December 30, 2010 at 12:56 pm | Leave a Comment
Well, another year has come and gone and Earth hasn’t been blasted apart by rogue asteroids, visited by aliens, irradiated by killer space beams from the center of the galaxy, or any of a bunch of other pseudo-scientific “death from the cosmos” scenarios that get floated around the IntarWebs every year. I don’t know about you, but I’m relieved. Of course, it’ll all start up again (does the ignorant rumor-mongering ever quit?) in the New Year. I’ve already been getting a few spam mails from people trying to convince everybody that the year 2012 is the End of Time As We Know It, as supposedly predicted by the Maya people, the flying saucer people, the Greys, the Pleiadians, the Trilateral Commission, the Planet X/Nibiru/N*ncy-Bot people, and all kinds of other folks who seem to take endless delight in making up stuff out of nothing and then using it to scare people/sell stuff/get attention. Chances are you’ve read about their “predictions” from time to time, and hopefully you’ve laughed at their endless prattling in blogs (complete with CAPITAL LETTERS AND LOTS OF !!! AND ??? and silly comments like “No one has ever seen this before” and “NASA is baffled” and “the truth the government doesn’t want you to know about aliens” and other such horse manure).
Now, just because these paranoid shills are making stuff up about the cosmos doesn’t mean that the cosmos is a benign place. Quite the contrary. For example, there ARE asteroids out there. Thousands of them. Most of them are in the Asteroid Belt and are quite likely to stay there, happily orbiting the Sun until the end of time. But, there are other asteroids on their own orbits, some of them quite close to the Sun and which could pose a danger to any of the planets whose orbits they intersection (and not just Earth).
Since its formation some 4.5 billion years ago, Earth and all the other planets, have been bombarded by asteroids and comets. That’s the nature of life in the solar system. If you look at it from a systems evolution standpoint, it’s completely obvious that planets are going to get smacked at some point in their histories. It’s not terribly different from putting a bunch of race cars in a racing oval and letting them go. The race evolves from a bunch of cars in their own lanes to cars that might collide, which then causes other collisions, and eventually you could have cars smashed together into bigger balls of debris.
The early solar system was not made of cars, but it was full of debris circling in orbit around the newborn Sun. Those chunks of ice and rock ran into each other, or were gravitationally attracted to each other. As planets coalesced from that debris, they collided with the leftovers as they, too, orbited the Sun. Earth and all the other planets have pretty much swept their own orbits relatively clean of debris. But, there’s still a lot of debris left over, and each of those pieces (the comets and asteroids) are on their OWN orbits.
Sometimes those orbits intersect another planet’s orbit. And, the inevitable happens — a collision. That’s true of every world in the solar system. And, of course, that includes Earth. Its orbit intersects orbits of asteroids. Now that we’re getting better at detecting those asteroids, we can predict when such intersections might occur. I say “might” because a given orbit can change over time as the object gets a little gravitational “kick” from nearby worlds. So, if we spot an asteroid today, astronomers plot its path using the discovery and followup observations. If that asteroid’s orbit takes it close to a larger body (such as a planet), it could pick up that gravitational kick, which would alter the orbit slightly.
Asteroids and comets don’t suddenly veer off course, as I’ve read in some breathless prose on the IntarWebs. In particular, they don’t just jump from one orbit into another on their own volition just because they feel like or because some mystical space beam is pushing them along. They have to be physically acted on from another body or force. And, those forces have to be pretty big to overcome the orbital inertia that asteroids and comets have. Nor are nearby spacecraft powerful enough to do it, so that blows the “aliens are sending asteroids toward” us theories out of the water. It takes a big body, like a moon or a planet, or a lot of gravitational force, or a collision with another body to create the nudge that affects an asteroid or comet orbit. Interestingly, in the case of comet nuclei in the outer solar system, a passing star could supply the gravitational nudge to dislodge a nucleus or several, sending them on headlong trips toward the Sun.
The worlds of the solar system are bombarded constantly – make no mistake about that. Earth itself sweeps up incoming debris all the time. Most of it is dust, but sometimes bigger rocks fall from space and hit the ground. This is entirely normal and, unless it’s a HUGE rock, nothing to worry about. And, when a big rock does take aim at us, that, too, will be entirely normal. It’s what happens in solar systems. And, instead of devoting our mental capabilities to making up and believing mystical BS about asteroids and killer x-rays and all that other horse manure that passes for pseudo-science these days, it’s best if we spend time understanding just how the orbits of worlds play a part in these entirely normal and rarely world-shaking events. That’s the nature of science — and science is what opens our eyes to the wonders of the cosmos.
So, here at year’s end, take some time to enjoy the cosmos for what it is — and what it does. Not what somebody imagined it to be in order to scare you or to sell you a book or get you to believe in their cock-eyed theories that don’t stand up to reality. It’s a wonderfully fascinating cosmos.
Note: my old friend Phil Plait (The BadAstronomer) has written a wonderful book called “Death from the Skies” that examines a lot of “end times” scenarios that the cosmos can throw at us — in great scientific detail and a wonderful sense of humor. Check it out!
December 23, 2010 at 11:03 am | Leave a Comment
Looking Up: It’s Worth It, so Give it a Try
The lunar eclipse adventure the other night had a lot of people looking up at the sky. It’s probably safe to say that for many, it was probably the first time ever, or at least the first time in a long time. Granted, the weather this time of year isn’t always conducive to stargazing, particularly so for those of us in the northern hemisphere where cold temps are a constant. But, what’s the excuse of those who aren’t in the cold climates? Too much light pollution? Not safe to go out after dark? If so, that’s sad.
Other reasons are more interesting, like the one I heard from a store clerk the other day: “The night sky scares me.” I asked him why and he said that he likes to look at the stars, but he stays close to the house because it feels like he’ll fall into the sky. That blew me away because I had that same experience once — feeling like I’d fall up into the sky. It happened on Mauna Kea on the Big Island of Hawai’i. I was observing using one of the big telescopes up there, and I stepped outside onto a catwalk that circled the dome. It was absolutely pitch-dark out and the sky was so clear that it really DID look like velvet with diamonds scattered on it. Suddenly I felt like I was about to float up there and out of sight, and I did find myself sort of grabbing for the side of the building. But, it wasn’t scary. Just kind of exhilirating. Still, I did know how the guy felt, in a way.
The night sky isn’t scary, but I imagine our human-reptilian brains are programmed to find dark places somewhat disturbing. And, there is this feeling that you get of being a small thing in a very big cosmos. THAT can also be disconcerting, at first.
However, the night sky is actually rather like a puzzle. You see all these stars up there and, at first, they seem to be randomly scattered across the darkness. Then, after a while, you start to see patterns in the star distribution. Shapes leap out at you, and before you know it, you’re recognizing the Big Dipper, Orion, the northern or southern cross, and other well-known shapes. It’s rewarding and visually links you with the universe you’re a part of. No matter where you are.
So, give it a try. Here’s a star map that I sent out with my holiday cards this year. It’s northern-hemisphere oriented, but Orion is visible fairly far south, as are most of the other labeled objects. It’s set for December 25, around 9:30 p.m., but will be good for a few days before and after that date, so give it a try.
December 21, 2010 at 2:30 am | 2 Comments
Well, That Will Teach Me
Amazingly enough, the sky cleared up enough for us to see the eclipse from our deck. That will teach me to post a gloomy note about how we probably weren’t going to see the lunar eclipse! In fact, it cleared up so nicely that we had a starry sky for quite a while during totality. Quite a contrast to the snowy, rainy and cloudy day we experienced.
As I write this, the clouds are starting to move in and totality has ended. But, here are four of the best images we took during the event. And now… time to get some sleep! Great eclipse, gorgeous red color and… best of all… we got to see it! Win-win all the way around!
December 20, 2010 at 11:26 am | Leave a Comment
Hit or Miss on the Lunar Eclipse
You may have heard there’s a spectacular lunar eclipse starting late tonight and going in to early tomorrow morning, visible to those of us in North and Central America. It coincides with the winter solstice (Dec. 21), which is a rarity in itself. And, by all accounts, it should be a great viewing spectacle. Of course, you need clear skies to see the lunar eclipse, and in my neck of the woods (western U.S.), that’s going to be a tough one. We’re clouded over and probably will get rain or snow through the night. Still, hope springs eternal, and I will stay up and see if any sucker holes open up that will allow me to see the events as they unfold high overhead.
That’s the nature of observational astronomy from the surface of Earth: you’re at the mercy of the elements. That hasn’t stopped any of us from going out and trying to see sky phenomena, despite the weather forecast. It didn’t stop William Herschel, who made some of his most far-reaching discoveries from under the often-cloudy skies of Ireland and England. I often take inspiration from him and his sister Caroline. They persevered despite the conditions they had to work under. And, I can always hope that maybe the weather forecast won’t play out the way the meterologists have been predicting. That’s the nature of weather… predictable and changeable, both at once. If you’re going to be an astronomer, weather is something you’ll be very familiar with as you do your stargazing. Last month, we battled some pretty cold weather in Iceland to see (and film) the northern lights. It was cold, but worth the effort for the eerie experience of watching the auroral dance.
So, take heart: if you have clear skies and live in North America or Central America, step out tonight and early tomorrow and check out the Moon. It’ll be a lovely sight. For more information on the eclipse and when/where to look, check out Sky and Telescope’s Web site.
December 19, 2010 at 16:48 pm | Leave a Comment
Giving the Gift of Astronomy
We went shopping the other day. This is the season for prolongued bouts of buying stuff for our loved ones, friends, bosses, whoevers, and of course, you can find all kinds of gew-gaws out there to give. Mr. Spacewriter and I were looking for specific objects, and we did find a few things, but not quite what we were looking for. Still, it was interesting to browse the aisles of some stores and see what the marketing types thought we should be giving to others: electronic book readers, the latest phones, computers, perfumes, clothes, and even household things like vacuum cleaners. Not knocking those things — I’m sure that somebody’s baby out there wants one of those objects and whoever gets it for them will be a hero, at least for the holidays.
If you’ve been out there bulling your way through the maddening crowds and haven’t found something that quite matches for someone you want to impress/love/woo/etc., why not consider giving an astronomy- or space-related gift? I’ve got a few suggestions here that might help you out of what could be a tough gift bind. (Or, maybe you want to treat yourself to something spacey…)
First, I am a member of Friends of the Observatory, the support group for Griffith Observatory in Los Angeles, California. You can be, too, and you don’t even have to live there. I don’t live in SoCal, but I do find myself working/visiting/doing business out there throughout the year, and a trip to Griffith is always one of my stops. FOTO, as it’s lovingly called, does a lot of good things for the observatory — which is one of the most popular public observatories in the world. Among other things, FOTO gathers the funds to bring students from the Los Angeles Unified School District on fifth-grade school field trips. This is a trip that, without funding, many school kids would never get to experience, and I support anything that brings the science of astronomy to kids in a meaningful way. You can join for as little as $45.00, which gets you a number of great benefits, including a one-year subscription to the world-famous Griffith Observer. I’ve been supporting Griffith for a number of years now through FOTO, and even though I don’t live there, I find it to be a wonderfully rewarding investment. So might you. Check out FOTO at the link above. (For the record, I also wrote all of Griffith Observatory’s exhibits — so, if you go there, check out the words on the walls… I guarantee, you’ll learn some astronomy!)
I’m also a member of the Astronomical Society of the Pacific, an astronomical organization that works to increase the understanding and appreciation of astronomy by everyone, using scientists, educators, enthusiasts, and the public to advance science and science literacy. I have been working with this group for a couple of years now on a project called “Astronomy Behind the Headlines” — a series of podcasts that’ll bring you in contact with scientists at the cutting edge of astronomy. ASP is a godsend for teachers and outreach specialists, as well as folks who are just plain curious about the universe. GO check out their Web page and see if a membership or donation to ASP is a fit with your gifting goals.
As many of my long-time readers know, I love books. I’ve written a couple about astronomy and space science, and I like to read astro books, too. Just in time for the holidays a couple of really neat ones have landed on my desk and you might like them, too.
The first is called “Postcards from Mars” — written by Dr. Jim Bell, astronomer and planetary scientist at Cornell University in New York, and published by Plume Books. Jim was in charge of the photography teams on the Spirit and Opportunity missions that are still sending back images from Mars. For this book, which is gorgeous, he spent hundreds of hours selecting images from the rovers, cropping and processing them, and aseembling them into a book that tells the tale of the rovers from launch to the continuous stream of image deliveries they’ve made during their mission lifetimes. I really enjoyed this book — twice. First, I simply leafed through it, admiring all the wonderful images. Then, I read through it, appreciating the story of two missions as told by one of the mission scientists who put these images in front of us. It’s really a great find and if you have a Mars lover on your gift list (or if you are one), then this is a great find. I know I loved looking through it — but then again, I’m an old Mars fanatic from way back. You can’t beat postcards from another planet as a way to impress your giftee!
The other book that found its way onto my reading list is called Sizing up the Universe: a New View of the Cosmos and published by National Geographic. Anyone who studies astronomy is instantly engulfed by the scales of objects we explore. From the sizes of planets to the limits of the observable universe, the scale of the cosmos can sometimes be more than we can easily comprehend. That’s where this book comes in — it seeks to help you understand just how big things are and how far away they are — in terms that won’t completely boggle your mind. It uses scaled maps and comparisons of objects at different scales, by way of gorgeous illustrations, to help readers understand size comparisons in the universe. It presents the vast distances of the cosmos in a very beautiful and graphical way — including an instantly understandable Gott-Juric Map of the Universe in Chapter 4 that has been reprinted as a foldout map. The authors, Princeton professors J. Richard Gott and Robert J. Vanderbei, write in a very clear and approachable way and their explanations of distances and sizes by analogy are very good. For example, there’s a set of beautiful images in a section called “Exoplanets Compared” that shows some of the known exoplanets overlying their parent stars, and with solar system planets overlaid in comparison. You instantly “get” the size of these worlds and their stars. The book is a treasury of these kinds of comparisons. There’s a lot more, which makes this book a great gift for that person in your life who is curious about what’s “out there,” how big it is, and how far away it is.
In closing, I have to admit that I do really enjoy reading actual books. I’ve been pondering getting a Kindle or a Sony reader or something, and I actually played with one the other day. But, you know… it just doesn’t hold a candle (or Kindle) to turning the pages and basking in the loveliness of a book on a lazy afternoon… and, I wonder just how well an astronomy book like these two would work out on the readers. And, of course, NO reader is going to give you the same experience as visiting a place like Griffith or belonging to a group like ASP… they’re all worthy experiences, requiring different applications of your personal attention.
Happy Space Gifting!
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Image of Horsehead Nebula: T.A.Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)
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