It is 0530 in the morning, you are on a walk towards a hill in your area. You reach the peak right at the dawn and spot a bright object in the sky seemingly rising with the Sun. You take out the sky map and discover it is Venus - a relatively violent and hellishly hot planet. Indeed, a beautiful sight to behold. Admiring the planet and sunrise, you end the walk and start the day with a great amount of enthusiasm.
Being an avid stargazer, now and then you spot few planets or some stars but on a particular weekend night, you come across a scientific paper about the past and upcoming encounters of stars with our Solar System.
This paper contains detailed information of stars that have and will pass relatively close to our Solar System, collected by the Gaia Space Observatory. The data shows that nomadic stars pass through our system quite commonly.
The most recent encounter was with a binary system wherein the primary star, known as the Scholz star, brushed past the Oort cloud with its companion, likely a brown dwarf. Still unclear whether this affected the icy bodies and nudged them towards the Sun and even if they are heading in our direction, it would take them well over 2 million years. If by then, events like an asteroid impact - similar to that caused the Jurassic extinction, a global pandemic or a nuclear war does not wipe humanity out, these bodies eventually will.
The universe is a very chaotic place. Stars move at breakneck speeds and their hulking gravity can disturb the quiet place as such our Solar System. The Scholz star system was screaming away at 80 kilometers per second and has only 0.15 solar masses, which might not pose a threat to an extinction level but there is a possible future encounter that has a potential to throw the massive icy bodies of the Oort cloud towards us or even kick planets from their orbits, given, it comes closer than expected.
In ~1.29 million years, Gliese 710 - a star half as massive as the sun, will cruise closer than the nearest star - Proxima Centauri and thus will be the brightest in the night sky, even visible as a dim orange orb during the day. Models suggest, this encounter might be dangerous for us, drawing two possible scenarios - Gliese 710, which is hurtling at a speed of 51,499 kilometers per hour, will pass through the Oort cloud, sending asteroids, comets and other icy bodies hurtling towards the inner Solar System. There is a chance of Earth getting bombarded by those bodies at regular intervals. One asteroid the size of a car and humanity is doomed to go extinct. Secondly, our Sun's gravity might influence Gliese 710's trajectory and pull it closer causing mayhem in planet orbits and kick them from the system. Chances are extremely unlikely but not impossible. Any of the scenarios is a threat to humanity, if they seek to exist around then.
The Gliese 710 encounter might not be comfortable for humanity but we can draw different ways to avoid this or perhaps abandon the Earth altogether. This got me so intrigued that the whole purpose of this article revolves around the question - how can we survive if such an event is to occur in near future? What if Earth becomes a rogue planet?
You are gazing into the night sky, pollution obscures the sight making it harder to gaze. For a week, you are observing an unusually bright object in the sky. Being a person into astronomy, you conclude it to be Venus and adore the beauty of a scorching and violent planet from a relatively calm place. Few months pass by and the brightness of the object has been steadily increasing. It instantly sparks curiosity and you reach the internet for answers. In no time, you come across the news of Gliese 710, a star about half the mass of our Sun, is about to pass very close (on an astronomical scale) to the Solar System. Your mind whispers, “humanity is about to witness a star pass through the Solar System” and this excites you to the core.
Few years pass by, apart from the gradual brightening of the star, nothing much of a significant has happened. Current estimates state, the star will pierce through the Oort Cloud, disturbing millions of icy bodies with its hulking gravity but out of nowhere, Gliese 710 has changed its traversing path and will come dangerously closer to the inner Solar System.
Astronomers are expecting the worst case of planets getting kicked from the Solar System. We only got a few more years to construct a plan for survival - either we leave the Earth, colonize exoplanets or stay here while Gliese 710 kicks Earth out of the orbit, into the cold and dark universe. By the time Earth reaches the orbit of Jupiter, temperatures would drastically fall below the survival point and thus becoming a barren and deadland, no more habitable as it once used to be.
By the Kuiper Belt, humanity would already be gone. With no light and warmth from the Sun, Earth will be covered with a thick (a few kilometers thick) layer of ice and for a few hundreds, if not millions of years, Earth will be floating through space like a free but frozen ball, unless another Sun like star captures it where the conditions are just right for the life to evolve again.