Category: Science

  • Astronomy Picture of the Day | Hubble Remix: Active Galaxy NGC 1275

    Hubble Remix: Active Galaxy NGC 1275
    Credit: DataHubble Legacy Archive, ESA, NASA

    Explanation: Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. Wild-looking at visible wavelengths, the active galaxy is also a prodigious source of x-rays and radio emission. NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy’s core. This color composite image, recreated from archival Hubble Space Telescope data, highlights the resulting galactic debris and filaments of glowing gas, some up to 20,000 light-years long. The filaments persist in NGC 1275, even though the turmoil of galactic collisions should destroy them. What keeps the filaments together? Observations indicate that the structures, pushed out from the galaxy’s center by the black hole’s activity, are held together by magnetic fields. Also known as Perseus A, NGC 1275 spans over 100,000 light years and lies about 230 million light years away.

  • Astronomy Picture of the Day | The Dark Tower in Scorpius

    Image Credit & Copyright: Thomas V. Davis

    This object is an obscure cometary globule in Scorpius. I think the name came from John Gleason who imaged it in h-alpha. Actually only a few images of it exist, all I believe taken in h-alpha except for David Malin’s color film version. Its a cool target and seems to be the southern hemisphere’s equivalent to Vdb 142 (IC1396A). I hope you enjoy it.

    Bright rimmed globules and their more evolved cousin the cometary globule represent fascinating dynamic structures formed by the interplay of cold molecular clouds and hot ionizing stars. Typically the head of the globule faces a hot O-type star. Intense radiation from the star boils away lower density gas from the head. The evaporated rim of gas becomes ionized by the stars ultraviolet flux forming a bright glowing rim we associate with many of these globules including CG4. Intense stellar winds from the ionizing star evaporate gas and dust away from the head forming the “tail” and completing the cometary shape. The globules are known to be the birthplace of low mass stars. Stars form within the globules by the mechanism known as “radiation driven implosion”. This process occurs when ultraviolet flux from a hot star compresses surviving clumps of cold molecular gas eventually causing collapse and core formation within the dense compact clouds. Lower and intermediate mass stars ultimately form from the compact gas and dust within the globules.

    In silhouette against a crowded star field toward the constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across the gorgeous telescopic view. Known as a cometary globule, the swept-back cloud, extending from the lower left to the head (top of the tower) right and above center, is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231, off the right edge of the scene. That energetic ultraviolet light also powers the globule’s bordering reddish glow of hydrogen gas. Hot stars embedded in the dust can be seen as bluish reflection nebulae. This dark tower, NGC 6231, and associated nebulae are about 5,000 light-years away.

  • Dr Craig Venter Announces First Synthetic Living Cell. Never did god look smaller and pettier.

    Can we say that we’re just a step away from disproving the existence of god? 

    The least we can say is that god and religion are getting smaller and pettier by the minute.

    [youtube=http://www.youtube.com/watch?v=eoqBSNmYJYI&hl=en_US&fs=1&rel=0&color1=0x006699&color2=0x54abd6&border=1]

    Dr Craig Venter, of the J Craig Venter Institute, explained how they created what he described as “the first species…. to have its parents be a computer”.

     

     

    Figure 1

    Man-made DNA has booted up a cell for the first time.

    In a feat that is the culmination of two and a half years of tests and adjustments, researchers at the J. Craig Venter Institute inserted artificial genetic material — chemically printed, synthesized and assembled — into cells that were then able to grow naturally.

    “We all had a very good feeling that it was going to work this time,” said Venter Institute synthetic biologist Daniel Gibson, co-author of the study published May 20 in Science. “But we were cautiously optimistic because we had so many letdowns following the previous experiments.”

    On a Friday in March, scientists inserted over 1 million base pairs of synthetic DNA into Mycoplasma capricolum cells before leaving for the weekend. When they returned on Monday, their cells had bloomed into colonies.

     

    “When we look at life forms, we see fixed entities,” said J. Craig Venter, president of the Institute, in a recent podcast. “But this shows in fact how dynamic they are. They change from second to second. And that life is basically the result of an information process. Our genetic code is our software.”

    Coaxing the software to power a cell proved harder than expected.

    Figure 5 [Converted]

    After the Venter Institute announced in early 2008 that it had assembled a synthetic Mycoplasma genitalium genome, the assumption was that it would be running cells in no time. But this particular cell type, despite its minimal size, was not an ideal research partner. One problem was speed.

    “We had to deal with the fact that M. genitalium had an extremely slow growth rate,” Gibson said. “For every experiment that was done, it took more than a month to get results.”

    Moreover, transplanting the code into recipient cells was failing. So researchers cut their losses and called in a substitute, opting for the larger, speedier and less finicky Mycoplasma mycoides. The choice was a good one.

    “Over the last five years the field has seen a 100-fold increase in the length of genetic material wholly constructed from raw chemicals,” said synthetic biologist Drew Endy of Stanford University. “This is over six doublings in the max length of a genome that can be constructed.”

    Plunging costs of synthesis allowed a leap past the 1 million base-pair mark, from code to assembly. “Imagine doubling the diameter of a silicon wafer that can be manufactured that much, going from 1 cm to 1 meter [fabrications] in just five years,” Endy said. “That would have been an incredible achievement.”

    “They rebuilt a natural sequence and they put in some poetry,” said University of California at San Francisco synthetic biologist Chris Voigt. “They recreated some quotes in the genome sequence as watermarks.”

    It’s an impressive trick, no doubt, but replicating a natural genome with a little panache is also the limit of our present design capabilities.

    Researchers, for instance, figure yeast can handle the assembly of 2 million base pairs, but they’re not sure about more. And an energy-producing cyanobacteria that sequesters carbon, Gibson says, is still several years off.

    The ultimate goal, of course, is a brand-new genome from the ground up. Now, Voigt said, “what do you do with all that design capacity?”

    Images: 1) Schematic demonstrating the assembly of a synthetic M. mycoides genome in yeast./Science/AAAS. 2) Images of the phenotype of the JCVI-syn1.0 and WT strains./Science/AAAS.

    Posted via web from Monicks: Unleashed