The only way to finish college
The only way to finish college
“We still don’t know how life in the Universe got its start, or whether life as we know it is common, rare, or a once-in-a-Universe proposition. But we can be certain that life came about in our cosmos at least once, and that it was built out of the heavy elements made from previous generations of stars. If we look at how stars theoretically form in young star clusters and early galaxies, we could reach that abundance threshold after several hundred million years; all that remains is putting those atoms together in a favorable-to-life arrangement. If we form the molecules necessary for life and put them in an environment conducive to life arising from non-life, suddenly the emergence of biology could have come when the Universe was just a few percent of its current age. The earliest life in the Universe, we must conclude, could have been possible before it was even a billion years old.”
When the Universe was first born, life was absolutely impossible. There were no planets for life to reside on; there were no organic molecules to self-replicate; there were no energy gradients or sources of heat and light; there weren’t even heavy elements or neutral atoms. In order for life to exist, the Universe had quite a bit of work to do.
Our Earth formed after more than 9 billion years of cosmic evolution, and life began on our planet shortly after that. But there’s no reason to believe that Earth is the only world with life on it; in fact, if we put everything we know about the Universe together, many other locations should have gotten there billions of years earlier.
“As time goes on, the amount of mass lost by the Sun will increase, particularly as it enters the giant phase of its life. But even at this relatively steady rate, the growth of helium in the Sun’s core means that we will heat up here on planet Earth. After about 1-to-2 billion years, the Sun will be burning hot enough that Earth’s oceans will boil away entirely, making liquid water impossible on the surface of our planet. As the Sun gets lighter and lighter, it will counterintuitively get hotter and hotter. Our planet has already used up approximately three-quarters of the time we have where Earth is habitable. As the Sun continues to lose mass, humanity and all life on Earth approaches its inevitable fate. Let’s make these last billion-or-so years count.”
As the Sun burns through its nuclear fuel, it loses mass in not one, but two ways. Sure, in its core, it’s fusing hydrogen in a chain reaction into helium, with the reduction in mass corresponding to a gain in energy: the energy that powers the Sun and gives life to all the planets. But it also blows off particles, including electrons, protons, and atomic nuclei, in a phenomenon called the solar wind. Even though more massive stars burn hotter and brighter than less massive ones, the Sun, perhaps paradoxically, will increase in temperature and luminosity as it loses mass to these two processes. The Sun is getting lighter and lighter, and the problem of its increasing energy output will eventually destroy all life on Earth.
“In 2020, two next-generation rovers will launch: ESA’s ExoMars and NASA’s Mars 2020. Instead of indirect inferences and possibilities, we’ll actually be able to understand whether the origin of these molecules is geological or biological in nature. It’s important to keep an open mind and let science, rather than our hopes or fears, decide the answer. The evidence is building, and we’re finally gaining a more robust picture of how, exactly, Mars works.
It’s producing methane seasonally, contains loads of carbon-based compounds, and had a very watery past. But does that all add up to life, past or present? In 2018, the evidence doesn’t say “yes” just yet. But in just a few years, we just might have the answer. In a few years, for the first time, we might finally know if there’s life beyond Earth.”
We use the word “organics” a lot when we talk about life (and molecules) beyond Earth. But while that word may conjure up images of reproducing molecules, new cells, and life, the scientific definition is far more mundane: a molecule containing carbon. That means carbon monoxide and cyanide are organic, even though they may be toxic to life itself. The discovery of seasonally-varying methane on Mars is interesting, but it may be better evidence for something geologically compelling than it is for anything biological. Regardless of how you interpret it, one thing is for certain: everything we’ve found on Mars so far is not yet enough to claim evidence for life.
“It’s true that stars that are very different from our Sun have restrictions on what conditions their planets can have and still be habitable. For red dwarf stars like Proxima Centauri, their worlds have conditions that make it unlikely for life to have taken the exact same evolutionary pathway that life on Earth took. But that doesn’t spell doom for life; it merely indicates that alternative pathways are required to arrive at similar outcomes. Frequent flares and excessive blasts of ultraviolet radiation may spell doom if Earth-based life were subject to those conditions, but organisms that have adapted to their environments could survive these outbursts routinely. A few solar hiccups a year should pose no problem for life forms that developed under those exact. harsh conditions. On every world, after all, it should be the organisms most robust against the adversarial conditions they face that will survive.”
The nearest star to us, Proxima Centauri, was discovered to have an Earth-sized planet in its habitable zone just two years ago. In that time, scientists have observed catastrophic flares comfing from the red dwarf star, fearing for the survival of any life on the planets orbiting it. Many now claim that planets orbiting red dwarfs are completely inhospitable to life, since the combination of tidal locking, ultraviolet-rich flares, ozone depletion, and a lack of higher-energy light in general would make photosynthesis and life-as-we-know-it an impossibility. How narrow-minded of us to go down that road! In reality, the energy source is there, the conditions are right for liquid water, the atmosphere as a whole will stick around, and there are many, many adaptations that could lead to life not only surviving, but thriving on a world like Proxima b.
It’s easy to look at a world that’s different from ours and declare how life like ours wouldn’t do well, but the key is to figure out what kind of life would do well there. That’s where the greatest chances for success are. That’s where we need to look.
“How soon after the Big Bang would there have been enough heavy elements to form planets and possibly life?”
Making anything in this Universe takes time. After the Big Bang, there are a whole slew the Universe needed to take before rocky planets and life were possible. This includes the formation of atomic nuclei, neutral atoms, dense enough gas clouds to make stars, multiple generations of stars living-and-dying, and only then will the Universe be filled with the right ingredients to create rocky worlds and, potentially, life. But Earth didn’t come into existence until more than 9 billion years after the Big Bang, and these ingredients were around long before that. The heavy elements from the first supernovae could have made rocky, Earth-like planets very early on, but interestingly enough, it takes longer to form enough carbon to make life a reasonable possibility.
Star Trek: Discovery’s Greatest Science Moments Rethink What It Means To Be Alive
“While most of the famous aliens encountered by Federation crews have been humanoid — including Klingons, Vulcans, Romulans, Ferengi, and Cardassians — there have been notable exceptions. The vampire cloud of The Original Series, the crystalline entity of The Next Generation, the changelings of Deep Space 9 and many others have challenged our conventional notions of what intelligence or life might look like. Now that we’re in the late 2010s, science has advanced tremendously, and so has our imagination for what might be possible.”
It’s pretty easy to point to the new Star Trek series and criticize the science they’ve gotten wrong, oversimplified, misinterpreted, or simply ignored. That’s something, honestly, you could do for any science fiction series if you tried hard enough. But there are a few things about science that Star Trek gets right, and one in particular that it’s breaking new ground in: how life, and intelligent life in particular, might be vastly different from what we expect. Other depictions of intelligence in alien species have focused on two types almost exclusively: human-like, autonomous, chemical-based beings, and artificially intelligent robot-like beings. But what if there were organic pathways and mechanisms out there that went far beyond what we presently understand, where quantum entanglement across galactic scales dominated or even non-matter-based life forms existed? Sure, it sounds like pure fiction today, but being open to these possibilities is vital.
“There may never have been another intelligent, technologically advanced alien species in the entire history of the Universe. When you take into account that there may be 400 billion stars in the Milky Way, up to three potentially habitable worlds in many of these star systems, and some two trillion galaxies in the entire Universe, it seems like intelligent life is an inevitability. But our intuition can often lead us astray; what we feel is no substitute for science. The magnitude of the unknowns that abiogenesis, evolution, long-term habitability and other factors bring into the equation throws many of our assumptions about life into doubt. It’s true that there are an astronomical number of possibilities for intelligent, technologically advanced lifeforms, but the huge uncertainties make it a very real possibility that humans are the only spacefaring aliens our Universe has ever known.”
Given the huge number of stars, planets, and chances at life that the galaxy and the Universe has given us, it seems paradoxical that we haven’t yet encountered any form of alien intelligence or even life. The discoveries make in the field of exoplanet studies, particularly by the Kepler mission, make this an even bigger problem than we anticipated: more than 10^22 planets with Earth-like conditions are expected to exist in our Universe. But having so many chances, even with an astronomically large number like that, doesn’t necessarily mean we aren’t alone. The origin of life, the sustainability and development of complex, intelligent life, and the odds of technological success and ambition of a species that makes it are complete unknowns. We might enjoy thinking about these questions and exploring the Universe to hunt for answers, but the fact is that we don’t know.
If you could have a complete answer to one of these 5 questions what would it be?
1.) Did cosmic inflation happen or was there another process?
2.) Is earth the only place in the cosmos with life?
3.) How [can we] merge general relativity and quantum mechanics?
4.) What is dark energy and dark matter?
5.) How did life begin on Earth?
There are a very large number of unsolved mysteries in the Universe, many of which would revolutionize our understanding of what it all is… and what it all means. If you could know the answer to only one of these questions, but know it immediately and fully, which one would you pick? Would you want to know more about the origin of the Universe, pushing things back before the Big Bang? Would you want to know about life elsewhere in the Universe, far beyond Earth? Would you choose quantum gravity, or how to merge our two great, incompatible theories of how everything works? Would you want to know what dark matter and dark energy truly are? Or would you go for the origin of life on Earth?
“Either life began on Earth with a complexity on the order of 100,000 base pairs in the first organism, or life began billions of years earlier in a much simpler form. That could have been on a pre-existing world, whose contents migrated into space and eventually came to Earth in a great panspermic event, which is certainly possible. But it also could have been in the depths of interstellar space, where the energy from the galaxy’s stars and cataclysms provided an environment for molecular assembly. It may not necessarily have been life in the form of a cell, but a molecule that can collect energy from its environment, perform a function, and reproduce itself, encoding the information essential to its existence in the reproduced molecule, just might qualify as life.”
We talk about the origin of life on Earth with bated breath, wondering all the time how things occurred to make our planet unique. But within that big question lies an assumption that may not be true: that life on Earth originated on Earth itself. It’s entirely possible, based on what we’ve seen out there in the Universe, that life didn’t originate here at all. Rather, it could have come from a primitive, pre-existing world, or even from the depths of interstellar space itself. If it’s the latter case – interstellar space – then perhaps we don’t even require a planet at all to create the more primitive forms of life itself. Perhaps all you need is a molecule that encodes information, reproduces itself, and converts external energy for use in biological processes. And if that’s the case, the origin of life may bear very little resemblance to what life has evolved into today.