23 Mar, 2014 · Sascha · Wissenschaft · Comments
Diese Woche ging auf dem Blog nicht unbedingt super viel, weshalb ich viele Nachrichten verpennt habe und deshalb hole ich die jetzt hier mal kombiniert nach.
Einer der sympathischsten Aspekte der Wissenschaft war für mich schon immer, dass neue Information schnell vorherige Annahmen alt und lustig aussehen lassen. So erging es jetzt Neil deGrasse Tyson, der letzte Woche noch in seinem Raumschiff in der großartig wieder aufgelegten Cosmos-Serie mit seinem Raumschiff über die Methan-Seen auf dem Mond Titan flog und bemerkte, dass es sehr ruhig ist. Falsch gedacht, man hat nun festgestellt, dass es auch Wellen gibt. Super kleine, aber hey, Ozeanographie ist jetzt außerirdisch. Höchstwahrscheinlich.
“We think we’ve found the first waves outside the Earth,” he told the meeting. “What we’re seeing seems to be consistent with waves at just a few locations in Punga Mare [with a slope] of six degrees.” He said other possibilities, such as a wet mudflat, could not be ruled out. But assuming these were indeed waves, Dr Barnes calculates that a wind speed of around 0.75 m/s is required to produce ripples with the requisite slope of six degrees. That points to the waves being just 2cm high. “Don’t make your surfing vacation reservations for Titan just yet,” Dr Barnes quipped.
BBC: ‘Waves’ detected on Titan moon’s lakes
Die größte Nachricht dieser Woche, wenn nicht sogar seit Ewigkeiten: Die haben Baby-Photos des Universums entdeckt. Uralte Gravitationswellen geben Rückschlüsse auf die Anfänge unseres Univerums und werkeln gerade daran, dass die Big Bang Theorie zum Big Bang Fakt wird. This is heavy, doc.
Gravitational waves are tremors in space-time caused by intense gravitational forces. The Harvard team found evidence for primordial gravitational waves – those set in motion during the first trillionth of a second of the universe. Primordial gravitational waves are seen as the smoking gun for a theory called cosmic inflation. Conceived in its original form more than 30 years ago by Alan Guth at MIT, inflation says that the early universe experienced a terrific burst of expansion. The growth spurt lasted a mere fraction of second, but smoothed out irregularities in space, and made the cosmos look almost the same in every direction.
Guardian: Gravitational waves discovery: ‘We have a first tantalising glimpse of the cosmic birth pangs’
Vulkanische Aktivität auf Venus hat man bis vor Kurzem für erloschen gehalten, nun muss man das aber wohl überdenken, sollten sich neuen Daten als korrekt herausstellen. Das könnte auch noch mehr Aufschlüsse über die toxische Atmosphäre geben.
Scientists discovered four transient bright spots in a relatively young rift zone known as Ganiki Chasma, which was observed 36 times by the spacecraft’s Venus Monitoring Camera. “Venus might have ongoing volcanism,” planetary scientist Alexander Bazilevskiy, with the Max-Planck Institute for Solar System Research in Germany, said at the Lunar and Planetary Science Conference in Houston on Monday. Bazilevskiy and colleagues constructed mosaics from images taken during the orbital passes and computed the relative surface brightness. They found four transient flashes, estimated to be between 980 degrees and 1,520 degrees Fahrenheit – well above the planet’s normal 800 degree Fahrenheit surface temperature.
Space.com: Active Volcanoes Revealed on Venus
Die MESSENGER Sonde der NASA umkreist den kleinsten Planeten unseres Sonnensystems nun seit genau 3 Jahren und kann durch seine langfristige Beobachtung nun erste Ergebissene veröffentlichen.
The first comprehensive survey of the surface of Mercury by NASA’s MESSENGER spacecraft shows that planet’s crust has contracted as it cooled by as much as 4.4 miles (7 kilometers), significantly more than previous estimates. The findings clear up a long-standing clash between scientists’ understanding of the heat production and loss and the contraction of Mercury.
“These new results resolved a decades-long paradox between thermal history models and estimates of Mercury’s contractions,” said study lead author Paul Byrne of the Carnegie Institution for Science in a statement.
Over the billions of years since its formation at the birth of the solar system, the planet has slowly cooled, a process all planets suffer if they lack an internal source of heat renewal. As the liquid iron core solidifies, it cools, and the overall volume of Mercury shrinks.