Insane Planets Most Hostile to Life in Our Galaxy

**Sanitized Transcript:**

Mayday, mayday! The ship’s thrusters erupt into a plume of fire, and the blinking of bright red emergency lights floods every chamber. The crew is panicking, instinct causing them to try and run despite being trapped aboard the doomed vessel. They need to land fast, and they need somewhere safe to do it. Rallying his crew, the Captain charts a course to the nearest recorded planet. What nobody aboard realizes is that they’re not out of danger yet. Aboard the remnants of their deep space vessel, they are about to go on a tour of some of the most dangerous planets in our galaxy!

The first planet that appears on the ship’s radar is a gas giant. From the observation deck, they see a blue ball of gas suspended in deep space. Named after the Roman god of the Sea and first discovered in 1846, Neptune is far from the sanctuary that the crew is seeking. The one positive of approaching the ice giant is that it at least tells the crew where exactly in the galaxy they are; the downside is that it’s a long way from home. Neptune is the most distant planet from us, three billion miles away, more than thirty times the distance from the Earth to the Sun. It’s so far away that Neptune is the only planet in our solar system that isn’t visible to the naked eye from Earth, and as such, we initially discovered the planet through the use of mathematical calculations.

But just being at such a considerable distance away from Earth isn’t all that makes Neptune so dangerous. Much of the planet is covered by ice and rocks, although it doesn’t have a solid surface to speak of, with most of the planet’s mass being made up of a hot, dense mixture of water, methane, and ammonia surrounding a small, rocky core. Its atmosphere consists primarily of hydrogen and helium, with smaller amounts of methane in the mix too. In fact, it’s the presence of this methane that gives Neptune its vivid blue appearance, fitting for such a cold, dark planet.

Traveling closer to Neptune, it’s likely that, after breaching the atmosphere, a vessel would essentially free fall straight towards the ice giant’s core, which has a temperature of over seven thousand Kelvin, or well past 12,000 degrees Fahrenheit. But even making it through the atmosphere would be a short-lived feat, and one that would be nearly impossible to survive thanks to the harsh conditions Neptune has to offer. Much of Neptune’s danger comes from its incredibly high-speed winds. A light breeze? Is that all? Doesn’t sound all that bad… except these winds are around nine times stronger than those found on Earth. Clouds of frozen methane are whipped across Neptune at speeds upwards of 1200 miles per hour, whereas even the most powerful winds found here on Earth will only ever reach 155 miles per hour.

In short, the winds of Neptune are faster than the speed of sound and could easily tear a spacefaring vessel to shreds. The weather patterns of Neptune are wildly unpredictable, with many intense storms occurring in the ice giant’s southern hemisphere – the fastest storms in the solar system. And if you think you could simply wait for these storms to pass and the winds to die down, then you’d be wrong. Many of Neptune’s storms can last several years before dissipating, particularly within an area known as the Great Dark Spot. And that’s not all; Neptune is, unsurprisingly due to its distance from the sun, a very cold planet. While its core could easily melt metal, the ice giant’s temperature further up towards its clouds is considerably lower, at around -360 degrees Fahrenheit.

In fact, it’s this difference between Neptune’s hot core and well below freezing atmosphere that causes such massive storms. As you can probably imagine, this means that Neptune is inhospitable. Its extreme and unpredictable environment is so actively hostile that it’s not conducive to sustaining life. Although disheartened, the crew follows the next directives from the captain and charts a course back through the solar system. They might not have enough fuel reserves or working thrusters to make it all the way back to Earth safely, but as long as they’re heading away from Neptune, then they’ll at least be getting closer to home.

But another sudden blare of emergency lights fills the ship, readouts on the main display declaring yet another malfunction. The ship’s navigational computer is offline, disengaging along with the manual steering as a cascade of system failures begins to occur. One by one, the critical systems start toppling like a row of dominoes. The ship’s computer tries to compensate by engaging an emergency protocol to return to Earth using its autopilot to make a lightspeed jump. But it’s conflicting with the Captain’s previous directive; the computer is uncertain which of the two courses to follow. Amidst the chaos, someone manages to force a system shutdown, bringing the turbulent, shuddering remains of the ship to a halt… at Proxima B.

Nobody can tell which horror outweighs the other; realizing they’ve jumped too far and ended up way past the edge of our solar system, or knowing the danger of being so close to this particular planet. Located 4.3 light years away from Earth, we find Alpha Centauri, the closest star system to our own. The crew now faces a big problem. They’re so far away from Earth that if they flew back at the fastest speed achieved by a human spacecraft, Voyager 1, which is flying away from Earth at around 38,610 miles per hour, it would take them over 74 thousand years to get back.

Within Alpha Centauri are three suns, each called Alpha Centauri A, B, and C, respectively, as well as a smaller red dwarf star called Proxima Centauri. Its name literally means the ‘nearest star of Centaurus,’ since the star is located within the southern constellation of Centaurus, one of the arms of the Milky Way galaxy. Two planets are known to exist in orbit of Proxima Centauri, with one of them being Proxima B. Had the ship arrived at its neighbor, Proxima C, then the crew aboard might have made it to a habitable planet. Little is known about this exoplanet, and it could well be a gas planet similar to Neptune. But given the great distance from Earth, it’s hard for astronomers to say for certain what its surface looks like.

The crew might still be stranded light years from Earth, but at least they’d be able to survive. On Proxima B, though, there are far slimmer chances of survival. Unlike Neptune and even a number of other worlds in our own star system, Proxima B does have a rocky surface. It’s even widely believed that, at some point in its history, Proxima B could have sustained an Earth-like atmosphere and possibly even contained water. However, the greatest danger of Proxima B is its home star, Proxima Centauri. Proxima B is tidally locked to the red dwarf it orbits, meaning one side of it faces towards the star at all times. This makes that half of Proxima B extremely hot, while the other is left cold.

While that might not sound that bad, the fact that Proxima Centauri is a red dwarf means it poses a danger to anyone even remotely close to Proxima B. Red dwarfs can hurl scorching solar flares and violently powerful solar winds across space. Over time, these would have destroyed the atmosphere of Proxima B, and the surface would have likely been bathed in deadly levels of heat and radiation thanks to the bombardment of solar flares. To make matters worse, solar flares are wildly unpredictable and can ignite at any time, meaning that being in close proximity to Proxima B means you’re in range and at a constant risk of being exposed to a sudden blast of extreme heat and radiation.

Having rebooted the ship’s computer, the crew is suddenly faced with an even greater danger. A sudden alert warns them that a solar flare is imminent, coming from Proxima Centauri. Thinking fast, the Captain gets the engineering team to retrofit the vessel’s solar panels to absorb some of the excess heat and convert it into energy for the ship. It’s an insane gamble; the power of the solar flare could easily decimate the entire outer hull and incinerate everyone in seconds. But their alternative is doing nothing, so they get to work and brace for impact. The plan works, sending them hurtling through space faster than the speed of light…

The crew opens their eyes to see a small blue planet before them. A wave of relief collectively washes over them all. It looks just like Earth; they’ve made it home. Except the navigator checks the star map and quickly notices that they’re a long, long way from Earth. To be exact, 64 million light years away. For reference, a light year is the distance that light travels during one Earth year, which is about 6 trillion miles. Now, times that by sixty-four million. The planet beyond the ship’s viewport might look like Earth from a distance, sharing that blue hue that feels so familiar. In actuality, it’s another exoplanet – a planet that exists outside our solar system – known as HD 189733 B. It’s sixteen percent heavier than Jupiter, the largest planet in our solar system, and was first discovered in 2005, orbiting a star designated HD 189733.

Astronomers noticed the planet transiting past the star and blocking out a portion of its light and radiation every two point two days. In 2008, the Hubble Space Telescope was able to detect and monitor the visible light on HD 189733 B, noticing that the light it reflected back into space consisted of a larger amount of blue light than red. This blue coloration of HD 189733 B doesn’t come from any oceans or other large bodies of water, like the Earth’s; it comes from HD 189733 B’s turbulent atmosphere, one that makes it uninhabitable to human beings… or anything else in the universe, for that matter.

When it was observed through the Hubble Space Telescope, a full spectrum of HD 189733 B’s atmosphere was gathered. It consisted mainly of nitrogen, methane, and carbon monoxide, and had been heated to well over 1832 degrees Fahrenheit. This not only means there’s no water on its surface but also causes raging winds within the planet’s atmosphere. These winds are seven times faster than the speed of sound and would likely tear a spacefaring vessel to pieces. Additionally, the orbit of the planet around its star is so fast that it likely causes the direction of rain on HD 189733 B to be horizontal instead of coming down vertically from the atmosphere above.

Still, a little rain never hurt anyone, right? Well, here, it might just cut you to pieces, as it’s not just high temperatures that make HD 189733 B dangerous. Its atmosphere is also home to clouds that are rich in particles of silicate. These are naturally occurring particles that contain silicon and oxygen. On Earth, the closest compound we have to this is glass. Thanks to the heat from the nearby star, the silicate particles in HD 189733 B’s atmosphere are heated to the point where they become molten and are then blown horizontally by howling winds traveling at well over 5,000 miles per hour. In short, on HD 189733 B, it rains molten glass – sideways.

Much like Proxima B, one side of HD 189733 B is constantly facing its nearest star, and it’s thanks to the thousand-degree heat that this hemisphere is subjected to molten glass rain. The other hemisphere facing away from HD 189733 might also experience its share of weird weather, with the calcium and magnesium silicates from the atmosphere crystallizing and blowing through the air as a sort of snow. However, we wouldn’t recommend a winterly stroll on the darker hemisphere of HD 189733 B, as while there’s no water on the planet’s surface, there’s a possibility that these silicates can condensate on their way through the atmosphere, raining down as solid glassy fragments.

But these are far from the only planets harboring deadly secrets in the far reaches of the galaxy. AU Microscopii b was first discovered by NASA in 2020, part of the AU Microscopii planetary system located 32 light years from Earth. It’s one of the youngest planetary systems ever observed by astronomers, but don’t think that just because it’s comparatively young it isn’t just as deadly. AU Mic b is constantly blasted with powerful X-rays, sterilizing the surface of the planet and making life there physically impossible. Then there’s KELT-9 b, an exoplanet only half as dense as Jupiter but with three times greater mass. It orbits a star twice as large and hot as our Sun and so has a dayside temperature of 7,799 degrees Fahrenheit. Needless to say, this is a temperature that no organism could possibly survive.

In that sense, it has similar problems to 55 Cancri e and Kepler-10 b, a pair of planets where the surface is entirely covered in molten lava. But Kepler-10 b isn’t the only planet in the system where heat is a serious and deadly problem. First spotted in 2013 and then properly investigated by the Very Large Telescope in 2020, WASP-76b permanently faces its parent star, meaning that the dayside of the planet is always a scorching 4,532 degrees Fahrenheit and constantly bombarded with deadly radiation. However, the nightside of the planet carries its own unique and terrifying danger. Because of the constant heat bombarding the dayside of WASP-76b, iron that naturally exists on the planet is evaporated. Strong winds end up blowing this iron vapor from the dayside into the much cooler – but still much hotter than Earth – side of the planet, where it cools and rains down as molten iron.

Clearly, it’s not a place the crew could safely stay. The weary and worried space travelers try to make one more lightspeed jump, a last-ditch effort to take them from the furthest edges of the galaxy back to the familiar confines of our own solar system. Everybody prays, and nobody expects it to work, but to the surprise of the whole crew, after a brief rush they find themselves staring up at an enormous – but familiar – planet: Jupiter. They’ve at least made it back to the right part of space, but they haven’t made it back home yet. Named after the king of the gods in ancient Roman mythology, Jupiter itself is the fifth planet from the Sun and bigger than all of the other planets in the solar system combined – times two. Its sheer size cannot be understated, dwarfing any vessel that could even get close to it. It’s more than eleven times the diameter of our planet and could fit 1300 Earths inside it.

While from space, the huge planet’s distinctive stripes of various brownish tones might make it look like it’s home to a variety of rocky, desert-like strips of land, Jupiter’s distinctive look actually comes from the gases in its atmosphere. Cold winds carry clouds of ammonia and water through an atmosphere of hydrogen and helium, and in some areas of the gas giant – like the iconic Great Red Spot – there are storms bigger than the entire Earth that have been raging for hundreds of years. Since Jupiter is made up of gas, you might wonder if a ship could simply pass through it and come out of the other side unscathed. Sure, there would be some intense winds to deal with, but it sounds plausible, right? Wrong.

First and foremost, you would need to navigate through the rings that surround the planet. Much like Saturn, Jupiter also possesses rings; however, rather than being made of ice and visible to the naked eye, its rings are far fainter and composed of dust. Providing you were able to make it close enough to Jupiter, the pressure and gravity produced by the planet would be so high that after only 75 miles, these forces would combine with the wind and destroy your craft, leaving nothing behind. That’s a very specific number. How do we know it’s 75 miles? Well, because humanity has tried it before. In 1995, a space probe, Galileo, was sent into space to study Jupiter and its many moons, becoming the first ever spacecraft to orbit an outer planet. However, in 2003, the probe was ultimately caught in Jupiter’s gravity and got pulled towards the gas giant. Lacking the fuel it needed to escape, Galileo was forced to deliberately crash into Jupiter, making it only seventy-five miles before communication was lost and the probe was destroyed.

Even if, by some miracle, you were in a vessel that was able to make it past the point that Galileo couldn’t, the temperature within Jupiter would only increase more and more as you got closer to the planet’s core. The temperature and pressure of this planet and its atmosphere are too extreme for living organisms to survive. Even if your spacecraft could protect you against these elements, then the heat and the pressure from the density of Jupiter’s atmosphere would mean you wouldn’t be able to see or hear anything. Radio signals would be cut off, and with no way to call for help, you’d likely be caught in the gravitational pull of the planet, with no way to turn back and fly out. Eventually, temperatures within would be higher than those found on the surface of the Sun, and that would spell a fiery end to anyone unfortunate enough to make it this far.

Weighing up their options, the crew considers taking a stop on Europa, one of the many moons of Jupiter. While the planet of Jupiter itself isn’t capable of sustaining life, it’s theorized that beneath the surface of Europa there are icy oceans, meaning that life could possibly be supported there. But life on Europa is only a hollow substitute for life on Earth. So, everyone watches as the Captain fires up the barely functioning engines and tries to steer the decimated ship back home. They make it close, within 43 million miles of Earth. But then the engines cut out. The ship loses power, the life support now running off emergency reserves. They’re adrift in space, and everyone watches in horror as they slowly float towards the one planet they never wanted to stumble upon: Venus.

It’s the most dangerous planet in our solar system, perhaps even in our entire galaxy. It’s the second closest planet from the Sun and our closest neighbor other than Mars and our own Moon. In a lot of ways, Venus is similar to Earth. It’s close to the same size, mass, composition, and even proximity to the Sun. Given all the similarities, you wouldn’t expect it to be all that different from Earth. But you’d be very wrong. What might seem like a slight distance on an astronomical scale can make a huge difference to the environment and conditions of a planet. And Venus’ are some of the harshest around – in fact, the planet is completely inhospitable.

Possessing a dense atmosphere of carbon dioxide and nitrogen, Venus is the hottest planet in the solar system, even hotter than Mercury, which is closer to the Sun. Its heat doesn’t just come from its close proximity to the Sun; however, Venus is also littered with active volcanoes. Thanks to the density of its atmosphere, the heat and carbon dioxide from the planet become trapped within, creating a cycle that raises Venus’ overall temperature. Carbon dioxide is, as you