Trans-Neptunian Object (TNO) is any minor planet in the Solar System that orbits the Sun at a greater average distance (semi-major axis) than Neptune, 30 astronomical units (AU). Twelve minor planets with a semi-major axis greater than 150 AU and perihelion greater than 30 AU are known, which are called extreme trans-Neptunian objects (ETNOs).
The first trans-Neptunian object to be discovered was Pluto in 1930. It took until 1992 to discover a second trans-Neptunian object orbiting the Sun directly, 15760 Albion. As of February 2017 over 2,300 trans-Neptunian objects appear on the Minor Planet Center’s List of Transneptunian Objects. Of these TNOs, 2,000 have a perihelion farther out than Neptune (30.1 AU). The most massive known trans-Neptunian object is Eris, followed by Pluto, 2007 OR10, Makemake and Haumea. The Kuiper belt, scattered disk, and Oort cloud are three conventional divisions of this volume of space, though treatments vary and a few objects such as Sedna do not fit easily into any division. — Wikipedia
Voyager Program is an American scientific program that employs two robotic interstellar probes, Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable alignment of Jupiter and Saturn, to fly near them while collecting data for transmission back to Earth. After launch the decision was taken to send Voyager 2 near Uranus and Neptune to collect data for transmission back to Earth. As of 2022, the Voyagers are still in operation past the outer boundary of the heliosphere in interstellar space. They collect and transmit useful data to Earth. — Wikipedia
Interstellar Boundary Explorer (IBEX or Explorer 91 or SMEX-10) is a NASA satellite in Earth orbit that uses energetic neutral atoms (ENAs) to image the interaction region between the Solar System and interstellar space. The mission is part of NASA’s Small Explorer program and was launched with a Pegasus-XL launch vehicle on 19 October 2008. IBEX is in a Sun-oriented spin-stabilized orbit around the Earth. — Wikipedia
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
- Why build megastructures? Just move planets...on September 26, 2023 at 1:27 pm
In 1960, Freeman Dyson proposed how advanced civilizations could create megastructures that enclosed their system, allowing them to harness all of their star's energy and multiplying the habitable space they could occupy. In 2015, the astronomical community was intrigued when the star KIC 8462852 (aka Tabby's Star) began to dim inexplicably. While an analysis of the star's light curve in 2018 revealed that the dimming pattern was more characteristic of dust than a solid structure, Tabby's Star […]
- Whether Saturn's rings are young or old, its...on September 14, 2023 at 6:28 pm
Saturn is best known for two things: its iconic ring structures and its large system of natural satellites. Currently, 146 moons and moonlets have been discovered orbiting the ringed giant, 24 of which are regular satellites. These include the seven largest moons, Titan, Rhea, Iapetus, Dione, Tethys, Enceladus, and Mimas, which are icy bodies believed to have interior oceans.
- Japanese astrophysicists suggest possibility of...on September 1, 2023 at 2:24 pm
A pair of astrophysicists, one with Kindai University, the other the National Astronomical Observatory of Japan, both in Japan, have found possible evidence of an Earth-like planet residing in the Kuiper Belt. In their paper published in The Astronomical Journal, Patryk Sofia Lykawka and Takashi Ito describe properties of the Kuiper Belt that they believe are consistent with the existence of a planet not much bigger than Earth.
- Asteroid named after Portuguese astrophysiciston July 7, 2023 at 6:18 pm
The International Astronomical Union (IAU) has named an asteroid after Pedro Machado, astrophysicist at Institute of Astrophysics and Space Sciences (IA), at the Faculty of Sciences of the University of Lisbon (Portugal). Along with the nomination of Pedro Machado, there were over a hundred other nominations of asteroids and other small bodies.
- There could still be a ninth planet in our solar...on June 15, 2023 at 5:43 pm
,We all used to think there were nine planets. But in 2006, the solar system was left with only eight planets, when Pluto was no longer classified as such. But is it still possible there is a planet out there beyond Neptune—possibly way beyond it?
- Redness of Neptunian asteroids sheds light on...on March 28, 2023 at 4:51 pm
Asteroids sharing their orbits with the planet Neptune have been observed to exist in a broad spectrum of red color, implying the existence of two populations of asteroids in the region, according to a new study by an international team of researchers. The research is published in the journal Monthly Notices of the Royal Astronomical Society: Letters.
- A new ring system discovered in our solar systemon February 8, 2023 at 4:00 pm
Scientists have discovered a new ring system around a dwarf planet on the edge of the solar system. The ring system orbits much further out than is typical for other ring systems, calling into question current theories of how ring systems are formed.
- Flying to (hypothetical) Planet 9: Why visit it,...on September 14, 2022 at 4:08 pm
In a recent study submitted to Earth and Planetary Astrophysics, an international team of researchers discuss the various mission design options for reaching a hypothetical Planet 9, also known as "Planet X," which state-of-the-art models currently estimate to possess a semi-major axis of approximately 400 astronomical units (AU). The researchers postulate that sending a spacecraft to Planet 9 could pose scientific benefits much like when NASA's New Horizons spacecraft visited Pluto in 2015. […]
- Stellar flybys leave a permanent mark on newly...on August 1, 2022 at 1:30 pm
What do UX Tauri, RW Aurigae, AS 205, Z CMajoris, and FU Orionis have in common? They're young stellar systems with disks where planets could form. It appears those disks were disturbed by stellar flybys or other close encounters in the recent past. Astronomers want to know: did those events disrupt planet formation in the disks? What do they do? Does this happen in other systems? And, did our own solar system experience a strange encounter in its youth?
- Pluto's orbit is surprisingly unstableon April 21, 2022 at 4:54 pm
In 1930, astronomer Clyde Tombaugh discovered the fabled "Ninth Planet" (or "Planet X") while working at the Lowell Observatory in Flagstaff, Arizona. The existence of this body had been predicted previously based on perturbations in the orbit of Uranus and Neptune. After receiving more than 1,000 suggestions from around the world, and a debate among the Observatory's staff, this newfound object was named Pluto—which was proposed by a young schoolgirl from Oxford (Venetia Burney).
Here are links to pages about closely related subjects.
Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid