Stargazer Steve is a weekly astronomy column for The Arthur
Mercury: More interesting than you think
Poor Mercury: After Pluto lost planet status, Mercury became the runt of the litter. While it is possible to see it with the naked eye, its close proximity to the sun makes viewing it limited to only 2 hours during the twilight of sunset or sunrise. Even if you are able to catch a good look at it, it looks like just a slightly larger version of our moon: grey, dry, and littered with impact craters. But thanks to the recent MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) mission, we’re learning that the tiny, sun-baked ball of dust has a lot of secrets.
Firstly, at just under 2,500 kms in radius, it’s less than half the size of the Earth. Despite this, it has a magnetic field. It’s small, and it’s weak, but it’s there. A magnetic field is a bit like a giant shield, protecting a planet from deadly cosmic rays. Life was able to take root on Earth in part because the earliest peptides and amino acids were shielded from being torn apart by cosmic radiation. So why does Mercury having a magnetic field mean anything significant? Firstly, it tells us that it has a core made of iron. Not only that, but the core is active (spinning). Most astronomers aren’t 100% certain as to why it’s able to be so small and still maintain an active core, but it probably has something to do with the huge tidal forces (the same forces that our Moon has on our oceans) that the Sun yanks on it, causing compression waves to keep the core hot. Mars, in contrast, has no magnetic field. It does have an iron core, one that used to spin in much the same way that Earth’s core did. But its core has cooled, and effectively solidified, spinning no more. So at least from a radiation standpoint, you’d stand a better chance at surviving a walk on Mercury than on Mars...but wear sunscreen.
Perhaps the most surprising thing found by MESSENGER, is that Mercury actually has water. Like the Earth, all of its water has been deposited by comets, bringing in huge amounts of water-ice from the outer parts of our solar system, the Kuiper Belt and Oort Cloud. Being so close to the sun, Mercury has had almost its entire atmosphere blown away, including its water. By contrast, Earth was able to hang onto its water because of its atmosphere, gravity, and the distance from the sun. So how was this tiny amount of water able to survive? Craters and axis. Mercury’s rotational axis is the most vertical of all the planets, and it’s also covered in impact craters. This means that the craters on the poles have regions that are permanently in the shade, allowing water-ice to hide indefinitely, or until some other impact blows it off into space.
Another surprising fact about Mercury is that despite its petite size, Mercury is actually the second densest planet in the entire system, only slightly less dense than Earth. Let that stew in for a moment: pound-for-pound, Mercury is the smallest planet, and is denser than of the other planets except our own. How did this happen? Well, despite being so heated up by the sun, Mercury has suffered from the worst case of shrinkage in the solar system. Mercury is actually smaller than it used to be. Early in its life, Mercury was hit by as asteroid so large that if it were to hit Earth today, it would wipe out all life within minutes. This impact blew off huge amounts of material, and then the slow, gently pull of gravity was allowed to re-form the planet. But since so much of the original Mercurial mass was sucked into the sun, or ejected into space (some of it may even have landed on Earth!), Mercury, Mark II was smaller. The mantle, being robbed of so much mass, could not maintain its outward pressure, and so the crust shrank in on itself, much like a drying orange. Mercury still bears the scars of this episode of cosmic-shrinkage, and MESSENGER has sent back thousands of images of huge cliffs and deep valleys that emanate outwards in beautiful spider web-like patterns.
Hopefully this column has helped make the deceptively dull rock look a little more glamorous. In the years to come, MESSENGER will settle into a regular orbit and image a detailed map of the entire planet, so Mercury is only going to get more interesting.
If there are any other astronomical topics you would like me to cover, black holes, moons, galaxies, dark matter, space exploration etc….leave a message in the comments section, or email me at firstname.lastname@example.org, and I’ll gladly answer your questions.
Stargazer Steve is a weekly astronomy column for The Arthur.
The Night Sky: What's up with that?
Over the summer, I took up astronomy. I would have done this earlier, but I was a bit overwhelmed with all the gadgets that I thought would be necessary, on top of the staggering array of complexity of the night sky, it seemed a daunting task. Then after a little (very little) research, I learned that it took surprisingly little to do some amateur astronomy. This week, I'll tell you how.
1) The Naked Eye: Finding a dark sky can reveal a surprising number of secrets. The spiral arm of the Milky Way, binary systems, nebula, planets, even distant galaxies are visible with the naked eye...if you know where to look. I recommend you familiarize yourself with the constellations. Constellations are very useful to amateur astronomers as their stars tend to point to other objects. For instance, the distinctive "W" shape of Cassiopeia can easily point one to a double-globular cluster, and the Andromeda Galaxy...all visible with the naked eye.
2) Binoculars. Even a cheap pair of binoculars can reveal some startling detail in the moon. With a pair of steady-hands holding them, you can even make out the 4 largest moons of Jupiter. That's how I accidentally got into all this stargazing business: My grandmother gave me the pair of binoculars that my grandfather used to use for bird watching. Driving south one evening, I saw a particularly bright star. Suspiciously bright, in fact. Once home, I decided to look at that object with the binoculars, and lo! Jupiter and her 4 largest moons did appear! What I saw that night was pretty much exactly what Galileo saw 398 years go. I still use binoculars when I go out with my scope as they're 7 times more sensitive than my eyes, and they're compact, light, and easy to use: just point.
3) Cameras: Only recently, I learned that a digital camera is much more sensitive to light, if you know the camera a little bit. I've had no camera experience prior to this, so believe me when I say it's easier than you think. Odds are, you have a typical point-and-shoot digital camera (I have a Canon Powershot A430) like I do, and that can pick up more than you think. It's affordable, and easy. All you need to do is tell your camera to keep the shutter open a little longer than normal (which typically happens during the "night" setting). By opening the shutter a little longer and increasing the ISO speed (it has to be at least 400 if you want to see anything) your camera will pick up more images than the human eye can see. The next step is a tripod. Much to my surprise, there are small, affordable tripods available for $10. Stabilize the camera, and take yourself a neat image. But for really impressive images, you need to keep the shutter open a little longer than most point-and-shoot cameras offer. Sadly, for this you must upgrade to an SLR Camera....they're not cheap. But if you can get one (I have a Canon Rebel), you can keep the shutter open as long as you want, and even without a telescopic lens, you can catch the dimmest stars, and faintest colours invisible even through a telescope.
4) Telescope. If you're like me, you'll likely want to upgrade sooner rather than later. This is a step that requires a little more care and research. Firstly, don't waste your money with those low-power telescopes you see at the department store. They're fine in a pinch, but you will very quickly be frustrated by the limited abilities of the scope, coupled with the poor functionality. If you do have one of these lying around in your garage collecting dust, you may have been similarly frustrated with how little you can see through its miniscule eyepiece, and probably figured that it was not the telescope that's going wrong, but you must be doing something wrong. Well, it's not. It's the telescope. It's cheap, and looking through a telescope should never be difficult. There are several types of scopes you can get, and chances are your first scope will be a refractor, or possibly a reflector. If and when you do choose to buy a scope, be careful to choose what you want one for. Is it astrophotography, or just casual viewing? Do you want to look for planets or deep-sky objects (such as galaxies), or a bit of both? Be careful not to go too big, or you'll have to lug the damn thing outside. Speaking from experience, it can be a real pain to bring out a huge scope, only to have clouds roll over, or the moisture in the air blanket you scope with dew.
5) Ask someone else. Amateur astronomers are some of the nicest group of hobbyists you will ever meet, and they're always willing and eager to show people the wonders of the night sky. I joined the Peterborough Astronomical Association, and there were loads of people there willing to help a beginner like me out. If you know someone who has a scope, ask them if you can tag along....odds are they'll be only too happy for a)the company and b) the chance to show off a little. I myself have taken out about a dozen people in my brief astronomical travels, so if you're at all interested, you can get in touch with me, and I'll even take you out the next time I go (plus, you can help me carry the telescope!). You can email me, or add me on facebook, and I'll happily show you around the next time I go out (which is often).
I hope this column helps a little. In the coming weeks planets which have been hiding all summer are going to re-appear and will surely be a sight to see.
Are skeptics inherently combative? Is there something about skeptic activism that requires jerk-like derision, or is it just a select number of skeptics? I, for one, believe that it's well within the bounds of respectful discourse to ridicule the ridiculous. I'm concerned far less about hurting someone feeling than I am concerned about being right. There may be more-respectful ways of doing things, but frankly, while people are calling for skeptics to play nice, the other side simply isn't.
As with all activism, there certainly is a degree of derision and insults within the skeptical community. But in my experience, skeptics just aren't as mean as people present them as. Perhaps the rudest (who, for the purposes of this discussion must also be the most public rude ones, otherwise you might not know who I'm talking about) among us are Penn Jillette, Richard Dawkins, Christopher Hitchens and PZ Myers. But the rude parts that people outside the community hear about are far from a representative sample. It doesn't take a lot of digging to find that these people are really loving, caring, respectful people who are at the same time realists and optimists. Once in a while they get pushed too far, and they push back in kind. And yet it is they who get lambasted, not the ones spreading lies, bad thinking, or personal attacks.
For every "It's just a frakkin-cracker!" out there, there are a dozen people willing to say the most abhorent things about a skeptic, their profession, or even the very method of science...and at least when it comes to alternative medicine, they are winning. They wage a battle of pseudo-science and their weapon of choice is language, not evidence. When skeptics retort with evidence, they are derided for not carefull, respectful wording. Skeptics are called insulting, but no one stops to consider the countless times that skeptics, and skepticism itself is insulted. Can they really be blamed for fighting back?
For my money, someone is always going to get pissed off about these issues. It's not that skeptisicm is inherently combative and insulting, but that the pseudo-sciences themselves are inherently emotional. No amount of respectful discourse, carefully treading on glass is going to prevent it's followers and practicioners from taking things personally. Is this really an enterprise that skeptics should undertake? Hells-no. Skeptics tend to be some of the most respectful community of thinkers that I have ever come across, (far more than my university), and for all the charges of derision and insults, skeptics aren't the ones throwing stones.
We're just throwing the stones back.
But not always, because some stones are just too damn big and ugly to touch.
I know this is an unpopular thing to say within geek and skeptical circles, but I'll say it:
Talk Like a Pirate Day is lame.
With better equipment, comes better pictures.
The following is the first of what will hopefully be a weekly column to be published in the Arthur, the student paper of Trent University
Stargazer-Steve: Your weekly journey through the cosmos with a really lame title.
Pluto: What the hell?
Welcome to Stargazer-Steve, a lamely-titled weekly column to provide you with all the astronomical news and insights you could shake stick at, and then stop shaking that stick, because it’s a dumb metaphor. Honestly, who shakes a stick at things that are large in number? This week, the business is Pluto. Or to be more specific, Pluto: what the hell?
Pluto was discovered in 1930. Its finding and subsequent naming quickly made it the most endearing planet in the solar system. After all, how can you not be charmed by a planet that’s smaller than our moon, and was named by an 11-year old girl? Without a clear understanding of what defines a planet, it was granted planet status, and the solar system had a new, bizarre little brother skimming around the outermost limits of our planetary system, occasionally kissing the orbit of Neptune.
But astronomers kept looking in that area. The more they looked, the more they found. Before long, and as technology became more precise, several other Pluto-like objects were found in the vicinity: Eris, Sedna, Orcus, Varuna, and most recently, Makemake. Were all these objects planets? The problem quickly became clear: scientists needed a clear definition of what a planet was, and wasn’t. If everything that looked remotely like Pluto, then our planetary family would have over 20 members by now, and with no clear taxonomy to separate them for ease of understanding.
Enter, 2006. The International Astronomical Union (IAU) convened to decide: expand the definition of a planet, which would not only allow Pluto to maintain its status, but force the inclusion of the objects Eris and Ceres (whose planetary ambitions very closely mimic that of Pluto), or limit the definition of planet, while creating a new class. We all know which way they went by now.
Part of what was decided would allow planet status, is the ability of an object to “clear the path”. A planet must have substantial mass so that a) the other objects in its region either get blown off course 2) completely captured as satellites of the planet, or c) crash into the planet. In short: gravitational dominance. Pluto fails here. Pluto’s companion, Charon (pronounced, Karon) doesn’t actually orbit Pluto, at least not in the same way that a normal moon does (does that make me moon-normative now?). Charon has roughly half the mass that Pluto has, and that means half the gravity. Since Pluto is so small, and Charon is so massive (relative to Pluto), the two bodies orbit each other at a point between them, right smack dab in the middle of space. The centre of gravity of a planet can’t be off the surface of the friggin planet. That’s no way for a planet to behave.
The more observant of you may have pointed out by now that Pluto’s orbit intersects with that of Neptune, so shouldn’t that mean that Neptune isn’t a planet? What do you think of that, fancy-pants astronomy-guy? Well, good try, regular-pants: the orbits of Neptune and Pluto overlap, but they don’t intersect. Even if they did, there are no Neptune-sized objects in Neptune’s orbit. Neptune and Pluto will never, ever collide. They cannot, simply by virtue of their paths around Sol, our sun.
In addition, if you could cast some huge Harry Potter spell to magically place Pluto in with its fellow rocky brethren, it would have a huge ice-tail, like a comet, as the heat from the sun evaporated about a 3rd of Pluto’s icy innards out into space. After a few thousand years, it would be even smaller. That’s no way for a planet to behave.
In the end, Pluto was reclassified as a “dwarf planet”, along with Eris and Makemake. In addition, Ceres was upgraded from asteroid to dwarf planet: a net gain for our solar system. Pluto’s demotion needn’t be disheartening. If anything, I think its charm real estate as grown: rather than be one of 9 (or 12) planets, Pluto is one of only 4 dwarf planets, and its cohorts are equally adorable and charming. But most important of all, we now understand our universe just a little bit better.
Clear Skies, and don’t steal my lame title!
I love my family. I love my sister. My sister is going through a rather traumatizing breakup right now, and she's in town visiting. I can't say I blame her...when in similar situations, I've wanted to just frig-off and leave town for a while too.
But, my sister's skeptical skills are....lacking. Whereas I'll read books by Phil Plait, James Randi and Carl Sagan, she'll read books on astrology, tarot, and yes, The Secret. (I refuse to link to it). I keep my family somewhat insulated from my skeptical activism (such as this blog), as my family tends to find it difficult to accept that when I'm ripping into woo, I'm not actually ripping into them. So my sister arives last night, tears in her eyes, and I play the careing little brother role. She's always welcome, and that's that.
One of her first questions to me was, "Is there a psychic in town that you know of?" I knew exactly where this was going, but I wasn't about to launch into a tirade. I calmly said that "I think you're asking the wrong guy", hoping that would be it. But she asked "why?". But I wasn't about to be moved, "I just don't like psychics very much" was the most diplomatic answer I could give to her in this VERY fragile state. For the moment, it was dropped, and we went for dinner (with another friend.....a very good friend who also happens to see a chiropractor...but whatevs....still a friend to th'end). The uncomfortable, misery-driven evening wore on, my sister asked my friend (who is equally skeptical about psychics as I am, but more diplomatic and whimsical than I can swallow my soul enough to be) if she knew of any psychics in town. She calmly, politley replied no, "but if you find one, I'll go with you. I don't believe in psychics but they can still be fun". That's a fine view of things, but my sister isn't going for "fun". She needs healing, and she thinks she'll find it from a psychic.
Then, the convseration unveiled itself, and I kept my mouth shut (actually, stuffed with food). My sister mentinoned that she only sees this particular psychic whenever she goes through something distressful, and that the last time she went (a few days ago), the psychic "knew" that my sister had a mold problem.
Here is what I WOULD have said: 1) The fact that you only go when you're stressed should be a warning sign: when you're going under a lot of personal turmoil, your critical thinking skills aren't exactly sharp, and you'll easily tend to believe the first thing that someone tells you what you WANT to hear. Indeed, the psychic told her that she will get over it this time (remember, she has seen this person whenever she goes through this, so the psychic already has lots of prior knowledge of my sister) a little faster, and when she does, she will be ready to move on. WHAT THE CRAP IS THAT KINDA TALK?? Can you be any more vague??? Once a person gets over a breakup, of COURSE they'll be ready to 'move on'. jezzus kryst.
As some bizzare way to provide a form of evidence of the psychic's ability, she mentioned that the psychic "knew" that my sister's apartment had a mold problem. My sister continued, "Only two other people knew that, my friend, and my mother" (who, in case you're not keeping score, is also my mother). Now, I remembered this from the last time she saw the psychic, it was a case of the psychic throwing out vague lines like, "you don't live in an apartment, do you?", and my sister reinforced it, by saying, "yes, i live in a basement apartment". That's one for the psychic to file away for future use. And she did, revealing the stunning conclusion that a basement apartment has a mold problem. Brilliant. Confirmation bias on the part of my sister, remembering the hits, and forgetting the misses, and boom: evidence (good enough for her, that is).
I'm torn, because I truly want my sister to feel better, but this psychic fraud is slowing down that process. She will have a difficult road ahead, and she needs to face it, head-on. By hearing vague-generalities from someone who is utterly un-trained and has no gift of insight into the paranormal, her healing process is slowed, even stunted. But in her very fragile state, I feel like I can't say this, because she'll view that as her younger brother not supporting her in the way she needs right now: unconditional support.
I am torn.
Well, a weekly tradition almost died of neglect almost as soon as it learned to crawl. To make up for it, here are SEVERAL pictures to make up for the times I missed. The added bonus is that these are all pictures that I took. This has definatley been the Summer O'Astrono-Me, and here's a buncha pics I took recently: