THE SIGHTS OF SPACE: A Voyage to Spectacular Alien Worlds

 

This is the Navis III, an imaginary ship that can take you anywhere in the Milky Way. Its maiden voyage will take you on a tour of the wildest planets we have yet discovered. These worlds will give us a glimpse into how deep nature's imagination goes and create a map for future pioneers. As our journey to new worlds begins, we set sail for the closest alien planet, 40 trillion kilometers away.

But the long road to our cosmic neighbor is paved with strange sights of its own. Past the distant orbit of Neptune, we slip into a no man's land of icy cosmic debris called the Kuiper Belt. This massive disc of frozen material contains hundreds of millions of icy scraps. Out here, among the scattered bits of rock and ice, live something strange... Haumea, a tumbling dwarf planet shaped like an egg.

Haumea is not alone. There is a whole eccentric family of miniworlds lurking out here. Dwarf planets like Makemake and Gonggong, a red-tinted mini-Pluto with a thin atmosphere of methane. The Kuiper Belt could hold as many as 200 dwarf planets, and thousands more could be floating in the space beyond.

And when we finally outgrow our home system, the one nearest to Earth will be waiting: Alpha Centauri. In this triple star system, a tiny red dwarf star known as Proxima Centauri orbits around a pair of sun-like stars: Alpha Centauri A and B. The closest exoplanet to home is Proxima Centauri b, with a mass almost identical to Earth's and a density that suggests a rocky composition. It orbits right inside its star's habitable zone, giving it potential to hold liquid water.

As we push farther into space, we leave the familiar behind and come across a world beyond all human comprehension. Gliese 436b is about as different from Earth as you can get. Orbiting extremely close to its star, its surface is a scorching 438°C. But this Neptune-sized world is something else entirely - a world of burning ice. Its massive gravity compresses water vapor in the atmosphere into an exotic form of ice called Ice VII.

39 light years away, a tiny red dwarf star is home to a potential planetary oasis. This is the Trappist-1 system, a family of seven rocky planets huddled closely around their sun. Four of the middle worlds orbit in the star's habitable zone, making this system a possible bonanza for life. These worlds are far older than Earth, giving potential life forms here a 3 billion year head start.

Further beyond, 64 light years away, lies a world that looks deceptively peaceful. As we get closer, this gas giant reveals its harsh nature. The winds here are the fastest known in space, and the atmosphere is so hot that it can melt solid gold.

400 light years from Earth, out of the darkness comes a truly brilliant sight. This newborn planet has a massive ring system that is 200 times larger than Saturn's rings. Within a gap in the rings, there may lie a huge moon where the views would resemble something from an acid trip.

Evidence that our home solar system has not prepared us for how varied and dazzling other systems can be. By some estimates, nearly half of all sun-like star systems contain more than one sun, implying billions of worlds that are home.

To Poetic Twin Sunsets: Exploring the Wonders of the Universe

Imagine worlds where not just two or three, but even four stars orbit. Lands where your body casts multiple shadows, and you can witness both sunsets and sunrises simultaneously. This mesmerizing image captures a three-star system in the Orion Nebula, revealing massive rings of gas and dust swirling around a triplet of newborn stars. Within this swirling debris, there is evidence of a hidden planet, the first planet known to orbit three stars at once.

But the wonders of the universe don't stop there. Some worlds resemble stars themselves rather than planets. Take this colossal gas giant, for example, which is tidally locked to its star, causing the day side to reach a blistering 3000 degrees Celsius, hotter than the surface of some stars. As heavy metals are lofted into the atmosphere, violent winds blow them to the night-facing side, where they condense into clouds made of metal. This phenomenon gives rise to huge metallic dust storms that can rage from one hemisphere to the other, releasing a torrential rain of liquid gemstones.

And there are even more extraordinary planets to behold. A supermassive rocky planet located 21 lightyears from Earth could potentially be the ultimate piece of cosmic bling. Its extreme atmosphere, rich in aluminum and calcium, may form vast deposits of rubies and sapphires. Scientists even speculate that there could be planets made entirely of pure diamond. One such candidate is WASP-12b, with its equal ratio of carbon to oxygen. However, this diamond world remains hidden beneath dark clouds of methane and carbon monoxide that trap 94% of light, making it darker than black coal. Additionally, its close proximity to its star has stretched the planet into the shape of an egg, giving it a limited lifespan of three million years.

For some planets, death is not the end of their story. When massive stars go supernova, any nearby planets are obliterated. However, the death of one world can sometimes lead to the birth of another. In the aftermath of a supernova explosion, certain stars collapse into rapidly spinning cores called pulsars, which absorb stellar debris. The remaining material on the outer edge can cool and condense, eventually forming a new world—a zombie planet built from the ashes of the dead. These zombie planets are incredibly rare, but a billion-year-old pulsar located 2300 light-years away hosts not one, but three potential zombie planets. The closest is Draugr, a tiny rocky world smaller than Mercury, likely stripped bare from intense X-ray radiation. The other two, called Poltergeist and Phobetor, are zombie superearths more than triple the mass of Earth. These planets are exposed to the strobing light of their dead stars, and the view from their surface would be utterly alien, with charged particles raining down and illuminating the night skies with brilliant auroras.

Although it may seem impossible for worlds like these to sustain life, the thick atmospheres surrounding such planets can convert deadly X-rays into heat, allowing for the presence of liquid water and potentially even life itself. Thriving on a zombie planet, encircling the spinning corpse of an exploded star, is a concept that challenges our understanding of habitability.

As we venture over 2000 light-years from Earth, we have only scratched the surface of what lies beyond. There are approximately 700 quadrillion other worlds waiting to be explored. Picture planets illuminated by the blazing center of the galaxy, worlds orbiting the rims of supermassive black holes, and giant water planets with oceans thousands of kilometers deep. These far-off lands remain a dream for our descendants to fulfill, as they step foot on alien soil and feel the heat of new suns. They will remember us as the first generation to have knowledge of these awe-inspiring worlds, to study their formation and nature, and to dream of one day calling some of them home.