Life
The team hopes that these findings may help our own search for life beyond Earth, by expanding the number of potential signatures of life to look for when we learn to analyze planetary atmospheres in more detail.
"A planet in a later stage of its habitable development may appear uninhabited if we only look for the signs of life as we know it on Earth today," said O'Malley-James.
"Knowing what other potential signatures life could have could help us make a positive detection of life on a planet that may previously have been ignored."
Always Look on the Bright Side
While this model points to a gloomy future for our planet, O'Malley-James and colleagues think that their timeline for future life is probably a conservative one. There are still a lot of unknowns when it comes to predicting what life will do under duress, said O'Malley-James.
"It is difficult, if not impossible, to predict what evolutionary tricks life may have up its sleeve to cope with these future extreme environmental changes," he said.
But the study no doubt shows that life on Earth is naturally quite resilient to change. If the past is any indication, we can take heart: Despite major environmental upheavals and mass extinctions, life has never been entirely snuffed out since it emerged.
"While it is depressing to know that life will end one day, there is still plenty of comfort in the fact that it won't happen for an unimaginably long period of time," O'Malley-James said.
The dinosaurs were able to rule the earth for about 160 million years. I hope man can prove he is at least as smart as they were and set a new record.
Lets worry about the next million years. The rest after that should be easy.
The galaxy Andromeda will collide with the Milky Way before the earth burns up. We should look for a planet in Andromeda that will come close to our earth and plan to switch planets.
Indeed, when the sun will be 10% warmer than today, well sooner that the red gian phase, animals surviving under the soil or in the water can no more support the heat and will disappear, preceeding the extincvion of plants and microbian life.
But as the Earth will continue to warm up, when the Sun will be 15% warmer than today, rivers and water of the oceans will evaporate, releasing a huge amount of water steam in the atmosphere.
At the end, in 2.8 bln years the life on earth will be impossible, the surface temperature exceeding 400°C.
Later, when the sun will enter into the giant red phase, its enveloppe will reach Venus, increasing the temperature on Earth to 1200°C.
The Sun will be 2000 times hotter than today and its size could reach 180 to 200 times its current size ! At that time, the Sun will shine 10,000 times stronger than today at magnitude -36 and will underlie a angle of 69° at the surface of the earth.
In some scenarii the Sun could reach the orbit of the Earth and even the one of Mars.
This prediction is scary.But according to religious concept and prespecive
the warld will end abrubtly without warning and life ceases to exist one time for all species in a fruction of a second.When this incident happens life goes as usual as it is today or as normal no matter how it evolves as it continues to that day that nobody knows except God himself..
I for one don´t even think man will exist in a billion years. In less than, oh, 10 000 years, I believe drastic changes will have been made.
You cannot create nor destroy energy in this physical universe. Energy and its mass transforms into something new constantly. That is the physical world of change, what about the metaphysical world, the world of our minds. Yes the body needs to go somewhere to survive in this physical universe, seeking somewhere outside to move in a direction. What about the mind? The sages say the mind can also seek somewhere to go and that is somewhere inside us. Sages say the mind can find a place inside this physical experience that transcends this mind and body universe. Wow! What a concept that someone's mind created? Carl Jung said, "The ones who look outside dream and the ones who look inside awaken." What does that mean?
A gamma ray burst could snuf a whole lotta things out, a solar wind may blow our atmosphere away, a few super volcanoes may explode, a variety of projectiles from space could smash into us, an errant Black Hole may drift by, or the Republicans may win the presidency.
AT THAT TIME EVOLUTION WILL HAPPEN IN SUCH A WAY THAT, THE LIVING BEING CAN WITHHOLD EVEN THE SUN'S HEAT
Might be a "new study", but it's old news. I've known this thesis about the sun since the 80's and most probably would have been formulated decades before that.
All stars go through that. And the universe is so big, they might have life elsewhere. Our psychiatry professor at Medical College Patiala mentioned that man's ego is so big although man's size is so small compared to the big universe, might be microscopic etc.
The Earth will never be "healthy" as long as man is here. If history repeats itself, man will be long gone in less than a million years.
Not to worry, through greed and ignorance humans will kill all life on the earth a long time before the sun does.
Come on people, we already know that our sun is in a Main S. star life and it will longer that more luminous stars are. But don't you think before our star become a Red Giant star, 20 light years away from us, there is another Gian Star and it will explode Supernovae type 2(very soon, compared 2.8 b. years) and possibly will affect our solar system, before actually our star becomes a red Giant... In 2.8 b years i don't believe the life will be on Earth, but not just because Sun is gonna die or become a Giant star, just because of other universe surprises....
@Paul Green What a strange comment . Earth will be destroyed in 2.3 . Plan to switch planets ?? why when we could have switched planets well before that . When Andromeda collides planets are not going to pass by us
@Paul Green Andromeda is expected to collide with the Milky Way in 4.5 billion years, we all die in 2.3 billion years
@Omar Abdi And why are you bringing religion into this? LOL.
@Omar Abdi Here we do not speak about the influence of God... we speak about science and maths.
@Dr. T. K. Stone Regards to you .... Pranam
@Tom Pugh Yes, the sun is the least of our eminent worries. If humans can survive religion and politics for another 500 years, they will have become a type 2 civilization by then, and would have control of all planets within our Galaxy. In 2,000 years humans will probably be a type 4 civilization and would have control of everything in the universe. When they reach type 5, they will be able to jump from universe to universe and will be like gods. and that's just 2,000 years.
Even evolution is limited by the laws of chemistry. No amount of evolution can save photosynthesizing organisms from the complete loss of atmospheric CO2. No amount of evolution can save microbes from the complete loss of liquid water. No amount of evolution will enable organisms to survive temperatures above the point when DNA is broken down.
@Seth Petra Mars IS very hot, and very cold, on the dark side.
The new study defines the timeframe more accurately. The old hypotheses postulated a very wide range of dates for exactly when plants would die off, and when all life would be extinguished.
@Brian Jaimes Thats A BIG star to snuff out,considering the earth is the size of a pin head compared to the mass of the sun...
@Ramnik Kaur Josan Microscopic is right....like I said above the earth is the size of a pin head compared to the mass of the sun,now imagine what humans look like in comparison. the sun rules the solar system we are in, i cant imagine what would happen if Jupiter was to go astray falling out of its orbit, now thats the largest planet in our solar system, that planet can reek havoc, lets look at ego now..
@michael g. never happen the suns corona will burn up anything coming close to it
@michael green I don't think that there is one that big. The sun gets hit all the time. Many just burn up.
To be big enough to have any effect at all, it would have to be so big that it wouldn't be an asteroid. We're talking Jupiter size big here. Even earth-sized would have no noticeable effects.
@norman h. Humans will always be destructive creatures
No. Nothing humans can do will even come close to inconveniencing the bacteria as a group.
@norman h. Kill off the Human Species... most likely, but life will prevail and prosper without Humans here.
@Denis Kharin i believe you are right I think earth will experience a blast from a super nova from somewhere outside the universe, its already happened just this last year but earth wasn't in the path of the rays..
The likelihood that a supergiant star will go supernova within 20 light years some time in the next 2.8 billion years is roughly the same as the probability that a supergiant star would have gone supernova some time in the last 2.8 billion years.
And since life is pointedly still here, that means that either the chance of a such a supernova is low enough that it has not happened, or that a supernova at 20 light years isn't as terrible a threat to life's existence as you might think.
@Dennis Kharin There are way too many variables to take into account. What are the directions of travel for the closest stars? Which ones are expected to explode in our proximity during the the next two billions of years? And this is just about the stars, which are a few when compared with the ridiculous amount of objects found in our own solar systems. How many comets will pass by? How many asteroids will enter our atmosphere? What effect on life shall have the slow departure of the Moon? Etc, etc, etc...
@Religions have stated for a long time that the earth (and universe) will end, as we know them. Science is starting to prove that to be true. What surprises me is that science and religion are perceived as opposites. if people open their minds to both, they will see that they can complement each other.
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