Saturday, November 22, 2014

The Rosetta Probe: The Little Spacecraft That Could?

Launched from earth over a decade ago to rendezvous with a comet more than half a billion miles away from earth, is the Rosetta Probe the little robotic spacecraft that could? 

By: Ringo Bones 

When it was launched off the Arianne spaceport in French Guiana back in March 2, 2004, the European Space Agency’s Rosetta Probe with a mission to rendezvous with a comet more 10 years later could for all intents and purposes pass muster as a mission to the unknown. The craft was placed in a decade long hibernation once it escaped the bonds of earth’s gravity and was reactivated earlier this year. It gained headline news status and attention of the major news networks when it successfully caught up to and orbited around Comet 67P - also known as Comet Churyumov-Gerasimenko - during the middle of November 2014. Although once it – more or less – successfully landed the Philae Lander on the surface of Comet 67P back in November 15, 2014 did the Rosetta Space Probe became the little spacecraft that could. 

The major unavoidable hazard of launching space-probes on long-duration space missions is that when they arrive at their destinations, they will inevitably be using what was the state-of-the-art technology at the time of their launch date. The Rosetta Probe’s 4-megapixel Osiris camera – although very state-of-the-art back when it was designed and built back in 2003 – is somewhat quaint by comparison to the built in cameras used on entry level mobile smart-phone cameras circa 2014, except the Rosetta Probe’s mere 4-megapixel camera – though lacking in resolution in comparison to contemporary consumer counterparts – can see portions of the electromagnetic spectrum that the latest i-Phone can’t with quantum efficiencies better than Ronald Reagan era Keyhole reconnaissance satellites. 

Although it was the Philae Lander that eventually became the star of the show when it successfully landed on the surface of Comet 67P despite a “shaky” bouncy landing due to the failure of deployment of the beryllium-copper harpoons supposedly used to anchor the Lander on the surface of the comet because the gravitational pull on the surface of Comet 67P is 100,000 times less than that on the earth’s surface. The washing machine sized Philae Lander – which weighs 100-kilograms on the earth’s surface – only weighs 1 gram on the surface of Comet 67P thus the necessity of the beryllium-copper harpoons needed to anchor the Lander firmly on the comet’s surface. 

Even though Professor Derrick Pitts – chief astronomer of the Franklin Institute – was concerned when the Philae Lander bounced off into a dark part / shadowy cliff of the surface of the Comet 67P which it can’t use its solar photovoltaic panels to power its instruments in analyzing the composition of the comet, the Lander had enough juice in its on-board reserve batteries to do a series of scientific analysis of the comet and sent the valuable data back to earth before losing power and reverting to sleep mode. Preliminary analysis of the data sent by the Philae Lander has shown that it has detected a wealth of organic compounds on the comet’s surface near the landing zone. And it is also worth mentioning that at the distance between Comet 67P / Comet Churyumov-Gerasimenko and earth, radio signals sent from the Philae Lander - even moving at 186,000 miles per second or 300,000 kilometers per second - takes almost an hour to arrive to the satellite telemetry sites tuned in to the Lander here on earth.

Tuesday, June 3, 2014

Cosmic Diamond: The Universe’s Largest Uncut Diamond?

It might be the ultimate jeweler’s dream here on planet Earth to work on such sized stone, but is the cosmic diamond the Universe’s largest uncut piece of diamond? 

Given that diamonds are just an allotropic form of low impurity carbon whose atoms are arranged differently than ordinary carbon that makes them one of the hardest naturally formed materials, are there conditions elsewhere in the cosmos that would allow the creation of the Universe’s largest chunk of uncut diamond? Fortunately, there is such a place. 

These are called cosmic diamonds and astrophysicists had long theorized their existence since humanity had figured out the working principles behind how stars work and how they are created, live out their lives and eventually die. Cosmic diamonds are an ultra compressed crystal of carbon believed to lie in the core of a white dwarf star as an end product that resulted after a main-sequence star’s helium burning phase. It is a whole, uncut diamond – likely spherical in shape – and could be thousands of miles in diameter, easily making it one of the largest uncut pieces of diamonds in the Universe. Given the physical conditions we currently know that prevail in the core of white dwarf stars, cosmic diamonds could have a wholly different atomic and molecular structure in comparison to the diamonds we are familiar with that are formed by planet Earth’s geological processes. 

Despite the financial and scientific interests fueling our curiosity of cosmic diamonds, at present, we can only study them from afar via our sensitive astronomical spectroscopic instruments because on average, the nearest white dwarf stars are tens to hundreds of light-years away from us. And given out current space travel technology, we won’t be able to reach one and make a sample return mission using robotic spacecraft within a practical human timescale. A round-trip mission to Alpha Centauri using our current space travel technology could take at least a little over 1-million years for a sample return mission. 

Monday, May 26, 2014

Y-Class Brown Dwarf Stars: Coolest Stars Ever?

Though they are real stars – not just some fictional astronomical phenomena conjured up in Gene Roddenberry’s Star Trek – are Y-Class brown dwarf stars truly qualify as the coolest stars ever in terms of temperature?

By: Ringo Bones

Given that a star’s spectral class / color temperature can now easily determined after seeing it and taking spectroscopic , bolometric and other tests via that “Oh Be A Fine Girl Kiss Me Smack” mnemonic device. But it seems we still have to add another letter to than mnemonic device to accommodate recently discovered new classes of stars that – if you were to excuse the pun – are actually very cool. The latest stellar spectral type classification mnemonic had to be changed and now goes as: “Oh Be A Fine Girl Kiss Me Less Tongue, Yo”.  

Discovered back in 2011 by the onboard astronomical instruments on the Wide-field Infrared Survey Explorer or WISE spacecraft that “see” in the infrared portion of the electromagnetic spectrum, Y Class Brown Dwarf stars were said to be the coolest stars discovered to date. Despite the existence of clouds of iron vapor being picked up by the WISE spacecraft’s instrument and “snow” made up of iron filings on a Y-Class Brown Dwarf star it is studying, the mean surface temperature of the said star is only 80 degrees Fahrenheit  - a temperature cool enough to be touched with one’s own hands.  

Basing on the data gathered so far astronomers believe that Y-Class Brown Dwarf stars are believed to be an intermediate stage between planets and stars. They are on average bigger than the planet Jupiter. While some astronomers label them as “failed stars” – as in stars not big enough to have the requisite gravity to initiate full blown fusion to burn hot enough to be a bona-fide star.  

Tuesday, April 22, 2014

Zodiacal Light: Oft Ignored Astronomical Phenomena?

Even though it seems to longer register in the consciousness of most amateur astronomers, are they missing out on observing one of the most interesting astronomical phenomena?

By: Ringo Bones 

Although no prominent astronomers – amateur or otherwise – had been recently talking about it, are first time amateur astronomers missing out one of the most interesting astronomical phenomena that can even be seen by the naked eye. But why does it ever seldom if ever even mentioned at all?

The zodiacal light or the zodiacal band is a faint glow of light seen along the ecliptic just after sunset or before sunrise is another manifestation of the interplanetary meteoric material. This “zodiacal light” is caused by the reflection of sunlight from the meteoric grains moving in interplanetary space. A still fainter diffuse luminous spot called the gegenschein or “counter glow”, found directly opposite the sun in the sky and the false “F corona” of the sun seen during total eclipse are the two other phenomena caused by this interplanetary material. Although such material is slowly spiraling into the sun, it is continually replenished by the destruction of comets.  

The zodiacal light appears as a large, faint pyramidal glow whose base is the horizon after the twilight glow has faded. This form is best seen on spring evenings and mornings in October. A fainter incarnation of zodiacal light stretches clear across the sky along the ecliptic – as in the orange line in our sky maps. Because urban light pollution overpower the glow, the vast majority of amateur astronomers will only get a chance to see the zodiacal band at a star party located at a rural location devoid of most urban light pollution – where the skies are usually quite dark - as in Class 1 to Class 4 - in the Bortle Dark Sky scale. Though urban regions that register as Class 5 in the Bortle Dark Sky scale will provide adequate Zodiacal Light observations for non demanding amateur astronomers. 

Observing the zodiacal band is one of those funny things. You don’t generally notice it until someone points it out, then – under a dark sky – it is fairly straightforward to see. Keep in mind that the zodiacal light is a magnitude or two fainter than the Milky Way.

One way to detect the zodiacal band is to watch for the sky background brightness to change as you slowly scan up from the horizon. Initially you’ll see a brighter horizon haze followed by darkness, then the sky will brighten a bit – this is the zodiacal band – only o fade as you look higher. You might have to block the light from Jupiter with your hand – it’s that dim.

Once you recognize this faint belt, you’ll notice that Saturn clearly lies beneath it as shown on the Path of the Planets map if you are on the northern hemisphere.

Monday, April 21, 2014

John Bevis: The Greatest Forgotten Amateur Astronomer?

His “popularity” may have last peaked during the middle of the 1990s, but does anyone this day and age still remember John Bevis – probably England’s greatest amateur astronomer? 

By: Ringo Bones 

Amateur astronomers who had spent enough time in the library doing old school style research will probably associate amateur astronomer John Bevis with the discovery of the Crab Nebula in 1731 and his observations on an occultation by the planet Venus of Mercury back in May 28, 1737. But does his name still register in the overall consciousness of today’s amateur astronomical community?
Though he probably gained a “brief” peak in popularity during the mid 1990s in lieu of Mike Judge’s Beavis and Butt-Head on the MTV Channel, John Bevis would have been both forgotten and relegated into the dustbin of history had it been for the “old school” researcher repeatedly uncovering his “Ghost Book of Manchester” since the 1980s. Born in old Sarum Witshire back in November 10, 1695, John Bevis was more well-known as a doctor in his hometown than as an accomplished astronomer before passing away back in November 6, 1771. 

And given the mainstream press attention of the dramatic Shoemaker-Levy 9 comet impact on the surface of the planet Jupiter back in July 16, 1994 and the subsequent Hollywood’s interest in the possibility of comets and gigantic asteroids hitting the planet earth causing an extinction level event – it made two box office grossing movies during the latter half of the 1990s as in Deep Impact and Armageddon – and not to mention that the mainstream press recently found out there are more people manning America’s fast food industry than looking at the skies for comets and asteroids that might wreck havoc on earth, it has become a cause célèbre back then to “empower” the amateur astronomer so they might become joint partners of NASA’s Spaceguard Survey given the results of the 1992 Spaceguard Report and the 1995 Shoemaker Committee Report. 

London physician John Bevis would only had been remembered as a good doctor – instead of an accomplished amateur astronomer – had his plans to publish a very extensive star atlas more detailed than anything ever published before had destined to failure. In 1738, Bevis erected a private observatory at Stoke Newington on the outskirts of London where he began an ambitious project – the compilation of a star atlas that was to contain many more stars than Johann Bayer’s Uranometria of 1603 and to have greater exactness. The final product was to be Bevis’ Uranographia Britannica, an atlas of 51 charts to be accompanied by a catalog of star positions. 

Given the high cost of publishing at the time, John Bevis started to look for patrons and subscribers to cover the cost of publishing his Uranographia Britannica. Bevis collected more than 180 subscriptions and the plates are beautifully engraved each having a dedication to the particular individual or learned society in the United Kingdom and across Europe that had subscribed to the work. The first mention of the Uranographia is in a letter Bevis sent to Nicolas Louis de Lacaille in 1748, promising to send him a copy as a present. Despite of famous royal patrons at the time – like Frederick Louis, Prince of Wales – Bevis’ Uranographia Britannica wind up being proverbially called as a “Ghost Book of Manchester” and might sent Bevis to ignominious historical obscurity. 

John Bevis was rescued from ultimate “historical obscurity” back in 1981 when William B. Ashworth Jr. of the University of Missouri in Kansas City published a paper entitled “John Bevis and his Uranographia (ca. 1750).” The paper which appeared in the February 1981 Proceedings of the American Philosophical Society contained both a description and a critique of the work, which seems to describe the very atlas.  Until William B. Ashworth Jr. published his paper in 1981, Bevis’ star atlas had been largely forgotten by the scientific community. And thanks to the November 1997 research by the Manchester Astronomical Society for mid to late 18th Century “ghost books”, Kevin Kilburn, Michael Oates and Anthony Cross finally unearthed a filed copy of Bevis’ atlas in the Manchester Astronomical Society’s library back in November 12, 1997. The atlas consists of the elaborate frontispiece, 51 star charts, the advertising broadsheet and an index. Thus the Manchester copy is one of the most complete and best preserved of the 1786 “ghost book”.