<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"><meta http-equiv="Content-Type" content="text/html charset=us-ascii"><meta http-equiv="Content-Type" content="text/html charset=us-ascii"><div style="margin: 0px; font-size: 12px; "></div><div style="margin: 0px; font-size: 12px; font-family: Arial; "><span style="letter-spacing: 0.0px">The sinuous gullies are longer, narrower, and curvier than the short, wide, straight gullies. They tend to start from V-shaped, collapsed regions described as "alcoves" and merge with other gullies. Scientists think different processes formed the two types of gullies and have been looking at images of Earth, Mars and other small bodies for clues. </span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin: 0px; font-size: 12px; font-family: Arial; "><span style="letter-spacing: 0.0px">"On Earth, similar features - seen at places like Meteor Crater in Arizona -- are carved by liquid water," said Christopher Russell, Dawn's principal investigator, also based at UCLA. "On Mars, there is still a debate about what has caused them. We need to analyze the Vesta gullies very carefully before definitively specifying their source." </span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin: 0px; font-size: 12px; font-family: Arial; "><span style="letter-spacing: 0.0px">Indeed, scientists have suggested various explanations for gullies on Mars since fresh-looking gullies were discovered in images from NASA's Mars Global Surveyor in 2000. Some of the proposed Martian mechanisms involve water, some carbon dioxide, and some neither. One study in 2010 suggested that carbon-dioxide frost was causing fresh flows of sand on the Red Planet."</span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin: 0px; font-size: 12px; font-family: Arial; color: rgb(2, 30, 170); "><span style="text-decoration: underline ; letter-spacing: 0.0px"><a href="http://www.nasa.gov/mission_pages/dawn/multimedia/pia16489.html">Full Image and caption 1<span style="letter-spacing: 0px; "></span></a></span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; color: rgb(2, 30, 170); "><span style="text-decoration: underline ; letter-spacing: 0.0px"><a href="http://www.nasa.gov/mission_pages/dawn/multimedia/pia16490.html">Full Image and caption 2<span style="letter-spacing: 0px; "></span></a></span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; color: rgb(2, 30, 170); "><span style="text-decoration: underline ; letter-spacing: 0.0px"><a href="http://www.nasa.gov/mission_pages/dawn/multimedia/pia16491.html">Full Image and caption 3<span style="letter-spacing: 0px; "></span></a></span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin: 0px; font-size: 12px; font-family: Arial; color: rgb(2, 30, 170); "><span style="text-decoration: underline ; letter-spacing: 0.0px"><a href="http://www.nasa.gov/multimedia/videogallery/index.html?collection_id=65362&media_id=143122771">Dawn's Virtual Flight over Vesta<span style="letter-spacing: 0px; "></span></a></span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin: 0px; font-size: 12px; font-family: Arial; color: rgb(2, 30, 170); "><span style="letter-spacing: 0.0px; color: #000000">A gallery of images can be found online at: <a href="http://www.nasa.gov/mission_pages/dawn/multimedia/gallery-index.html"><span style="letter-spacing: 0px; ">http://www.nasa.gov/mission_pages/dawn/multimedia/gallery-index.html</span></a>.</span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin: 0px; font-size: 12px; font-family: Arial; "><span style="letter-spacing: 0.0px">For more information on the Dawn mission, visit the Dawn home page: <a href="http://www.nasa.gov/mission_pages/dawn/main/index.html"><span style="letter-spacing: 0px; color: rgb(4, 51, 255); ">http://www.nasa.gov/mission_pages/dawn/main/index.html</span></a>.</span></div><div style="margin: 0px; font-size: 12px; font-family: Arial; min-height: 14px; "><span style="letter-spacing: 0.0px"></span><br></div><div style="margin: 0px; font-size: 12px; font-family: Arial; "><span style="font-family: Helvetica; "></span></div></body></html>