We've all seen the photograph. Known as The Blue Marble, the image was captured by an Apollo 17 crew member on December 7, 1972, from a distance of about 18,300 miles from the planet's surface. It's become one of the most widely distributed photos in history and a symbol representing Earth's beauty, its fragility, and its isolation amid the vastness of space.
About that vastness of space... It can be difficult to visualize just how empty space is and just how far apart celestial bodies are from one another. After a certain point, the mind just boggles. Do we really have a good grasp of how far 18,300 miles is, let alone 183,000,000 miles? Maybe it'd be easier to understand if we scaled things down a bit. What if Earth was, in reality, the size of the famous photo's namesake? A blue marble. Let's say our mini-Earth is 2 centimeters in diameter, roughly the size of of a large toy marble. (In the halcyon days of my youth we called these "boulders.") What would our solar system look like at that scale?
I'm sure you remember the illustrations in your third-grade science textbooks of the solar system. They probably looked something like this. (Yes, this one has Pluto because I was in third grade waaaay before Pluto's 2006 demotion, but that's a different topic for a different post!)
These drawings were useful for learning the names and order of the planets but not exactly drawn to scale, and therefore not a good indication of the distances we're going to be discussing. The numbers I'm about to share with you are highly scientific (meaning I've Googled them) and peer reviewed for accuracy (meaning that I ran them past my cat who is rolling around on the floor next to my desk chair right now.)
The Sun
"Mighty Sol" is 865,370 miles (1,392,678 km) in diameter and the largest body in our solar system by far. It was worshipped by many ancient civilizations, and perhaps rightfully so, as it's literally the bringer of light and life to what would otherwise be this dark and depressing rock hurtling through space. After crunching the numbers, I've determined (very scientifically, mind you) that in our miniature solar system, our mini-sun would be about 2 meters in diameter. Roughly the size of a giant, novelty-sized beach ball. There. There's our sun! Bask in its magnificence! (But don't look directly at it.)
Remember, Earth is the size of a 2 centimeter marble next to this behemoth. Let's go ahead and map out the rest of the planets!
Mercury
Mercury is the smallest planet in our solar system and the closest to the Sun. It's about 3,030 miles (4,876 km) in diameter or approximately two-fifths the size of Earth. It's even smaller than Jupiter's and Saturn's largest moons. Its orbit is a little wonky. In fact, its orbit is the most elliptical of all the planets, so its distance from the Sun varies by millions of miles depending on the time of its solar year. For the purposes of our new solar system, we'll just average everything out—36 million miles (almost 58 million km). Our chickpea-sized Mercury would be about 108 meters (354 ft) from the Sun. To visualize that, let's place our majestic beach ball sun on top of home plate of your favorite major league baseball park. Mercury would be in the vicinity of the leftfield wall.
Venus
Venus is like Earth's (evil) twin in a lot of ways. It's only marginally smaller, but it's the hottest planet in the solar system despite being second in line to the Sun. Venus surface temperatures average about 867°F (464°C) due to its runaway greenhouse effect and thick atmosphere. It orbits about 67 million miles (107.8 million km) away from the Sun, but in our solar system model, Venus would be 170 meters (558 ft) from home plate—I mean the sun. This would put our marble-sized Venus in the middle of the street outside the ballpark.
Earth
This planet hardly needs an introduction. If you're reading this, you're probably already familiar. Earth has a diameter of 7,926 miles (12,755 km) and orbits about 93 million miles (149.6 million km) away from the Sun. But where would this blue marble reside in our scaled-down solar system? About 240 meters (787 ft) away. Our home is rolling down the sidewalk on the next street over from Venus. To put this in perspective, it takes sunlight 8 minutes and 20 seconds to reach Earth.
Mars
Mars is the last stop before we leave the inner solar system. The Red Planet is 4,212 miles (6,779 km) in diameter—roughly half the size of Earth and orbits at around 142 million miles (228.5 million km). Our centimeter-sized Mars (about the size of a standard marble) would be 390 meters (about a quarter mile) out—still within walking distance at four or five city blocks away. Mars' journey around the Sun is 687 Earth days. As we move on to the outer solar system, you'll notice that the distances really start to ramp up in size.
Jupiter
Jupiter is the largest planet in our solar system and has 95 moons. (They will probably have discovered a few more by the time you read this...) This planet is massive. Eleven Earths would fit side by side across its face. It has a diameter of 89,000 miles (143,231 km). It makes its orbit around the sun in about twelve Earth years, but its day is only 10 hours long. After crunching some numbers and double-checking them with my cat Apollo, I've determined that our Jupiter would be 22 centimeters (almost 9 inches) in diameter. A soccer ball! Pretty hefty, but still dwarfed by our bouncy beach ball. At 483 million miles (777.3 million km) from the Sun, you might want to hop on a bus for this one: 1.2809 kilometers (eight-tenths of a mile), or about 15 city blocks. It takes sunlight 43 minutes to reach Jupiter. You probably noticed that we've more than tripled Mars' the distance from the Sun.
Saturn
Now it's on to the poster child of the solar system. Photogenic Saturn, with its flashy system of icy rings, is not the only planet that has them, but none are as dazzling as this primadonna's. Saturn, (which we already established thinks it's better than all the other planets) puts Jupiter to shame with its 146 moons. It has an equatorial diameter of 74,897 miles (120,535 km) and orbits about 886 million miles (1.4 billion km) from the sun. You're going to want to get on the bus again because we'll be nearly doubling our distance. Our volleyball-sized Saturn is 2.3706 kilometers away from the comically oversized beach ball, or nearly one and a half mile.
Uranus
If Saturn is the crown jewel of the solar system then Uranus is the butt of many an immature joke, butt we're above such things. Aren't we? Uranus is just downright weird, though. There's no denying it. It's the only planet whose equator is nearly at a right angle to its orbit, causing the most extreme seasons in the solar system. For nearly a quarter of each Uranian year, the Sun shines directly over each pole, throwing the other half of the planet into a 21-year long winter. It also rotates in the opposite direction than most of the other planets. (Earth's evil twin Venus does this too. Go figure.) Uranus has a diameter of 31,763 miles. (51,117 km) (We're above such things, remember?) It does its weird, gimpy, lopsided orbit 1.8 billion miles (2.9 billion km) from the Sun. In our solar system model, Uranus would be a good-sized navel orange and 4.7099 kilometers away, or nearly 3 miles away from the mighty beach ball.
Neptune
We're nearing the end of our journey. Neptune is the eighth and final planet of our solar system and this ice giant is not very inviting. It's dark, cold, and its atmosphere features supersonic winds. It's the only planet in our system that's not visible to the naked eye. It's so far out there that astronomers predicted its existence by noticing perturbations in Uranus' orbit long before it was observed directly. Neptune's diameter is about 30,755 miles (49,495 km) and it orbits 2.8 billion miles (4.5 billion km) from the Sun. Our Neptune, however, is only slightly larger than a baseball and is hiding in a dark alley 7.1135 kilometers away from the beach ball. That's 4.42 miles. It takes sunlight four hours to reach Neptune.
Pluto
Pluto is no longer categorized as a planet, but I'm including it to placate those who took the dwarf planet's demotion as a personal affront. (There, there...) This wanna-be planet is a mere 715 miles (1,151 km) in diameter. There are seven moons in the solar system bigger than this runt, including our own. Pluto skulks around at an average distance of 3.7 billion miles (4.5 billion km) away from the Sun. In our model, Pluto is smaller than an unpopped popcorn kernel and is 11.563 kilometers away! That's over 7 miles from our baseball park beach ball.
To drive the point home, I've created this nifty graphic to illustrate the distances. I've used San Francisco (not for any particular reason other than the location of its ballpark made it convenient for me to make some... ballpark estimates). I've excluded the inner planets since we're all figuratively and literally crammed into a few square blocks in our sun's neighborhood.
let's keep going...
So, to illustrate just how isolated our little corner of the galaxy is, let's travel a little further out. Let's visit Proxima Centauri, the closest star to our system. This red dwarf star is 4.24 light years away and is only about one-seventh the diameter of our own Sun. It has a mass that is 120 times greater than Jupiter's but it's diameter is only about 1.5 larger than Jupiter's diameter. Despite being the closest star to the Sun, Proxima Centauri is too small and faint to be discerned with the naked eye. Using our model's scale, this medicine ball sized-star would be 39,636 miles (63,789 km) away from our beach ball, which is roughly equivalent to two and half times the length of the Earth's equator.
So, the next time you're gazing up at a star-filled sky pondering whether or not we're alone, you can be reminded of just how far out in the boondocks we really are.
Comentarios