Luck Played a Major Role in Keeping Earth Fit for Life

Potentially Habitable Exoplanets

Artist’s rendering of potentially habitable exoplanets. Credit: NASA/JPL-Caltech/R. Hurt (SSC-Caltech)

A study by the University of Southampton gives a new perspective on why our planet has managed to stay habitable for billions of years – concluding it is almost certainly due, at least in part, to luck. The research suggests this may lengthen the odds of finding life on so-called ‘twin-Earths’ in the Universe.

The research, published in the Nature journal Communications Earth and Environment, involved conducting the first-ever simulation of climate evolution on thousands of randomly generated planets.

Geological data demonstrate that Earth’s climate has remained continuously habitable for more than three billion years. However, it has been precariously balanced, with the potential to rapidly deteriorate to deep-frozen or intolerably hot conditions causing planet-wide sterility.

Professor Toby Tyrrell, a specialist in Earth System Science at the University of Southampton, explains: “A continuously stable and habitable climate on Earth is quite puzzling. Our neighbors, Mars and Venus, do not have habitable temperatures, even though Mars once did. Earth not only has a habitable temperature today, but has kept this at all times across three to four billion years – an extraordinary span of geological time.”

Many events can threaten the continuous stability of a planet – asteroid impacts, solar flares and major geological events, such as eruptions of supervolcanoes. Indeed, an asteroid that hit the Earth 66 million years ago caused the extinction of more than 75 percent of all species, killing off the dinosaurs along with many other species.

Previous computer modeling work on Earth habitability has involved modeling a single planet: Earth. But, inspired by discoveries of exoplanets (those outside of our solar system) that reveal that there are billions of Earth-like planets in our galaxy alone, a Southampton scientist took a novel approach to investigating a big question: what has led Earth to remain life-sustaining for so long?

To explore this, Professor Tyrrell tapped into the power of the University of Southampton’s Iridis supercomputing facility to run simulations looking at how 100,000 randomly different planets responded to random climate-altering events spread out across three billion years, until they reached a point where they lost their habitability. Each planet was simulated 100 times, with different random events each time.

Planets Temperature Time

Credit: Kate Davis

Having accrued a vast set of results, he then looked to see whether habitability persistence was restricted to just a few planets which were always capable of sustaining life for three billion years, or instead was spread around many different planets, each of which only sometimes stayed habitable for this period.

The results of the simulation were very clear. Most of those planets which remained life-sustaining throughout the three billion year period only had a probability, not a certainty, of staying habitable. Many instances were of planets which usually failed in the simulations and only occasionally remained habitable. Out of a total population of 100,000 planets, nine percent (8,700) were successful at least once – of those, nearly all (about 8,000) were successful fewer than 50 times out of 100 and most (about 4,500) were successful fewer than 10 times out of 100.

The study results suggest chance is a major factor in determining whether planets, such as Earth, can continue to nurture life over billions of years. Professor Tyrrell concludes: “We can now understand that Earth stayed suitable for life for so long due, at least in part, to luck. For instance, if a slightly larger asteroid had hit Earth, or had done so at a different time, then Earth may have lost its habitability altogether.

“To put it another way, if an intelligent observer had been present on the early Earth as life first evolved, and was able to calculate the chances of the planet staying habitable for the next several billion years, the calculation may well have revealed very poor odds.”

Given these seemingly poor odds, the study speculates that elsewhere in the Universe there should be Earth-like planets that had similar initial prospects but which, due to chance events, at one point became too hot or too cold and consequently lost the life upon them. As techniques to investigate exoplanets improve, and what seem at first to be ‘twin Earths’ are discovered and analyzed, it seems likely that most will be found to be uninhabitable.

Reference: “Chance played a role in determining whether Earth stayed habitable” by Toby Tyrrell, 11 December 2020, Communications Earth & Environment.
DOI: 10.1038/s43247-020-00057-8

40 Comments on "Luck Played a Major Role in Keeping Earth Fit for Life"

  1. Chance is not real. It is an imaginary idea used to say, “we don’t really understand why things happen.”
    Also, it is a provable fact light is not constant. Experiments show lights slow. Our entire cosmology has to be rewritten.

    • Torbjörn Larsson | March 2, 2021 at 12:00 pm | Reply

      ? And what is the relevance here?

      But FWIW, all experiments show that light in vacuum has the universal speed limit expected from relativity.

      Our cosmology looks fine as well.

  2. Well I guess God got lucky

  3. I have always thought that applying the law of mediocrity was wrong. As all we learned so far is that both or planets core, size and distance of our moon and the overall low activity g-star are incredibly rare. So rare we haven’t spotted any planet with such abnormal moon, or any planet that is in the goldy zone that has such strong magnetic field to protect it from the star.

    • Torbjörn Larsson | March 2, 2021 at 12:03 pm | Reply

      What would be the significance of a rare Earth (if it is) in relation to the work here, or our moon (abnormal how!?), or our geodynamo field? For instance, Earth lose more water to space than Venus or Mars.

  4. Lol luck has nothing to do with it. GOD MADE IT, it s all by design and with purpose, best give credit. Luck will not save you.

  5. It’s not luck genius, it is God! I guess it wouldn’t hurt admitting.

  6. Luck? That’s not very scientific of you……

  7. yes it was God… because in Psalm 104:5 says “He set the earth on its foundations; it can NEVER BE MOVED.” so another words the Earth will never be destroyed

    • Torbjörn Larsson | March 2, 2021 at 12:06 pm | Reply

      Erroneous superstition.

      And please keep your personal superstition magic incantations to yourself.

  8. Well u are wrong u call it luck i call it destiny

  9. Well u are wrong u call it luck i call it destiny / fate some who wont understand what they cant see and even more feel but one thing with out humans there wouldnt be no earth but with out earth they wouldnt be no humans but with out light there wouldnt be nothin lil light big light bang

  10. That’s the work of God nothing else. The sooner earthlings start accepting this the better.

  11. Luck is such a lame excuse for why the Earth exists… God is the one who sustained Earth thus far, and that’s what makes Earth so special. God eventually is the one who is behind all that “luck” anyway.

  12. Geoff Taylor | March 2, 2021 at 5:32 am | Reply

    Amazing! So much delusion on an allegedly scientific website. Don’t you realize that all religions and rituals are human-made? Invented by humans to try and explain the gaps in their knowledge, what they don’t yet understand. Once upon a time humans believed that the universe revolved around the earth….

    • Any clear evidence that it is human-made? Isn’t the so-called “luck” that’s trying to explain the gaps in their knowledge, what they don’t yet understand?

      • Torbjörn Larsson | March 2, 2021 at 12:17 pm | Reply

        Yes, evidence by continuity. Religions exist in some human societies, hence it is a product of humans as everything else cultural.

        And explicitly so, if you study the indoctrination and artifacts that belong to these practices.

        • It seems like you have a misunderstanding with the word “religion” here. The word religion, first of all, is human-made, and Christianity is not about the Christian cultures, but of faith. Of course, you will not know the difference if you are an unbeliever. And indoctrination artifacts as well do not have anything to do with whether it is human-made or not.
          And please confirm you are NOT a spammer.

  13. Torbjörn Larsson | March 2, 2021 at 11:58 am | Reply

    I can easily see how such an ensemble method can result in a lower than expected likelihood to find Earth twins.

    However, I’m not so sure how such an ensemble result has much to say on Earth climate stabilization through plate tectonics and associated erosion and volcanism regulation of CO2 (and ice albedo) forced greenhouse temperatures.

    There are plenty of specific Earth climate models that gives robust results.

    “Here we review the faint young Sun problem for Earth, highlighting the latest geological and geochemical constraints on the early Earth’s atmosphere, and recent results from 3D global climate models and carbon cycle models. Based on these works, we argue that the faint young Sun problem for Earth has essentially been solved.”[ ].

    Speaking of the need to have full 3D climate models to understand already Earth climate, the paper used 0D equations to be computationally feasible.

  14. The anthropic principle applies. If the Earth were not fit for life in the way that it is there wouldnt be any professors making calculations and nobody would be making comments, including me.

  15. I say look for stars with the same ingredients as our own star first. 2nd look for water planets around those stars focus on those planets. Let’s see if it is inevitable with the right kind of star you get life?

  16. Who cares either way kids lol let’s find some life out there. Same kinda star same kind of resolution I think.telescopes are getting better so it’s a matter of time and apparently the uni has lots. Ice planets included of course

  17. Genesis 1:1 duh

  18. Keaton Reilly | March 5, 2021 at 12:55 pm | Reply

    No it didnt dumbasses aliens primed life for earth

  19. Rajib Mukherjee | March 6, 2021 at 4:48 am | Reply

    Lovelock predicted so in his Gaia Hypothesis

  20. Saying “God did it” is explaining the scientifically improbable with the scientifically impossible. You’re worse off.

  21. Like a human that builds a space suit, life collectively manipulates the Earth to its advantage. Although luck matters up to a point, (like having a large moon and a magnetic field), there is also evolution by natural selection on a global scale, affecting the oceans and climate.

  22. Paul Gerard holland | March 7, 2021 at 7:09 am | Reply

    We will never know unless or until we find life elsewhere.
    I go with luck or probability which we see plenty of in our daily lives. I owe my career to a job advertisement that I saw only by chance. Hitler could easily have been killed in World War 1, and had he not died in WW2 America might have had President Joe Kennedy.
    However, with the size of the Universe and sheer numbers of planets, I wouldn’t be surprised if life similar to ours evolved elsewhere

  23. Benjamin Brown | March 7, 2021 at 8:25 am | Reply

    Torbjorn. You are superstition. There are things you do not know you poor mortal. If you understand quantum mechanics even the basic concept you will understand that when timelines merge you get idiots like you

  24. Nelson Ndhlovu | March 8, 2021 at 3:51 am | Reply

    It can only be the work of God. I can state with certainty that life only exists on earth by design.

    God is a God of order and detest confusion.

    Imagine for a second how much chaos would erupt if
    1. dinosaurs still existed on earth
    2. The Eqyptian civilisation survived
    up to present age

    There would be total chaos. So all factors that were a threat to existence of mankind were tactically eliminated by God.

    My theory is that any form of life from another planet would be a danger to mankind. So God has made life impossible on other planets.

    Someone made life possible on earth by providing right temperature, water and other conditions. The sun influences all planets and ensures life is sustained. This is not by chance. It is by design. That someone is God almighty.

  25. Mr Torbjorn Larsson, the 4 forces of the physical universe were formed in the first one (1) millionth, of the first second, of the Big Bang. At the EXACT same time. In PERFECT proportion to each other. So without what you call a superstition, God, please explain how that happened? And being pretty literate in quantum mechanics and physics, don’t worry about talking over my head! Statistics are a science and they say no you.

  26. Kevin B., Please read my comment to Mr Larsson above and I ask you the same question about the 4 forces of nature. Explain that please.

  27. Edwin Hidalgo | March 13, 2021 at 6:23 pm | Reply

    When luck surpasses by far average coincidence probabilities, it is not luck anymore. There must be a guided system.

  28. Hi,

    Here are my questions/thoughts:

    1. Can matter come into existence from nothingness?

    2. Can dead matter be intelligent?

    3. Laws of physics are bound to be set before creation of matter, matter followed those laws for coming into existence and remaining intact.

    4. Who set those laws and implemented on all matter that exist?

    5. Aren’t we amazed by the seamlessness, cluelessness and spontanuety of the universal system set by SOMEONE!

    6. Science is in search of Creator and Sustainer since inception, who cannot be found in physical form as The Creator cannot be composed of his own creations i-e matter, bcz He existed before creation of matter.

    7. We can feel Him through His attributes but cannot see him in physical form.

    8. Having to have Creator and Sustainer is our compulsion and not a matter of choice.

    9. Considering that this whole universe and all the life on earth has resulted accidently is absolutely absurd.

    10. If He is Almighty, then there is no question of his presence at two different locations at the same time, let alone at what speed can He travel….He is everywhere at all times.

    11. He has made all the laws of physics applicable to matter, so He is not bound by those laws as he is not composed of matter. Further, he can order anything beyond the laws of physics set by Him, as He is Almighty.

    12. As for His mercy, reward or punishment, the concept of life hereafter in all monotheistic religions serves as a counterweight to all injustices and anomalies occurring in this world. So Hitler and others who killed lot of innocent people will be punished for their bad deeds and those innocents will be rewarded in eternal life. For believers, this is the biggest hope and fear, which guides them to the right path. For atheists, well …. law of jungle in this life…. and darkness ever after as they dont believe in God.

    13. Infact, uniqueness and oneness is God’s absolute identity. In different religions and languages people use various names to describe God; but in all cases, only and only same One God is meant by whatever name called. For example if we translate Bible in pure Arabic, the word to describe God is “Allah”, and if we translate Quran in pure english the word to describe Allah is “God”.

    14. Science and religion seek the same goal i-e to reach God. Religion gives the path to live a balanced life and encourages to think scientifically. Scientist should stop considering religion as bygone stories of ancient people. There is lot of guidance in those old st

  29. Torbjorn may I ask you a question? I can see you are believing in the luck part of this article. The odds are very long. If you are wrong about the luck part do you want to trust your eternal soul to those kind of odds. Honestly think about that. I don’t believe the luck part at all but the earth is truly amazing. Have a nice day.

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