Liquid water is thought to be a requirement for life, and identifying the signs of past water on extraterrestrial bodies such as Mars is the first step toward determining whether life could have once existed in these locations. Scientists have often viewed the presence of carbonates -- minerals formed when negatively charged carbonate ions and positively charged ions such as calcium, magnesium or iron combine in a liquid solution -- as an indication that water was once present. A good deal of Mars exploration has focused on hunting for carbonates. The minerals have actually been found in the Mars meteorite ALH84001, and in meteorites known as chondrites. However, some new research may cause researchers to rethink whether carbonates point to past water. Ciska Kemper, a doctoral student at the University of Amsterdam, may have recently identified carbonates in the dry dust surrounding dying stars NGC 6302 and NGC 6537. Kemper and her colleagues believe no water could exist in such an environment, and the amount of carbonates present is far too great to have originated from recently vaporized planets. They conclude that carbonates alone don't prove that a planetary body was once wet. But some researchers dispute the validity of KemperÂs research, or say that the implications of Kemper's claims have been overstated by certain press reports. For example, astrobiologist David McKay states that specific characteristics of the carbonates in ALH84001 confirm that they precipitated from liquid.
Dec 07, 2001 | SCIENCE, MISSIONS, TECHNOLOGIES
Europe Heads for Mars
(NASA Astrobiology Institute) - The Beagle 2, a compact, lightweight lander carried on the European Space Agency (ESA) Mars Express orbiter, will search for signs of life on the Red Planet.
Aug 22, 2001 | SCIENCE, MISSIONS
Mars Enigma: One Scientist's Contentious Theory about Planet May Hold Water
(San Francisco Chronicle) - A geoscientist argues that erosion features on Mars were carved not by water but by liquid carbon dioxide.
Jul 17, 2001 | SCIENCE
New Kind of Hydrothermal Vent Discovered
(Nature) - Hydrothermal vents and the ecosystems they support may be more common than previously thought.
May 09, 2001 | SCIENCE
Life's Baby Steps
(NASA Astrobiology Institute/Carnegie Institution of Washington) - Billions of years ago, amino acids somehow linked together to form chainlike molecules. Now scientists have discovered what may be a key step in this process.
Mar 28, 2001 | SCIENCE, MISSIONS, TECHNOLOGIES
The Lure of Hematite
(Science@NASA) - On rusty-red Mars, a curious deposit of gray-colored hematite (a mineral cousin of common household rust) could hold the key to the mystery of elusive Martian water.
Feb 14, 2001 | SCIENCE, MISSIONS, TECHNOLOGIES
Carbonated Mars
(NASA) - Here on Earth the only way to make carbonate rocks is with the aid of liquid water. Finding such rocks on Mars might prove, once and for all, that the barren Red Planet was once warm and wet.
Feb 07, 2001 | SCIENCE
Looking for life, astrobiologists dive deep
(NASA Astrobiology Institute) - Coral-like mounds on the floor of a Canadian lake may make it easier someday to identify life on other planets.
Sep 02, 1999 | SCIENCE
Mound on Mars may have been built by microbes
(New Scientist) - Researchers in Turkey and Scotland say that a huge rock within a Martian crater strongly resembles a stromatolite, a mound of minerals created by single-celled organisms called cyanobacteria.
Jul 20, 1999 | SCIENCE, MISSIONS
Scientists debate implications of Mars pictures
(CNN) - At the Fifth International
Conference on Mars, researchers differed over what the photos from Mars Global Surveyor tell us. They discussed the evidence of water and the possibility of life on past and present Mars.
