There’s a new post up at the new home of The Martian Chronicles about a recent study that suggests that one in four sun-like stars had earth-sized planets. Head on over and check it out, and update your bookmarks and subscriptions for the new site! I won’t be posting here for much longer…
Archive for the ‘Uncategorized’ category
That’s right folks! As of today, this blog has moved over to the AGU Blogosphere! So, head over to check out my new digs and update your bookmarks and RSS feeds While you’re there, take a look at the other excellent blogs that are part of the network.
I’ll keep cross-posting here for a little while to give you a little time to make the switch, but pretty soon this version of the blog will be retired.
Big news folks! Sometime next week, this blog will be moving over to the American Geophysical Union‘s new blog network! AGU is the organization responsible for the Journal of Geophysical Research – Planets, which is one of the most important journals in planetary science, particularly for the terrestrial planets. AGU also hosts the enormous “fall” meeting each December, causing 16,000 scientists to descend on downtown San Francisco like over-educated locusts.
I’m really excited to be representing planetary science as part of the AGU blog network, and I’ll be in very good company. Here is a list of the other geobloggers who will be joining me in the move:
Dave’s Landslide Blog by Dave Petly
Dan’s Wild Wild Science Journal by Dan Satterfield
Mountain Beltway by Callan Bently
Magma Cum Laude by Jessica Ball
Terra Central by John Freeland
Outdoor Science by Vivienne Raper
I’ll keep you posted as the transition occurs, and I should be able to cross-post to both versions of The Martian Chronicles for a while to give you time to update your subscriptions. Stay tuned!
Donors Choose is a charity organization that allows teachers to post requests for supplies that they can’t afford and allows donors to (get this!) choose which teachers to donate to. Some requests are for basic school supplies, others are for computers or video cameras or other big-ticket items that a teacher’s district can’t afford. It’s a great organization, and you should go check out the projects and donate to the most deserving.
But if I may suggest one to donate to, my wife is a physics teacher and she recently put in a request at Donors Choose for funding to buy motion detectors for her physics classes. She uses these in a bunch of different projects, and they are great for showing students how motion in the real world can be recorded as data on a graph. Making that connection – that graphs actually mean something – is a cornerstone of science, and she (and her students, and I) would be eternally grateful if you donated to her project. Thanks in advance!
Normally I stick to topics that are at least tangentially related to science on this blog, but I’m making an exception. My grandfather, who is 92 this year, has entered the story of how he met my grandmother into an online writing contest. They were happily married for 68 years, and their story is truly touching. I hope you’ll take a moment to go and read it, and if you like it, vote by leaving a comment.
I am getting married in August of this year and I asked my grandpa to say a few words about marriage, because 68 years is a long time to spend with someone, and I thought he would have some words of wisdom to pass on to my fiancee and I, and our friends and family members. Once you read Hoyt and Ruth’s story, you’ll see exactly why I asked him to speak about marriage at our wedding.
Continuing my re-posting of the solar-system tour that I made back in 2005 with a couple of other astronomy undergrads, here’s Mars! The target audience for this tour was younger than that for this blog, so you’ll have to forgive the simplistic tone…
Mars (the Roman god of War, also known as Ares in Greek) is sometimes called the Red Planet because of its rusty red color. It is the fourth planet out from the sun, and the seventh largest. Mars has two tiny moons which orbit very close to the martian surface: Phobos and Deimos (Fear and Dread, fitting companions for the God of war). Mars’ orbit is more elliptical than Earth’s (it looks more oval than Earth’s orbit). One consequence of this is a large temperature variation (about 30 degrees Celcius) between the point in its orbit when it is closest to the sun and the point in its orbit when it is farthest away. The average temperature on Mars is about -51 F, but Martian surface temperatures range widely from as little as -124 F to about 23 F on the day side during summer. These temperatures don’t seem too bad compared to other planets in the solar system. That, and the fact that there was once liquid water on Mars, makes it the most earth-like planet (in terms of climate, not size!) Mars is much smaller than Earth; its surface area is about the same as the land surface area of Earth. Because it is not that far from earth (it’s the next planet out from the sun) it is easy to spot in the sky, and has been known since prehistoric times.
Even though Mars is small, it is home to some dramatic geologic features. It has the largest volcano in the solar system, Olympus Mons. Olympus Mons rises 78,000ft (that’s almost 15 miles high!) above the surrounding plain. Its base is several hunderd miles across and it is surrounded by a cliff almost 4 miles high. Here’s what it looks like:
And, a 3D view:
Mars is also home to the largest canyon in the solar system: Valles Marineris. This canyon is 2500 miles long (That’s about as long as the United States) and up to 4 miles deep! For comparison, the Grand Canyon on earth is about 500 miles long and 1 mile deep. There are points in Valles Marineris where it is so wide that if you were standing at the base of one wall, the other wall would be below the horizon. Here’s a picture of the canyon:
The southern hemisphere of Mars is predominantly ancient cratered highlands somewhat similar to the Moon. In contrast, most of the northern hemisphere consists of plains which are much younger, and lower in elevation. No one knows for sure why there is such a striking difference. Mars Global Surveyor has produced a nice 3D map of Mars that clearly shows these features.
The interior of Mars is known only by educated guesses that scientists take based on 4 facts that can be observed from space: planet radius, planet mass, moment of inertia (a measure of how evenly distributed mass is in the planet) and core nutation (whether or not the core and the rest of the planet rotate around the same axis). These 4 facts give clues about the core size and mass, and the mantle size and mass. The most likely scenario is a dense core about 1700 km in radius, a molten rocky mantle somewhat denser than the Earth’s and a thin crust.
Like Mercury and the Moon, Mars doesn’t seem to have plate tectonics. That means its crust is a solid shell, rather than plates that move around like on earth. There is evidence that there may have once been liquid water on Mars, however at this time all the water seems to be stuck in the permanent polar icecaps that exist at both poles, much like the polar icecaps on Earth.
Scientists wonder if there might be life on Mars too! So when they sent spacecraft (Viking landers) they made sure to perform experiments to test if there might be life on Mars. The results were not very clear but most scientists now believe that they show no evidence for life on Mars (there is still some controversy, however). The Mars Science Laboratory mission will be carrying a bunch of instruments to search for evidence of life and help solve the mystery once and for all. But there are definitely not martians bigger than single-celled organisms: I wouldn’t be worried about Mars attacking anytime soon!
Do vaccines cause autism? Are genetically modified crops safe to eat? Is organic farming better than conventional? Is race a scientifically valid concept? What is the future of biotechnology now that a synthetic cell has been created?
If you’ve ever asked those questions, then you should check out Denialism, by Michael Specter. If you think you know the answer to any of those questions, then you need to read Denialism.
In this book, Specter catalogs the myriad ways that irrational thinking even in the face of overwhelming scientific evidence can have a profound and negative effect on our lives. He begins with the example of Vioxx, the anti-inflammatory drug that was recalled due to a link with risk of heart-attack and stroke. Using this example, Specter seeks to explain the distrust that people harbor for science and technology, and especially corporations.
He goes on to examine the well-known claim that vaccines cause autism. They don’t, and dozens of scientific studies can back that up, but more and more parents are opting not to vaccinate their children, placing entire populations at risk of diseases that until recently were thought of as all but eradicated. Specter does a good job describing the history of the antivax movement, and discussing the reasons for the movement’s existence.
From vaccines, Specter goes on to tackle the growing obsession with “organic foods” and the irrational fear of genetically modified food. I found this chapter informative and also challenging. I live in Ithaca, where everywhere you go you can’t help but hearing about how organic and local and natural everything is. Heck, I have a farm share and get organic vegetables weekly all summer long from a local farm. Still, I have always had a healthy skepticism of the many claims about “organic” and “natural” products. Specter does a good job of debunking some myths about organic farming while also supporting other reasons that people choose to eat organic and local food. He also does a nice job with genetically modified organisms, although I wish he had spent more time on some of the counter-arguments such as Monsanto’s dubious ethics when it comes to selling seeds.
Moving on from food, Specter continues with the theme of genetics in discussing how mapping the human genome is revealing how to treat patients with different genetics based on where their ancestors lived. This is a touchy subject, because we’re all taught that race has no basis in genetics, but as Specter points out, that’s obviously not entirely true. There are differences between people, and those differences are in the DNA. He discusses some interesting examples where treatment of patients needs to be varied due to slight differences in their genetics that make certain drugs more or less effective.
The final chapter of the book deals with a topic that has been making a lot of headlines: artificial life. At the time the book was written, living things with a synthetic genome had not yet become a reality, but just a few weeks ago that changed. Specter talks with Craig Ventner about his work on synthetic life, as well as other biologists such as Drew Endy, who are working on figuring out the fundamental pieces of DNA to use as building blocks for entirely new organisms.
This final chapter reads like the premise to any number of distopian or utopian science fiction stories, and I found it really fascinating to think that not far in the future new life forms could be assembled from scratch with DNA building blocks. In particular, the idea that organisms could be designed that need not be able to reproduce (because you could just make more in the lab) was an eye-opening idea to me.
The whole last chapter has an interesting biology-as-computer analogy running through it, with the DNA as open-source software that anyone with the right know-how can meddle with.
Overall, I enjoyed Denialism. My main complaint is that too often Specter appears to be too much of a cheerleader of scientific progress. I love progress as much as the next guy, but I wish Specter had spent more time on the many valid concerns regarding many of the topics in the book, especially in the last chapter. Maybe he did not address these because they tend to drift out of the realm of science and into ethics, but I finished the book skeptical of his optimism on some issues.
(Update: he touches a bit on this during his TED talk, embedded below. He says, specifically regarding genetically engineered food: “The things I constantly hear are: ‘too many pesticides’, ‘hormones’, ‘monoculture – we don’t want giant fields of the same thing, it’s wrong! We don’t want companies patenting life! We don’t want companies owning seeds’ And you know what my response to all of that is? Yes! You’re right! Let’s fix it. It’s true, we’ve got a huge food problem, but this isn’t science! This has nothing to do with science. It’s law, it’s morality, it’s patent stuff. Science isn’t a company. It’s not a country. It’s not even an idea. It’s a process. Sometimes it works and sometimes it doesn’t. But the idea that we should not allow science to do its job because we’re afraid is really very deadening.” I have to say, I’m with him on this.)
I should be clear: this book will not be read by hard-line denialists. Specter shows quite a lot of (mostly justified) disdain throughout the book towards people who question science, and even though I often agree with him, I’m not sure he’s going to convert many people that way. But that does not mean the book fails in its mission. It is a really excellent reminder to those of us who like to think that we are science-minded that we need to be aware of denialism. It is not limited to uneducated people. Denialism is prevalent in highly-educated communities, such as college towns, where everyone loves their organic food and vitamin supplements. The book serves as a great reality check and also will continue to serve as a great reference for me any time I need to lay down the facts about things like vaccine safety or GMOs.
Overall I recommend the book Denialism. It may be preaching to the choir, but it also arms the choir with more knowledge to draw upon so that we can recognize denialism and do what we can to fight it.
If you’d like a preview of the content of the book, here is Specter giving a great TED talk on the same subject: