What if Earth’s orbit ventured as far from the Sun as Pluto, and got as close to it as Venus?
Would the Sun burn the planet to a crisp at the closest encounter? How cold would it get at the farthest point away from our star?
Would humans be able to survive such extreme changes in temperature? And if we could, what are the chances that Earth would follow this orbit safely through space without crashing into another planet?
The Sun has a stronger gravitational pull on us than any other body in the Solar System. But other planets are slightly pulling us toward themselves, too. That, together with the Earth’s velocity, makes the planet’s orbit elliptical.
The difference between the farthest and the closest point to the Sun in our orbit is less than 5 million km (3 million miles). That’s nothing compared to the overall distance of 150 million km (93 million miles) from us to the Sun.
But what if that difference was much, much greater?
The Earth orbits the Sun at just the right distance – not so far away that we turn into an icy rock, and not so close that we burn to a crisp. We’re in the Sun’s habitable zone, where water can exist in liquid form. Even the slightest shift in the Earth’s orbit would change that.
The closer we got to the Sun, the more heat would hit the planet. Think it would be nice to have summer all year long; everywhere on Earth? I bet you’d change your mind pretty fast. As the heat became more extreme, all the ice on the planet would start to melt. Global sea levels would rise 70 meters (230 feet): enough to cover London’s Tower Bridge and flood most of the planet.
With little land left to absorb the scorching heat from the Sun, global temperatures would skyrocket. Our oceans would begin to evaporate.
All this would leave us with a tremendous amount of carbon dioxide in the air, and little to no water left. As we approached the orbit of Venus, the surface temperature of Earth would go up to 460°C (860°F). Being outside would give you severe burns, no matter how much sunscreen you put on your skin.
After getting an incredible suntan on our vacation near Venus, we’d head back across the Solar System all the way to Pluto.
The Earth would cool down on the way. But it wouldn’t matter for most life forms on the planet. They wouldn’t have survived the extreme heat. Maybe, if we moved slow enough, some new life form would evolve on the Earth while it’s traveling to the habitable zone again. But that life wouldn’t last too long, either.
The upcoming winter would be long, and very cold. If there was any water left on Earth, it would freeze as we reached the -220 °C (-360 °F) temperature of Pluto’s orbit.
If the Earth kept moving at the same speed it does today, it would take it about 20 years to make a full orbit – from the hottest spot closest to the Sun to the coldest edge of our Solar System. That’s if we didn’t collide with any other planet on the way, which isn’t all that unlikely.
And it’s likely that we’ll be making this trip solo. The Moon might not be able to handle the pressure of this extreme orbital journey. Lifeless and moonless, the Earth would at least get to enjoy some spectacular views.
Who knows? Maybe we’d sail too close to Jupiter and become one of the moons of the gas giant. But that’s a story for another WHAT IF.
- “What If Earth Changed Its Orbit?“. Howstuffworks. Accessed November 8 2018.
- “Earth’s Orbit Around The Sun“. Phys.Org. Accessed November 8 2018.
- “If The Earth Was In Venus’s Orbit, Would It Be Habitable?“. Astronomy Stack Exchange. Accessed November 8 2018.