Category: sistemasolar

Ceres is the largest object in the asteroid be…

Ceres is the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter, slightly closer to Mars’ orbit. Its diameter is approximately 945 kilometers (587 miles), making it the largest of the minor planets within the orbit of Neptune. The 33rd-largest known body in the Solar System, it is the only dwarf planet within the orbit of Neptune. Composed of rock and ice, Ceres is estimated to compose approximately one third of the mass of the entire asteroid belt. Ceres is the only object in the asteroid belt known to be rounded by its own gravity (though detailed analysis was required to exclude 4 Vesta). From Earth, the apparent magnitude of Ceres ranges from 6.7 to 9.3, peaking once every 15 to 16 months, hence even at its brightest it is too dim to be seen with the naked eye except under extremely dark skies. 

Dawn revealed that Ceres has a heavily cratered surface; nevertheless, Ceres does not have as many large craters as expected, likely due to past geological processes. An unexpectedly large number of Cererian craters have central pits, perhaps due to cryovolcanic processes, and many have central peaks. Ceres has one prominent mountain, Ahuna Mons; this peak appears to be a cryovolcano and has few craters, suggesting a maximum age of no more than a few hundred million years. A later computer simulation has suggested that there were originally other cryovolcanoes on Ceres that are now unrecognisable due to viscous relaxation. Several bright spots have been observed by Dawn, the brightest spot (“Spot 5”) located in the middle of an 80-kilometer (50 mi) crater called Occator. From images taken of Ceres on 4 May 2015, the secondary bright spot was revealed to actually be a group of scattered bright areas, possibly as many as ten. These bright features have an albedo of approximately 40% that are caused by a substance on the surface, possibly ice or salts, (with the realization of new studies are now likely deposits of salt composed mainly of hydrated magnesium sulphate). reflecting sunlight.

Mimas – January 30 2017

Mimas – January 30 2017

Image credit: NASA/JPL/Kevin M. Gill

images of the Sun captured during the first ye…

images of the Sun captured during the first year of NASA’s Solar Dynamics Observatory (SDO) mission.

Credit: NASA/SDO

Pathfinder on Mars

Pathfinder on Mars

Image credit: NASA/JPL

This shot of Pluto, taken by New Horizons ju…

This shot of Pluto, taken by New Horizons just minutes after closest approach

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory /Southwest Research Institute/Ian Regan.

Ten interesting facts about Pluto

Here is a list of some interesting facts about Pluto. A dwarf planet with a very different geology than previously thought, and despite being a small celestial body – Pluto has its own moons.


Pluto was known as the smallest planet in the solar system and the ninth planet from the sun until it was reclassified by the International Astronomical Union in 2006.


Today, Pluto is called a dwarf planet. A dwarf planet orbits the sun just like other planets, but it is smaller. It is large enough for its gravity to pull it into the shape of a ball but it is too small to clear other objects and debris out of its path around the sun.


Pluto was discovered on February 18th, 1930 by the Lowell Observatory.
For the 76 years between Pluto being discovered and the time it was reclassified as a dwarf planet it completed under a third of its orbit around the Sun.


On average, Pluto is more than 3.6 billion miles (5.8 billion kilometers) away from the sun. That is about 40 times as far from the sun as Earth is. Pluto orbits the sun in an oval like a racetrack. Because of its oval orbit, Pluto is sometimes closer to the sun than at other times. At its closest point to the sun Pluto is still billions of miles away but is actually closer than Neptune.


This dwarf planet has five moons. Its largest moon is named Charon (KAIR-uhn). Charon is about half the size of Pluto. 


Pluto has four other, much smaller, moons. They are named Nix, Hydra, Kerberos, and Styx. They were discovered in 2005, 2005, 2011, and 2012, respectively. NASA’s Hubble Space Telescope took pictures of the new moons. All four are small.


Observations of Pluto’s surface by the New Horizons spacecraft revealed a variety of surface features, including mountains that reach as high as 11,000 feet (3,500 meters), comparable to the Rocky Mountains on Earth. While methane and nitrogen ice cover much of the surface of Pluto, these materials are not strong enough to support such enormous peaks, so scientists suspect that the mountains are formed on a bedrock of water ice.


Pluto’s surface is one of the coldest places in the solar system, at roughly minus 375 degrees Fahrenheit (minus 225 degrees Celsius). When compared with past images, pictures of Pluto taken by the Hubble Space Telescope revealed that the dwarf planet had apparently grown redder over time, apparently due to seasonal changes.


When Pluto is closer to the sun, its surface ices thaw and temporarily form a thin atmosphere, consisting mostly of nitrogen, with some methane. 


Pluto’s low gravity, which is a little more than one-twentieth that of Earth’s, causes this atmosphere to extend much higher in altitude than Earth’s.

The Spiral North Pole of Mars A  mosaic …

The Spiral North Pole of Mars

A  mosaic from ESA’s Mars Express

and by the Mars Orbiter Camera on board the Mars Global Surveyor

shows off the Red Planet’s north polar ice cap and its distinctive dark spiralling troughs.

Image credit: NASA/ESA 

Galilean moons The Galilean moons are the f…

Galilean moons

The Galilean moons are the four largest moons of Jupiter — Io, Europa, Ganymede, and Callisto. They were first seen by Galileo Galilei in January 1610, and recognized by him as satellites of Jupiter in March 1610. They are the first objects found to orbit another planet. Their names derive from the lovers of Zeus.

They are the first objects found to orbit another planet. Their names derive from the lovers of Zeus. They are among the largest objects in the Solar System with the exception of the Sun and the eight planets, with a radius larger than any of the dwarf planets. 

  • Io is the fourth largest moon in the Solar System.

    With over 400 active volcanos, Io is the most geologically active object in the Solar System. Its surface is dotted with more than 100 mountains, some of which are taller than Earth’s Mount Everest. Unlike most satellites in the outer Solar System (which have a thick coating of ice), Io is primarily composed of silicate rock surrounding a molten iron or iron sulfide core. Although not proven, recent data from the Galileo orbiter indicate that Io might have its own magnetic field.

  • Europa the second of the four Galilean moons, is the second closest to Jupiter and the smallest at 3121.6 kilometers in diameter, which is slightly smaller than the Moon. The name comes from a mythical Phoenician noblewoman, Europa, who was courted by Zeus and became the queen of Crete, though the name did not become widely used until the mid-20th century. 

    It has a smooth and bright surface, with a layer of water surrounding the mantle of the planet, thought to be 100 kilometers thick. The smooth surface includes a layer of ice, while the bottom of the ice is theorized to be liquid water. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably serve as an abode for extraterrestrial life. 

  • Ganymede is the largest moon in the Solar System, and is even bigger than the planet Mercury. It is the only satellite in the Solar System known to possess a magnetosphere, likely created through convection within the liquid iron core. 
  • Callisto  is the fourth and last Galilean moon, and is the second largest of the four, and at 4820.6 kilometers in diameter, it is the third largest moon in the Solar System, and barely smaller than Mercury, though only a third of the latter’s mass. It is named after the Greek mythological nymph Callisto, a lover of Zeus who was a daughter of the Arkadian King Lykaon and a hunting companion of the goddess Artemis. It is one of the most heavily cratered satellites in the Solar System, and one major feature is a basin around 3000 km wide called Valhalla. 

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  • image credit: NASA/JPL

Two moons of Uranus: Titania and Oberon. Both …

Two moons of Uranus: Titania and Oberon. Both moons were discovered by William Herschel in 1787.

Credit: NASA/JPL

Composite image of Wright Mons, one of two p…

Composite image of Wright Mons, one of two potential cryovolcanoes spotted on the surface of Pluto by the New Horizons spacecraft in July 2015.