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Martian biology in plain view? Mar 28, 2003
Strongest evidence yet for water flows on Mars Mar 13, 2003
Jovian moons galore Mar 7, 2003

Suspected water flows on Mars
Martian biology in plain view?
(Mar 28, 2003)

There are dangers in reading too much into surface markings on other worlds – remember Percival Lowell and the saga of the Martian canals? However, there's mounting interest, not just among eager amateurs armed with downloaded NASA images and PCs, that something is happening on Mars that points to movements of liquid on or near the surface and possibly even the coming and going of life itself. The latest surge in speculation centers on certain dark streaks (see also the article below this one) that have appeared from nowhere over a period measured in months. Reporting her research at the 34th Lunar and Planetary Science Conference (LPSC), held March 17-21, 2003, in Houston, Texas, Tahirih Motazedian, a student at the University of Oregon, believes the streaks are caused by small amounts of liquid water flowing in regions that are geothermally active. David McKay, a NASA space scientist at the Johnson Space Center, went further at the conference, and suggested that the dark coloration of the stains may be due to colonies of microorganisms that are rejuventaed from their normally dormant state by the sudden availability of water. Although he acknowledges there may be other explanations, he says "it seems to me that with our current data we cannot exclude it." This adds credence to the claims of Hungarian researchers Tibor Ganti and Andras Horvath, who also attended this month's LPSC and presented evidence of a link between water near the surface of Mars and the formation of so-called "dark dune spots" (DDSs). Since 1998, they have plotted the regular appearance and disappearance of DDSs, and have reached the conclusion that the spots point to "some kind of biological activity of putative Mars surface organisms, acting on, or in, the material of the dark dunes."

For more, see this article (, the Astrobiology Encyclopedia entries for vegetation and other life on Mars, and these earlier news stories: Mystery spots deserve closer look and Hungarian claims of vegetation on Mars.

Suspected water flows on Mars
Strongest evidence yet for water flows on Mars
(Mar 13, 2003)

New images and analysis suggest that the slopes around Mars' biggest volcano, Olympus Mons, bear dark stains caused by briny water flowing downhill. The new results suggest that underground ice deposits can sometimes melt and flow across the surface and add enormous weight to increasing speculation that life may exist near the planet's surface. Suspected water flows on MarsAccording to Tahirih Motazedian of the University of Oregon, it is the first time that changes on Mars have been seen due to water. She has examined images of Mars taken at different times and has seen new streaks form within a period of months. She speculates that geothermal activity driven by volcanic heat may be causing the melting of subsurface ice. The water dissolves surrounding minerals to form a super-salty solution that can remain liquid at much lower temperatures and pressures than pure water can. When the brine trickles onto the surface, it flows downhill staining the surface. Suspected water flows on Mars "The streaks originate from distinct geologic horizons below the Martian surface, where the water/ice table has been intersected by crater and valley walls," Motazedian says. Significantly, the dark streaks are never overlain or cut by other features like craters or sand dunes. Instead, they passively overlay existing features except where they are forced to flow around obstacles. The dark streaks always begin upslope as points, then widen downhill, just like flowing water. Images taken of the Mangala Valles region show that the dark streaks are being formed at the present time. Two images taken a few months apart show new streaks have appeared.

two of Jupiter's new moons found in Feb. 2003
Jovian moons galore
(Mar 7, 2003)

Seven new moons have been found around Jupiter, bringing the big planet's satellite tally to 47. Saturn is now a distant second with 30. Jupiter's new satellites were discovered in early February 2003 by Scott Sheppard and David Jewitt of the University of Hawaii, working with Jan Kleyna of Cambridge University, and publicly announced on March 4. They were found using the world's two largest digital cameras at the 8.3-meter Subaru Telescope and the Canada-France-Hawaii 3.6-meter telescope on Mauna Kea in Hawaii. The new moons are all small, two to four kilometers across, and orbit Jupiter at distances ranging from about 11 million to more than 24 million km. Two of the seven new satellites (S/2003 J1 and S/2003 J6) have an orbit around Jupiter that is in the same direction as Jupiter's spin. The other five have distant retrograde orbits like the majority of the known irregular satellites of Jupiter. My encyclopedia entry for Jupiter's moons here includes the previously known 40 moons and will be updated to include the seven new ones as soon as possible.

For comprehensive, up-to-date information on all the known Jovian moons, visit Scott Shepard's pages here.


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