Ring System around Saturn

Ring System Around Saturn

Why is there not a single large satellite instead of a ring system around Saturn? The closer a ring particle is to Saturn, the faster its orbital speed (the faster it is “falling” around the planet – Kepler’s third law); the inner particles are streaming past the outer ones (the “passing lane” as we see it is always to the left). Although the whole assemblage is tearing around the planet itself at some 20 kilometers per second, the relative speed of two adjacent particles is very low, only some few centimeters per minute. Because of this relative motion, the particles can never stick together by their mutual gravity. As soon as they try, their slightly different orbital speeds pull them apart. If the ring were not so close to Saturn, this effect would not be so strong, and the particles could accrete, making small snowballs and eventually growing into satellites. So it is probably no coincidence that outside the rings of Saturn there is a system of satellites varying in size from a few hundred kilometers across to Titan, a giant moon nearly as large as the planet Mars. The matter in all the satellites and the planets themselves may have been originally distributed in the form of rings, which condensed and accumulated to form the present moons and planets.

For Saturn and for Jupiter, the magnetic field captures and accelerates the charged particles of the solar wind. When a charged particle bounces from one magnetic pole to the other, it must cross the equatorial plane of Saturn. If there is a ring particle in the way, the proton or electron is absorbed by this small snowball. As a result, for both planets, the rings clear out the radiation belts, which exist only interior and exterior to the particle rings. A close motion of Jupiter or Saturn will likewise gobble up radiation belt particles, and in fact one of the new moons of Saturn was discovered in just this was: Pioneer 11 found an unexpected gap in the radiation belts, caused by the sweeping up of charged particles by a previously unknown moon.

We have embarked on epic voyages. Blue Sculptures by ©  Elena

The solar wind trickles into the outer solar system far beyond the orbit of Saturn. When Voyager reaches Uranus and the orbits of Neptune and Pluto, if the instruments are still functioning, they will almost certainly sense its presence, the wind between the worlds, the top of the sun’s atmosphere blown outward toward the realm of the stars. Some two or three times father from the Sun than Pluto is, the pressure of the interstellar protons and electrons becomes greater than the minuscule pressure there exerted by the solar wind.

That place, called the heliopause, is one definition of the outer boundary of the Empire of the Sun. But the Voyager spacecraft will plunge on, penetrating the heliopause sometime in the middle of the twenty-first century, skimming through the ocean of space, never to enter another solar system, destined to wander through eternity far from the stellar islands and to complete its first circumnavigation of the massive center of the Milky Was a few hundred million years from now.

Titan, Satellite of Saturn

Titan, Satellite of Saturn

In composition and in many other respects Saturn is similar to Jupiter, although smaller. Rotating once every ten hours, it exhibits colorful equatorial banding, which is, however, not so prominent as Jupiter’s. It has a weaker magnetic field and radiation belt than Jupiter and a more spectacular set of circumplanetary rings. And it also is surrounded by a dozen or more satellites.

The most interesting of the moons of Saturn seems to be Titan, the largest moon in the solar system and the one with a substantial atmosphere. Prior to the encounter of Voyager I with Titan in November 1980, our information about Titan was scanty and tantalizing. The only gas known unambiguously to be present was methane, CH4, discovered by G. P. Kuiper. Ultraviolet light from the sun converts methane to more complex hydrocarbon molecules and hydrogen gas. The hydrocarbons should remain on Titan, covering the surface with a brownish tarry organic sludge, something like that produced in experiments on the origin of life on Earth.

What is responsible for the reddish coloration of Titan? Extraterrestrial elements, no doubt about it! Image: Large Mosaic by © Elena

The lightweight hydrogen gas should, because of Titan’s low gravity, rapidly escape to space by a violent process known as “blowoff”, which should carry the methane and other atmospheric constituents with it. But Titan has an atmospheric pressure at least as great as that of the planet Mars. Blowoff does not seem to be happening. Perhaps there is some major and as yet undiscovered atmospheric constituent – nitrogen, for example – which keeps the average molecular weight of the atmosphere high and prevents blowoff. Or perhaps blowoff is happening, but the gases lost to space are being replenished by others released from the satellite’s interior. The bulk density of Titan is so low that there must be a vast supply of water and other ices, probably including methane, which are at unknown rates being released to the surface by internal heating.

When we examine Titan through the telescope we see a barely perceptible reddish disc. Some observers have reported variable white clouds above that disc – most likely, clouds of methane crystals. But what is responsible for the reddish coloration? Most students of Titan agree that complex organic molecules are the most likely explanation. The surface temperature and atmospheric thickness are still under debate. There have been some hints of an enhanced surface temperature due to an atmospheric greenhouse effect. With abundant organic molecules on its surface and in its atmosphere, Titan is a remarkable and unique denizen of the solar system. The history of our past voyages of discovery suggests that Voyager and other spacecraft reconnaissance missions will revolutionize our knowledge of this place.

Discovering Europa

Discovering Europa

The Voyager 2 spacecraft will never return to Earth. But its scientific findings, its epic discoveries, its travelers’ tales do return. Take July 9, 1979, for instance. At 8:04 Pacific Standard Time on this morning, the first pictures of a new world, called Europa, after an old one, were received on Earth.

How does a picture from the outer solar system get to us? Sunlight shine on Europa in its orbit around Jupiter and is reflected back to space, where some of it strikes the phosphors of the Voyager television cameras, generating an image. The image is read by the Voyager computers, radioed back across the immense intervening distance of half a billion kilometers to a radio telescope, a ground station on the Earth. There is one in Spain, one in the Mojave Desert of Southern California and one in Australia (on that July morning in 1979 it was the one in Australia that was pointed toward Jupiter and Europa). It then passes the information via a communications satellite in Earth orbit to Southern California, where it is transmitted by a set of microwave relay towers to a computer at the Jet Propulsion Laboratory, where it is processed.

The picture is fundamentally like a newspaper wirephoto, made of perhaps a million individual dots, each a different shade of gray, so fine and close together that at a distance the constituent dots are invisible. We see only their cumulative effect. The information from the spacecraft specifies how bright or dark each dot is to be. After processing, the dots are then stored on a magnetic disc, something like a phonograph record. There are some eighteen thousand photographs taken in the Jupiter system by Voyager 1 that are stored on such magnetic discs, and an equivalent number for Voyager 1. Finally the end product of this remarkable set of links and relays is a thin piece of glossy paper, in this case showing the wonders of Europa, recorded, processed and examined for the first time in human history on July 9, 1979.

The wonders of Europa are now recorded, processed and examined. Image: ©  Elena

What we saw on such pictures was absolutely astonishing. Voyager 1 obtained excellent imagery of the other three Galilean satellites of Jupiter. But not Europa. It was left for Voyager 2 to acquire the first close-up pictures of Europa, where we see things that are only a few kilometers across. At first glance, the place looks like nothing so much as the canal network that Percival Lowell imagined to adorn Mars, and that, we now know from space vehicle exploration, does not exist at all. We see on Europa an amazing, intricate network of interesting straight and curved lines. Are they ridges – that is, raised? Are they troughs – that is, depressed? How are they made? Are they part of global tectonic system, produced perhaps by fracturing of an expanding or contracting planet? Are they connected with plate tectonics on the Earth? What light do they shed on the other satellites of the Jovian System? At the moment of discovery, the vaunted technology has produced something astonishing. But it remains for another device, the human brain, to figure it out. Europa turns out to be as smooth as a billiard ball despite the network of lineations. The absence of impact craters may be due to the heating and flow of surface ice upon impact. The lines are grooves or cracks, their origin still being debated after the mission.

Signs of Intelligent Life

Signs of Intelligent Life

Intelligent Beings on the Earth and in the Universe.

Like organisms, machines also have their evolutions. The rocket began, like the gunpowder that first powered it, in China, where it was used for ceremonial and aesthetic purposes. Imported to Europe around the fourteenth century, it was applied to warfare, discussed in the late nineteenth century as a means of transportation to the planet by the Russian schoolteacher Konstantin Tsiolkosky , and first developed seriously for high altitude flight by the American scientist Robert Goddard. The German V-2 military rocket of World War II employed virtually all of Goddard’s innovations and culminated in 1948 in the two-stage launching of the V-2/WAC Corporal combination to the then-unprecedented altitude of 400 kilometers. In the 1950’s, engineering advances organized by Sergei Korolov in the Soviet Union and Wernher von Braun in the United States, funded as delivery systems for weapons of mass destruction, led to the first artificial satellites. The pace of progress has continued to be brisk: manned orbital flight; human orbiting; then landing on the moon; and unmanned spacecraft outward bound throughout the solar system. Many other nations have now launched spacecraft, including Britain, France, Canada, Japan, China, the society that invented the rocket in the first place.

Among the early applications of the space rocket, as Tsiolkovsky and Goddard (who as a young man had read Wells and had been stimulated by the lectures of Percival Lowell) delighted in imagining, were an orbiting scientific station to monitor the Earth from a great height and a probe to search for life on Mars. Both these dreams have now been fulfilled.

Intelligence reveals itself through the geometric regularity of its constructions. Image : © Elena

Imagine yourself a visitor from some other and quite alien planet, approaching Earth with no preconception. You view of the planet improves as you come closer, and more and more fine detail stand out. Is the planet inhabited? At what point can you decide? If there are intelligent beings, perhaps they have created engineering structures that have high-contrast components on a scale of a few kilometers, structures detectable when our optical systems and distance from the Earth provide kilometer resolution. Yet at this level of detail the Earth seems utterly barren. There is no sign of life, intelligent or otherwise, in places we call Washington, New York, Moscow, Boston, London, Tokyo, Paris, Beiging, Berlin. If there are intelligent beings on Earth, they have not much modified the landscape into regular geometrical patterns at kilometer resolution.

But when we improve the resolution tenfold, when we begin to see detail as small as a hundred meters across, the situation changes. And intelligent life on Earth first reveals itself through the geometric regularity of its constructions.

An intelligent being: a cat. An average cat is much more intelligent than any human, but cats are deep plunged or immersed inside their inner contemplation to object the Human domination. Image: © Megan Jorgensen.

Working Conditions

Working Conditions

Looking for the Perfect Job

America wants less work, more play, more family time, and better benefits

Feeling overwhelmed by the job-family-house juggling act? Are you willing to give up a higher salary for more time with time with family and flexible working conditions? If so, you’re not alone. Across America, workers are opting for jobs that give them more control over their work schedules, more autonomy at the office and better dependent care benefits. The bottom line : Americans want more balance in their lives, more time to smell the roses.

It’s no wonder, given that 42 percent of American workers went through downsizing and 28 percent see cutbacks in their companies’ management ranks every year. Workers know that they can no longer depend on a job for life and a guaranteed pension. Without that security, they’ve no longer willing to commit themselves entirely to their jobs.

Does this mean that American workers are increasingly disloyal to their bosses? Hardly, but according to a Families and Works Institute (FWI) study on the changing American work force. American workers are more dedicated to their own jobs and their own well-being than to their supervisors or companies.

“Americans are looking for something different,” notes FWI co-president Ellen Gallinsky. “They want quality – in their own work, in their work environment, and in their relationships at home and work. And when they get it, they are more committed, productive employees.”

Equality in jobs? Credit image: Elena.

The workplace may be more diverse than ever, but many workers still feel victimized by discrimination and believe unfair barriers are holding them back. While 15 percent of U.S. Workers say they have experienced discrimination in their current jobs, more than one-fifth of minorities feel they have. Minority men and women, as well as white women, feel white men have the best chance at success. Overall, men are more confident in their opportunities than women. And workers seem ambivalent, at best, about diversity in the workplace. Galinsky’s study suggests that most people prefer working with others of the same sex, race, and education. On the other hand, those already working in ethnically diverse environments prefer them.

Some habits are particularly resistant to change. Women still hear the brunt of household chores. They do most of the cooking, cleaning, shopping, paying bills, and child care. But when people living in dual-income homes were asked if the housework was evenly split, 43 percent of the men said yes, while only 19 percent of the women did. The division of labor inside the home is unlikely to change any time sooner – younger men are no more likely to do an equal share of the housework than older ones.

Daydream Nation

The results of an Exec magazine survey of 3,000 readers about office daydreams:

Can you daydream while simultaneously talking with someone, including your boss? – Yes – 59%, No – 41%. Did you ever daydream about being CEO of your company – Yes – 73%, No – 27%. Do you ever drean about having sex with a co-worker? – Yes – 77%, No – 23%.

What workers want

The following statistics are a snapshot of the hopes and aspirations of American workers as gleaned from a 1993 study by the Families and Work Institute. Here’s what workers said when they were asked what they consider “very important” in finding the right job.

Open communications – 65%; Effect on personal/family life – 60%; Nature of work – 59%; Management quality – 59%; Supervisor – 58%; Gain new skills – 55%; Control over work content – 55%; Job security – 54%; Co-worker quality – 53%, Stimulating work – 50%; Job location – 50%; Family-supportive policies – 46%; Fringe benefits – 43%; Control of work schedule – 38%; Advancement opportunity – 37%; Salary/wage – 35%; Access to decision makers – 33%; No other offers – 32%; Management opportunity – 26%; Size of employer – 18%.

How do you spell success?

Respondents were asked what being successful in their work life means:

Personal satisfaction from doing a good job – 52%;

Earning the respect of recognition of supervisors and/or peers – 30%;

Getting ahead or advancing in job or career – 22%;

Making a good income – 21%;

Feeling my work is important – 12%;

Having control over work content and schedule – 6%.

Equal Partners?

How fair is your household’s division of labor? A breakdown of who does the work in dual-income households:

Cooking: men – 15%, women – 81%;

Cleaning — men – 7%, women – 78%;

Shopping – men – 18%, women – 087%;

Paying bills – men – 35%, women – 63%;

Repairs – men – 91%; women – 14%.

Working shoes. Photo: Elena

Equal responsibility?

Inequality in child rearing continues despite the increase of working women.

Working women who say they take major responsibility for their children – 71%; men who do – 5%.

Equal Opportunity?

Managers were asked how the perceive their opportunities for professional advancement:

Poor – men 7%; women 19%.

Fair – men 9%; women 20%;

Good – men 51%; women 34%;

Excellent – men – 33%; women – 26%.

Working Hard for the Money: a Roundup

    The average worker spends more than 45 hours a week on the job, including overtime and commuting.

    Eighty percent of workers say their jobs require them to work very hard, and 65 percent say they require working very fast.

    Forty-two percent of workers say they feel “used up” by the end of a workday.