dwarf planets
18 questions tagged dwarf planets — spanning every one of the seven Ws.
Which is the largest dwarf planet?
Pluto is the largest known dwarf planet by diameter (about 2,377 km), though Eris is slightly more massive.
Where is Pluto’s moon Charon located in the sky of Pluto?
Charon appears as a large moon in Pluto’s sky and is always near Pluto because the pair are tidally locked.
Which dwarf planet is the largest known?
Pluto is the largest dwarf planet by volume in the classical list of dwarf planets. It is about 2,377 kilometers across.
Whose mission first flew by Pluto?
NASA’s New Horizons mission, led by principal investigator Alan Stern, made the first Pluto flyby in 2015. It transformed Pluto from a blurry dot into a real world.
Whose discovery of Ceres made the first-known dwarf planet the first object found in the asteroid belt?
Giuseppe Piazzi discovered Ceres on 1 January 1801. It was initially thought to be a planet before later being classified as a dwarf planet.
How do astronomers find dwarf planets like Pluto if they are so faint?
They search for slow-moving points of light across multiple telescope images. Pluto was discovered in 1930 by Clyde Tombaugh using this method.
When was Pluto visited by a spacecraft for the first time?
NASA's New Horizons flew past Pluto on 14 July 2015.
Where is Pluto’s heart-shaped region located?
Pluto’s famous heart-shaped feature is on the side of the dwarf planet visible to New Horizons in 2015. It is called Tombaugh Regio.
Where is Sputnik Planitia located?
Sputnik Planitia is a giant basin on Pluto and the bright left lobe of its heart-shaped region. It is filled with nitrogen, carbon monoxide, and methane ices.
Where is Ceres located in the Solar System?
Ceres is located in the main asteroid belt between Mars and Jupiter. It is the only dwarf planet in the inner Solar System.
Whose spacecraft first flew by Pluto?
NASA’s New Horizons mission, led by project scientist Alan Stern, performed the first flyby of Pluto in 2015. It revealed the dwarf planet’s surprisingly complex surface.
Whose mission first reached Pluto and showed that it has a heart-shaped plain?
NASA’s New Horizons. In 2015 it flew past Pluto and revealed the bright heart-shaped Tombaugh Regio.
How do astronomers know what Pluto is made of from so far away?
They analyze reflected sunlight with spectroscopy, which reveals Pluto’s surface ices such as nitrogen, methane, and carbon monoxide.
Where is Ceres located?
Ceres is in the asteroid belt between Mars and Jupiter. It is the belt’s largest object and classified as a dwarf planet.
Which dwarf planet is the largest by diameter?
Pluto is the largest known dwarf planet by diameter, at about 2,377 kilometers across. It is slightly larger than Eris by diameter, though Eris is more massive.
Whose calculations helped discover the first asteroid, Ceres?
Giuseppe Piazzi discovered Ceres in 1801, and Carl Friedrich Gauss’s orbit calculations helped locate it again after it was lost in the Sun’s glare. Piazzi’s observation and Gauss’s mathematics together made the recovery possible.
Whose discovery showed that Pluto is not the only small world beyond Neptune?
Eris was discovered by Michael E. Brown and colleagues in 2005. It helped redefine the Solar System and contributed to Pluto being classified as a dwarf planet.
How do scientists know that Pluto is smaller than Earth's Moon?
They measure Pluto's diameter directly with telescopes and spacecraft imaging, then compare it to the Moon's known size.