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Stem cells turn into seek-and-destroy cancer missiles
SIMON FRASER/SCIENCE PHOTO LIBRARY
THIS WEEK
Stem cells to seek and destroy cancer Linda Geddes
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Bubble trouble at the centre of the galaxy IS THE Milky Way blowing giant bubbles? A pair of gamma ray bubbles, shaped like an hourglass, seem to be spewing from the black hole we think lies at the centre of our galaxy. That is according to the latest maps from the Fermi Gamma-ray Space Telescope. Its large area telescope has been scanning the whole sky every three hours since June 2008. 12 | NewScientist | 5 June 2010
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The source of the bubbles is a mystery but it seems unlikely that dark matter is responsible. This was what Douglas Finkbeiner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, first suspected when he looked at the maps with his colleagues last year (arxiv.org/ abs/0910.4583&. But a new analysis with more Fermi data suggests that the gamma radiation traces out a pair of distinct bubbles that span some 65,000 light years from end to end – towering above the 2000-light-year-thick disc of the galaxy. Such a well-defined
–Target acquired–
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shape is inconsistent with dark matter, which you would expect to be smoothly distributed and produce a diffuse glow, from gamma rays produced as dark matter particles meet and annihilate each other. “We are pretty sure the majority of emissions are not from dark matter,” says Finkbeiner’s student Meng Su. Instead, they think the bubbles may have been blown out by the explosion of short-lived, massive
stars born in a burst of new star formation about 10 million years ago. Alternatively, the bubbles may have been forged 100,000 years ago by high-speed jets of matter created when roughly 100 suns’ worth of material fell into the black hole at the centre of our galaxy. The team presented its analysis last week at the American Astronomical Society meeting in Miami, Florida. Fermi team members have also found more gamma radiation than expected in the region but say it’s too soon to tell whether it forms an hourglass shape or what its source may be. Rachel Courtland N
“The bubbles may have formed when 100 suns’ worth of stuff fell into our galaxy’s giant black hole”
THIS WEEK
Stem cells to seek and destroy cancer Linda Geddes
DBKBQF@>IIVjlafcfbapqbj`biip ^obql_bfkgb`qbafkqlqeb_o^fkp lc`^k`bom^qfbkqp)tebobqebvtfii `lksboq^kfk^`qfsb`^k`boaord fkql^mlqbkq^kaq^odbqba qrjlro*hfiifkd^dbkq+ Pqbj`biip^obpqolkdiv^qqo^`qba qlt^oap`^k`bo`biip)plfqfpelmba qe^q^ptbii^peljfkdfklkqeb j^fkqrjlro)qebvtfii^ipl_b ao^tkqlpb`lka^ovdoltqep)lo jbq^pq^pbp+Qefptfiibk^_ib efdeboalpbplcaordql_b abifsbobaql`^k`bo`biiptefib jfkfjfpfkdqebofphlcpfabbccb`qp fkqebobpqlcqeb_lav+ >qb^jiba_vH^obk>_llav^q qeb@fqvlcElmb?b`hj^kObpb^o`e FkpqfqrqbfkAr^oqb)@^ifclokf^)rpba kbro^ipqbj`biiplofdfk^iivabofsba coljerj^kcbqrpbptef`ee^a _bbkdbkbqf`^iivbkdfkbbobaql molar`b`vqlpfkbab^jfk^pb+Qefp fp^kbkwvjbqe^q`lksboqp^aord `^iiba2*cirlol`vqlpfkb%2*C@&fkql ^k^`qfsb`ebjlqebo^mvaord) 2*cirlolro^`fi%2*CR&)_rqlkiv fkqebfjjbaf^qbsf`fkfqvlc qebpqbj`bii+ Qebqb^jqebkfkgb`qbaqeb jlafcfbapqbj`biipfkqlqeb_o^fkp
Bubble trouble at the centre of the galaxy IS THE Milky Way blowing giant bubbles? A pair of gamma ray bubbles, shaped like an hourglass, seem to be spewing from the black hole we think lies at the centre of our galaxy. That is according to the latest maps from the Fermi Gamma-ray Space Telescope. Its large area telescope has been scanning the whole sky every three hours since June 2008. 12 | NewScientist | 5 June 2010
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The source of the bubbles is a mystery but it seems unlikely that dark matter is responsible. This was what Douglas Finkbeiner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, first suspected when he looked at the maps with his colleagues last year (arxiv.org/ abs/0910.4583&. But a new analysis with more Fermi data suggests that the gamma radiation traces out a pair of distinct bubbles that span some 65,000 light years from end to end – towering above the 2000-light-year-thick disc of the galaxy. Such a well-defined
–Target acquired–
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shape is inconsistent with dark matter, which you would expect to be smoothly distributed and produce a diffuse glow, from gamma rays produced as dark matter particles meet and annihilate each other. “We are pretty sure the majority of emissions are not from dark matter,” says Finkbeiner’s student Meng Su. Instead, they think the bubbles may have been blown out by the explosion of short-lived, massive
stars born in a burst of new star formation about 10 million years ago. Alternatively, the bubbles may have been forged 100,000 years ago by high-speed jets of matter created when roughly 100 suns’ worth of material fell into the black hole at the centre of our galaxy. The team presented its analysis last week at the American Astronomical Society meeting in Miami, Florida. Fermi team members have also found more gamma radiation than expected in the region but say it’s too soon to tell whether it forms an hourglass shape or what its source may be. Rachel Courtland N
“The bubbles may have formed when 100 suns’ worth of stuff fell into our galaxy’s giant black hole”