![]() ![]() JPL is a division of the California Institute of Technology, Pasadena. JPL manages the mission for NASA's Science Mission Directorate, Washington. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The findings provide insight into particle acceleration at the shocks surrounding the remnants of stellar explosions. Under these conditions, significant particle acceleration was detected for the first time. 3, 2007, Cassini recorded a particularly strong shock in a "quasi-parallel" orientation, where the magnetic field and the direction of the front of the shock's movement are almost aligned. Saturn's magnetosphere is depicted in grey, while the complex bow shock region – the shock wave in the solar wind that surrounds the magnetosphere – is shown in blue. Specular reflection of protons at Earths supercritical quasi-perpendicular bow shock has long been known to lead to the thermalization of solar wind particles by velocity-space dispersion. Watch an excerpt of the MAVEN Mission Briefing.This artist's impression by the European Space Agency shows NASA's Cassini spacecraft exploring the magnetic environment of Saturn. Read the full press release about this finding. Thanks to MAVEN, scientists can now observe the solar wind at Mars during both normal and extreme conditions, allowing them to study the Sun's ongoing role in the evolution of the Martian climate. MAVEN's observations confirm the existence of a bow shock, with a density and shape matching the predicted pattern. The visualization on this page compares a simulation of the solar wind at Mars with data from the MAVEN spacecraft. During solar storms, the bow shock pushes even deeper into the atmosphere and is accompanied by increased rates of ion escape. ![]() The inner boundary of this bow shock reaches the Mars ionosphere, and can accelerate ions to escape velocities. Instead, charged particles from the Sun slam into the Mars upper atmosphere, piling up in a bow shock ahead of the planet. Unlike Earth, Mars lacks a global magnetic field to deflect the incoming solar wind. ![]() One of the prime suspects is the solar wind, a stream of electrically charged particles continuously blowing outward from the Sun. Scientists think that climate change on Mars was caused by the loss of an early, thick atmosphere, and NASA's MAVEN mission is investigating what could have driven its escape. Today, Mars is a global desert with an atmosphere far too thin to support bodies of flowing water, but evidence shows that Mars was considerably wetter in the ancient past. ![]()
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