Aliens, the trending topic, always made everyone curious. When I heard about the TRAPPIST-1 star system, I was curious about the possibilities of life. And I was like, the planets have oceans bigger than Earth’s oceans combined — wow! And these planets orbit a star that will live for trillions of years. How would the night sky look from the surface of that world? We could see the planets like moons in the sky. That was the first exoplanet news that got me curious.

Later I came to know Titan, Ganymede, Europa, Callisto, and a few small moons have icy oceans. And a few have the possibility of liquid-water seas under the ice. They also have the possibility of life. That was really good to know. I was like, we could have settlements there when we have good nuclear power plants that can give us electricity, and we can grow multiple food crops on the surface of those moons under sealed conditions.

More interestingly, some people say we have billions of galaxies, they have millions to billions of stars, and each star has a few planets — but only a handful of planets are in the habitable zone. Yet we found the possibility of life only on Earth. Life is very rare. And a few people include theology in that. That’s another discussion. But I don’t agree with that.

“Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying.”

— Arthur C. Clarke

And I have the question: Is life really very rare?

Recently, we saw NASA’s article discussing the finding of leopard spots on the surface of Mars. Many articles say that could be a possible sign of past microbial life on Mars. What the NASA administrator said about this in a press meet was:

“We can’t find another explanation. This very well could be the clearest sign of life that we have ever found on Mars.”

— Sean Duffy (Acting NASA Administrator)

And another article most of you must have noticed: life in the clouds of Venus — a pretty interesting article. It discusses multiple molecules that can be produced by microbial life, like phosphine (though there are other explanations for its formation), in the upper layers of the clouds of Venus. Research also found icy crystals on top of the clouds. This means there is a possibility of liquid water and water vapour in the cloud layers, where the density and temperature of Venus’ atmosphere are enough for life. And some research says there are molecules essential for photosynthesis. So maybe we can find microbial life there too.

Why did these two planets become barren wastelands?

Mars lost its atmosphere and water oceans because of the loss of its magnetic field. Radiation from the Sun swept the atmosphere and surface water away. And Mars’ temperature is very low because it doesn’t have a thick atmosphere to hold the temperature through the greenhouse effect. But Mars still has polar ice caps and underground lakes containing water.

But Venus’ story is different. It has a weak induced magnetic field, and it has a very slow rotation speed. That causes the Sun to roast the entire planet and heat up the atmosphere with the help of dense gases, making it a hell. Some say Venus was also once capable of having life.

The similarity between Venus and Mars is that they are at the edges of the habitable zone of our Sun. Once, Mars had a liquid cycle, rivers, seas, lakes. If Mars had sustained its life, maybe we would have had some pretty good companions or pet dinosaurs.

What if the life possibilities are true and confirmed?

This would be evidence that the habitable zone and the presence of water and an atmosphere can possibly create life and support a life cycle — like the water cycle and a good set of organisms that depend on each other. And enough time for molecular structures to evolve into organisms. I think yellow dwarf, orange dwarf, and red dwarf stars will definitely give enough time for the evolution of complex molecular structures. And the good news is that we have millions and millions of stars in our Milky Way that fall into these categories. Most stars can have one or two planets in the habitable zone. Even gas giants have the possibility of life in their dense atmospheres, with organisms swimming through the foggy, cloudy sky.

The big moons like Europa, Ganymede, Callisto, and Titan have a high possibility of hosting life because of the oceans beneath their ice shells, and the volcanoes below them can create a suitable environment for life to develop. A few of these moons have their own magnetic fields, while others are protected by their parent planet’s magnetic field.

This definitely increases the probability of the start of life on planets and moons.

But another problem will definitely arise: extinction events like what happened on Mars. This is the risk of losing life that has already arisen from molecules. And big gas giants’ strong magnetic fields create ionised particles that can cause disruptions in life-forming processes. But that can also make complex molecular structures that can lead to life. Also, very small planets cannot have atmospheres because of weak gravity. And some Mars-like planets cannot have strong magnetic fields.

What are the ideal planets that can have life? Earth-like planets, Super-Earths, Mini-Neptunes, and Neptune-like planets have a high possibility of life. Also, a planet’s rotation plays a crucial role in the formation of life. If the rotation is slow, then it will make the planet like a big pan-flip toast — one side roasted, and then the other.

Also, these three types of stars give enough time for the formation of life. But red dwarfs have a large number of dark spots, which lead to ejection of stellar flares from their surface because of the magnetic field of the star. This is exactly the same problem as big gas giants like Jupiter. But this makes a slightly more extreme environment than gas giants. Still, red dwarfs give trillions of years, which may allow advanced life forms to survive radiation problems.

These factors reduce the probability of life, but the discoveries increase the possibility of life more than before. And this increase in probability also increases the probability of intelligent life. But it needs multiple factors. There should be no predators wiping out the ancestors of intelligent life.

We survived because of an asteroid that wiped out the big lizards ruled the earth.

Let’s see how the results of this research go. And we humans have plans to take samples from Mars. So if they come to Earth, we can find out if there really was life. And we need more technology to identify life on Venus.

These new discoveries definitely doubled the possibility of alien life. Let’s wait for the new discoveries reveal this Alien mystery.

“Claiming there is no other life in the universe is like scooping up some water, looking at the cup and claiming there are no whales in the ocean.” 

-Neil deGrasse Tyson