Get Free Membership. Remember me. Forgot your login? Ask the Experts. University Departments. Discussion Forums. Online Chat. Einstein eGreetings. Science eStore. These icy, rocky bodies are called Kuiper Belt objects, transneptunian objects, or plutoids. Pluto is about two-thirds the diameter of Earth's Moon and probably has a rocky core surrounded by a mantle of water ice. Interesting ices like methane and nitrogen frost coat the surface. Due to its lower density, Pluto's mass is about one-sixth that of Earth's Moon.
Pluto's surface is characterized by mountains, valleys, plains, and craters. The temperature on Pluto can be as cold as to degrees Fahrenheit to degrees Celsius. Pluto's tallest mountains are 6, to 9, feet 2 to 3 kilometers in height. The mountains are big blocks of water ice, sometimes with a coating of frozen gases like methane. Long troughs and valleys as long as miles kilometers add to the interesting features of this faraway dwarf planet.
Craters as large as miles kilometers in diameter dot some of the landscape on Pluto, with some showing signs of erosion and filling. This suggests tectonic forces are slowly resurfacing Pluto. The most prominent plains observed on Pluto appear to be made of frozen nitrogen gas and show no craters. These plains do show structures suggesting convection blobs of material circulating up and down.
Pluto has a thin, tenuous atmosphere that expands when it comes closer to the Sun and collapses as it moves farther away — similar to a comet. The main constituent is molecular nitrogen, though molecules of methane and carbon monoxide have also been detected.
When Pluto is close to the Sun, its surface ices sublimate changing directly from solid to gas and rise to temporarily form a thin atmosphere. Pluto becomes much colder during the part of each year when it is traveling far away from the Sun. During this time, the bulk of the planet's atmosphere may freeze and fall as snow to the surface.
It isn't known whether Pluto has a magnetic field, but its small size and slow rotation suggest little or none. Introduction Pluto is a complex and mysterious world with mountains, valleys, plains, craters, and maybe glaciers. A 3D model of Pluto. The lives and accomplishments of both women aviation pioneers have now been honored with the naming of landmarks on Pluto.
JPL's lucky peanuts are an unofficial tradition at big mission events. Full Moon Guide: October - November A new paper details how the hydrological cycle of the now-dry lake at Jezero Crater is more complicated than originally thought.
This year, the minimum extent of Arctic sea ice dropped to 1. Researchers will use Webb to observe 17 actively forming planetary systems. The lander cleared enough dust from one solar panel to keep its seismometer on through the summer, allowing scientists to study three big quakes. Scientists found evidence that an area on Mars called Arabia Terra had thousands of "super eruptions" over a million-year period.
Perseverance successfully collected its first pair of rock samples, and scientists already are gaining new insights into the region. Astronauts trying to land a spaceship on the surface of Jupiter would find that there is no solid surface at all! Jupiter is made mostly of hydrogen, with some helium, and small amounts of other elements Figure below.
Deeper within the planet, pressure compresses the gases into a liquid. Some evidence suggests that Jupiter may have a small rocky core of heavier elements at its center. These bands rotate around the planet, but also swirl around in turbulent storms. This storm is more than three times as wide as the entire Earth. Clouds in the storm rotate in a counterclockwise direction, making one complete turn every six days or so.
The Great Red Spot has been on Jupiter for at least years, since astronomers could first see the storm through telescopes. Do you think the Great Red Spot is a permanent feature on Jupiter? How could you know? The white storm just below the Great Red Spot is about the same diameter as Earth. Jupiter has a very large number of moons — 63 have been discovered so far. Four are big enough and bright enough to be seen from Earth, using no more than a pair of binoculars.
These moons — Io, Europa, Ganymede, and Callisto — were first discovered by Galileo in , so they are sometimes referred to as the Galilean moons Figure below. The Galilean moons are larger than the dwarf planets Pluto, Ceres, and Eris. Ganymede is not only the biggest moon in the solar system it is even larger than the planet Mercury! This composite image shows the four Galilean moons and their sizes relative to the Great Red Spot. From top to bottom, the moons are Io, Europa, Ganymede, and Callisto.
Sizes are to scale. Scientists are particularly interested in Europa because it may be a place to find extraterrestrial life. What features might make a satellite so far from the Sun a candidate for life? Although the surface of Europa is a smooth layer of ice, there is evidence that there is an ocean of liquid water underneath Figure below.
Europa also has a continual source of energy — it is heated as it is stretched and squashed by tidal forces from Jupiter. Numerous missions have been planned to explore Europa, including plans to drill through the ice and send a probe into the ocean.
However, no such mission has yet been attempted. The surface ice may have motions similar to plate tectonics on Earth. In , two spacecrafts — Voyager 1 and Voyager 2 — visited Jupiter and its moons. Photos from the Voyager missions showed that Jupiter has a ring system.
This ring system is very faint, so it is difficult to observe from Earth. Saturn, shown in Figure below, is famous for its beautiful rings. In Roman mythology, Saturn was the father of Jupiter. Saturn is also the least dense planet in the solar system.
It is less dense than water. What would happen if you had a large enough bathtub to put Saturn in? Saturn would float! Saturn orbits the Sun once about every 30 Earth years. This image of Saturn and its rings is a composite of pictures taken by the Cassini orbiter in Like Jupiter, Saturn is made mostly of hydrogen and helium gases in the outer layers and liquids at greater depths.
The upper atmosphere has clouds in bands of different colors. These rotate rapidly around the planet, but there seems to be less turbulence and fewer storms on Saturn than on Jupiter.
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