Could Earth Become a Rogue Planet?
As of 4.5 billion years ago, Earth has been in a stable orbit around our local star; the Sun. Whilst writing this, the Earth is 91.41 million miles away from its parent star, which means its around its perihelion, which is the point where Earth is nearest to the Sun. Around July 2019, Earth will approach its Aphelion, where it will be at its furthest of 94 miles away — meaning the Earths orbit isn’t a perfect circle, but is an oval, similar to the other seven planets orbiting the centre. It may not seem so, but we are quite lucky to be living on a planet that has this stable orbit, as in the days of the Early Solar System, huge planet sized objects were tossed into one anther (like Earth and Theia, which is now the Moon), as well as tossed out of the Suns orbit, these huge bodies now wondering the vast emptiness of space alone. Its estimated that fifty percent of all planets in the universe are rogue, without a parent star, and its not underheard of for a stable system like our own to fling planets out of orbit, like our own.
There are billions of rogue planets in the Milky Way alone, most of which were caused by the hostile environmental of a developing star system, where a large object could have hit them, altering there orbit, or a larger planet may have altered there own orbit, affecting the smaller planets of the inner system. Though, even if a planet has survived the growing pains of formation, it doesn't mean its safe. An outside flyby object, like a star, other rogue planet or black hole could disrupt the orbits of any celestial body, causing it to leave the system. Now the story of a rogue planet isn’t exactly pleasant as it drifts across the darkness. Whilst its star becomes smaller as days go by, it will become cooler and darker with less gravity, until its surface freezes in temperatures of minus two — hundred and seventy degrees world wide, rendering it dead.
If a large enough object were to come close to the solar system, like a rogue white dwarf, rogue planet or even just a really big asteroid, then the planets orbit could shift. Lets create a scenario, where a white dwarf is passing close enough to the solar system for Earth to be flung away from the Sun. Bear in mind that this is extremely unlikely, as despite our limited technology to detect these large rogue objects, space is really big. Like so big that it would take 4 years to travel to the nearest star system, Proxima Centauri, at light speed. Which by the way is 670,616,629 mph. The fastest we’ve ever gone is 38,000 mph, meaning if we were to travel at that speed it would take 70,591 years to get there. And besides a few small space rocks in-between us and that, its mostly just the cold emptiness of a vacuum, with utterly nothing for a long, long time. So yeah, its pretty unlikely to happen.
But what if it did? What if a lone White Dwarf strayed to close to the Solar System and altered the Earths orbit? The short answer is that everything would probably die. The long answer is more interesting. Picture this. Its October the 31st 2020, everyone is preparing for Halloween and after years of knowing, without anyway to counter this problem, NASA does an emergency broadcast, letting everyone know that its going to get really cold, a lot lighter in gravity and a lot darker for the next few months as Earth is steadily moving away from its source of heat. At first everyone thinks its just an extensive Halloween scare, but no. Slowly reality catches up, as does the idea of the inescapable demise of all life everywhere.
I suppose I've dramatized it a little, but as soon as the world realizes that there's no escape, the order established over the 200,000 years of Human existence will slowly erode into chaos. Despite a majority trying to live life as normal as possible for the next few months, the extremist minority completely ignoring the law would spread there ideals like the black death until its eradication when the cold becomes too much to bear.
As this is theoretical, its hard to define the speed of which we’d be flung out into the endless abyss of space, as this would depend on the speed and size of the passing star and probably a thousand other inconvenient factors of which would hinder my imagination to a halt. So lets keep it simple. Earths orbital speed is 29,800 metres a second (or 66,660 mph), which is faster than most things we’ve ever sent into space. Lets just say that this speed stays consistent as it moves away in one direction, presuming the sun is staying in the same place, because if it wasn’t, math would be getting really complicated (for me anyway).
As Earth is launched away from the sun at its orbital speed, the first notable thing it would be likely to contact is the Martian orbit. This would take about 21 days to reach. That's quite a while in terms of waiting for your impending doom. Climatically, Earth would be very similar, with the planets greenhouse gases trapping enough of the Suns heat in to accommodate the planets eco — systems, though it would be slightly cooler, which on a positive note, would counter global warming. Though on a negative note, it would dark enough for photosynthesis to be a lot slower, so for those remaining on Earth, food would be becoming far more scarce, slowing the production of much needed resources.
One-hundred and forty-one days later we would have just reached the asteroid belt. Now a common misconception of the asteroid belt is that it is a minefield of debris, with tiny particles in size, to dwarf planets of rock, stretching as far as the eye could see. That view is very wrong. In fact, its so wrong, Earth could make it through the asteroid belt without hitting anything, as its actually a very sparse region of the solar system, where the debris that makes it up is 4% the mass of the Moon. The larger asteroids that could impact the rogue Earth would be about the distance of the journey to the moon and back, so we’ll probably be alright. Though, when concerned with climate, we are now well out of the habitable zone and sunlight is less than 30%, so plants would take about four times as long to grow in an environment with an average temperature of about ten degrees. Yep, its cold, and that's at the equator; the greenhouse affect is slowly losing its strength and its about to get a lot colder too. From the North pole to the latitude of southern Britain, it would start becoming a frozen desert, likewise from the South Pole to Southern Australia.
Moving on a swift two-hundred and sixteen days and Earth has met with the King of the solar systems orbit; Jupiter. If Earth was at all close to this monster of a gas giant, then it would likely be captured in its orbit and become a moon or, less enticingly, would be swallowed hole. Presuming we were caught in its orbit, the Earth would far slightly better off; the orbit would heat up Earth a little, but by the time it would have reached Jupiter, Earth would be a teeth shattering minus one-hundred degrees. The seas of Earth would be largely frozen as hard as bedrock, though, closer to the bottom, near volcanic vents life would still flourish as it had been doing for the four billion years before hand. But the last Humans would have died out on the surface with the failing harvests coming out of the asteroid belt. But Humans are definitely still alive, living under the ground in a developing metropolises developed over the 378 days since the event, previously established by NASA and other societies, of which were keeping this event secret. As the Earth has been slowly freezing, these underground habitats would be based near volcanic areas to harvest energy, using artificial lighting and heaters, much like in current greenhouses to produce crops and purify water.
If we were to continue pass Jupiter to the last planet in the Solar System, Neptune 1762 days would have passed; everything from the surface to those last underwater havens would be completely and utterly frozen at a temperature of minus 210 degrees. If you’d like to ask about the atmosphere that saved Earth for a while thanks to its green house effect, then that’s been condensed, and frozen to the surface. We’re now literally just a giant piece of floating rock, with a race that is extremely different to Humans now, with pale skin and large eyes, likely a lot smaller in stature, living deep below the surface where the cold can’t reach. Though, they still have access to the empty vacuum that they are lost in, as many of there ancestor would have colonised other regions of space, meaning that these underground megacities would likely be a hub for colonies, and with greater access to mining due to access to the great caverns of the Earth. Maybe, this scenario is actually saving Humanity from its fate of global warming.
Around 165,000 days later (or 452 years later) we would have just entered the Oort Cloud, and two million, seven-hundred days later (or 739,726 years later) we would have just left it. Much like the Asteroid belt, the Oort Cloud is made up of huge to tiny chucks of material left over from the formation of the solar system and covers the entirety of the solar system in a ‘protective’ layer of materials (I say protective, but a large majority of the larger asteroids that could threaten Earth originated here, making it more of a love-hate relationship). Unlike the Asteroid belt, this cloud of rock is seriously less dense; the average piece of debris is about the distance of the Earth to Saturn, so we’d likely be fine passing through it. So it took 739,726 years to exit the solar system; the Suns rays can barely touch us at four trillion miles away from our original position, and nothing more is affected by its gravity.
Now we could float infinitely, continually distancing ourselves away from the sun. There would likely be nothing to stop us. Though slowly, our core would lose energy, so eventually geothermal energy could no longer be used, as the inside would fair off similarly to the outside, resulting in a mass of rock, completely frozen solid as hard as anything known to man. Considering this is about seven hundred thousand years into the future, Humanity would have probably complete moved off of this pointless rogue planet, leaving just a fossil of the civilization that once lived there.
Though, its likely, thousands of years before exiting the solar system, the evolved human race could have realigned the orbit of Earth with the sun and would have moved it back to the original position of October 31st 2020, due to their evolved knowledge of pretty much everything, assuming they survive. By this point man may no longer be man, but due to its expansion into the stars could now be multiple species, evolved in differing ways. If Earth was left to float away into the nothingness of space, then those whose relatives once lived on it, could have completely forgotten about there ancestry; ‘Humans’ and ‘Earth’ could be an unknown concept to them now, forgotten words in thousands of intelligent species that would have derived from man on a slowly freezing rock, distancing itself further away from the light that it once called home.
Despite this rather interesting theory, its very unlikely the Earths orbit would be affected so greatly resulting in it becoming rogue. The billions of already rogue planets do account for 50% of all planets in the Milky Way, though a very high percentage of these would have been fired out in the early formation of there systems. A big enough star, black hole or rogue planet coming close enough to our solar system would be really unlikely to and even less unlikely to affect out planets orbit to fire it off into wild space, beyond the Oort Cloud. But still, it could. And who knows, maybe it’ll turn out like this, or maybe we’ll all die.
