Thursday, September 6, 2012

Saturn’s Rings: Here Today, Gone Tomorrow?

They seem to be the same age as their parent planet, but is there evidence that Saturn’s rings are younger than their parent planet? 

By: Ringo Bones 

Conventional wisdom suggests that Saturn’s rings are the same age and therefore always been a permanent fixture of the planet itself but research done since 1984 have seem to prove otherwise. Many scientists have been forced to abandon the long-established notion that the rings of Saturn are as ancient and as enduring as the solar system itself. It now appears that the rings could not have formed along with the planet 4.5 billion years ago. Rather, they are a recent addition – as in no more than 100 million years old. Furthermore, the same processes that created them are already sowing the seeds of their destruction. This makes Saturn’s rings a “passing fancy” that will disappear before the next 100 million years go by. In all likelihood, Saturn has “fathered” several generations of rings over the course of the planet’s lifetime. 

“I’m interested in all the ring systems,” says Jeffrey Cuzzi of NASA’s Ames Research Center in Mountain View, California, who was drawn to his work by the confounding mystery and beauty of Saturn’s rings. What we currently know about the astrophysical principles behind planetary ring formation theory suggest they are primarily created by the breakup of a planet’s own moons going to pieces or captured comets caught on the fly and then torn to shreds by competing gravitational forces. If you scoop up all the scattered particles of ice and dust glittering Saturn’s ring system – or other planetary ring systems – and pack them together, you could mold a moon about the size of Saturn’s moon Mimas – a little under 250 miles in diameter. Such a satellite probably existed quite close to the planet Saturn about 100 million years ago. Then came along a comet or another big celestial body on a collision course and blasted this ancient moon to bits. 

This ill-fated moon, more likely, lay within Saturn’s Roche Limit – named for the 19th Century French mathematician Edouard Roche and defined the region close to a planet where where competing gravitational forces are strong enough to shatter unstable satellites or prevent them from forming in the first place. Within the Roche Limit, the destructive tidal forces dominate other effects. Tidal forces pull those parts of an orbiting body that are relatively close to the planet more strongly than the parts farther away; as a result, the satellite – held together only by the weak glue of its own gravity – may literally be pulled to pieces. Though not all orbiting bodies must submit to tidal forces – NASA’s fleet of space shuttles and the International Space Station, for example, orbits well within planet Earth’s Roche Limit yet does come undone, because its constituent parts are held together by nuts, bolts and the fierce crystal cohesion of the molecules of its metallic parts. 

“The ring systems are a little bit like poppies on a hill,” muses Cuzzi, “You come back next year to the same place, and you’ll still see poppies on the hillside, but they’re not the same poppies you saw last year. In the same way, the rings of the planets may not be the same rings that were there a million years ago – or 10 million or 100 million years ago. They’re just the most recent incarnation. And the process just keeps on going.” Sadly, there's probably only a very small handful in the global astronomical community who is accommodating to the theory that Saturn's rings might not be more than 100 million years old.

Wednesday, August 8, 2012

NASA’s Mars Curiosity Rover: A New Era In Unmanned Space Exploration?

At a little over 2 billion US dollars and several generations more advanced than the 2 Viking Landers from the mid 1970s, does NASA’s Mars Curiosity Rover truly represent the new era in unmanned robotic space exploration?

By: Ringo Bones

In today’s social network world, the NASA Mars Curiosity Rover seems to have revealed something that I thought vanished long ago – as in American’s jumping for joy in anticipation of an awe-inspiring scientific discovery. With news of viewing parties by elementary, middle-school, high-school and college students across the nation, it seems that the Mars Curiosity Rover is now the most social network inclusive of all of NASA’s unmanned robotic spacecraft. Even the NASA Mission Control guy with a Mohawk haircut managed to earn a sizable social network following previously reserved for reality show participants. But the question now is, will the new Mars Curiosity Rover uncover scientific data about the red planet that the two Viking Landers previously missed?

Back in May 31, 1977, the biological instruments of Vikings 1 and 2 were shut off. Scientists concluded they had found no life on Mars, but was it really due to the “anomalous results” when the Vikings 1 and 2 tested the Martian soil back then? That’s why everyone – as in mere civilian science buffs - interested in the prospect of finding life on Mars are currently rooting for the Mars Curiosity Rover because it is way more advanced than any unmanned robotic spacecraft sent to explore the red planet. Remember, when the Viking Landers were sent to Mars, the meteorite ALH84001 was yet waiting to be found in the icy wastes of Antarctica.  

The primary hurdle that makes any unmanned robotic exploration of the red planet a Herculean task is distance. Even though at 186,000 miles per second we send and receive data and signals elsewhere on our planet almost instantaneously, it takes on average 20 minutes to send a data-filled radio signal to Mars – making autonomous function a necessity for unmanned robotic exploration of Mars since the Vikings 1 and 2. Despite these hurdles, the new Mars Curiosity Rover managed to send back standard resolution pictures of the Gale Crater and Mount Sharp – the high resolution pictures take a little longer to send back to Earth because the new rover’s space-worthy little transmitter can only handle so much data at any given time.

According to NASA, the Mars Curiosity Rover is the most advanced robotic space probe they have built so far. Advanced as these robotic spacecraft are, they can’t fully replace the versatility of a human being actually landing and exploring Mars – and remember, when was the last time the American public threw a ticker tape parade for a robotic spacecraft down Madison Avenue for a mission accomplished celebration? Expensive, risky or not, a manned exploration to Mars should be NASA’s next priority.    

Wednesday, July 4, 2012

Cyanogen Gas in Comets: Threat Or Menace?

We may have known a lot – science wise – about comets since Halley’s Comet’s scheduled return back in 1910, but can anything we don’t know about comets actually endanger humanity? 

By: Ringo Bones 

Science-wise, comets pose a real threat to mankind when on very rare occasions it manages to collide with our planet releasing vast amounts of kinetic energy. Like the Tunguska, Siberia incident of 1908 or the suspected comet that hit us 65-million years ago that wiped out the dinosaurs. Besides kinetic energy impacts, are there other “esoteric” threats posed by comets to humanity and all life on Earth? 

A “comet scare” occurred back in 1910 when Halley’s Comet’s scheduled return flyby will make the planet Earth pass through its tail stream. And during the time, it was just recently discovered via spectroscopic analysis that Halley’s Comet contains vast amounts of cyanogen gas that could poison all oxygen-breathing life on Earth. By the way, cyanogen gas is a colorless, flammable poisonous gas that behaves as a univalent radical that is also present in simple and complex cyanide compounds. 

Back in 1910, insurance companies issued a somewhat hastily formulated comet insurance that was primarily aimed to compensate any loss of human life and / or livestock in an event of mass cyanogen gas poisoning. But when planet Earth passed through Halley’s Comet’s tail with no ill effects back in May 13, 1910 – the idea of comet insurance with cyanogen gas poisoning coverage was relegated to the more esoteric footnote of history. But does the cyanogen gas “scare” posed by Halley’s Comet scientifically valid? 

During the first decade of the 20th Century, the science of spectroscopy was significantly way more advanced compared to when Isaac Newton experimented with its fundamental processes back in 1666. When Newton discovered that the white light from the Sun was dispersed into a colored spectrum by passage through a prism. 

In Germany in 1814, J. Fraunhofer extended Newton’s discovery by observing that the Sun’s spectrum, when sufficiently dispersed, was crossed by a large number of fine dark lines, later known as Fraunhofer Lines. Terrestrial sources, such as flames, were found to emit bright lines which were characteristic of the chemical elements in the flame. 

Focault – the French physicist – observed in 1848 that a flame containing sodium would absorb the yellow light emitted by a strong arc placed behind it. These facts were brought together in 1855 by G. Kirchoff in his famous law: That the ratio between the powers of emission and the powers of absorption for rays of the same wavelength is constant for all bodies at the same temperature. 

Kirchoff explained that the Fraunhofer Lines in the Sun’s spectrum were caused by action of chemical elements in the cooler part of the sun’s atmosphere in absorbing the continuous spectrum emitted by the hotter interior of the Sun. Analysis of the Sun’s atmosphere thus became possible. The method was extended later to stellar spectra and constitutes our only means – for a time before sample-return robotic spacecraft were invented – of studying the chemical elements occurring in the stars and other heavenly bodies. 

The observation and interpretation of the light emitted by physical objects – more especially, the interpretation of the light emitted by excited atoms and molecules in their states might have provided data to astronomers in the first decade of the 20th Century that Halley’s Comet is chock full of cyanogen gas. It didn’t, however, predicted that planet earth could pass through Halley’s Comet’s tail with no ill effects whatsoever. 

Wednesday, June 6, 2012

Transit of Venus: Once-In-A-Lifetime Astronomical Event?

Though it’s been cloudy for three days straight in my neck of the woods, does the June 6, 2012 transit of the planet Venus across the face of the Sun really the once-in-the-lifetime astronomical event it was touted to be?

By: Ringo Bones

I just caught the one back in 2004 using an improvised welder’s protective glass as an ad hoc filter for my trusty-but-rusty Celestron. And comparing one view via the “protected” naked eye observations, all I can say that the transit of Venus across the face of the Sun would seem rather “abstract” to the astronomically uninitiated; But why the fuss across the global astronomical community?

 First of all - transit is an astronomical term defined by the passage of a celestial body across a line or region in the sky. A star in transit when on the celestial meridian; the planets Mercury and Venus appear as dark spots when the transit across the disc or face of the Sun; a moon or a natural satellite is in transit when it crosses the disc of the primary planet such as Jupiter. Transits that are visible to the (protected if necessary) naked eye are extremely rare astronomical events.

The transit of Venus across the Sun’s disc only happens every 105 years, and they usually last about seven hours. The first recorded viewing of the phenomena was back in 1639 Jeremiah Horrocks and William Crabtree. Another reason why the astronomical community makes a big deal about it is that transits are a very reliable method of confirming the existence of planets orbiting in other star systems / solar systems. In other words, they are a very useful method in finding extra-solar planets tens or even hundreds of light-years away.