One of the most important things to begin with is to carefully choose the site you will use set up and use your telescope at. While it would be tempting to take your new telescope out of the box and use it that night, it’s best to wait just a day or two! Begin the first clear night by going outside a taking a good look around. You want to choose an observing site where the view is as unobstructed and as dark as possible. While you are doing this, keep in mind that it must be comfortable to you as well. While the vista might be far improved a kilometer away – do you really want to have to take your equipment that distance each time you want to use it? Look at many different alternatives. If you live in a city, perhaps a rooftop will serve well. Urban settings often have very suitable yards that will work for most observing projects and rural settings are ideal.
Light pollution is another factor when choosing your site. Again, keep in mind that you must have a site that is accessible to enjoy. It isn’t always possible if you live in a well-lit area to take your equipment remote each time you want to use your telescope – but a sheltered area, such as in the shadow of a house, often blocks stray light well enough to enjoy using your telescope right at home. Of course, finding a dark sky site is also important, too. But not half as much as just finding a spot that you will enjoy and use.
While out during the day, look for level, solid ground. No one wants to see their telescope take a tumble. While it is tempting to set up on a deck, remember that any footsteps will cause vibration in the image. Setting up on places like a blacktop driveway or concrete can also cause thermal issues, too. Avoid them when you can, but do not discard these types of sites if they are comfortable and accessible.
How To Set Up Your Telescope
While every telescope set-up is slightly different, they are all basically the same in some respects. There must be an optical tube of some type, a mount and eyepieces. Take the time to become familiar with all the components of your telescope! If you must assemble and dis-assemble your telescope each time you use it, it’s a very wise idea to practice a few times before you go out in the dark. There is simply nothing more frustrating that trying to learn to set up your equipment when you cannot see what you are doing – or to loose a small part in the dark. If it is at all possible, leave your telescope and tripod fully assembled and in a place where it is easy to set outside at a moment’s notice. You’ll find that you’ll use it far more often if it takes less work.
Your telescope’s view is also dependent on ambient temperature. If you wear eyeglasses, you understand why! If you go from a very cool environment, such as a air-conditioned house, into a humid outdoors setting, your glasses fog up, don’t they? And so will your telescope’s optics. The same is true when observing outdoors in the winter. When taking your telescope from a heated climate to a cold one, you must give the telescope time to “cool down”. Even just a few degrees can mean waiver in the image.
Align your finderscope in advance! While this sounds rather strange, another frustrating thing to do in the dark is to align a finderscope – especially on a moving target. Once you have learned to assembly your telescope, learn to align your finder. Set up your scope and aim at a distant object. Now align your finder to that object as well. This will make things much easier, later!
Once your telescope is set up, the last thing to remember is to stow your things neatly so you won’t have any problems finding them when it comes time to put things away. Dust covers and eyepieces cases are so easy to lose. Keep things neat and you won’t have any problems. Choose the eyepiece you think you will need in advance and have them in a place where you won’t need to fumble in the dark. Have your red flashlight and maps handy. These are just little things that make using your telescope much more enjoyable!
Choose Your Observing Times
Experience will become your best teacher. It won’t take long before you realize that very humid nights or exceptionally cold ones are not particularly good times to observe. Unless you plan on looking at the Moon itself, nights that are well moon-lit are also not good times to search for a faint galaxy, either. Little things, like waiting for a planet to clear the atmospheric “murk” at the lower horizon mean a much better viewing experience.
How To Use A Telescope
Now that you have your observing site, learned to set up, and established a time to practice astronomy… Let’s learn how to use your telescope!
If you have an equatorial mount, align the axis to the pole star. Altazimuth mounts do not need this step. Take off your dustcaps and stow them away. Double check to make sure your tripod legs are secure. Choose your low power eyepiece and put it in the focuser. Are you ready? Now, loosen the axis and take aim at a star using your finderscope. When the star is aligned in the center of the finder, tighten the axis and it’s time to go to the eyepiece. Gently adjust the focus in or out until you have a crisp, clean image. Now watch the star move. This direction is always west – regardless of the orientation in the eyepiece. For equatorial mounts, use your slow motion cables to learn to “track” the star. For altazimuth mounts, use the pan control or shift the tube manually (dobsonian models). Once you have learned to “follow” and object, it’s time to star hop!
Each time you go to a new object with an equatorial mount, you must unlock the axis. The same is true with some styles of altazimuth mounts. Once you have the general location in the finder, lock the axis back up and use the slow motion cable controls or panhandle control to make small moves. Using a low power eyepiece first will help you locate things much easier, and you can then switch to more magnification once the object is located.
When you are finished for the evening, make sure to replace all your dustcaps. If your optics should become dewed, don’t wipe them off. Allow them to air dry to avoid micro-scratches on delicate coatings. Always make sure to give your observing area one last check before leaving just in case you’ve forgotten something!
On this night – October 6 – in 1784, Sir William Herschel was busy at the eyepiece of his telescope with a new galaxy he’d just discovered. It was a beauty, too. A pencil-slim, edge-on galaxy with a dark dust lane. Herschel marked it down in his fifth catalog as discovery 19, but when he got excited talking about his sister Caroline’s discoveries, he made a mistake. Let’s learn…
Even though William Herschel later confused NGC 891 with Caroline’s independent discovery of NGC 205 (M110), you can understand how the brother/sister astronomy team could honestly make a mistake. In the words of Caroline Herschel; “I knew too little of the real heavens to be able to point out every object so as to find it again without losing too much time by consulting the Atlas. But all these troubles were removed when I knew my brother to be at no great distance making observations with his various instruments on double stars, planets, etc., and I could have his assistance immediately when I found a nebula, or cluster of stars, of which I intended to give a catalogue; but at the end of 1783 I had only marked fourteen, when my sweeping was interrupted by being employed to write down my brother’s observations with the twenty-foot.”
Oddly enough, Herschel’s mistake was perpetuated by Admiral William Henry Smyth – who when he retired from the Royal Navy spent his time in his private observatory equipped with a 6-inch refractor. There he observed a variety of deep sky objects, including double stars, clusters and nebulae, and kept careful records of his observations, publishing his work as the “Cycle of Celestial Objects” – including Herschel’s mistake. But in the end, does it really matter which Herschel discovered it? It’s what’s out there that counts…
Located some thirty million light years away in the Local Super Cluster, NGC 891 is wrapped by a cold, gaseous halo. According to Tom Oosterloo (et al); “HI observations are among the deepest ever performed on an external galaxy. They reveal a huge gaseous halo, much more extended than seen previously and containing almost 30 % of the HI. This HI halo shows structures on various scales. On one side, there is a filament extending (in projection) up to 22 kpc vertically from the disk. Small halo clouds, some with forbidden (apparently counter-rotating) velocities, are also detected. The overall kinematics of the halo gas is characterized by differential rotation lagging with respect to that of the disk. The lag, more pronounced at small radii, increases with height from the plane. There is evidence that a significant fraction of the halo is due to a galactic fountain. Accretion from intergalactic space may also play a role in building up the halo and providing low angular momentum material needed to account for the observed rotation lag. The long HI filament and the counter-rotating clouds may be direct evidence of such accretion.”
Accretion? Accretion from where? Is NGC 891 gathering material from somewhere else? Apparently so. According to work of Mapelli (et al): “It has been known for a long time that a large fraction of disc galaxies are lopsided. We simulate three different mechanisms that can induce lopsidedness: flyby interactions, gas accretion from cosmological filaments and ram pressure from the intergalactic medium. Comparing the morphologies, HI spectrum, kinematics and m = 1 Fourier components, we find that all of these mechanisms can induce lopsidedness in galaxies, although in different degrees and with observable consequences. The time-scale over which lopsidedness persists suggests that flybys can contribute to ~20 per cent of lopsided galaxies. We focus our detailed comparison on the case of NGC 891, a lopsided, edge-on galaxy with a nearby companion (UGC 1807). We find that the main properties of NGC 891 (morphology, HI spectrum, rotation curve, existence of a gaseous filament pointing towards UGC 1807) favour a flyby event for the origin of lopsidedness in this galaxy.”
Ah, ha! So, we have a nearby companion galaxy. We’ve learned recently that combining galaxies produces starburst activity and the case is true of NGC 891 as well. Studies done as recently as June 2008 indicate starbust activity based on the strength of the polycyclic aromatic hydrocarbon (PAH) features. And where are those PAHs? Why, in the halo, of course. According to the work of Rand (et al): “We present infrared spectroscopy from the Spitzer Space Telescope at one disk position and two positions at a height of 1 kpc from the disk in the edge-on spiral NGC 891, with the primary goal of studying halo ionization. Our main result is that the [Ne III]/[Ne II] ratio, which provides a measure of the hardness of the ionizing spectrum free from the major problems plaguing optical line ratios, is enhanced in the extraplanar pointings relative to the disk pointing. Using a 2D Monte Carlo-based photoionization code that accounts for the effects of radiation field hardening, we find that this trend cannot be reproduced by any plausible photoionization model and that a secondary source of ionization must therefore operate in gaseous halos. We also present the first spectroscopic detections of extraplanar PAH features in an external normal galaxy. If they are in an exponential layer, very rough emission scale heights of 330-530 pc are implied for the various features. Extinction may be non-negligible in the midplane and reduce these scale heights significantly. There is little significant variation in the relative emission from the various features between disk and extraplanar environment. Only the 17.4 ?m feature is significantly enhanced in the extraplanar gas compared to the other features, possibly indicating a preference for larger PAHs in the halo.”
So where is all this going? Current research shows a correlation between PAH abundance with galactic age. When asymptotic giant branch cough their carbon dust back into the interstellar medium at the end of their evolution, they become the primary source of PAHS and carbon dust in galaxies. As we know, a galaxy is one big recycling plant, and the ejecta is returned back to the interstellar medium after a few hundred million years along the line of main sequence evolution. But, the filamentary pattern extending away from the galactic disc of NGC 891 may very well point to stellar supernova explosions. By contrast, those, huge, massive stars that end up as Type II supernovae are the ones that blast dust and metals everywhere the moment they form.
So is this the result of old – or new – activity? According to Popescu (et al): “We describe a new tool for the analysis of the UV to the sub-millimeter (sub-mm) spectral energy distribution (SED) of spiral galaxies. We use a consistent treatment of grain heating and emission, solve the radiation transfer problem for a finite disk and bulge, and self-consistently calculate the stochastic heating of grains placed in the resulting radiation field. We use this tool to analyse the well-studied nearby edge-on spiral galaxy NGC 891. First we investigate whether the old stellar population in NGC 891, along with a reasonable assumption about the young stellar population, can account for the heating of the dust and the observed far-infrared and sub-mm emission. The dust distribution is taken from the model of Xilouris et al. (1999), who used only optical and near-infrared observations to determine it. We have found that such a simple model cannot reproduce the SED of NGC 891, especially in the sub-mm range. It underestimates by a factor of 2-4 the observed sub-mm flux. A number of possible explanations exist for the missing sub-mm flux. We investigate a few of them and demonstrate that one can reproduce the observed SED in the far-infrared and the sub-mm quite well, as well as the observed radial profile at 850 mu m. For the models calculated we give the relative proportion of the dust radiation powered by the old and young stellar populations as a function of FIR/sub-mm wavelength. In all models we find that the dust is predominantly heated by the young stellar population.”
Although it may have been busy at one time, NGC 891 is quiet now. According to Rowan Temple, “Using a sample of other local galaxies, we compare the X-ray and infrared properties of NGC 891 with those of `normal’ and starburst spiral galaxies, and conclude that NGC 891 is most likely a starburst galaxy in a quiescent state.” So take a look when you have time. This magnitude 10 beauty is located at (RA 2 : 22.6 Dec +42 : 21) at is often considered to be one of the finest deep sky objects Messier never cataloged.
No matter which Herchel discovered it.
Many thanks to AORAIA member Ken Crawford for the use of his superb image!
Mercury, prior to MESSENGER's closest approach. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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This morning at 4:40 am EDT, the MESSENGER spacecraft passed only 200 kilometers (124 miles) above Mercury’s surface as it made its second flyby of the mission. Now, the spacecraft is speeding away from Mercury, continuing its science observations for about 20 hours following closest approach. This flyby should provide the first global perspective of Mercury, as, if all went well, we should have images in total covering about 95 percent of the planet. “This second flyby will show us a completely new area of Mercury’s surface, opposite from the side of the planet we saw during the first,” said Louise M. Prockter, scientist for the mission.
If you’re looking for images and data from the flyby here, sorry to disappoint, but data will be transmitted to Earth only after the completion of all science observations. So, for now, even the MESSENGER science team has to wait. But scientists are already eagerly exploring the optical navigation images acquired just prior to the flyby. Shown here is a Narrow Angle Camera (NAC) image from the eighth and final optical navigation image set, taken about 14.5 hours before the flyby’s closest approach.
As in the earlier seven sets, Mercury appears as a thin sunlit crescent. Though much of Mercury is in darkness in this image, the visible portion had never been seen by spacecraft before. This portion of Mercury’s surface was not viewed during any of Mariner 10’s three flybys or during MESSENGER’s first flyby earlier this year. The newly imaged terrain shows a wide range of geologic features, and scientists have marked them on the image. Near the northern limb of the planet, extensive smooth plains, possibly volcanic in origin, are identified. A nearby crater is the brightest feature visible in the image, suggesting a relatively young age. In the southern region, a large basin is seen with a smooth floor, likely also a product of volcanism. A large scarp that appears to cut through this basin may have formed as Mercury cooled and contracted.
For this flyby, MESSENGER was a “green” spacecraft – meaning it didn’t require the firing of its thrusters to fly precisely where the scientists wanted to make observations. Instead, engineers used a type of “solar sailing,” to guide the spacecraft. “There are no refueling station in interplanetary space, so we’re stuck with the amount of fuel we had at launch,” said principal investigator Sean Solomon during a press conference last week. “Some of that fuel is required to get us into orbit (of Mercury in 2011). By not using fuel on some smaller maneuvers makes the mission more reliable and saves propellant, and allows us to have it in our back pocket when we need it for contingencies.” This is the first spacecraft to use this technique with such precision. Planetary flyby has been described as a complex ‘threading of a needle,’ and the MESSENGER team is getting better and better. The spacecraft’s first flyby was in January 2008, and a third will take place on Sept. 29, 2009. Orbit insertion will be on March 18, 2011.
We’ll post the MESSENGER images from this second flyby as soon as they’re available.
Page from Ilan Ramon's diary. Credit: Israel Museum
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Pages from an astronaut’s diary survived the explosion of the space shuttle Columbia in 2003, and on Sunday, selected pages went on display at a museum in Jerusalem. Israeli astronaut Ilan Ramon kept a personal diary during his time in orbit, and portions of it were found about two months after Columbia broke apart on February 1, 2003 while returning to Earth following the STS-107 mission. “Today was the first day that I felt that I am truly living in space. I have become a man who lives and works in space,” Ramon wrote in an entry on his sixth day in orbit. Astronaut Ilan Ramon departs for his flight aboard Columbia. Credit: Chris O’Meara/Associated Press
37 pages survived the extreme heat of the explosion, as well as the 60 km (37-mile) fall to earth and several days of wet weather before they were found. “It’s almost a miracle that it survived — it’s incredible,” Israel Museum curator Yigal Zalmona said. “There is no rational explanation for how it was recovered when most of the shuttle was not.”
Diary pages as they were found. Credit: Israel Ministry of Public Security
The pages were found in a field just outside of Palestine, Texas. On some pages, the writing was washed out, other pages were tattered and torn, pocked with irregular holes as if debris had ripped through them. Pieces were twisted into tightly crumpled wads smaller than a fingernail. Some pages were stuck tightly together and had to be delicately pried apart.
Once it had been verified that the pages were relevant to the Columbia debris, the papers were collected and given to Colonel Ramon’s family. Ramon’s wife, Rona, decided to bring the papers to Israel for deciphering the damaged writing and, ultimately, conservation of the torn and tattered pages.
Most of the pages contain personal information which Mrs. Ramon did not wish to make public. “We agreed to do the restoration completely respecting the family’s privacy and the sensitivity about how intimate the document is,” museum director James Snyder said.
The diary took about a year to restore, Zalmona said, and it took police scientists about four more years to decipher the pages. About 80 percent of the text has been deciphered, and the rest remains unreadable, he said. Page of Ramon's diary that was restored using Photoshop™ and Image-Pro Plus™
Two pages will be displayed at the museum. One contains notes written by Ramon, and the other is a copy of the Kiddush prayer, a blessing over wine that Jews recite on the Sabbath. Zalmona said Ramon copied the prayer into his diary so he could recite it on the space shuttle and have the blessing broadcast to Earth.
There is no information available as to where the pages of the diary were situated during reentry, for example if they were in a pocket of Ramon’s spacesuit or in a padded, heat resistant container or simply held under his leg, as one astronaut suggested.
The diary provides no indication Ramon knew anything about potential problems on the shuttle. Columbia’s wing was gashed by a chunk of fuel tank foam insulation at liftoff and broke up just 16 minutes before it was scheduled to land at the Kennedy Space Center in Florida. All seven astronauts on board were killed.
The diary is being displayed as part of a larger exhibit of famous documents from Israel’s history, held to mark the country’s 60th anniversary this year.
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Another week, another roundup of your questions. This week listeners asked: if forces are communicated through particles, can we run out? If you were traveling at light speed, when would you know to stop? And there’s even more. If you’ve got a question for the Astronomy Cast team, please email it in to [email protected] and we’ll try to tackle it for a future show.
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We’ve talked about the Sun before, but this time we’re going to look at the entire life cycle of the Sun, and all the stages it’s going to go through: solar nebula, protostar, main sequence, red giant, white dwarf, and more. Want to know what the future holds for the Sun, get ready for the grim details.
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Curious and curiouser things began happening when telescopes opened up to the skies. Richard Baum’s book entitled “The Haunted Observatory – Curiosities from the Astronomer’s Cabinet” has the reader thinking like Alice might have in her wonderland. Bright lights, aspiring dots, gleaming trails of a forgotten impression can all fool a mind into perceiving reality where none may exist. Thus, when it comes to making reason out of the unexpected, some astronomer’s lives get so entertaining and worthwhile and ends up making this book so entertaining.
In the seventeenth century, Galileo built his own telescope, viewed moons and rebuilt our perception of the universe. Jumping off from this, telescopes came into ever more common usage so that by the eighteenth and nineteenth centuries, it seemed like everyone and their brother’s uncle had one and was getting excited about what they saw. With the increasing number of observers, some odd things were seen or at least imagined. Perhaps the sights were real events or perhaps they were dust on a lens. In any case, sometimes different people provided different interpretations, thus leading to vibrant discord. Such discord is the resonance of this book as it looks at how some disagreements were solved and how some remain to be solved.
As spiritual hauntings are resolved from much investigation, so to are the oddities in Baum’s book. As if to prove the point, the book has a quarter of its pages dedicated to references and bibliographies. Yet this content is pertinent, as Baum’s writing style interposes many large passages and quotes from external sources and intermixes them with his connecting sentences. With seven of the eleven essays previously published in 1973 and since updated, the result is a smooth flowing discourse. However, Baum likes his verbiage, as seen with phrases like ‘a chaotic vade mecum of the incongruous, the variegated and the exotic’. Given that this isn’t most people’s dictum of the day, the average reader may get bogged down. But, as Baum’s curiosities are mostly set in old European times, his words add to the book’s flavour, thus setting the tone of his investigative reporting.
And, in effect, his book reads like a collection of investigative reports. Within it, Baum usually identifies observers, equipment, date, atmospheric conditions and stellar location for each. For example, ‘he [Schroter] with the seven-foot again fit for use, picked up Venus before sunset and at six o’clock proceeded to examine it with a magnifying power of x95’. Such exact detail allows the reader to work alongside the investigation and resolve for themselves possible factors and events that might have given rise to an unexpected observation. But, the reader will quickly discover that these cases are extremely ‘cold’. That is, either the issue has been resolved (e.g. Venus doesn’t have polar ice caps) or there’s never been a repetition (e.g. strange bright light source beside Venus just as the light set on one day). Thus, the reader will enjoy this book if they like a sense of mystery and intrigue but not if they expect to resolve the investigation on their own.
An historian would also get great pleasure from reading this book. In particular, the book shows the rise of transition of technical ability, as with astronomy, into a mature, understood science. Personalities come to the fore, then they influence observations for all the right and wrong reasons and eventually shuffle quickly off this mortal coyle. Conjecture rises, flourishes and gets dashed, with no thought for social niceties. With this, the book provokes a harsh but real glimpse into scientific investigation and human frailties.
In consequence, though no spiritual ghosts permeate through the pages, Richard Baum’s book “The Haunted Observatory – Curiosities from the Astronomer’s Cabinet” is hauntingly nice. Perhaps the reader will see themselves in the pages as the young, fresh observer or the seasoned, opinionated veteran. In either case, there’s some rewarding reading when opening up this book’s pages.
Direct hit - could a huge impact on Mars have snuffed the chances of life? (Karen Carr)
[/caption]We keep sending missions to Mars with the key objective to search for past or present life. But what if a huge impact early in the Red Planet’s history hindered any future possibility for life to thrive? Recent studies into the Martian “crustal dichotomy” indicate the planet was struck by a very large object, possibly a massive asteroid. Now researchers believe that this same impact may have scrubbed any chance for life on Mars, effectively making the planet sterile. This asteroid may have penetrated the Martian crust so deep that it damaged the internal structure irreparably, preventing a strong magnetic field from enveloping the planet. The lack of a Mars magnetosphere thereby ended any chance for a nurturing atmosphere…
Mars looks odd. Early astronomers noticed it, and today’s observatories see it every time they look at the red globe. Mars has two faces. One face (the northern hemisphere) is composed of barren plains and smooth sand dunes; the other face (the southern hemisphere) is a chaotic, jagged terrain of mountains and valleys. It would appear the crustal dichotomy formed after a massive impact early in the development of Mars, leaving the planet geologically scarred for eternity. But say if this impact went beyond pure aesthetics? What if this planet-wide impact zone represents something a lot deeper?
To understand what might have happened to Mars, we have to first look at the Earth. Our planet has a powerful magnetic field that is generated near the core. Molten iron convects, dragging free electrons with it, setting up a huge dynamo outputting the strong dipolar magnetic field. As the magnetic field threads through the planet, it projects from the surface and reaches thousands of miles into space, forming a vast bubble. This bubble is known as the magnetosphere, protecting us from the damaging solar wind and prevents our atmosphere from eroding into space. Life thrives on this blue planet because Earth has a powerful magnetic solar wind defence.
Although Mars is smaller than Earth, scientists have often been at a loss to explain why there is no Martian magnetosphere. But according to the growing armada of orbiting satellites, measurements suggest that Mars did have a global magnetic field in the past. It has been the general consensus for some time that Mars’ magnetic field disappeared when the smaller planet’s interior cooled quickly and lost its ability to keep its inner iron in a convective state. With no convection comes a loss of the dynamo effect and therefore the magnetic field (and any magnetosphere) is lost. This is often cited as the reason why Mars does not have a thick atmosphere; any atmospheric gases have been eroded into space by the solar wind.
However, there may be a better explanation as to why Mars lost its magnetism. “The evidence suggests that a giant impact early in the planet’s history could have disrupted the molten core, changing the circulation and affecting the magnetic field,” said Sabine Stanley, assistant professor of physics at the University of Toronto, one of the scientists involved in this research. “We know Mars had a magnetic field which disappeared about 4 billion years ago and that this happened around the same time that the crustal dichotomy appeared, which is a possible link to an asteroid impact.”
During Mars’ evolution before 4 billion years ago, things may have looked a lot more promising. With a strong magnetic field, Mars had a thick atmosphere, protected from the ravages of the solar wind within its own magnetosphere. But, in an instant, a huge asteroid impact could have changed the course of Martian history forever.
“Mars once had a much thicker atmosphere along with standing water and a magnetic field, so it would have been a very different place to the dry barren planet we see today.” – Monica Grady, professor of planetary and space sciences at the Open University.
Losing its magnetic field after the deep asteroid impact catastrophically damaged the internal workings of the planet, Mars quickly shed its atmosphere, thereby blocking its ability to sustain life in the 4 billion years since. What a sad story…
Foton M3 after landing in Kazakhstan after the experiment. Samples, including Orkney sample, are screwed onto
[/caption]In an effort to understand how organic chemicals might survive after a period in the vacuum of space and then violent re-entry through the atmosphere, scientists have uncovered some interesting results. Last year, the ESA/Russian Foton-M3 mission was launched to test the effects of microgravity on various biological samples. However, a sample of Orkney rock had a harder journey than most. Attached to the outside of the craft, this sample underwent extreme heating during the descent toward the plains of Kazakhstan. Although most of the sample was vaporized, scientists have unveiled results that the sample still contains very obvious signs that it once harboured life. These exciting results set new limits on how organic chemicals may survive unaltered for long periods in space before plunging through a planetary atmosphere, plus it raises some interesting questions into how future searches for extraterrestrial life may be performed…
The principal mission objective for many planetary missions is the search for extraterrestrial life. Although many of our robotic explorers cannot detect life directly, they are able to carry out a host of mini lab experiments on samples taken from the planets surface. NASA’s Phoenix Mars Mission for example has been tirelessly slaving over its hot oven (a.k.a. the Thermal and Evolved-Gas Analyzer, or TEGA for short), dropping samples of Mars soil into its single-use kilns for the last few months. This effort is to vent any prebiotic chemicals into a gas form so instrumentation can then “sniff” the vapour. Should organic chemicals be found, there will be an improved chance that life may have evolved on the Red Planet’s surface.
But say if there is an easier (and cheaper) way to look for ET? Rather than sending hundreds of millions of dollars-worth of hardware to Mars to look for organic chemicals, why can’t we analyse all the rocky samples littered across the globe that originated from space? After all, we now know that some meteorites originate from Mars itself, surely we can perform a far more detailed analysis on these samples instead of depending on a robot millions of miles away?
The big stumbling block comes if we consider the extreme temperatures meteorites are put under during re-entry into the terrestrial atmosphere. Generally one would expect any evidence for past life (whether that be organic chemicals or fossilized remains) to be blow-torched out of existence by reentry temperatures up to 3,000°F (1,650°C). So, researchers from the University of Aberdeen, Scotland, decided to test a chunk of rock from a Scottish island by subjecting it to several days in space and then seeing if any evidence of life in the rock sample remained intact after the descent.
the Kazakhstan landing site of Foton-M3 in September 2007 (R. Demets/F. Brandstatter)
“The specially prepared piece of Orkney rock took part in the unmanned Foton M3 mission which aimed to examine the rock’s behaviour when it was exposed to the extreme temperatures involved in it’s re-entry through the Earth’s atmosphere,” Professor John Parnell, lead scientist in the study, said.
The reason why Orkney rock was used is because of the material’s robustness when exposed to extreme heat. After all, meteorites need to be made of tough stuff to make it to the ground. “Three quarters of the rock, which was about the size of a small pork pie, was burnt off in the experiment. However, the quarter which returned to Earth has shown us that if intelligent life were to have come into contact with the rock, it would have provided them with evidence that life exists on another planet.”
Now this is where the implications behind these results become abundantly clear. If this piece of rock was sent out into space, only for it to eventually encounter an alien world with intelligent life on its surface, it is conceivable that the rock would survive reentry, preserving the organic chemicals for further study by extraterrestrials. Of course, the reverse is true. If life existed (or exists) on Mars, perhaps we should take a closer look at those Martian meteorite samples…
In the case of the Orkney sample, it contains the remains of 400 million year-old algae, providing a rich chemical signature that Parnell and his team could detect. “We would be extremely excited if we found similar remains in a meteorite arriving from another world,” he added.
Although this experiment only scratches the surface of how organic chemicals may last, unaltered, in space (after all, should a meteoroid sample float in space for millions of years, could organic chemicals be altered by cosmic rays?), it does help us understand that for lower energy reentries, organic chemicals can indeed survive the burn…
Could the magnetic field of the Earth really reverse in 2012? I wouldn't bet on it...
[/caption]Apparently, on December 21st 2012, our planet will experience a powerful event. This time we’re not talking about Planet X, Nibiru or a “killer” solar flare, this event will originate deep within the core of our planet, forcing a catastrophic change in our protective magnetic field. Not only will we notice a rapid reduction in magnetic field strength, we’ll also see the magnetic poles rapidly reverse polarity (i.e. the north magnetic pole will be located over the South Pole and vice versa). So what does this mean to us? If we are to believe the doomsayers, we’ll be exposed to the vast quantities of radiation blasting from the Sun; with a reversing magnetic field comes a weakening in the Earth’s ability to deflect cosmic rays. Our armada of communication and military satellites will drop from orbit, adding to the chaos on the ground. There will be social unrest, warfare, famine and economic collapse. Without GPS, our airliners will also plough into the ground…
Using the Mayan Prophecy as an excuse to create new and explosive ways in which our planet may be destroyed, 20 12 2012 doomsayers use the geomagnetic shift theory as if it is set in stone. Simply because scientists have said that it might happen within the next millennium appears to be proof enough that it will happen in four years time. Alas, although this theory has some scientific backing, there is no way that anyone can predict when geomagnetic reversal might happen to the nearest day or to the nearest million years…
Firstly, let’s differentiate between geomagnetic reversal and polar shift. Geomagnetic reversal is the change in the magnetic field of the Earth, where the magnetic north pole shifts to the South Polar Region and the south magnetic pole shifts to the North Polar Region. Once this process is complete, our compasses would point toward Antarctica, rather than northern Canada. Polar shift is considered to be a less likely event that occurs a few times in the evolutionary timescale of the Solar System. There are a couple of examples of planets that have suffered a catastrophic polar shift, including Venus (which rotates in an opposite direction to all the other planets, therefore it was flipped upside down by some huge event, such as a planetary collision) and Uranus (which rotates on its side, having been knocked off-axis by an impact, or some gravitational effect caused by Jupiter and Saturn). Many authors (including the doomsayers themselves) often cite both geomagnetic reversal and polar shift as being one of the same thing. This isn’t the case.
So, on with geomagnetic reversal…
How often does it happen? The Earths interior (University of Chicago)The reasons behind the reversal of the magnetic poles is poorly understood, but it is all down to the internal dynamics of Planet Earth. As our planet spins, the molten iron in the core flows freely, forcing free electrons to flow with it. This convective motion of charged particles sets up a magnetic field which bases its poles in the North and South Polar Regions (a dipole). This is known as the dynamo effect. The resulting magnetic field approximates a bar magnet, allowing the field to envelop our planet.
This magnetic field passes through the core to the crust and pushes into space as the Earth’s magnetosphere, a protective bubble constantly being buffeted by the solar wind. As the solar wind particles are usually charged, the Earth’s powerful magnetosphere deflects the particles, only allowing them into the polar cusp regions where the polar magnetic fieldlines become “open.” The regions at which these energetic particles are allowed to enter glow as aurorae.
Usually this situation can last for aeons (a stable magnetic field threaded through the North and South Polar Regions), but occasionally, the magnetic field is known to reverse and alter in strength. Why is this?
A chart showing Earths polarity reversals over the last 160 million years. Black = normal polarity, White = reversed polarity. From Lowrie (1997)
Again, we simply do not know. We do know that this magnetic pole flip-flop has occurred many times in the last few million years, the last occurred 780,000 years ago according to ferromagnetic sediment. A few scaremongering articles have said geomagnetic reversal occurs with “clockwork regularity” – this is simply not true. As can be seen from the diagram (left), magnetic reversal has occurred fairly chaotically in the last 160 million years. Long-term data suggests that the longest stable period between magnetic “flips” is nearly 40 million years (during the Cretaceous period over 65 million years BC) and the shortest is a few hundred years.
Some 2012 theories suggest that the Earth’s geomagnetic reversal is connected to the natural 11-year solar cycle. Again, there is absolutely no scientific evidence to support this claim. No data has ever been produced suggesting a Sun-Earth magnetic polarity change connection.
So, already this doomsday theory falters in that geomagnetic reversal does not occur with “clockwork regularity,” and it has no connection with solar dynamics. We are not due a magnetic flip as we cannot predict when the next one is going to occur, magnetic reversals occur at seemingly random points in history.
What causes geomagnetic reversal? The model Earth, can a magnetic field be modelled in the lab? (Flora Lichtman, NPR)Research is afoot to try to understand the internal dynamics of our planet. As the Earth spins, the molten iron inside churns and flows in a fairly stable manner for millennia. For some reason during geomagnetic reversal, some instability causes an interruption to the steady generation of a global magnetic field, causing it to flip-flop between the poles.
In a previous Universe Today article, we discussed the efforts of geophysicist Dan Lathrop’s attempts to create his own “model Earth,” setting a 26 tonne ball (containing a molten iron analogue, sodium) spinning to see if the internal motion of the fluid could set up a magnetic field. This huge laboratory experiment is testament to the efforts being put into understanding how our Earth even generates a magnetic field, let alone why it randomly reverses.
A minority view (which, again is used by doomsayers to link geomagnetic reversal with Planet X) is that there may be some external influence that causes the reversal. You will often see associated with the Planet X/Nibiru claims that should this mystery object encounter the inner Solar System during its highly elliptical orbit, the magnetic field disturbance could upset the internal dynamics of the Earth (and the Sun, possibly generating that “killer” solar flare I discussed back in June). This theory is a poor attempt to link several doomsday scenarios with a common harbinger of doom (i.e. Planet X). There is no reason to think the strong magnetic field of the Earth can be influenced by any external force, let alone a non-existent planet (or was that a brown dwarf?).
The magnetic field strength waxes and wanes… Variations in geomagnetic field in western US since last reversal. The vertical dashed line is the critical value of intensity below which Guyodo and Valet (1999) consider several directional excursions to have occurred.New research into the Earth’s magnetic field was published recently in the September 26th issue of Science, suggesting that the Earth’s magnetic field isn’t as simple as we once believed. In addition to the North-South dipole, there is a weaker magnetic field spread around the planet, probably generated in the outer core of the Earth.
The Earth’s magnetic field is measured to vary in field strength and it is a well known fact that the magnetic field strength is currently experiencing a downward trend. The new research paper, co-authored by geochronologist Brad Singer of the University of Wisconsin, suggests that the weaker magnetic field is critical to geomagnetic reversal. Should the stronger dipole (north-south) field reduce below the magnetic field strength of this usually weaker, distributed field, a geomagnetic reversal is possible.
“The field is not always stable, the convection and the nature of the flow changes, and it can cause the dipole that’s generated to wax and wane in intensity and strength,” Singer said. “When it becomes very weak, it’s less capable of reaching to the surface of the Earth, and what you start to see emerge is this non-axial dipole, the weaker part of the field that’s left over.” Singer’s research group analysed samples of ancient lava from volcanoes in Tahiti and Germany between 500,000 and 700,000 years ago. By looking at an iron-rich mineral called magnetite in the lava, the researchers were able to deduce the direction of the magnetic field.
The spin of the electrons in the mineral is governed by the dominant magnetic field. During times of strong dipolar field, these electrons pointed toward the magnetic North Pole. During times of weak dipolar field, the electrons pointed to wherever the dominant field was, in this case the distributed magnetic field. They think that when the weakened dipolar field drops below a certain threshold, the distributed field pulls the dipolar field off-axis, causing a geomagnetic shift.
“The magnetic field is one of the most fundamental features of the Earth,” Singer said. “But it’s still one of the biggest enigmas in science. Why [the flip] happens is something people have been chasing for more than a hundred years.”
Our meandering magnetic pole The movement of Earth's north magnetic pole across the Canadian arctic, 1831--2001 (Geological Survey of Canada)Although there appears to be a current downward trend in magnetic field strength, the current magnetic field is still considered to be “above average” when compared with the variations measured in recent history. According to researchers at Scripps Institution of Oceanography, San Diego, if the magnetic field continued to decrease at the current trend, the dipolar field would effectively be zero in 500 years time. However, it is more likely that the field strength will simply rebound and increase in strength as it has done over the last several thousand years, continuing with its natural fluctuations.
The positions of the magnetic poles are also known to be wondering over Arctic and Antarctic locations. Take the magnetic north pole for example (pictured left); it has accelerated north over the Canadian plains from 10 km per year in the 20th Century to 40 km per year more recently. It is thought that if the point of magnetic north continues this trend, it will exit North America and enter Siberia in a few decades time. This is not a new phenomenon however. Ever since James Ross’ discovery of the location of the north magnetic pole for the first time in 1831, it’s location has meandered hundreds of miles (even though today’s measurements show some acceleration).
So, no doomsday then?
Geomagnetic reversal is an engrossing area of geophysical research that will continue to occupy physicists and geologists for many years to come. Although the dynamics behind this event are not fully understood, there is absolutely no scientific evidence supporting the claim that there could be a geomagnetic reversal around the time of December 21st, 2012.
Besides, the effects of such a reversal have been totally over-hyped. Should we experience geomagnetic reversal in our lifetimes (which we probably won’t), it is unlikely that we’ll be cooked alive by the Solar Wind, or be wiped out by cosmic rays. It is unlikely that we’ll suffer any mass extinction event (after all, early man, homo erectus, lived through the last geomagnetic shift, apparently with ease). We’ll most likely experience aurorae at all latitudes whilst the dipolar magnetic field settles down to its new, reversed state, and there might be a small increase in energetic particles from space (remember, just because the magnetosphere is weakened, doesn’t mean we wont have magnetic protection), but we’ll still be (largely) protected by our thick atmosphere.
Satellites may malfunction and migrating birds may become confused, but to predict world collapse is a hard pill to swallow.
In conclusion:
Geomagnetic reversal is chaotic in nature. There is no way we can predict it.
Simply because the magnetic field of the Earth is weakening does not mean it is near collapse. Geomagnetic field strength is “above average” if we compare today’s measurements with the last few million years.
The magnetic poles are not set in geographical locations, they move (at varying speeds) and have done ever since measurements began.
There is no evidence to suggest external forcing of internal geomagnetic dynamics of the Earth. Therefore there is no evidence of the solar cycle-geomagnetic shift connection. Don’t get me started on Planet X.
So, do you think there will be a geomagnetic reversal event in 2012? I thought not.
Once again, we find another 2012 doomsday scenario to be flawed in so many ways. There is no doubt that geomagnetic reversal will happen in the future for Earth, but we’re talking about time scales anything from an optimistic (and unlikely) 500 years to millions of years, certainly not in the coming four years…
Sources: NASA, US News, SciVee, How To Survive 2012, AGU
While every telescope set-up is slightly different, they are all basically the same in some respects. There must be an optical tube of some type, a mount and eyepieces. Take the time to become familiar with all the components of your telescope! If you must assemble and dis-assemble your telescope each time you use it, it’s a very wise idea to practice a few times before you go out in the dark. There is simply nothing more frustrating that trying to learn to set up your equipment when you cannot see what you are doing – or to loose a small part in the dark. If it is at all possible, leave your telescope and tripod fully assembled and in a place where it is easy to set outside at a moment’s notice. You’ll find that you’ll use it far more often if it takes less work.
Your telescope’s view is also dependent on ambient temperature. If you wear eyeglasses, you understand why! If you go from a very cool environment, such as a air-conditioned house, into a humid outdoors setting, your glasses fog up, don’t they? And so will your telescope’s optics. The same is true when observing outdoors in the winter. When taking your telescope from a heated climate to a cold one, you must give the telescope time to “cool down”. Even just a few degrees can mean waiver in the image.
Experience will become your best teacher. It won’t take long before you realize that very humid nights or exceptionally cold ones are not particularly good times to observe. Unless you plan on looking at the Moon itself, nights that are well moon-lit are also not good times to search for a faint galaxy, either. Little things, like waiting for a planet to clear the atmospheric “murk” at the lower horizon mean a much better viewing experience.
Now that you have your observing site, learned to set up, and established a time to practice astronomy… Let’s learn how to use your telescope! 
