the explorers journal the global adventure issue - The Explorers Club

fields and rugged icepackin uncharted territory. Forinformation, visit: www.beyondshackleton.com.Brightest SupernovaEver Spottedis one coming to a galaxy near you?The brightest stellar explosionever recorded may be a longsoughttype of supernova,according to observationsby NASA’s Earth-orbitingChandra X-ray Observatoryand ground-based opticaltelescopes in Hawaii. Thisdiscovery indicates that violentexplosions of extremelymassive stars were relativelycommon in the early universe,and that a similar explosionmay be ready to go off in ourown galaxy.“This was a truly monstrousexplosion, a hundred timesmore energetic than a typicalsupernova,” said NathanSmith of the University ofCalifornia at Berkeley, who leda team of astronomers fromCalifornia and the Universityof Texas in Austin.First detected in September2006, the SN 2006gy explosionoccurred in a galaxyknown as NGC 1260, some240 million light-years away.It brightened over the course10EXPLORATION NEWSof 70 days, and at its peakemitted more than 150-billion-Sun’s worth of light.Scientists estimate thatamong the 400 billion starsin the Milky Way, there areonly a dozen or so as massiveas SN 2006gy. The star thatproduced SN 2006gy apparentlyexpelled a large amountof mass prior to exploding.This large mass loss issimilar to that seen from EtaCarinae, a massive star 7,500light-years away in our owngalaxy, raising suspicion thatit may be poised to explodeas a supernova. An unstablestar, Eta Carinae is currentlyradiating about five milliontimes more energy than ourSun and is undergoing eruptionson its surface that aresimilar to what scientiststhink happened on the starthat produced SN 2006gyjust before it blew.“Eta Carinae’s explosioncould be the best star-showin the history of modern civilization,”said Mario Livio of theSpace Telescope ScienceInstitute in Baltimore,” notingthat despite its relativelyclose proximity to us, EtaCarinae’s death is not likelyto pose any significant threatto life on Earth.Scientists believe thatafter the violent collapse ofstars such as SN 2006gy,runaway thermonuclear reactionsensue and the explodingstars spew their remains intospace rather than completelycollapsing to a black hole astheorized. “In terms of theeffect on the early universe,there’s a huge difference betweenthese two scenarios,”said Smith. “One pollutesthe galaxy with large quantitiesof newly made elementsand the other locks themup forever in a black hole.”Information and images of thesupernova are available at:http://chandra.nasa.govSo What’s in a Comet?not the kitchen sinkThe heart of comet Tempel-1,which spurted out some ofits contents during the DeepImpact spacecraft encounterin July 2005, contains amixture of materials usuallyfound in very different environments,scientists report.Carey M. Lisse of JohnsHopkins University AppliedPhysics Laboratory in Laurel,MD, and colleagues tracedthe mineral compositionof the ejecta from infraredspectra taken with theSpitzer Space Telescope.The mixture included highlyvolatile organic ices, clays,and carbonates formed inenvironments with waterpresent, and highly crystallinesilicates formed at temperaturesexceeding 1,000degrees Kelvin. “Some typeof global mechanism formixing these materials musthave been available duringthe solar system’s earliestdays,” says Lisse.