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Many of us recall memorizing the phrase 'My Very Excellent Mother Just Served Us Nachos' during our elementary science lessons. This acronym helps students remember the sequence of planets in our solar system: 'My' stands for Mercury, 'very' for Venus, and so on. Other fundamental astronomical concepts include understanding that Earth revolves around the Sun, that the Sun is a massive sphere of hot gas, and that we reside within the Milky Way Galaxy. Some may also have been taught the names of constellations or the phases of the moon.
However, eventually, many of these facts, along with our perception of space, will undergo significant transformations. Some of these changes will have far-reaching consequences, perhaps more profound than the day we lost Pluto's planetary status. Whether it's the total destruction of something or an event that lights up our skies, these shifts are inevitable and will have an impact on life here on Earth, so brace yourselves.
10. The Sun's Demise
Stars, much like living beings, have a life cycle: they are born, they exist, and eventually, they perish. Our Sun follows the same natural progression. In fact, in approximately 5 billion years, our Sun will eventually burn out. So, if you haven't already, it might be a good time to start planning.
A star reaches the end of its life when it has exhausted its fuel. Throughout its existence, a star undergoes nuclear fusion, where it takes hydrogen from its core, heats it to extreme temperatures, and transforms it into helium. Once the hydrogen is depleted, the star expands into a red giant. Its outer layers cool and spread out, while the core, now composed of helium, heats up, causing the helium to fuse into carbon. From here, things can unfold in different ways. For massive stars, the fusion continues, creating heavier elements until iron is formed, triggering a supernova explosion. This explosion leaves behind either a neutron star or a black hole.
Stars with lower mass, such as our Sun, take a quieter path. They swell into red giants, but rather than exploding, they shed their outer layers, leaving behind their dense cores. These remnants are called white dwarfs.
The demise of the Sun will ultimately scorch the Earth. While the Sun will not explode violently, its expansion will engulf Mercury, Venus, and Earth. When Earth enters the Sun’s swollen layers, catastrophic changes will occur. First, all water will evaporate and disintegrate into its basic components, hydrogen and oxygen. The hydrogen will escape into the atmosphere, while the oxygen will be absorbed by the ground. Second, the atmosphere will undergo a drastic transformation, primarily consisting of nitrogen and carbon dioxide. These shifts, combined with the unbearable heat, will render Earth uninhabitable. In short, when the Sun perishes, so do we.
9. The Collision of Galaxies
Before we even face the Sun’s eventual demise, there’s another significant event to consider. Our galaxy, the Milky Way, will not always remain our home. In approximately 4 billion years, long before the Sun reaches the end of its life, it will collide with the Andromeda galaxy, our closest neighbor.
This was uncovered when scientists were measuring the speed of Andromeda and noticed something unexpected: instead of red-shifting, or moving away from us as anticipated, it was actually blue-shifting. These terms refer to the wavelengths of light emitted by the object. When an object is moving away, its light wavelengths stretch, causing a red shift. In contrast, blue-shifting occurs when the object moves toward us, compressing its wavelengths. Through further measurements and calculations, scientists were able to determine Andromeda's size, motion, and speed. It turns out that the Milky Way and Andromeda are racing toward each other at an incredible 402,000 kilometers per hour, or around 250,000 miles per hour.
As for our solar system, there's no need to worry. The chances of our solar system or Sun being ejected or destroyed are very slim due to the nature of the collision and the galaxies themselves. The collision won’t be like two cars crashing on a highway. Instead, it will be a spiral, much like animals circling each other in a fight and slowly drawing closer. This spiraling motion means that the outer edges of the galaxies will collide first, causing some disruption, but the likelihood of our solar system or Sun being lost is under 15%. The collisions will continue until the stars are pulled into one center of gravity during the final phase of merging. Eventually, the two supermassive black holes at the center of each galaxy will merge, creating a massive warp in space-time and consuming surrounding matter. This newly formed super-supermassive black hole will push surrounding stars, including our Sun, outward, forming an elliptical galaxy.
Since Earth will survive, and the Sun hasn’t burned out yet, future Earthlings will actually be able to witness this cosmic event. So, stargazers, don’t forget to mark your calendars!
8. Betelgeuse Will Detonate
This event isn't catastrophic nor will it have a major impact on the universe, but it will radically alter our night sky, leaving both scientists and stargazers eagerly awaiting its arrival.
Betelgeuse (not Beetlejuice) is a red giant star, its distinctive reddish hue visible from the Northern Hemisphere. It resides in the constellation Orion, forming what is considered the 'right shoulder' of the constellation. For observers, it's located on the left side of the massive Orion, directly above the belt.
Unlike our Sun, Betelgeuse is a much larger star, now nearing the end of its life. As a red giant, it burns helium in its outer layers and processes carbon and other heavier elements at its core. Eventually, this star will undergo a supernova explosion. This could happen at any moment, and it will be impossible to miss.
Already the ninth brightest star in the Milky Way, when Betelgeuse explodes, it will shine as brightly as the moon. Not only will it illuminate the night sky, but it will be visible even during the day due to its intensity. The supernova will last for several weeks as the star expands, reaches its peak brightness, and then gradually fades.
The last supernova in the Milky Way occurred in 1604 when astronomer Johannes Kepler observed the supernova that was later named after him. The most recent notable supernova visible from Earth was in 1987 when supernova 1987a erupted in the Large Magellanic Cloud, a neighboring galaxy to the Milky Way. Although there have been many supernovae since then, this one was the first major event since the 1600s. It was visible only from the southern hemisphere and wasn’t as bright as Betelgeuse's explosion will be.
7. Expanded Solar System
If you thought memorizing the order of 8 (or 9) planets was challenging as a child, imagine trying to learn the order of over 100.
Yes, a solar system with around 110 planets could be on the horizon. This doesn’t mean that more than 100 planets have been discovered, but instead, the definition of a planet might change to include over 100 celestial bodies, such as the Moon and Pluto. Earlier this year, scientists reignited the debate on what constitutes a planet, and, as expected, the discussion was intense.
Currently, a planet is defined as a celestial body with strong gravity and its own distinct gravitational domain. For instance, Earth is a planet because it is large and governs its own gravitational space. The Moon, once considered a planet centuries ago, is no longer classified as one because it orbits Earth and isn’t in control of its own domain. This definition was set in 2006 and is the reason Pluto was demoted. The new definition proposed this year focuses less on gravity and more on the composition of the body. According to the new definition, a planet is any object large enough to have its own gravity but not so massive that it starts nuclear fusion, like a star. This means the Moon, Pluto, Pluto’s moons, and many objects in the Kuiper Belt could be considered planets in our Solar System.
While the change in this definition doesn’t physically affect Earth, it’s worth noting. Just think of the extra homework kids will have to do to memorize over 100 planetary names!
6. Ninth Planet—Once More
In contrast to the idea of adding 100 planets, scientists in California revealed last year the potential discovery of a single ‘planet’ lying past Neptune. This enormous icy object is ten times the size of Earth and possesses a powerful gravitational pull. This means it would satisfy both the current definition of gravitational dominance and the ‘new’ definition based on composition.
The catch? Scientists haven’t actually observed this planet. In fact, they can’t even confirm if it is indeed a planet, though the evidence is compelling. The planet was detected through the unusual behavior of nearby objects. Researchers noticed that the orbits of these distant bodies were being influenced by an unseen force, which could very well be the gravitational pull of a planet. Currently, two telescopes are actively searching for it. However, given its vast distance, the Sun’s light may not be able to reach it, meaning no light would be reflected off the planet.
If this planet is indeed discovered—and if it truly is a planet—it would completely alter our understanding of the Solar System and might offer some comfort to those still mourning the loss of Pluto.
5. The Moon Is Leaving
Earth’s long-time companion, the Moon, has been gradually drifting away from us for billions of years at a rate of 1.48 inches annually. This slow separation is the result of tidal forces. The Moon and Earth exert gravitational and tidal forces on each other, which create friction. This friction pushes Earth’s tidal bulge ahead of the Moon. While this acceleration attempts to speed up the Moon’s orbit, it’s countered by the Moon’s loss of energy. Rather than speeding up, the Moon slows down, gradually pulling away from Earth.
This slight but ongoing shift could have far-reaching effects on Earth, including altering the length of our days. When the Earth and Moon first formed 4.5 billion years ago, a day lasted just about 5 hours. This change results in a yearly increase of 0.0000152 seconds, which doesn’t seem like much, but over time, it adds up. In around 250 million years, our days could be 25 hours long. While that might be a welcome change for those who wish for more hours in the day, it’s less ideal for the environment.
The slowing rotation of Earth will cause it to wobble, much like a spinning top losing speed. This wobble will dramatically affect our seasons, leading to extreme temperature shifts that could overwhelm many plants and animals, preventing them from adapting in time. Humans might manage, thanks to our advanced technology, but many species may struggle.
4. Martian Rings
While this event isn’t apocalyptic nor does it have significant consequences for Earth or our education system, like the eventual supernova of Betelgeuse, it will alter our view of the night sky.
Though we likely won’t be able to observe them with the naked eye, Mars may develop rings in around 70 million years. The planet’s moon, Phobos, is gradually moving closer to Mars, and when it reaches a critical distance, Mars’s gravity will tear the moon apart. The fragments will then be caught in orbit, forming rings around the planet.
Even though this doesn’t have much of an impact on Earth, it’s a great excuse to grab your telescope and explore the skies!
3. The Big Rip
This scenario, like the cooling of Earth’s core, is hypothetical, but it’s based on a real phenomenon. Scientists have confirmed that the universe is not just expanding, but accelerating in its expansion. What happens as a result of this accelerating expansion remains a mystery, but one of the predictions paints a rather grim picture.
The 'Big Rip' is essentially the opposite of the Big Bang. While the Big Bang marks the creation of the universe and everything within it, the Big Rip would signal the destruction of all that has been created. The theory suggests that as the universe’s expansion accelerates, the mysterious force behind it—dark energy—becomes more powerful. If this is true, dark energy’s strength will eventually overpower all other forces and objects, tearing everything apart, including us.
2. Earth’s Core Cooling
Earth’s intensely hot molten core is gradually cooling. If it cools to a certain point, it could potentially lead to Earth’s destruction.
Currently, the core is both freezing and melting. As the core cools and solidifies, it releases heat into the metal-rich layer between the core and the crust known as the mantle. This heat causes convection currents within the mantle, where warm material rises and cool material sinks. These movements transport magnetic iron, generating Earth’s magnetic field. While this is the usual process, there are spots along the core-mantle boundary where energy from the mantle flows back into the core, causing those areas to melt.
The core is both losing and gaining heat at the same time, but if it were to completely cool, the consequences could be catastrophic. The most significant impact would be on our protective magnetic field. Without the core’s heat driving convection, the magnetic field would cease to exist. This field shields Earth from space hazards, such as harmful radiation and intense solar winds. Without it, Earth could be vulnerable to these dangers.
While it's unlikely to happen, this possibility hasn’t been entirely ruled out. In fact, it might be better for us not to dwell too much on what could occur.
1. Solar System Destruction
There is a slight, yet significant, chance that the orbits of the inner four planets could become unstable, leading to destructive collisions. This all begins with Mercury’s unusual orbit. First, its orbit around the Sun is much more elongated and oval in shape compared to the other planets. Second, Mercury’s orbit undergoes more pronounced precession, meaning its closest point to the Sun (perihelion) shifts over time. One year its perihelion may be at point A, the next year it could be at point B, and so on.
The key factor in this scenario is the eccentricity of Mercury’s orbit. Researchers have discovered that Jupiter’s gravitational influence could pull Mercury further out, using its elongated orbit to possibly bring it into Venus’s path. In another possibility, Mercury might even pass Venus’s orbit and collide with Earth. If the first scenario occurs, it likely won’t affect Earth, so it would be a fascinating event to witness! However, if the second scenario takes place, it’s game over for us.
No need for alarm, though. While these possibilities aren’t entirely out of the question, the likelihood of them happening is incredibly low. Still, you’ve got around 3 billion years to get ready.
