Life Beyond: Are we alone?
Is Earth the only chapter in the story of life? The answer lies somewhere in distant space and distant time. The search will reveal who we are and who we might become.In the search for life out there, we must first look inward.
What we see around us is staggering complexity. What does it take to create life? Living organisms are created by chemistry. We are huge packages of chemicals. Now, what are the ideal conditions for chemistry? Well, first you need energy e.g. Sunlight, Geothermal Heat. But not too much. What you want is just the right amount and planets that turn out are just right, because they are close to stars but not too close. You also need a great diversity of chemical elements e.g. Oxygen, Carbon, Sulfur etc. And you need liquid, such as water. But why liquid? Well, in gases atoms move past each other so fast that they can’t hitch up. In solid, atoms are stuck together i.e. they can’t move. In liquids, they can cruise and cuddle and link up to form molecules. Molecules can dissolve in water to form more complex chains. Now, where do you find such goldilocks conditions?
Well, planets are great, and our early Earth was almost perfect. Let’s recall our mother Earth to 4 billion years ago. It was just a right distance from its star to contain huge oceans of liquid water. And deep beneath those oceans, at cracks in the Earth’s crust, fantastic chemistry began to happen. Atoms combined in all sorts of exotic combinations. The exact recipe is still a mystery, but the ingredients for life are simple- energy, organic molecules and liquid water. Somewhere in the seas of early Earth, basic chemistry became biology- perhaps even more than once. The first cells were likely born in hot volcanic waters in conditions once thought impossible for biology. The closer we study life, the more extreme places we find it thriving. Here on our planet microbes have adapted to survive the most hostile conditions – arid deserts, frozen Himalayas, in trenches under thousands of tons of pressure in the ocean deeps.
In the vacuum of a space simulator, life forms have been flourishing for years without oxygen. New research suggests that life emerged over 4 billion years ago when Earth was an alien and deadly place. The planet was ravaged by intense volcanism and an asteroid storm that lasted 100 million years. Yet even in these extreme conditions, life quickly found a foothold. As soon as the Earth cooled off its formation, life began here. Because it happened quickly here on Earth, it is thought to happen quickly on other planets as well.
The story of Earth gives us hope that life could be universally common. It teaches us that life is fast acting, tenacious and made of basic and common ingredients. After 4 billion years of isolation, the search for our cosmic kin has finally begun.
Where there is water, there is life – and so on our best chance to find it is to look for ocean worlds like Earth. Our search for Earth-like planets has only just begun and the findings are tantalizing. Some notable Earth like planets such as- KEPLER-62F (Distance: 1200 Light Years, Possible water world),TRAPPIST-1D (Distance: 41 Light Years, Possible water world) TEEGARDEN-B (Distance: 12 Light Years, Possible water world), K2-18B (Distance: 111 Light Years, Confirmed atmospheric water vapor). We have barely scratched the surface. Nature’s trove of secrets is bottomless. According to the scientists, the galaxy is awash in water. It’s awash in organic molecules and complex chemistry. All of the things that we know were necessary for life to begin on this planet exist in abundance throughout the galaxy. Did something similar to what happened on our own planet happen on those other planets?
Looking at the raw numbers, the existence of alien life seems almost inevitable. The latest data suggests that upto 1/4 of stars have rocky planets orbiting in their habitable zone – the right distance for liquid water. In our Milky Way Galaxy alone, that’s approximately 50 billion worlds like Earth. In the entire universe, the possible number of habitable planets is staggering – 100 quintillion.Imagine trillions and trillions of chemicals, soups, stewing for eons.
Among this abundance of worlds,many will be deadly to life as we know it. There will be planets in the habitable zone that are scorched, frozen and suffocated by poisonous gases. Many will lack an atmosphere, critical for temperature regulation or have one that is deadly. Venus, once thought to potentially support life, is now sterilized by a crushing toxic atmosphere. But life may not be confined to the habitable zone. Far from the warmth of their star, the moons of giant gas planets may be hidden oases of life. Their energy might not come from sunlight, but from gravity – the lurching push and pull of the host planet. Icy Enceladus has it all; a huge subsurface ocean with hydrothermal vents spewing the chemistry of life. Titan is especially alluring – larger than Mercury and speckled with methane lakes and organic compounds. In 2026, NASA plans to send a drone to Titan, seeking out signs of life in its valleys and craters. There may be upto 100 trillion exomoons in our galaxy alone-100 times the number of planets. Some may even be Earth sized with atmospheres and surface water. With so many places to find life, it seems only a matter of time before we make a discovery. Some think we already have.
On June 30, 1976, the Viking lander on Mars found something that still remains unexplained. After being injected with nutrients, Martian soil samples expelled signature radioactive gas just like soils from Earth. Was this signal a natural phenomenon, or our first encounter with alien biology? The discovery of just one Bacteria on Mars or any other body of the Solar System would indicate that the whole chain of evolutions, cosmic, chemical and biological, is at work everywhere. In that case, the creation of life anywhere in the universe would be more the rule than the exception.
If we haven’t found life already, it may not be long until we do. NASA Scientists now think that we are on the verge of discovery. According to them that’s all going to happen in the next 10 to 20 years. How exciting is that? If we do find life out there, what will we discover about ourselves? What chapter is Earth in the story of life?
The universe is nearly 14 billion years old. And our galaxy is something like 12 billion years old. So, there could be life out there that could be dramatically more advanced than the life that we have here on this planet. Is Earth a latecomer on the cosmic stage? Just how ancient could life be?
After The Big Bang, for its first few million years, the cosmos was too hot for life. When it finally cooled enough for life, there were no stars and planets; only huge lumbering clouds of hydrogen. After 70 million years, gravity took hold of these clouds and spun them into the first generation of stars. The first stars were massive and bright but there was no life to watch them rise. Vital heavy elements were still being forged in their hot stellar cores. Not even The Big Bang was hot enough to create them. The only elements that were created on The Big Bang were hydrogen, helium and a little bit of lithium. All the stuff that makes our life livable weren’t created on The Big Bang.The only place they were created is in the fiery cores of stars. The explosive death of the first mid-sized stars seeded the cosmos with the ingredients for life. From their ashes a second generation of suns – this time with rocky planets dancing around them were created. This is the moment: the raw ingredients for life together existed for the first time, nearly 13.7 billion years ago. Some believe the conditions for life existed even earlier, in the warm afterglow of creation. As the heat from the Big Bang faded, the universe passed through a goldilock era. Some 15 million years after time began, the ambient temperature reached a balmy 75°F (24°C). In theory, stars and planets could have formed this early on, in hypothesized ultra-dense regions of space. If such regions existed, liquid water could have flowed abundantly, even on rogue planets far from any star. Could this have been the dawn of life? Alien beings feeding off the heat of The Big Bang? Somewhere out there may be a planet with life nearly as old as the universe itself. With a 10 billion year head start, the universe could be teeming with life far more advanced than our own.
Despite decades of searching, no sign of alien life, intelligence or otherwise have ever been confirmed.
So where is everybody?
Could we really be alone ?
Maybe primitive life is common, but intelligence is exceedingly rare.
Maybe space is just too vast for feasible communication.
Or maybe we are the first.
The universe is young and the vast majority of planets are yet to be born. The ingredients for life will be stewing for another 100 trillion years. From this perspective, we are the dawn: the opening melody in a symphony of life. What might come long after us?
Red Dwarf Stars can live up to 10 trillion years bathing their planets in starlight for eons. Life is much probable on these time scales where conditions are stable for vast periods of life. Any beings close to these stars would have to contend with violent solar flares that continually threaten extinction. Many of these planets would be tidally locked-one side permanently exposed to the sun and the other frozen in darkness. But as Earth has taught us life is remarkably adaptable. What forms might life take when it has trillions of years to evolve?
One day, somehow, the story of life will come to an end. If we are the first chapter of that story, we have the chance to carry the torch of life far into the future. And if biology does persist far into the future, then we live in a privileged moment. In later chapters, the universe will seem far different. The expansion of space time will make distant stars invisible and the night skies will go dark. Perhaps life in the far future will wonder: What it was like to live in the universe’s brilliant early days? We are lucky enough to know the answer.
All we have to do is look up.