Our planet is pretty amazing. It's the only one in over 5,000 discovered planets we know for sure has life. But, in this infinite, expanding universe, have you ever wondered if there was something, I don't know, better. Well, it turns out there's a candy world, a diamond world, and all manner of other unbelievable places out there. So, prepare for liftoff, we're taking an intergalactic cruise around some newly discovered planets so unbelievable they seem to defy logic itself.
Whoa.
A galaxy far, far away. So, what makes a planet suitable for us to live on. Well, most importantly, it needs to support liquid water, or we'd be shriveled-up space raisins. Now, many planets orbit a star, ours is the sun, but a planet can only support liquid water if it's a certain distance away from its star. Too close and any water will evaporate from the heat, too far and it'll freeze. The sweet spot in between these two extremes, however, is known as the habitable zone. Because stars vary massively in intensity, the distance of the habitable zone can differ wildly from system to system. Comprende. Good. One such planet that lands right in that sweet spot is k218b. I hope it goes without saying that we can't get this close to these planets to take photos. Most, if not all, visuals we have are artists' impressions from the data we've obtained. Anyways, this exoplanet, meaning a planet orbiting a star outside our solar system, was discovered by NASA in 2015. Unbelievably, it's more than twice the size of Earth and is the first planet we've found with water vapor in its atmosphere. That means k218b could support human life. Incredible! So, what are we waiting for. Let's go check it out, right. Ah, that's the tricky part. k218b orbits a star in the constellation Leo, a staggering 124 light-years away from Earth. Let's put that in perspective. Light travels 186,000 miles in a single second, and a light-year is how far it travels in an entire year. So can you imagine how insanely far away 124 light-years is. Well, you don't have to, astonishingly, it's over 729 trillion miles. Hypothetically, a one-way ticket to k218b onboard our fastest space shuttle, Discovery, which travels around five miles a second, is still going to take you an unbelievable 4 1/2 million years. And that's without potty stops. Our earliest ancestors split from monkeys around five million years ago. So, it would take about as long for us to reach k218b as it's taken a bunch of chimpanzees to master space travel. In theory, any humans that arrived would resemble us about as much as we humans resemble chimps. Hot dang! That's wild. Space is frickin' huge. And here's me thinking the walk from my couch to the fridge feels too long.
Home away from home. Now you know how far away planets can be, you're probably wondering how the heck we find them in the first place, right. Well, the most popular way is the transit method. Scientists select a specific cluster of stars to observe over a period of time. If one of the stars dims, it could mean an orbiting planet is passing over it. The stars are trillions of miles away, so without a really high-end telescope, you'd never notice anything change. But the best telescopes can give us loads of data about a planet's size, orbit, and even atmosphere. Even so, some planets are so far away we know very little about them, like Kepler 442b. This planet was discovered in 2015, and at a literally astronomical 1,206 light-years away, none of our telescopes are capable of getting a good view. What we do know, however, is astounding. Kepler 442b is bigger than Earth and might even be better. Uh, what. Well, it's in that habitable zone I told you about, so it could have liquid water, but that's not all. It's also highly likely to be rocky, meaning it could look like Earth too. Here's where it gets really special, though. Its sun is about 40% smaller than our own, which means it burns much slower. So, whilst our sun is expected to last about 10 billion years, Kepler 442b's could last between 18 and 34 billion years. In other words, there's a planet out there just like Earth, but with twice the longevity. Damn! The problem is, it's so far away we can't tell what makes up its atmosphere, if anything. And that's a really big deal. On the one hand, it could be like the
Snack. All this traveling around the universe has my stomach rumbling. Funnily enough, there's a planet with an appetite just like mine. Except instead of glugging down 12 cans of wieners, WASP12b devours 94% of all light that enters its atmosphere. Wait, it eats the light. You bet! See, WASP12b is a "hot Jupiter," a giant gaseous planet that orbits very close to its parent star. In fact, it orbits so close that the star's gravitational force is warping the planet into an egg shape. Yep, the star is pulling the planet so intensely that it's literally stretching out. This close orbit also means WASP12b gets pretty toasty. Like, 4,700 degrees Fahrenheit toasty. Phew! Most hot Jupiters reflect about 40% of light, but WASP12b is so hot that hydrogen molecules in its atmosphere are broken down into atomic hydrogen. This is the fuel that makes stars burn, causing WASP12b to have an atmosphere less akin to a planet and more like a small star. Scientists believe this insane reaction is why practically no light reflects from the surface. While light doesn't reflect though, the incredible heat on the planet's surface does mean it emits an eerie molten red glow. But it doesn't just look freaky, the heat is so intense that it's boiling off the gaseous atmosphere of the planet, stripping it away to spill out into space. Whoa! I guess that's just what you get for munching up all the light. Nice to see karma still operates in the wider universe.
Sign of the Tides
Remember earlier I said habitable zones can be vastly different from one another. Well, in 2007, scientists discovered a planet called Gliese 581c which has been deemed habitable despite being just 6.8 million miles from its nearest star. Alright, that still seems pretty far, but it's much closer than the 93 million miles we are from our sun. Though, that's not what makes it so interesting. Gliese 581c is tidally locked, meaning the planet doesn't spin. One side always faces towards its star, while the other always faces away. So, if you stood on the inward-facing side, the scorching heat would burn so hot you'd be melted in a matter of seconds. Yowch! And the outer-facing side is so cold, you'd be solid ice in no time. But right in the middle, there's a strip of land neither too hot nor too cold, and instead just right for life to potentially exist on. It's the outer space equivalent of baby bear's porridge. The peculiar discovery got scientists wondering if anything of note could exist in that strip. For all we know, it could be harboring an entire civilization. So, back in 2008, they sent out a radio transmission, but because Gliese 581c is 20 light-years away, or 118 trillion miles, it's not expected to arrive until 2029. I'm not sure how I feel about that. Let's not forget, in 2008, we were all "Twilight" obsessed and still wore these. Ugh! If I was an advanced civilization living there and received that message, I'd leave us on "seen."
TOI Hot to Handle
My birthday is my favorite time of the year. I just wish it came around more often. Waiting 365 days for more presents feels so unfair. But if I lived on TOI849b, an exoplanet discovered in 2020, I'd have a much shorter wait. It completes a full orbit of its host star, which takes one year on Earth, in as little as 18 hours. Whoa! Sounds great, right? Hmm, not quite. A year this short isn't exactly cake all around. It can only complete this orbit because it's incredibly close to its parent star. So close that its surface temperatures reach a sweltering 2,800 degrees Fahrenheit. So, yeah, lots of birthdays, but you're the candles. And the heat isn't the only pitfall. This place is humongous. Over three times the size of Earth, the gravity from such a large planet like this should draw in an abundance of gas. But the sun is so close that its intense radiation has stripped all of it away, leaving TOI849b with practically no atmosphere. All that's left is one big, rocky, hellish core. Hmm. So, technically, it's the biggest rocky planet we've ever discovered, but it wasn't always that way, so it's kinda cheating. And going there to award it a gold medal isn't worth losing my beautiful eyebrows.
