Scientists analyze possible evidence for evolution of life distinct from LUCA
Step outside and look around you. Chances are, your eye will light upon something made from polymers. Even your own body is composed of polymers – your bones, muscle fibers, your very DNA – polymers all. While polymers can be found everywhere, scientists also have learned to manipulate polymers to create things not found in nature, such as plastic and nylon.
Polymers are composed of molecules called monomers. Monomers are defined by their ability to link up and form chains, lining up like beads on a string to form the polymers.
This is the hidden structure of life on Earth ...April 17, 2002 / Posted by: Shige Abe
It was a particularly clear night atop a Chilean mountain, as University of Arizona astronomers gazed 430 light-years away. What they imaged was a mysteriously hot, infrared glow of stardust. Could it be that in the Southern constellations between Scorpio and Centaurus, what they saw were precursors to Earth-like planets?
At the 199th National Meeting of the American Astronomical Society in Washington, D.C., Michael Meyer of the University of Arizona and his colleagues announced indeed, that in the direction of the constellation Centaurus, the star classified as HD 113766A, is likely hatching planetary embryos. To make matters more intriguing ...April 15, 2002 / Posted by: Shige Abe
The first results from the Mars Odyssey are in, and they reveal that the Southern Hemisphere of the Red Planet has a lot of water ice just below the surface.
“The signal that we’ve been getting – loud and clear – is that there’s a lot of ice on Mars,” says William Boynton of the University of Arizona. Boynton is the Principle Investigator for the Gamma Ray Spectrometer Suite on the Mars Odyssey. “Once we turned on the instrument, some of the signals were much stronger than we expected, and it really just blew us away.” ...March 04, 2002 / Posted by: Shige Abe
With over 70 planets identified around distant stars, astronomers are now looking for ways to classify which ones are most like Earth – that is to say, the ones most likely with biological potential. Some initial qualifications are already known: Earth-like planets are likely relatively small, or under the limit of 12 Jupiter-masses. Larger planets would qualify as more of a companion star capable of burning heavy hydrogen and radiating their own nuclear fusion heat. So key entries, like the following, must be made more specific for each new planet candidate found: what are its size, temperature and reflectance (or albedo ...February 27, 2002 / Posted by: Shige Abe
Molecular detectives have traced human ancestry back to the so-called Mitochondrial Eve, the last female common ancestor. More recent research has posited a Y-chromosome Adam, the last male common ancestor.
Monica Riley, a microbiologist specializing in molecular evolution, is aiming farther back. She and her colleagues at The Marine Biological Laboratory in Woods Hole, Massachusetts, are looking for molecular traces of precursors to the last common ancestor of all modern cells.
Riley seeks to estimate how many proteins, and what kinds of proteins, developed into the set of proteins that the first primitive cell may have used to carry out ...February 25, 2002 / Posted by: Shige Abe
How were body plans able to undergo large-scale changes during the course of evolution? For instance, how did something that looked like a centipede evolve into something as different as a fruit fly? This is a question that has long concerned biologists that study evolutionary history. Genetic mutations that would dramatically alter body structures could potentially kill an organism before it even had a chance to live.
Biologists at the University of California, San Diego, now have genetic evidence that explains how such drastic alterations to body plans were able to occur during the early evolution of animals.
In a ...February 22, 2002 / Posted by: Shige Abe
An adventurous science team recently returned from the deep Norwegian glacial fields, having tested an instrument which may one day be used to explore areas beneath the frozen surfaces of other worlds. As demonstrated by the Jet Propulsion Lab and Caltech, their robotic ice-pick, dubbed Cryobot, sports a heated nose-cone especially designed to melt frozen ground and drill cryogenically. Their most recent depths broke through the equivalent of an ice sheet the size of an eight-story building, or 23 meters (75 feet) into a glacier.
Glacier cutting combines an extreme operating environment with new technology to navigate and image the ...February 20, 2002 / Posted by: Shige Abe
We all know that metals like copper, iron and zinc are needed to maintain human health. Molybdenum is also an essential nutritional requirement, used by several enzymes in the body to help metabolize carbon, nitrogen and sulfur compounds. Most other life forms use molybdenum in similar ways. But a one-celled organism that lives in deep-sea volcanic vents has developed an alternative metabolism that uses tungsten instead of molybdenum.
Called Pyrococcus furiosus, the name means “rushing fireball” and refers to the microorganism’s quick rate of reproduction – P. furiosus can double its numbers in just 37 minutes – and its preferred ...February 15, 2002 / Posted by: Shige Abe
KATHLEEN – Michael, please give me your official title and tell me a little bit about your background and how you got involved with Astrobiology.
MICHAEL – I’m the Astrobiology discipline scientist at Headquarters; I also am the program scientist for the Mars 2001 Odyssey Mission. It’s kind of interesting, actually…I mean, how do you end up working in an area that’s as fun as Astrobiology? I was told that I should be an engineer since I was good at math, so I went to RPI as an engineer.
I just decided one year that I ...February 13, 2002 / Posted by: Shige Abe
It was almost the perfect crime.
Some perpetrator — or perpetrators — committed murder on a scale unequaled in the history of the world. They left few clues to their identity, and they buried all the evidence under layers and layers of earth.
The case has gone unsolved for years — 250 million years, that is.
But now the pieces are starting to come together, thanks to a team of NASA-funded sleuths who have found the “fingerprints” of the villain, or at least of one of the accomplices
The terrible event had been lost in the amnesia of time ...February 12, 2002 / Posted by: Shige Abe
When the crescent moon is just a sliver each month, the phrase—‘old moon in the young moon’s arms’— poetically describes a marvel of nature. This marvel shows the shadow of the Earth reflecting back the largely blue light from the Earth, known as earthshine. As recently presented at the 199th national meeting of the American Astronomical Society in Washington, D.C., astronomers from the University of Arizona Steward Observatory and the Harvard-Smithsonian Center for Astrophysics have benchmarked earthshine. Their findings provide clues as to how best to recognize distant planets that may harbor elements needed for life.
Those elements—mainly, water ...February 06, 2002 / Posted by: Shige Abe
By Astrobiology News staff writer
If the name of each species on Earth were put on a single recipe card, the box containing them all would stretch for over 6 miles. There are approximately 1.4 million species that have been named by researchers, but the true number of species on earth may be anywhere between 5 and 30 million species.
If just keeping those animal names straight wasn’t challenging enough, the shuffling of cards over time has captured the combined interest of a 25 member scientific team, first organized by Dr. Charles Marshall (now at Harvard). In reporting some ...February 01, 2002 / Posted by: Shige Abe
Over the past several years, scientists have discovered life in the most unusual places. From rocky abodes deep underground, to hot volcanic vents under the seas, there seems to be no place on Earth that life doesn’t exist.
All of this life, even the life that lives in total darkness, is dependent on the Sun for energy. Plants and many Bacteria get their energy directly from sunlight, through photosynthesis. Animals and other organisms get their energy indirectly, by feeding on the complex organic molecules of photosynthetic organisms. These sun-produced organics eventually filter down into the Earth’s darkest reaches ...January 30, 2002 / Posted by: Shige Abe
Around 9:48 on the morning of January 18, 2000, a 150-ton space rock plunged into the earth’s atmosphere. As it approached the Canadian remote territories, the meteor traveled at the speed of a fast highway car (67 miles per hour). A scientific consortium of 4 universities and NASA is now trying to uncover the debris and sample the early solar system’s unique chemistry.
Indeed, landing between the Yukon Territory and British Columbia in a remote vacation village, the rock volume started its descent totaling about the size of a small truck. At 5 meters (or 15 feet) across, the ...January 28, 2002 / Posted by: Shige Abe
A discovery by a NASA scientist of sugar and several related organic compounds in two carbonaceous meteorites provides the first evidence that another fundamental building block of life on Earth may have come from outer space. A carbonaceous meteorite contains carbon as one of its important constituents.
Previously, researchers had found in meteorites other organic, carbon-based compounds that play major roles in life on Earth, such as amino acids and carboxylic acids, but no sugars. The new research is reported in a paper, “Carbonaceous Meteorites as a Source of Sugar-related Organic Compounds for the Early Earth,” by Dr. George ...January 25, 2002 / Posted by: Shige Abe
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