"NASA Probe Sees Solar Wind Decline. The 33-year odyssey of NASA's Voyager 1 spacecraft has reached a distant point at the edge of our solar system where there is no outward motion of solar wind."
Friday, December 31, 2010
7 Exoplanets (Amazing video)
"Hundreds of planets around other stars have been discovered recently, but many centuries may pass before human eyes actually see them up close. Interpreting current data, Hugo award-winning artist Ron Miller takes us to seven of the most fascinating of these worlds."
Wonderful!
"And while we are not quite ready for something like Star Trek’s United Federation of Planets, the almost daily discovery of new planets has brought the number of known worlds to well over 450."
"And while we are not quite ready for something like Star Trek’s United Federation of Planets, the almost daily discovery of new planets has brought the number of known worlds to well over 450."
T-Rex bad reputation got worse
It seems that the largest land predators, which ever stalked the earth, were cannibals. As reported among news in Telegraph UK (15 Oct 2010), the reserchers noticed bite marks on the bones of the dinosaurs. Comparing the marks, the scientists realised that a T-Rex was the only animal large enough to have caused them.
T-Rex, Museo Scienze
Thera and the biblical plagues
Thera, a volcano in the Mediterranean sea, produced with its explosion around 3,500 year ago, one of the biggest cataclysms in the human history. The remains of Thera are the Mediterranean islands of Santorini, north of Crete. As we can read from an article of Telegraph, the volcanic ash of eruption could have clashed with thunderstorms above Egypt, producing severe hail storms (one of the biblical plagues).
According to Prof.Trevisanato, a Canadian biologist, another plague, the locusts, could be explained by the volcanic fall out from the ash. The ash fall out caused weather anomalies, which produced higher precipitations and humidity, fostering the presence of the locusts. The volcanic ash could also have caused the plague of darkness. In fact, pumice stones have been found during excavations of Egyptian ruins despite there not being any volcanoes in Egypt.
Very interesting article.
According to Prof.Trevisanato, a Canadian biologist, another plague, the locusts, could be explained by the volcanic fall out from the ash. The ash fall out caused weather anomalies, which produced higher precipitations and humidity, fostering the presence of the locusts. The volcanic ash could also have caused the plague of darkness. In fact, pumice stones have been found during excavations of Egyptian ruins despite there not being any volcanoes in Egypt.
Very interesting article.
Thursday, December 30, 2010
Powering the space missions
Deep-space missions are powered by a RTG system. A radioisotope thermoelectric generator (RTG, RITEG) is a generator that obtains its power from radioactive decay. The heat released by the decay of a radioactive material is converted into electricity by the Seebeck effect using an array of thermocouples (see "how did Georg do it?").
RTGs are systems quite suitable as power sources for satellites and space probes and also for remote facilities where the use of solar cells is not feasible (for instance, lighthouses built by the former Soviet Union inside the Arctic Circle). RTGs are able to give few hundred watts for very long periods. The problem is to guarentee a safe use of radioisotopes.
RTGs are systems quite suitable as power sources for satellites and space probes and also for remote facilities where the use of solar cells is not feasible (for instance, lighthouses built by the former Soviet Union inside the Arctic Circle). RTGs are able to give few hundred watts for very long periods. The problem is to guarentee a safe use of radioisotopes.
Where is Cassini spacecraft?
Cassini–Huygens is a robotic spacecraft currently studying the planet Saturn and its satellites. The launched spacecraft consisted of two elements: the Cassini orbiter, named for the astronomer Giovanni Domenico Cassini, and the Huygens probe, named for the astronomer, mathematician and physicist Christiaan Huygens. Cassini-Huygens was launched on October 15, 1997, and it entered into orbit around Saturn on July 1, 2004. On December 25, 2004, the Huygens probe was separated from the orbiter and reached Saturn's moon Titan on January 14, 2005. It descended into the atmosphere of the moon, sending information back to the Earth. This was the first landing ever accomplished in the outer solar system. The mission will continue until 2017.
On November 2, Cassini was triggered into a standby mode, after a bit flip caused it to miss an important instruction. Cassini was reactivated as scheduled on November 24 and has returned to perfect working order, in time for two scheduled close fly-bys with Enceladus.
http://saturn.jpl.nasa.gov/index.cfm
http://saturn.jpl.nasa.gov/index.cfm
What is powering Cassini?
Bacteria in Titanic rusticles
TITANIC BEING EATEN BY DESTRUCTIVE BACTERIA, by Rossella Lorenzi.
"A new bacterium isolated from the Titanic wreck is accelerating the wreck's disintegration into a pile of dust."
These are bacteria potentially dangerous to underwater metal structures. Shipwrecks disapper but also offshore oil and gas pipelines. The articecle tells that the newly discovered species could also have positive applications for industry for instance in the recycling of iron structures in deep ocean.
"A new bacterium isolated from the Titanic wreck is accelerating the wreck's disintegration into a pile of dust."
These are bacteria potentially dangerous to underwater metal structures. Shipwrecks disapper but also offshore oil and gas pipelines. The articecle tells that the newly discovered species could also have positive applications for industry for instance in the recycling of iron structures in deep ocean.
Striges (Owls)
Strix (pl. striges or strixes) was the Ancient Roman and Greek word for owl. The name is Greek in origin. From it, the name of the genus Strix was derived.
Wednesday, December 29, 2010
Treasure Island
A seafarer...
"This is a handy cove," says he at length; "and a pleasant sittyated grog-shop. Much company, mate?" My father told him no, very little company, the more was the pity.
"Well, then," said he, "this is the berth for me. Here you, matey," he cried to the man who trundled the barrow; "bring up alongside and help up my chest. I'll stay here a bit," he continued. "I'm a plain man; rum and bacon and eggs is what I want, and that head up there for to watch ships off. What you mought call me? You mought call me captain. Oh, I see what you're at-- there"; and he threw down three or four gold pieces on the threshold. "You can tell me when I've worked through that," says he, looking as fierce as a commander.
http://www.online-literature.com/stevenson/treasureisland/1/
Queste sono le parole con cui si presenta il vecchio lupo di mare alla locanda dell'Ammiraglo Benbow.
Isola del Tesoro, R.L. Stevenson
"This is a handy cove," says he at length; "and a pleasant sittyated grog-shop. Much company, mate?" My father told him no, very little company, the more was the pity.
"Well, then," said he, "this is the berth for me. Here you, matey," he cried to the man who trundled the barrow; "bring up alongside and help up my chest. I'll stay here a bit," he continued. "I'm a plain man; rum and bacon and eggs is what I want, and that head up there for to watch ships off. What you mought call me? You mought call me captain. Oh, I see what you're at-- there"; and he threw down three or four gold pieces on the threshold. "You can tell me when I've worked through that," says he, looking as fierce as a commander.
http://www.online-literature.com/stevenson/treasureisland/1/
Queste sono le parole con cui si presenta il vecchio lupo di mare alla locanda dell'Ammiraglo Benbow.
Isola del Tesoro, R.L. Stevenson
Paleolithic Crete
Oustanding!
A research team led by Thomas Strasser and Eleni Panagopoulou announced the discovery of stone tools at two sites on the island of Crete that are between 130,000 and 700,000 years old. The tools resemble those made by Homo heidelbergensis and Homo erectus, showing that our human ancestors boated across at least 40 miles of open sea to reach the island. This is the earliest evidence of seafaring.
http://www.archaeology.org/1101/topten/crete.html
A research team led by Thomas Strasser and Eleni Panagopoulou announced the discovery of stone tools at two sites on the island of Crete that are between 130,000 and 700,000 years old. The tools resemble those made by Homo heidelbergensis and Homo erectus, showing that our human ancestors boated across at least 40 miles of open sea to reach the island. This is the earliest evidence of seafaring.
http://www.archaeology.org/1101/topten/crete.html
Cenabis bene, mi Fabulle, apud me paucis, si tibi di favent, diebus, si tecum attuleris bonam atque magnam cenam, non sine candida puella et vino et sale et omnibus cachinnis.
Haec si, inquam, attuleris, venuste noster, cenabis bene; nam tui Catulli plenus sacculus est aranearum. Sed contra accipies meros amores, seu quid suavius elegantiusve est: nam unguentum dabo, quod meae puellae donarunt Veneres Cupidinesque; quod tu cum olfacies, deos rogabis totum ut te faciant, Fabulle, nasum.
Haec si, inquam, attuleris, venuste noster, cenabis bene; nam tui Catulli plenus sacculus est aranearum. Sed contra accipies meros amores, seu quid suavius elegantiusve est: nam unguentum dabo, quod meae puellae donarunt Veneres Cupidinesque; quod tu cum olfacies, deos rogabis totum ut te faciant, Fabulle, nasum.
Gaius Valerius Catullus
Revisiting the construction of pyramids
"The Kufu pyramid, with a volume of 2,7 millions of meter cubes, was completed over a period of 20 to 30 years. From this one can estimate a daily rhythm of 300 to 400 blocks, each having an average volume of 1 meter cube. This means one block put at the right place every 2 minutes. To achieve this goal, 1 meter square of block face would have to be hewn every 20 seconds! What a performance, with tools made of stone or with soft copper ..." As we can read in the Europhysics News Vol. 40, No. 1, 2009, pp. 27-31, Revisiting the construction of the Egyptian pyramids, Guy Demortier, www.europhysicsnews.org/epn20091p27.pdf ...
"In 1978, the French chemist Joseph Davidovits rejected the generally accepted technique of carving and hoisting stones. He proposed that the building method involved the moulding on site: blocks were made of a kind of concrete whose basic binding compound was natron: a sodium carbonate extracted very close to the site of Giza. The binder was obtained by some chemical reaction leading to a geopolymer (a name given by Davidovits). It is a poly-sialate containing an alkaline nucleus: sodium from natron. Natron, lime and water form caustic soda, which reacts with aluminous limestone to yield the basic geopolymer. X-ray fluorescence and X-ray diffraction have shown that the blocks consist of limestone (85 to 92%) associated with a binder. Additional analyses were performed by PIXE (Particle-Induced X-ray Emission), PIGE (Particle-Induced gamma-ray Emission) and by NMR-Spectroscopy for structural characterization in laboratories of Namur and Lecce. One of the pyramid’s samples appeared to be made of a central compact structure embedded in a material of different composition. The central part is identified as natural limestone but the outer part contains a large amount of F, Na, Mg, Al, Si."
http://en.wikipedia.org/wiki/Joseph_Davidovits
http://www.geopolymer.org/archaeology/pyramids/pyramids-3-the-formula-the-invention-of-stone/2
"In 1978, the French chemist Joseph Davidovits rejected the generally accepted technique of carving and hoisting stones. He proposed that the building method involved the moulding on site: blocks were made of a kind of concrete whose basic binding compound was natron: a sodium carbonate extracted very close to the site of Giza. The binder was obtained by some chemical reaction leading to a geopolymer (a name given by Davidovits). It is a poly-sialate containing an alkaline nucleus: sodium from natron. Natron, lime and water form caustic soda, which reacts with aluminous limestone to yield the basic geopolymer. X-ray fluorescence and X-ray diffraction have shown that the blocks consist of limestone (85 to 92%) associated with a binder. Additional analyses were performed by PIXE (Particle-Induced X-ray Emission), PIGE (Particle-Induced gamma-ray Emission) and by NMR-Spectroscopy for structural characterization in laboratories of Namur and Lecce. One of the pyramid’s samples appeared to be made of a central compact structure embedded in a material of different composition. The central part is identified as natural limestone but the outer part contains a large amount of F, Na, Mg, Al, Si."
http://en.wikipedia.org/wiki/Joseph_Davidovits
http://www.geopolymer.org/archaeology/pyramids/pyramids-3-the-formula-the-invention-of-stone/2
The owls of Harry Potter
Hedwig is the snowy Harry Potter's owl. At the following link, a precious discussion on the owls playing in the books and movies, by Laura L. Erickson, The Owls Of Harry Potter:
http://www.lauraerickson.com/bird/Species/Owls/HarryPotter/HarryPotter.html
http://www.lauraerickson.com/bird/Species/Owls/HarryPotter/HarryPotter.html
Hedwig