Three billion years ago, Earth was a very different place.
Hydrothermal vents along the mid-ocean ridges have drawn much attention from scientists who study Earth’s extreme environments – and what they may mean for the prospect of life elsewhere in the solar system.
But in recent years, researchers discovered life also thrives in other, much colder, lightless deep-sea ecosystems. Such habitats are created where faults in ancient sediments allow natural gas (methane) in deeply buried deposits to seep upward to the ocean floor to form methane ices known as gas hydrates.
These “methane seeps” are found all over the world on continental slopes some 500 to 1,000 meters (1 ...November 30, 2001 • Posted by: Shige Abe • Report issue
When microorganisms die in ponds of water or in the ocean, they slowly sink to the bottom, forming a thick black sludge. Over time, this sludge becomes buried and compacted by more organisms and layers of mud. If oxygen is left out of the mixture, the organic matter can’t decay and it eventually fossilizes into the material called kerogen.
Scientists have long believed that kerogen was a carbon ‘sink’ – a place where carbon was trapped and could not be recycled. But recently, a team of researchers led by Steven Petsch of the Woods Hole Oceanographic Institution (WHOI) discovered that ...November 28, 2001 • Posted by: Shige Abe • Report issue
The nature of life on Earth and the search for life elsewhere are two sides of the same question – the search for who we are.
On Friday, November 9, 2001, on what would have been Carl Sagan’s 67th birthday, the NASA Ames Research Center dedicated the site for the Carl Sagan Center for the Study of Life in the Cosmos. The cornerstone for the new Center was unveiled during the dedication ceremony.
“Carl was an incredible visionary, and now his legacy can be preserved and advanced by a 2lst century research and education laboratory committed to ...November 26, 2001 • Posted by: Shige Abe • Report issue
Based on an Arizona State University press release
There may have once been (and perhaps still is) life on Mars, but the evidence for it is barely stirring.
When, in 1996, a group of NASA researchers presented several lines of evidence for fossil bacteria in a Martian meteorite, a wave of excitement passed through the public and the scientific community alike. Of course, that wave was followed by a storm of controversy.
Five years of scrutiny and debate over the NASA group’s claims have since brought all but one of their arguments unceremoniously back to Earth. Non-biological processes and contamination ...November 23, 2001 • Posted by: Shige Abe • Report issue
The H.M.S. Beagle set sail from Britain late in the stormy December of 1831, bearing the young naturalist Charles Darwin on a quest to understand the natural history of the farthest lands humans could reach. One hundred and seventy two years later, the UK’s Open and Leicester Universities, together with Astrium, an Aerospace Industry partner, aims to reach a bit farther: to Mars. Beagle 2, a compact, lightweight lander carried on the European Space Agency’s (ESA) Mars Express, will search for signs of life on the red planet.
The H.M.S. Beagle’s captain, Robert ...November 14, 2001 • Posted by: Shige Abe • Report issue
It is difficult to speculate where this new biology may lead. We may learn to apply universal principles of biology to better understand our own type of life and to do such things as develop artificial cells, tissues and organs that might be better suited for certain purposes as compared to those that can be engineered based only on terrestrial principles.
As a potential location for our second datum of biology, our neighboring planet Mars once again beckons. The possibility that the labeled release experiment (LR), carried to Mars in 1976 aboard the two Viking landers, actually discovered microorganisms is ...November 02, 2001 • Posted by: Shige Abe • Report issue
On the deep sea floor, along the margins of diverging plates of ocean crust, communities of microscopic organisms live around hot volcanic vents. These seafloor hydrothermal systems have probably existed on Earth since the oceans first formed, more than four billion years ago. The microscopic life around the vents may also have an ancient heritage — genetic comparisons suggest that modern vent microbes are close kin to the earliest forms of life on Earth. These regions are therefore of special interest to astrobiologists, who study the geology, chemistry, and biology of hydrothermal vents to better understand how Earth’s early biosphere ...October 31, 2001 • Posted by: Shige Abe • Report issue
A team of researchers recently announced that they have found the deepest-living microbes on the planet. These bacteria eat into rock at the bottom of the sea floor, some burrowing down as far as 500 meters (1,640 feet), although most of the microbial activity seems to be in the upper 300 meters (984 feet) of the ocean crust.
“We’ve documented how extensive these microscopic organisms are eating into volcanic rock, leaving worm-like tracks that look like someone has drilled their way in,” says one of the paper’s co-authors, Hubert Staudigel of Scripps Institution of Oceanography at ...October 29, 2001 • Posted by: Shige Abe • Report issue
Based on a NASA press release
The United States returned to Mars last night as NASA’s 2001 Mars Odyssey fired its main engine at 7:26 p.m. Pacific time on Oct. 23rd (0226 UT on Oct. 24th) and was captured into orbit around the red planet.
At 7:55 p.m. Pacific time, flight controllers at the Deep Space Network station in Goldstone, Calif., and Canberra, Australia, picked up the first radio signal from the spacecraft as it emerged from behind the planet Mars.
“Early information indicates everything went great,” said Matt Landano, the Odyssey project manager ...October 26, 2001 • Posted by: Shige Abe • Report issue
When scientists first started to classify life, everything was designated as either an animal or a plant. But as new forms of life were discovered and our knowledge of life on Earth grew, new categories, called ‘Kingdoms,’ were added. There eventually came to be five Kingdoms in all – Animalia, Plantae, Fungi, Protista, and Bacteria.
The five Kingdoms were generally grouped into two categories called Eukarya and Prokarya. Eukaryotes represent four of the five Kingdoms (animals, plants, fungi and protists). Eukaryotes are organisms whose cells have a nucleus — a sort of sack that holds the cell’s DNA. Animals, plants ...October 22, 2001 • Posted by: Shige Abe • Report issue
Saturn’s giant moon Titan, cloaked in a thick nitrogen atmosphere laced with hydrocarbons, could provide a laboratory in the sky for scientists seeking insight into the origins of life. With the Cassini-Huygens mission, scheduled for a 2004 rendezvous with Saturn and Titan, scientists hope to find evidence for primitive organic chemistry, preserved in the extreme cold of the moon’s icy surface. For while “Titan is not a place where life began or could flourish,” says planetary scientist Jonathan Lunine, it is a good place to look for biomolecules.
Titan is a Mercury-sized world comprised of a 50-50 ...October 19, 2001 • Posted by: Shige Abe • Report issue
Cindy L. VanDover, a biologist and hydrothermal vent expert at the College of William and Mary in Williamsburg, VA. wondered if photosynthetic bacteria might live near hydrothermal vents. This was a striking speculation, considering that such vent systems lie thousands of feet deep in the ocean, well below the depth to which sunlight penetrates. The ecosystems surrounding such vents survive because of bacteria that garner energy from hydrogen sulfide, not from light.
But water emerges from hydrothermal vents at hundreds of degrees, kept from boiling only by the intense pressure. The hot water, and perhaps hot rocks, VanDover ...October 17, 2001 • Posted by: Shige Abe • Report issue
Adapted from an Arizona State University press release
Scientists have conducted an organic analysis of the Tagish Lake meteorite, a rare, carbon-rich meteorite classified as a carbonaceous chondrite. The meteorite fell on a frozen Canadian lake in January 2000, and is the most pristine carbonaceous chondrite specimen ever studied.
The analysis suggests there can be a different outcome for the evolution of organic chemicals in space than from what has been observed in other carbonaceous meteorites. This difference could be due to the possibility that the Tagish Lake meteorite contains carbon molecules that may have accumulated during the formation and ...October 12, 2001 • Posted by: Shige Abe • Report issue
Based on an Science@NASA press release by Doug Hullander and Patrick L. Barry
Everybody knows space is dangerous. Some of the perils are obvious: hard vacuum, extreme cold, and unpredictable blasts of radiation from the Sun.
Other perils are less conspicuous. The effects of prolonged weightlessness on the human body, for example, can be slow and subtle — yet no less dangerous if astronauts fail to take proper precautions.
Weakening of the bones due to the progressive loss of bone mass is a particularly serious effect of extended spaceflight. Studies of cosmonauts and astronauts who spent many months on ...October 10, 2001 • Posted by: Shige Abe • Report issue
We know that there are at least 75 planets outside our own solar system, orbiting their distant stars. The rate of planet discovery has sped up recently, and many more planets will likely be discovered in the weeks and years to come.
And yet, we have never seen any of these planets with our own eyes. Planets do not glow like a star – they only reflect light. That makes them a lot harder to see from far away. Any light reflecting off a planet also tends to be overwhelmed by the brightness of the host star.
So how do ...October 03, 2001 • Posted by: Shige Abe • Report issue