| |
| Risultati della ricerca nelle immagini - "Telescopes" |
034-Methane_of_Mars.jpgMap of the "Martian Methane"73 visiteCaption NASA:"Why is there Methane on Mars? No one is sure.
An important confirmation that Methane exists in the Atmosphere of Mars occurred last week, bolstering previous controversial claims made as early as 2003. The confirmation was made spectroscopically using large ground-based telescopes by finding precise colors absorbed on Mars that match those absorbed by Methane on Earth.
Given that Methane is destroyed in the open martian air in a matter of years, the present existence of the fragile gas indicates that it is currently being released, somehow, from the Surface of Mars.
One prospect is that microbes living underground are creating it, or created in the past. If true, this opens the exciting possibility that life might be present under the Surface of Mars even today. Given the present data, however, it is also possible that a purely geologic process, potentially involving volcanism or rust and not involving any life forms, is the Methane creator.
Pictured above is an image of Mars superposed with a map of the recent Methane detection".
Nota Lunexit: se la Mappa NASA è realmente accurata ed il quantitativo di Metano presente in Atmosfera è quello "suggerito" dalla Mappa stessa, allora - sempre seguendo la "Logica NASA" - ci troveremmo davanti a due possibili scenari:
1) Scenario Geologico (Metano come prodotto di processi geologici): Marte è ancora soggetto attivo di fenomeni vulcanici tutt'altro che minori e residuali, visti i quantitativi e la distribuzione del Metano nell'Atmosfera del Pianeta Rosso, oppure
2) Scenario Biologico (Metano come sottoprodotto di attività biologiche attuali): Marte è, letteralmente, "brulicante di Vita" - altro che batteri e micro-organismi - visti, come sopra, i quantitativi e la distribuzione del Metano nell'Atmosfera del Pianeta Rosso.
SOTTOLINEIAMO che queste nostre congetture DERIVANO LOGICAMENTE DALL'ANALISI DEI DATI NASA e NON da nostre speculazioni!
Vi suggeriamo, inoltre, di notare la posizione dei maggiori quantitativi di Metano nell'Atmosfera Marziana...MareKromium
|
|
11-Rima Hadley.jpgRima Hadley100 visiteCaption ESA originale:"Hadley Rille is the sinuous depression running across this image.
Beneath it are the 1 to 2 Km high Apennine mountains.
The large crater in the center of the image is the 30 Km diameter "Hadley C".
Location: The feature is centred at: 25,0° N and 3,0° E
Naming: In honour of the English scientist John Hadley who built telescopes in the eighteenth century".
|
|
33-SulpiciusGallus.jpgSulpicius Gallus' Region67 visiteThis mosaic of three images, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA's SMART-1 spacecraft, shows the area close to the Sulpicius Gallus crater on the Moon.
AMIE obtained this sequence on 18 March 2006, from a distance of 1200 kilometres from the surface, with a ground resolution ranging from 110 to 114 metres per pixel.
The area shown in the top image is centred at a latitude of 19.7º North and longitude 12.2º East; the image in the middle is centred at a latitude of 18.2º North and longitude 12.3º East; the bottom image is centred at a latitude of 16.7º North and longitude 12.5º East.
The prominent crater on the upper left area of this mosaic is called Sulpicius Gallus. It is a fairly fresh, bowl-shaped crater with a diameter of roughly 12 kilometres. The flat lava plains surrounding it belong to the Mare Serenitatis (the 'Sea of Serenity') on the north-eastern side of the Moon facing Earth. The mountains going diagonally through the middle part of the mosaic are called Montes Haemus. They are denoting the edge of the huge impact crater which formed the Mare Serenitatis.
The area around Sulpicius Crater is very interesting for lunar scientists – it is one of the most geologically and compositionally complex areas of the nearside of the Moon. The geologic history of this region has been shaped by impacts of different scales and epochs, by volcanism of variable style and composition with time, and by limited tectonics. Specific findings (Bell and Hawke, 1995) include the detection of relatively fresh highlands materials in the crater.
Good spectroscopic data (that is relative to the mineralogical composition) are available both from the Clementine mission and from ground-based observations, allowing to better constrain the geological evolution of our closest cosmic neighbour.
The area has been suggested to contain mixtures of glassy and black beads generated when large impacts melted part of the lunar surface. However, modelling the spectral properties of material similar to lunar material does not allow to unambiguously match the composition of the material to the measured data.
Colour observations of the AMIE camera will help in further clarifying these issues. So, the combination of high spatial resolution imaging and high spectral resolution spectroscopy from datasets from SMART-1, Clementine and ground based telescopes will finally allow to better model mineral mixtures on the Moon.
The crater Sulpicius Gallus is named after a Roman general, state man and orator. He is famous for having predicted an eclipse of the moon on the night before the battle of Pydna (168 BC). A man of great learning, in his later years he devoted himself to the study of astronomy.
|
|
36-Shackleton_Crater-AMI_EAE3_001775_00002_00020.jpgSchakleton Crater in natural colors56 visiteThe Advanced Moon Imaging Experiment Camera (AMIE) obtained this image on 13 January 2006 - close to the time of Lunar Southern Summer - from a distance of about 646 Km over the surface and with a ground resolution of 60 mt per pixel.
Shackleton crater lies at the Lunar South Pole (89,54° S. Lat. and 0° East Lng.) and has a diameter of approx. 19 Km.
SMART-1 monitored this area almost every orbit. This will allow to produce very high resolution maps of the area as well as illumination maps. The long shadows that surround the crater make it very hard to observe. The analysis of the data obtained allowed a very detailed map of its rim, surrounding ejectas and craters.
SMART-1 also made long repeated exposures to see inside the shadowed areas. The purpose was detecting the very weak reflected light from the crater rims, and therefore study the surface reflection properties (albedo) and its spectral variations (mineralogical composition). These properties could reveal patchy ice surface layers inside the crater.
On the 2-kilometre wide inner edge of the crater ridge, at times barely visible from Earth, astronomers using ground radio-telescopes have recently reported they were not able to detect a distinctive signature of thick deposits of ice in the area. Earlier measurements by NASA's Lunar Prospector reported of hydrogen enhancement over large shadowed areas.
"We still do not know if this hydrogen is due to enhanced trapping of solar wind, or to the water ice brought on the Moon by the bombardment of comets and asteroids," says Bernard Foing, ESA's SMART-1 Project Scientist. "These bodies may have deposited on the Moon patchy layers of ice filling about 1.5 percent of the areas in permanent shadow, down to one metre below the surface."
"We need to analyse all remote sensing data sets consistently. Future lander and rover missions to the Moon will help in the search and characterisation of lunar polar ice, both on the surface and below the subsurface," Foing continues. "In any case, one day we may even be able to simply combine the implanted hydrogen and the oxygen extracted from lunar rocks to produce clean water, like we do in laboratory experiments on Earth.”
The crater is named after Ernest Shackleton (1874-1922), an explorer famous for his Antartic expeditions.
MareKromium
|
|
AA-Neptune-HST-PIA01542.jpgThe weather on Neptune - HST54 visite Caption NASA originale:"Using powerful ground and space-based telescopes, scientists have obtained a moving look at some of the wildest, weirdest weather in the Solar System. Combining simultaneous observations of Neptune made by HST and NASA's Infrared Telescope Facility on Mauna Kea, a team of scientists led by Lawrence A. Sromovsky (University of Wisconsin-Madison) has captured the most insightful images to date of a planet whose blustery weather - monster storms and equatorial winds of 900MPH! - bewilders scientists. Blending a series of HST images, Sromovsky's team constructed a time-lapse rotation movie of Neptune, permitting scientists to watch the ebb and flow of the distant planet's weather. And while the observations are helping scientists tease out clues to the planet's stormy weather, they also are deepening some of Neptune's mysteries. The weather on Neptune, is an enygma: the mechanism that drives its near-supersonic winds and giant storms has yet to be discerned! On Earth, weather is driven by energy from the sun as it heats the atmosphere and oceans. On Neptune, the sun is 900 times dimmer and scientists have yet to understand how Neptune's weather-generating machinery can be so efficient".
|
|
B-Caron.jpgThe Discovey of Charon54 visiteCharon was discovered in June 1978 by U.S. Naval Observatory astronomers James Christy and Robert Harrington. They weren't even looking for satellites of Pluto - they were trying to refine Pluto's orbit around the Sun!
Charon was discovered when sharp-eyed Christy noticed the images of Pluto were strangely elongated - it looked like Pluto had an irregular blob attached to its side. Perhaps the telescope was joggled when the picture was taken? No, that possibility was quickly eliminated by noticing that the other stars on the photo were round. Moreover, the blob itself seemed to move around Pluto - the direction of elongation cycled back and forth over 6.39 days - Pluto's rotation period. From this, Christy, after being checked by Harrington, concluded that Pluto either possessed a mountain thousands of kilometers high or a satellite that orbited in its synchronous orbit.
Searching through their archives of Pluto images taken years before, Christy found more cases where Pluto appeared strangely elongated. Working independently, Christy measured the angle (from north) where the elongations appeared while Harrington calculated what the answer "should be" if the elongation was caused by an orbiting satellite. When the anxious moment came for them to compare their answers, they found perfect agreement. Just to be sure, they waited for the U. S. Naval Observatory 60-inch telescope to make one more confirmation. And sure enough, on July 2 new images showed the elongation due to a satellite right where it was supposed to be. They announced their discovery to the world on July 7, 1978. Christy proposed the name "Charon", after the mythological ferryman who carried souls across the river Acheron, one of the five mythical rivers that surrounded Pluto's underworld. Apart from the mythological connection for this name, Christy chose it because the first four letters also matched the name of his wife, Charlene.
Charon's satellite status was finally confirmed when Pluto and Charon began a series of mutual eclipses in 1985. Later, Hubble Space Telescope and even advanced ground-based telescopes were able to spot Charon orbiting nearby — just 1/4000th of a degree from Pluto!MareKromium
|
|
BHR71-PIA09338.jpgProtostellar Jet in BHR 71 Dark Cloud53 visiteTwo rambunctious young stars are destroying their natal dust cloud with powerful jets of radiation, in an infrared image from NASA's Spitzer Space Telescope.
The stars are located approximately 600 light-years away in a cosmic cloud called BHR 71. In visible light (left panel), BHR 71 is just a large black structure. The burst of yellow light toward the bottom of the cloud is the only indication that stars might be forming inside. In infrared light (center panel), the baby stars are shown as the bright yellow smudges toward the center. Both of these yellow spots have wisps of green shooting out of them. The green wisps reveal the beginning of a jet. Like a rainbow, the jet begins as green, then transitions to orange, and red toward the end. The combined visible-light and infrared composite (right panel) shows that a young star's powerful jet is responsible for the rupture at the bottom of the dense cloud in the visible-light image. Astronomers know this because burst of light in the visible-light image overlaps exactly with a jet spouting-out of the left star, in the infrared image.
The jets' changing colors reveal a cooling effect, and may suggest that the young stars are spouting out radiation in regular bursts. The green tints at the beginning of the jet reveal really hot hydrogen gas, the orange shows warm gas, and the reddish wisps at the end represent the coolest gas. The fact that gas toward the beginning of the jet is hotter than gas near the middle suggests that the stars must give off regular bursts of energy -- and the material closest to the star is being heated by shockwaves from a recent stellar outburst. Meanwhile, the tints of orange reveal gas that is currently being heated by shockwaves from a previous stellar outburst. By the time these shockwaves reach the end of the jet, they have slowed down so significantly that the gas is only heated a little, and looks red. The combination of views also brings out some striking details that evaded visible-light detection. For example, the yellow dots scattered throughout the image are actually young stars forming inside BHR 71. Spitzer also uncovered another young star with jets, located to the right of the powerful jet seen in the visible-light image. Spitzer can see details that visible-light telescopes don't, because its infrared instruments are sensitive to "heat."
The infrared image is made up of data from Spitzer's infrared array camera. Blue shows infrared light at 3.6 microns, green is light at 4.5 microns, and red is light at 8.0 microns.
MareKromium
|
|
Big_Dipper-1.jpgThe "Big Dipper"...again!54 visiteCaption NASA:"Why would the dome of a telescopic observatory appear translucent red? As one of the telescopes of the Etscorn Observatory of New Mexico Tech waited to inspect small portions of the night sky, playful observers decided to make this unusual image. Tricks needed to create this seemingly impossible shot included opening the observatory dome slightly, using a red light to illuminate the inside of the dome, spinning the dome, and using a long exposure. The open slit in the dome then allowed the camera to incrementally image the inside of the observatory, including the telescope. A fortuitous break in the clouds allowed the stars of the Big Dipper asterism to shine through". MareKromium
|
|
Cassiopeia_A-PIA11748.jpgSNR Cassiopeia "A"53 visiteFor the first time, a multiwavelength three-dimensional reconstruction of a SuperNova Remnant has been created. This stunning visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several telescopes: X-ray data from NASA's Chandra X-ray Observatory, InfraRed data from NASA's Spitzer Space Telescope and optical data from the National Optical Astronomy Observatory 4-meter telescope at Kitt Peak, Ariz., and the Michigan-Dartmouth-MIT 2.4-meter telescope, also at Kitt Peak. In this visualization, the green region is mostly Iron observed in X-rays. The yellow region is a combination of Argon and Silicon seen in X-rays, optical, and infrared — including jets of Silicon — plus outer debris seen in the optical. The red region is cold debris seen in the infrared. Finally, the blue reveals the outer blast wave, most prominently detected in X-rays.
Most of the material shown in this visualization is debris from the explosion that has been heated by a shock moving inwards. The red material interior to the yellow/orange ring has not yet encountered the inward moving shock and so has not yet been heated. These unshocked debris were known to exist because they absorb background radio light, but they were only recently discovered in infrared emission with Spitzer. The blue region is composed of gas surrounding the explosion that was heated when it was struck by the outgoing blast wave, as clearly seen in Chandra images.
To create this visualization, scientists took advantage of both a previously known phenomenon — the Doppler effect — and a new technology that bridges astronomy and medicine. When elements created inside a supernova, such as Iron, Silicon and Argon, are heated they emit light at certain wavelengths. Material moving towards the observer will have shorter wavelengths and material moving away will have longer wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction.
Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer — modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. — was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.
The blue filaments defining the blast wave were not mapped using the Doppler Effect because they emit a different kind of light —synchrotron radiation — that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.
This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star.
The flattened component — that astronomers were unable to map into 3-D prior to these Spitzer observations — consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as Oxygen, Neon, Silicon, Sulphur, Argon and Iron.
High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of Silicon appear in the North/East and South/West, while those of Iron are seen in the South/East and North. These jets were already known and Doppler velocity measurements have been made for these structures, but their orientation and position with respect to the rest of the debris field had never been mapped before now.
This new insight into the structure of Cas A gained from this 3-D visualization is important for astronomers who build models of supernova explosions. Now, they must consider that the outer layers of the star come off spherically, but the inner layers come out more disk-like with high-velocity jets in multiple directions.MareKromium
|
|
Cepheid-HST-2009-08-a-print.jpgRefined Hubble Constant narrows possible explanations for Dark Energy54 visiteWhatever Dark Energy is, explanations for it have less wiggle room following a Hubble Space Telescope observation that has refined the measurement of the Universe's present Expansion Rate to a precision where the error is smaller than 5%. The new value for the Expansion Rate, known as the "Hubble Constant", or "H0" (after Edwin Hubble who first measured the expansion of the universe nearly a century ago), is 74,2 Km-per-second-per-megaparsec (with an error margin of ± 3,6).
The results agree closely with an earlier measurement gleaned from Hubble of 72 ± 8 km/sec/megaparsec, but are now more than twice as precise.
The Hubble measurement, conducted by the SHOES (Supernova H0 for the Equation of State) Team and led by Adam Riess, of the Space Telescope Science Institute and the Johns Hopkins University, uses a number of refinements to streamline and strengthen the construction of a cosmic "Distance Ladder", a Billion LY in length, that astronomers use to determine the Universe's Expansion Rate.
Hubble observations of pulsating stars called "Cepheid Variables" in a nearby cosmic mile marker, the galaxy NGC 4258, and in the host galaxies of recent supernovae, directly link these distance indicators. The use of Hubble to bridge these rungs in the ladder eliminated the systematic errors that are almost unavoidably introduced by comparing measurements from different telescopes.
Riess explains the new technique: "It's like measuring a building with a long tape measure instead of moving a yard stick end over end. You avoid compounding the little errors you make every time you move the yardstick. The higher the building, the greater the error".
Lucas Macri, professor of physics and astronomy at Texas A&M, and a significant contributor to the results, said, "Cepheids are the backbone of the distance ladder because their pulsation periods, which are easily observed, correlate directly with their luminosities. Another refinement of our ladder is the fact that we have observed the Cepheids in the Near-InfraRed parts of the electromagnetic spectrum where these variable stars are better distance indicators than at optical wavelengths."
This new, more precise value of the Hubble Constant was used to test and constrain the properties of Dark Energy, the form of energy that produces a repulsive force in space, which is causing the expansion rate of the Universe to accelerate.
By bracketing the expansion history of the universe between today and when the universe was only approx. 380.000 years old, the astronomers were able to place limits on the nature of the Dark Energy that is causing the expansion to speed up.
(The measurement for the far, early universe is derived from fluctuations in the Cosmic Microwave Background (---> Radiazione di Fondo), as resolved by NASA's Wilkinson Microwave Anisotropy Probe, WMAP, in 2003.)
Their result is consistent with the simplest interpretation of Dark Energy: that it is mathematically equivalent to Albert Einstein's hypothesized Cosmological Constant, introduced a century ago to push on the fabric of space and prevent the Universe from collapsing under the pull of gravity. (Einstein, however, removed the Constant once the expansion of the universe was discovered by Edwin Hubble.)
"If you put in a box all the ways that Dark Energy might differ from the Cosmological Constant, that box would now be 3 times smaller", says Riess. "That's progress, but we still have a long way to go to pin down the nature of Dark Energy".
Though the cosmological constant was conceived of long ago, observational evidence for Dark Energy didn't come along until 11 years ago, when two studies, one led by Riess and Brian Schmidt of Mount Stromlo Observatory, and the other by Saul Perlmutter of Lawrence Berkeley National Laboratory, discovered Dark Energy independently, in part with Hubble observations. Since then astronomers have been pursuing observations to better characterize Dark Energy.
Riess's approach to narrowing alternative explanations for Dark Energy — whether it is a static Cosmological Constant or a dynamical field (like the repulsive force that drove inflation after the Big Bang) — is to further refine measurements of the Universe's expansion history.
Before Hubble was launched in 1990, the estimates of the Hubble Constant varied by a factor of two. In the late 1990s the Hubble Space Telescope Key Project on the Extragalactic Distance Scale refined the value of the Hubble constant to an error of only about 10%. This was accomplished by observing Cepheid variables at optical wavelengths out to greater distances than obtained previously and comparing those to similar measurements from ground-based telescopes.
The SHOES team used Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Advanced Camera for Surveys (ACS) to observe 240 Cepheid variable stars across 7 galaxies. One of these galaxies was NGC 4258, whose distance was very accurately determined through observations with radio telescopes. The other 6 galaxies recently hosted Type Ia Supernovae that are reliable distance indicators for even farther measurements in the Universe.
Type Ia Supernovae all explode with nearly the same amount of energy and therefore have almost the same intrinsic brightness.
By observing Cepheids with very similar properties at Near-InfraRed wavelengths in all 7 galaxies and using the same telescope and instrument, the team was able to more precisely calibrate the luminosity of Supernovae.
With Hubble's powerful capabilities, the team was able to sidestep some of the shakiest rungs along the previous Distance Ladder involving uncertainties in the behavior of Cepheids. Riess would eventually like to see the Hubble constant refined to a value with an error of no more than 1%, to put even tighter constraints on solutions to Dark Energy.MareKromium
|
|
Comets-Comet_Holmes-TW-P17HolmesWeb3_goldman.jpgComet 17-P-Holmes and its Golden Coma54 visiteCaption NASA, da "NASA - Picture of the Day", del 3 Novembre 2007:"Surprising Comet Holmes remains easily visible as a round, fuzzy cloud in the Northern constellation Perseus. Skywatchers with telescopes, binoculars, or those that just decide to look up can enjoy the Solar System's latest prodigy as it glides about 150 MKM from Earth, beyond the orbit of Mars.
Still expanding, Holmes now appears to be about 1/3 the size of the Full Moon, and many observers report a yellowish tint to the dusty coma. A golden color does dominate this telescopic view recorded on November 1, showing variations across the coma's bright central region.
But where's the comet's tail? Like any good comet, Holmes' tail would tend to point away from the Sun. That direction is nearly along our line-of-sight behind the comet, making its tail very difficult to see". MareKromium
|
|
Comets-Comet_Holmes-UV.gifComet 17-P-Holmes55 visiteCaption NASA, da "NASA - Picture of the Day" del 30 Ottobre 2007:"Go outside tonight and see Comet Holmes.
No binoculars or telescopes are needed -- just curiosity and a sky map.
Last week, Comet 17P/Holmes underwent an unusual outburst that vaulted it unexpectedly from obscurity into one of the brightest comets in recent years.
Sky enthusiasts from the Northern Hemisphere have been following the comet's progress closely. Pictured above Quebec, Canada, the coma of Comet Holmes has been noticeably expanding over the past few days. In the above picture, an image of Jupiter has been placed artificially nearby to allow for a comparison of angular sizes.
Jupiter has been scaled to the size it would appear at the current location of Comet Holmes. How Comet Holmes will further evolve is unknown, with one possibility being that the expanding gas cloud that started from its recent outburst will slowly disperse and fade".MareKromium
|
|
| 78 immagini su 7 pagina(e) |
1 |
 |
|
|
|
|
|
|
