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SPACE & SCIENCE NEWS: January 2002
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Five more Martian meteorites found Jan 30, 2002
Mars-like bugs on Earth Jan 18, 2002
Does extreme stellar radiation sterilize or accelerate evolution? Jan 12, 2002
First exoplanet found around a giant star Jan 10, 2002
Out of the shadows: a brown dwarf revealed Jan 9, 2002
Genes and multicellularity: a chicken-and-egg problem Jan 6, 2002


One of the new meteorites from Mars
Five more Martian meteorites found
(Jan. 30, 2002)


Researchers have recovered five meteorites from Antarctica and the deserts of Oman and the Sahara that have been identified as having come from Mars. This boosts the number of known Martian stones to 24. The new additions includes one weighing 13.7 kg, making it the second largest Mars meteorite fragment ever found.

For more, go here.

psychrophile
Mars-like bugs on Earth
(Jan. 18, 2002)


Two different types of microbial colonies found in extreme environments on Earth have boosted hopes of finding similar organisms on Mars. They also provide scientists with a way of developing techniques to search for Martian equivalents. The first consists of microbes (some of which are shown in the photo) discovered in extremely salty soil at depths of up to 8 cm below the surface of the dry valleys of Antarctica. For more on this go here. The second alien environment – 200 m below the surface of the Beaverhead Mountains of Idaho in a region of hot springs – yielded life-forms unlike any previously encountered. These microbes, 90% of which are archeans, use hydrogen gas, released from deep inside the Earth, as an energy source, and give off methane. They are exactly the type of creatures scientists would expect to find underground on Mars. If there are such "methanogens" on the Red Planet they could be detected indirectly by the Beagle 2 probe scheduled for launch next year which is able to sniff out methane in tiny concentrations.

For more on this, go here.

Crab Nebula
Does extreme stellar radiation sterilize or accelerate evolution?
(Jan. 12, 2002)


If a nearby star were to send a powerful burst of X-rays or gamma rays our way, how would life on Earth be affected? How, in general, are the biological prospects for a world influenced by energetic stellar radiation? These questions have been addressed by a team of researchers at the University of Texas at Austin. Many variables are involved, including the type, intensity, and duration of the radiation source, and the amount of protection provided by a planet's atmosphere. The radiation need not be lethal, but may instead induce episodes of intense mutational damage and error-prone repair, leading to evolution along very different lines than that on Earth. Evolution on a planet around a flare star – a red dwarf prone to occasional high-energy outbursts-could actually accelerate the evolution of life.

For more, go here.

Artist impression of planet orbiting Iota Draconis
First exoplanet found around a giant star
(Jan. 10, 2002)


To add to the recent flurry of exoplanet discoveries, astronomers have found the first planet in orbit around a giant star – the 100-light-year distant Iota Draconis, also known as Edasich. Like all giant stars, Iota Dra has exhausted its core supply of hydrogen (i.e. it has left the main sequence). It has expanded to be 13 times bigger than the Sun. In fact, it provides a glimpse of what will happen to the Sun itself in another five billion years or so. Until now, no one knew if planets could survive close by a red giant. The Iota Dra discovery shows that worlds can indeed endure the post-main-sequence evolution of their host star. The new planet completes one orbit every 1.5 years and has a mass 8.7 times the mass of Jupiter. Because the Doppler technique determines only the minimum mass of a companion, it is possible that the true mass of this object is higher and that it may be a brown dwarf. If this is is the case, however, it will still be a breakthrough-the first detection of a brown dwarf around an evolved star.

Brown dwarf around 15 Sge
Out of the shadows: a brown dwarf revealed
(Jan. 9, 2002)


The earliest seafloor hydrothermal vents – supposedly more than three billion years old – may be nothing more than deposits from underground springs active in the last few thousand years. That is the claim of two US geologists who carried out a new analysis of rocks from South Africa which were previously dated to the Archaean period – when life first began to diversify. The findings could have important implications for our understanding of the early Earth and the microbial life forms that lived there. But one authority on the geology of the Barberton greenstone belt – where the rocks are found – launched a vigorous defence of evidence that they contain ancient hydrothermal vents.

Read more. Source: BBC

Salpingoeca-a typical solitary choanoflagellate
Genes and multicellularity: a chicken-and-egg problem
(Jan. 6, 2002)


Sean Carroll, a University of Wisconsin-Madison professor of genetics, and his colleagues believe they have found a clue to the origin of multicellularity-a major landmark on the road to advanced life, including ourselves. In the Dec. 18 Proceedings of the National Academy of Sciences, Carroll et al. report the discovery of a key intercellular-communication gene in modern, single-celled microbes known as choanoflagellates. In other words they have found a set of instructions needed by a multicelled organism in a creature consisting of only a single cell. This supports the long-held suspicion that choanoflagellates living at least 600 million years ago were ancestral to all today's animals (for a primer on choanoflagellates, go here). But it also leads to a tricky chicken-and-egg problem. If this cell-to-cell communication gene is only useful to a multicelled organism, what is it doing in something that's unicellular?

Science is full of chicken-and-egg problems – and they're always the hardest to crack. For example, where did the universe come from? Cosmologists claim that it may have come from a spaceless, timeless nothing. But then, before there's time, how can nothing change into something; doesn't change require time? Closer to home, humans with essentially our mental capacity and capability were alive around 100,000 years ago. They had the dormant mathematical, musical, and other skills, that we employ today. But why would a brain with the potential to solve complex systems of equations and compose symphonies evolve tens of millennia before that potential was needed?

An answer that might work for both the early human brain and the choanoflagellate gene set is that nature is parsimonious. That is, if it's already evolved something that works for one task it will adapt it for use for another rather than developing something new from scratch. In particular, biologists have come to appreciate that nature is thrifty in its use of genes. Instead of inventing new genes to accomplish new tasks, animals tend to redeploy existing genes, inherited from more primitive ancestors, in new ways. Having said this, it isn't clear what a choanoflagellate would use a cell communication gene for. An alternative, and highly speculative idea, is that the appearance of genes ahead of their time, as it were, argues for panspermia, and specifically the introduction of ready-made genes into the terrestrial gene-pool from an extraterrestrial source. Intriguing, but far from the scientific mainstream (see this well-organized website for more on this notion.)

All we can be reasonably sure of at this stage is summed up by Carroll: "We're starting to get a glimpse of the genetic tool kit we have in common. In choanoflagellates, we've found genes that heretofore were believed to exist only in animals. It's a confirmation of the idea that the genes come first, before their exploitation by organisms."

For more on this work, go here (University of Wisconsin).

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