Asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called asteroids or minor planets. It is also called the main asteroid belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half its mass is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid belt is about 4% that of the Moon. Ceres, the only object in the asteroid belt large enough to be a dwarf planet, is about 950 km in diameter, whereas Vesta, Pallas, and Hygiea have mean diameters less than 600 km. The remaining bodies range down to the size of a dust particle. — Wikipedia
Dawn was a space probe that was launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt: Vesta and Ceres. Dawn entered orbit around Vesta on July 16, 2011, and completed a 14-month survey mission before leaving for Ceres in late 2012. It entered orbit around Ceres on March 6, 2015. In 2017, NASA announced that the planned nine-year mission would be extended until the probe’s hydrazine fuel supply was depleted. On November 1, 2018, NASA announced that Dawn had depleted its hydrazine, and the mission was ended. The spacecraft is currently in a derelict, but stable, orbit around Ceres. Dawn is the first spacecraft to orbit two extraterrestrial bodies, the first spacecraft to visit Vesta and Ceres, and the first to orbit a dwarf planet. — Wikipedia
In 1596, Johannes Kepler wrote, “Between Mars and Jupiter, I place a planet,” in his Mysterium Cosmographicum, stating his prediction that a planet would be found there. While analyzing Tycho Brahe’s data, Kepler thought that too large a gap existed between the orbits of Mars and Jupiter to fit Kepler’s then-current model of where planetary orbits should be found.
In an anonymous footnote to his 1766 translation of Charles Bonnet’s Contemplation de la Nature, the astronomer Johann Daniel Titius of Wittenberg noted an apparent pattern in the layout of the planets, now known as the Titius-Bode Law. If one began a numerical sequence at 0, then included 3, 6, 12, 24, 48, etc., doubling each time, and added four to each number and divided by 10, this produced a remarkably close approximation to the radii of the orbits of the known planets as measured in astronomical units, provided one allowed for a “missing planet” (equivalent to 24 in the sequence) between the orbits of Mars (12) and Jupiter (48).
When William Herschel discovered Uranus in 1781, the planet’s orbit matched the law almost perfectly, leading astronomers to conclude that a planet had to be between the orbits of Mars and Jupiter.
On January 1, 1801, Giuseppe Piazzi, chairman of astronomy at the University of Palermo, Sicily, found a tiny moving object in an orbit with exactly the radius predicted by this pattern. He dubbed it “Ceres”, after the Roman goddess of the harvest and patron of Sicily. Piazzi initially believed it to be a comet, but its lack of a coma suggested it was a planet. Thus, the aforementioned pattern predicted the semimajor axes of all eight planets of the time (Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, and Uranus). — 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.
- Glass beads in lunar soil reveal ancient asteroid...on October 1, 2022 at 2:00 pm
In 2020, China's Chang'e 5 mission sampled more than a kilogram of moon rock and soil and brought it back to Earth. The samples contain countless tiny beads of glass, created when asteroids hit the moon and splashed out droplets of molten rock around the impact site.
- Dinosaurs survived when CO2 was extremely high....on September 21, 2022 at 3:10 pm
How did plants and animals survive around 200 million years ago when the carbon dioxide concentration went up to 6,000 parts per million? Paul Olsen, a geologist and paleontologist at Columbia Climate School's Lamont-Doherty Earth Observatory, walked us through what scientists know about carbon dioxide levels over time.
- NASA's InSight hears its first meteoroid impacts...on September 19, 2022 at 4:51 pm
NASA's InSight Mars lander has detected seismic waves from four space rocks that crashed on Mars in 2020 and 2021.
- Is Pluto a planet? It is no longer considered...on August 31, 2022 at 6:31 pm
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Subject to memorization in school and known as the definitive planetary lineup, Pluto was included in the list until the International Astronomical Union determined it did not meet qualifications in 2006.
- Scientists have traced Earth's path through the...on August 24, 2022 at 12:58 pm
"To see a world in a grain of sand," the opening sentence of the poem by William Blake, is an oft-used phrase that also captures some of what geologists do.
- Were Phobos and Deimos once a single Martian moon...on August 22, 2022 at 3:30 pm
The origin of Phobos and Deimos, the two Martian moons, has been a mystery to astronomers. These two bodies are a fraction of the size and mass of the Moon, measuring just 22.7 km (14 mi) and 12.6 km (7.83 mi) in diameter. Both have a rapid orbital period, taking just 7 hours, 39 minutes, and 12 seconds (Phobos) and 30 hours, 18 minutes, and 43 seconds (Deimos) to complete an orbit around Mars. Both are also irregular in shape, leading many to speculate that they were once asteroids that got […]
- Mystery crater potentially caused by relative of...on August 20, 2022 at 2:30 pm
The ocean floor is famously less explored than the surface of Mars. And when our team of scientists recently mapped the seabed, and ancient sediments beneath, we discovered what looks like an asteroid impact crater.
- NASA's Lucy team discovers moon around asteroid...on August 17, 2022 at 6:26 am
Even before its launch, NASA's Lucy mission was already on track to break records by visiting more asteroids than any previous mission. Now, after a surprise result from a long-running observation campaign, the mission can add one more asteroid to the list.
- Modeling reveals how dwarf planet Ceres powers...on August 1, 2022 at 1:37 pm
For a long time, our view of Ceres was fuzzy, said Scott King, a geoscientist in the Virginia Tech College of Science. A dwarf planet and the largest body found in the asteroid belt—the region between Jupiter and Mars speckled with hundreds of thousands of asteroids—Ceres had no distinguishable surface features in existing telescopic observations from Earth.
- NASA releases Webb images of Jupiteron July 15, 2022 at 1:59 pm
On the heels of Tuesday's release of the first images from NASA's James Webb Space Telescope, data from the telescope's commissioning period is now being released on the Space Telescope Science Institute's Mikulski Archive for Space Telescopes. The data includes images of Jupiter and images and spectra of several asteroids, captured to test the telescope's instruments before science operations officially began July 12. The data demonstrates Webb's ability to track solar system targets and […]
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