Nebula Papers | Astronomy, Space & Physics Explained

  Every few months, the internet inherits a brand-new UFO mystery practically engineered to ignite social media feeds. The essential ingredients are always remarkably consistent: an unreleased classified recording, a high-stakes setting like a remote military installation, an earnest eyewitness wearing a uniform, and a jaw-dropping number that anchors the entire narrative. The latest episode in this long-running cultural ritual arrived courtesy of an exclusive report concerning two classified videos recorded over a Colorado military installation. According to sources familiar with the footage, a service member using a personal smartphone captured material on consecutive nights in 2023 showing a massive, pitch-black triangular craft gliding effortlessly across the night sky. The specific detail that immediately seized headlines and fueled fierce online debates was its reported scale: witnesses estimated the craft at roughly one hundred feet across. Within days, the Pentagon confirme...

  Imagine standing on a planet where the Sun never rises. There is no warm daylight. No blue sky. No bright star illuminating the landscape. Above you, the sky is permanently black, filled with distant stars that provide almost no warmth. The surface may be covered by ice, the atmosphere may have partially or completely frozen, and temperatures could fall far below anything experienced naturally on Earth's surface. This is one possible environment on a rogue planet . Rogue planets, also called free-floating planets , are planetary-mass objects that are not gravitationally bound to a star. Instead of orbiting a sun, they travel through interstellar space. Some may have formed within planetary systems and later been ejected by gravitational interactions. Others may have formed independently, through processes resembling the formation of stars and brown dwarfs. Because they do not receive continuous starlight, rogue planets are often imagined as frozen worlds. But how cold are they re...

  Imagine a planet wandering through the Milky Way with no star to illuminate its surface. There is no sunrise, no sunset, and no familiar planetary orbit. Instead, the planet travels through interstellar darkness, perhaps carrying a frozen atmosphere, an underground ocean, or geological activity hidden beneath an icy surface. These objects are known as rogue planets , or free-floating planets . Unlike Earth, Mars, or Jupiter, they are not gravitationally bound to a star. Some may have formed normally around a young star and later been expelled from their planetary systems. Others may have formed independently from collapsing clouds of gas and dust, more like extremely low-mass versions of stars. The difficulty is obvious: How can astronomers detect a planet that produces little or no visible light and does not orbit a star? The answer is one of the most fascinating aspects of modern astronomy. Scientists cannot usually observe rogue planets directly. Instead, they look for the sub...

  Imagine a planet with no sunrise. There is no star rising over its horizon, no warm summer season, and no familiar day-night cycle. Instead, the sky is permanently dark, illuminated only by distant stars and perhaps the faint glow of the Milky Way. Beneath the surface, however, an enormous planet may still retain heat from its formation, radioactive elements, or even internal geological activity. These strange objects are known as rogue planets , or free-floating planets . Unlike Earth, Jupiter, or Neptune, they do not orbit a star. They travel through space independently, following paths around the center of the galaxy rather than remaining gravitationally bound to a particular stellar system. But how can a planet end up alone? The answer is surprisingly complicated. Astronomers believe rogue planets can form in more than one way. Some may have been born inside ordinary planetary systems and later expelled into interstellar space. Others may have formed directly in isolation, th...