Science Nuggets

Titan's leaking atmosphere

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Saturn's largest moon Titan (Credit: NASA/JPL/U. Arizona)

Saturn’s enigmatic moon Titan is of special interest to scientists due to many of its Earth-like features such as lakes, a methane cycle similar to the water (hydrological) cycle on Earth and large organic molecules in its atmosphere. Titan is the only moon in the solar system with a substantial atmosphere and it is larger than the planet Mercury.

Mapping Saturn's magnetosphere

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Illustration of plasma production in Saturn's inner magnetosphere.

When walking or driving somewhere new most people would take a map or a GPS device to find their way around. Planetary scientists usually make maps of the surfaces of planetary bodies to understand surface features. For the most part, the magnetospheres (space environments) of the planets are invisible. We have to use instruments that detect particles and magnetic fields to find our way around, like using senses of taste, smell and touch to understand where we are inside a magnetosphere.

Dione's thin oxygen exosphere

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Image of Saturn's icy moon Dione. Credit: NASA/JPL/Space Science Institute

Dione is a moon of Saturn, discovered in 1684 by the Italian astronomer Giovanni Cassini. Over 300 years later, planetary scientists including Andrew Coates and Geraint Jones from MSSL-UCL, have discovered that Dione has a weak exosphere near its surface (at planets with denser atmospheres, the exosphere is the outermost layer of its atmosphere). This exosphere is very very thin, about a million billionth of the Earth's atmospheric density. The work shows that the exosphere contains molecular oxygen - the same form of oxygen as in Earth's atmosphere. This gives us important information about how the atmosphere is produced.

Counting electrons in space

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Image of the Crab Nebula. Credit: Hubble Space Telescope/NASA

Space isn't really a empty. In reality it's filled with particles that can be measured by instruments on spacecraft. But there aren't that many of them so special techniques need to be used to work out the density and temperature of the particles surrounding the planets, and our spacecraft.

Electrified ice from Saturn's moon Enceladus

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During the Cassini spacecraft’s first encounter with Saturn’s 500km-wide moon Enceladus, clear indications were detected by the spacecraft’s magnetometer that the way that this body was interacting with Saturn’s magnetosphere was highly unusual. Further observations in 2005 showed that the moon was expelling gas and dust from its south polar region.

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