[Space] NASA-ESA - Cassini-Hyugens

[gpc]

Originariamente inviato da GioFX
si, sono 19" LCD! e poi, hai visto i 16:9 da almeno 30"?

Sì

Comunque è una mia impressione o hanno tagliato di brutto il collegamento interropendo l'intervistatrice mentre parlava?

[GioFX]

Originariamente inviato da gpc
Sì

Comunque è una mia impressione o hanno tagliato di brutto il collegamento interropendo l'intervistatrice mentre parlava?

no, credo fosse concluso il collegamento... era incerta se stessero annunciando o meno qualcosa... cmq tra poco ci sarà una nuova press conference.

[Mixmar]

Sul discorso dell'antenna usata come parasassi... si vede che quello è il posto della nostra nazione nel cosmo!

Beh, meglio così che non averlo il posto, vero?

Scherzi a parte, il contributo italiano è veramente importante.

[gpc]

[Schummacherr]

Ci sono anche io

[gpc]

Originariamente inviato da Schummacherr
Ci sono anche io

Su Saturno? A cavalcioni di Cassini?

[GioFX]

First pictures from Saturn orbit show rich ring detail

BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: July 1, 2004

The first batch of photographs snapped by the Cassini Saturn orbiter earlier today reached the Jet Propulsion Laboratory around 8:30 a.m., zoomed-in shots of the planet's myriad rings showing a ghostly tapestry of icy, back-lit particles arrayed in sharply defined bands.


One of the images taken by Cassini from orbit of Saturn shows a close-up view of the planet's rings. Credit: NASA/JPL

Much brighter shots showing the rings from the sunlit side were expected to reach Earth later this morning, but scientists were elated at the initial results.

"Look at that structure, it's so regular!" marveled imaging team leader Carolyn Porco as a picture came in showing well-defined bands of brightness and darkness. "I'm wondering if we're looking at a density wave. This looks like it might be a density wave, but I'm not quite sure."

Density waves, caused by gravitational interactions with nearby moons, are thought to be "kissing cousins" of the waves that produce the spiral structure seen in galaxies like Earth's Milky Way.

"These are regions where the rings are communicating gravitationally with the moons exterior to them," Porco explained.

One of the objectives of Cassini's ring research is to study density waves in unprecedented detail and based on the first set of images, scientists will not be disappointed.

"With these kinds of images and with the data we're going to return from Cassini with stellar occulation observations, radio occulation observations, we are going to nail density waves, we are going to understand these critters," Porco said. "This is really a new era in the study of outer planet systems."

A few moments later: "There goes another one, which is mind blowing, absolutely mind blowing," Porco exclaimed. "Look at thatOoh... It's almost everywhere you look here, you can't miss one. They're just all over the place."

A few moments later: "Oh my God, look at that! ... These density waves are like books, just waiting to be read."

But this morning, as raw, unprocessed images flowed in, science wasn't the immediate objective. It was enough just to know Cassini's camera and other systems had worked as planned during close approach to Saturn.

The photo sequence began around 12:30 a.m., 18 minutes or so after Cassini finished a 96-minute rocket firing to brake into orbit around Saturn. Streaking just above the rings at speeds greater than 50,000 mph, Cassini's narrow-angle camera took a series of snapshots, opening its shutter for just five milliseconds per picture to avoid blurring.


One of the images taken by Cassini from orbit of Saturn shows a close-up view of the planet's rings. Credit: NASA/JPL

Each picture was separated from those on either side by about 600 miles because of Cassini's extreme velocity.

"We couldn't take a contiguous ring scan with images overlapping other images because we are speeding across the rings very fast," Porco said. "It takes us about a minute to take a picture and so in the time we shutter the exposure, read out the camera and get ready to take a picture again, we have crossed a thousand kilometers. Our field of view is only about, let's say, 100 to 200 kilometers. So never do we have overlapping images. Never will we be able to put this all together in a nice mosaic."

One of the world's leading ring experts, even Porco was surprised by the level of detail apparent in the first unprocessed pictures.

"I shouldn't be, I suppose, but I am surprised," she reflected. "You can think about this like we have done for 14 years and you know, well, we'll get density waves there and we'll take pictures. But it's remarkable to me at how startling it is to see these images for the first time. ... They're just beautiful, they're very sharp."

One picture that came in about an hour after the first image was received was especially intriguing, showing a density wave on the left with narrower and narrower bands of light and dark and a so-called bending wave on the right.

"Oh my God! This is, oh, this is really exciting!" Porco exclaimed. "If you look, the pattern now is decreasing to the left and that is the mark of a bending wave. ... And a bending wave, it's not the density of the particles that is being moderated or modified as you move across the rings, but it is the height of the ring plane. The darkness is created by shadows. Look at that! It's just a beautiful pair."

[GioFX]

cose da non credere... 810 km tra un'immagine e l'altra e ma soli 5 millisecondi di apertura del "diaframma"... infatti l'ernome velocità avrebbe reso le immagini sfocate con tempi di esposizione superiori!

[Mixmar]

Peccato non avere un filmatino... Ma suppongo che verrebbe un po' mosso...

[Schummacherr]

Originariamente inviato da gpc
Su Saturno? A cavalcioni di Cassini?

LOL

vi scrivo da lì infatti..non sapete che spettacolo sti anelli...solo ke ogni tanto mi arriva qualche roba strana in testa si gira forte quissù

[GioFX]

Scientists marvel at photos

BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: July 1, 2004

Making gravity visible, close-up images of Saturn's rings shot by NASA's newly arrived Cassini probe revealed an intricate, never-before-seen tapestry of icy particles herded into spiralling density waves by the effects of nearby moons.


One of the images taken by Cassini from orbit of Saturn shows a close-up view of the planet's rings. Credit: NASA/JPL

Carolyn Porco, leader of the Cassini camera team, a serious Beatles fan and one of the world's leading authorities on Saturn's ring system, was almost at a loss for words describing her initial impressions of the new vistas opened up by Cassini.

"I don't think you have to be a ring scientist to imagine what last night was like to us," she said of the spacecraft's arrival in Saturn orbit and the initial batch of ring pictures beamed back to Earth early today. "It was beyond description, it was mind blowing, it was every adjective you could think of.

"Even though we've had a long time to think about our images ... I'm surprised at how surprised I am at the beauty and the clarity of these images. They are shocking to me. You are going to see some images now, they were so shocking I thought my team here was playing tricks on me and showing me a simulation of the rings and not the rings themselves. It's just utterly remarkable."

Cassini snapped 61 black-and-white pictures of Saturn's rings early today after completing a 96-minute rocket firing to brake into orbit around the ringed planet. Program manager Bob Mitchell reported this afternoon that engineering data radioed back from Cassini shows the spacecraft survived two ring plane crossings without incident and that all of its myriad subsystems were in good health and operating normally.

Cassini skimmed over the top of the rings as it braked into orbit and shortly after main engine shut down, the spacecraft began carrying out commands to photograph the rings, first from the upper backlit side and then from below, where the thin disk of icy particles was bathed in direct sunlight.

Because of Cassini's enormous velocity - 60,000 mph or so at engine cutoff - its cameras were programmed with shutter speeds of five thousandths of a second to prevent blurring. In the minute required to snap a picture, record the data and be ready for another shot, Cassini moved hundreds of miles, preventing researchers from taking overlapping photos or the multiple images required for color.

But no one was complaining.


http://spaceflightnow.com/cassini/images/040701rings4.jpg

"The Cassini cameras are far more capable than the Voyager cameras were, which is in large part why these images are so spectacular," Porco said. "The other part, of course, is that the spacecraft gives us a very steady platform. This machine, you turn it, you point it and it stays there. It's like a tripod in space. So it allows us to take very sharp images."

Cassini will never again fly so close to the rings and the level of detail the craft's cameras captured was stunning. If there was a central theme to the pictures it was the ubiquitous presence of density waves, regions of alternating brightness and darkness that look like ripples in fine sand. The spacing of the ripples, caused by gravitational interactions with nearby moons, decreases as one moves outward from the planet.

"This is a telltale sign of a density wave, the wavelengths decreases as you go outward and also the amplitude of the wave damps so you see it disappear," Porco said, describing one picture. "These are characteristics ring scientists read like a book to discern what kind of properties the particles have, how densely they're packed and so on. As I said, this is unprecedented resolution for the imaging experiment."

One image showed a density wave thinning out to the right and a so-called bending wave moving to the left across the field of view.

In a bending wave, "it's not the number density of particles that is varying, it is literally the height of the ring plane," Porco said. "You can think of the feature on the right as being like corrugated cardboard where the ring is literally warped and its warped because the moons which are exciting that particular wave excite inclination (tilt) in the particle orbits and the particle orbits get phased in such a way that it forms this pattern, which in fact is a spiral pattern.

"If you followed it around the rings, it would take the spiral form," she said. "These are similar to the spiral arms of spiral galaxies."

Describing a blow up of a density wave image, Porco pointed out strange looking structures that "almost looks like straw. I don't know what this is. We think it's real, we see it in other images. ... So it's not some noise pattern in the image.

"There may be processes going on that make the particles clump on scales that you're seeing here. ... Nonetheless we're seeing something here and I literally don't have a clue. This may be brand new, something no one's ever predicted before."

The picture Porco initially thought was a joke was focused on a gap in the outer A ring known as the Encke division, a narrow void swept out by the tiny moon Pan. Along with showing ultra clear views of spiralling density waves on both sides of the gap, the ring material forming the inner edge had a sharply scalloped appearance. Even to the layman, the picture appeared unusual.


One of the images taken by Cassini from orbit of Saturn shows a close-up view of the planet's rings. Credit: NASA/JPL

"It just doesn't look real," Porco marveled. "It's so sharp, the wakes that you see in the interior to the Encke gap, you can see the classic scalloped edges. These are caused by gravitational impulses by Pan - there may be other moons there, we don't know - which force eccentricities in the orbits of the particles on the edge of the gap. With repeated passages of the moon ... it builds up this sinusoidal pattern, this beautiful classic pattern.

"This is like textbook physics, textbook ring physics right there in one image," she said.

At a news conference Porco was asked why the study of Saturn's rings was important.

"This is standard ring lore, that Saturn's rings especially are our closest analogue of the celestial disk system," she began. "Frank Shu, an astrophysicist, said this many years ago: there are two types of bodies in the universe. There are spheres and there are disks. And under certain circumstances, a sphere can collapse down into a disk and that's what will happen if you have a spherical cloud of debris and the particles are colliding, they lose energy but they preserve angular momentum and they all end up in a plane. That's a very common process and its given rise to lots of disk system.

"One is Saturn's rings, one was the solar nebula out of which our solar system and the planets formed. Astronomers now see lots of disks around other stars and even reaching way far out in size to the spiral galaxies, they are another disk system. Common physics applies to all of them.

"So in studying rings, we hope to study processes that go on in disks in general," Porco said. "And so we think we're seeing in Saturn's rings some of the processes that went on in the solar nebula before the planets formed. In fact, we may be seeing some of the processes that actually aided the development of the planets."

If one is interested in "understanding where the solar system came from or how it got here, how the planets were formed, then this is the place to go."

Ed Weiler, an astronomer by training who serves as NASA's associate administrator for space flight, offered another reason to study Saturn and its rings.

"When I was growing up, this kind of stuff was science fiction," he said. "We compete with a lot of things: Game Boys, X-Boxes and Play Stations. This isn't science fiction, we actually did this. We're in orbit around another planet taking these kinds of pictures with an incredible machine. We did this. This isn't animation, this isn't PowerPoint, this is real. I like data, and this is real data.

"So I hope we can excite at least a few more kids in this country to become scientists and engineers. If we can do that, it was worth every penny we spent on it."

"It just doesn't look real," Porco marveled. "It's so sharp, the wakes that you see in the interior to the Encke gap, you can see the classic scalloped edges. These are caused by gravitational impulses by Pan - there may be other moons there, we don't know - which force eccentricities in the orbits of the particles on the edge of the gap. With repeated passages of the moon ... it builds up this sinusoidal pattern, this beautiful classic pattern.

"This is like textbook physics, textbook ring physics right there in one image," she said.

At a news conference Porco was asked why the study of Saturn's rings was important.

"This is standard ring lore, that Saturn's rings especially are our closest analogue of the celestial disk system," she began. "Frank Shu, an astrophysicist, said this many years ago: there are two types of bodies in the universe. There are spheres and there are disks. And under certain circumstances, a sphere can collapse down into a disk and that's what will happen if you have a spherical cloud of debris and the particles are colliding, they lose energy but they preserve angular momentum and they all end up in a plane. That's a very common process and its given rise to lots of disk system.

"One is Saturn's rings, one was the solar nebula out of which our solar system and the planets formed. Astronomers now see lots of disks around other stars and even reaching way far out in size to the spiral galaxies, they are another disk system. Common physics applies to all of them.

"So in studying rings, we hope to study processes that go on in disks in general," Porco said. "And so we think we're seeing in Saturn's rings some of the processes that went on in the solar nebula before the planets formed. In fact, we may be seeing some of the processes that actually aided the development of the planets."

If one is interested in "understanding where the solar system came from or how it got here, how the planets were formed, then this is the place to go."

Ed Weiler, an astronomer by training who serves as NASA's associate administrator for space flight, offered another reason to study Saturn and its rings.

"When I was growing up, this kind of stuff was science fiction," he said. "We compete with a lot of things: Game Boys, X-Boxes and Play Stations. This isn't science fiction, we actually did this. We're in orbit around another planet taking these kinds of pictures with an incredible machine. We did this. This isn't animation, this isn't PowerPoint, this is real. I like data, and this is real data.

"So I hope we can excite at least a few more kids in this country to become scientists and engineers. If we can do that, it was worth every penny we spent on it."

[Spike]

Ma stavolta non ci sono le immagini da mille mila pixel?

[GioFX]

Originariamente inviato da Spike
Ma stavolta non ci sono le immagini da mille mila pixel?

emh... a parte che le immagini della pancam dei robot MER sono da 1 MP (le immagini in altissima risoluzione sono fatte grazie alle fantastiche lenti che montano), cmq queste immagini sono solo quelle scattate brevemente alla fine della fase SOI...

[cionci]

Ma poi di cosa sono fatti gli anelli ?

[GioFX]

line, rocce, sassi e polvere interstellare... che si dispone in fasce staccate a causa dell'influenza della magnetosfera (il campo magnetico di saturno) e dalla forze esercitate dalle lune più grandi.

[Bet]

ehm... non vorrei sfogliare tutto il 3d, ma a che distanza è arrivato dagli anelli?

[gpc]

Originariamente inviato da Bet
ehm... non vorrei sfogliare tutto il 3d, ma a che distanza è arrivato dagli anelli?

C'è passato in mezzo.



Pigro.

[Bet]

Originariamente inviato da gpc
C'è passato in mezzo.



Pigro.

opss... ma è la terza foto che ha pubblicato in questa pagina? (pigro al quadrato )

[gpc]

Originariamente inviato da Bet
opss... ma è la terza foto che ha pubblicato in questa pagina? (pigro al quadrato )

Mi dà anche del lei?
Direi di no comunque, non ho visto foto del momento in cui li attraversava (comunque è passato ovviamente per una delle fasce libere, va bene che avevano il parasassi italiano, però non era salutare usarlo a spazzaneve ).
In ogni caso la scuso per la sua pigrizia solo in ragione della sua veneranda età

[Bet]

Originariamente inviato da gpc
Mi dà anche del lei?
...

doppio opss...
Vi daro' del Voi

ps: prima o poi ti chiedero' consulenza sull'acquisto di un telescopio (economico naturalmente)