NASA’s Cassini spacecraft has detected a very tenuous atmosphere known as an exosphere, infused with oxygen and carbon dioxide around Saturn’s icy moon Rhea. The source of the carbon dioxide is less certain. Oxygen at Rhea’s surface is estimated to be about 5 trillion times less dense than what we have at Earth.
What two things make the moon Rhea unique in the solar system?
Rhea (/ˈriːə/) is the second-largest moon of Saturn and the ninth-largest moon in the Solar System. It is the smallest body in the Solar System for which precise measurements have confirmed a shape consistent with hydrostatic equilibrium….Rhea (moon)
| Discovery | |
|---|---|
| Surface temp. min mean max Kelvin 53 K 99 K | |
| Apparent magnitude | 10 |
What is Rhea made of?
Composition and Surface Features: With a mean density of about 1.236 g/cm³, Rhea is estimated to be composed of 75% water ice (with a density of roughly 0.93 g/cm³) and 25% of silicate rock (with a density of around 3.25 g/cm³).
Does Rhea have ice on it?
On the surface Rhea is an icy body with a density 1.233 times that of liquid water, which implies that it is three-quarters ice and one-quarter rock. The highly reflective surface provides further evidence.
What moons have a atmosphere?
Titan is bigger than Earth’s moon, and larger than even the planet Mercury. This mammoth moon is the only moon in the solar system with a dense atmosphere, and it’s the only world besides Earth that has standing bodies of liquid, including rivers, lakes and seas, on its surface.
Is Rhea breathable?
Rhea’s atmosphere is so thin that it is considered “collisionless” – in other words, the molecules never hit each other. Needless to say, we cannot breathe a vacuum, and that’s essentially what we’re talking about on Rhea. It is really really not breathable.
What is special about Rhea?
Rhea is the second largest moon of Saturn, but with a mean radius of 475 miles (764 kilometers) it is less than a third the radius of Saturn’s largest moon, Titan. Rhea is a small, cold, airless body that is very similar to sister moons Dione and Tethys. Both Dione and Tethys have more areas of smooth plains than Rhea.
What makes Rhea unique?
Rhea has a lot of water ice on the surface and it makes the moon highly reflective. Rhea is thought to have a surface that is older than its two sister moons of Tethys and Dione. Rhea’s two biggest craters are on the side that faces away from the parent planet, are incredibly old and are from 400-500 km across.
Is Rhea geologically active?
The surface of Rhea (949 miles or 1527 kilometers across) has been sculpted largely by impact cratering, each crater a reminder of a collision sometime in the moon’s history. On more geologically active worlds like Earth, the craters would be erased by erosion, volcanoes or tectonics.
Which Moon has the most oxygen?
An oxygen atmosphere has been found on Saturn’s second largest moon, Rhea, astronomers announced Thursday—but don’t hold your breath for colonization opportunities. For one thing, the 932-mile-wide (1,500-kilometer-wide), ice-covered moon is more than 932 million miles (1.5 billion kilometers) from Earth.
What are some facts about Rhea Moon?
Facts about Rhea Moon for Kids: Giovanni Cassini discovered two moons around Saturn and then discovered Rhea as the third moon and then a fourth moon. The original name of Rhea was Saturn V as the fifth moon from Saturn.
Is there an atmosphere on Saturn’s moon Rhea?
NASA’s Cassini spacecraft detected Rhea’s atmosphere during a close flyby of the frozen moon in March. The discovery marks the first time an oxygen-rich atmosphere has been found on a Saturn satellite. [Photo of the Saturn moon Rhea.] Oxygen atmospheres are known to exist on other natural satellites in our solar system.
How thick is Rhea’s atmosphere compared to Earth’s?
But that still makes Rhea’s atmosphere about 100 times thicker than that of Earth’s moon, or Mercury. Rhea isn’t the only Saturn moon known to have an atmosphere: Titan, Saturn’s largest satellite, has a thick, nitrogen-rich one. But the new study confirms an ice-derived, oxygen-rich atmosphere for the first time outside of the Jupiter system.
What is the composition of Rhea?
Rhea is Saturn’s second-largest moon, with Titan being the largest. The composition of Rhea is mostly water ice with some rocky material mixed in. There are many craters and fractures on Rhea’s icy surface, suggesting bombardment in the recent past. The History of Rhea Exploration
