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Full story at http://spacefellowship.com/news/art17500/apron-construction-contract-awarded-for-spaceport-america.html
Full story at http://spacefellowship.com/news/art17504/winter-high-school-alumnus-to-talk-with-wisconsin-students-representative.html
Full story at http://spacefellowship.com/news/art17508/masten-space-systems-looking-to-2010.html
I’m not too surprised to find out that a rigorous scientific test of ginkgo biloba found that it did not have the effects claimed by alt-med enthusiasts, including helping memory retention. Just speaking statistically, knowing the sheer number of claims made by people using "alternative" medicines, the vast majority of them are bound to actually not be true. Almost without exception, these kinds of claims are anecdotal in nature, which is unreliable. We need properly-handled blinded medical studies to find out the real nature of these claims, and this one, unfortunately, has not panned out.
I don’t expect this to have any impact whatsoever on either the sales of ginkgo biloba or the way it’s advertised, of course. In general, the practice of alt-med as it is presented to the public is not based in scientific analysis of evidence, so it doesn’t matter how much evidence is provided that shows that a particular claim is false.
That doesn’t mean we in the reality-based world want these tests to fail. My favorite part in the article is this:
The study finding is “disappointing news,” says Steven DeKosky, dean of the University of Virginia School of Medicine and the study’s senior author. The only positive thing the researchers found is that ginkgo appears to be safe, he says.
DeKosky is dean of a prestigious medical school, and says he’s disappointed. Of course he is. Despite what a lot of the alt-medders (and antivaxxers) say, doctors really do want what’s best for their patients. If ginkgo had panned out, then that would be another weapon in doctors’ arsenals to make us healthier, and make us healthier for longer in our lives. But it didn’t work, so he was disappointed.
Those of us skeptical of these alternatives to modern medicine don’t want these things to fail. We already know that some mainstream medicines are based on what could once have been called herbal medicines — aspirin is the obvious example, originally made from willow bark — so we know better than to dismiss these potential additions to medicine out of hand.
What we do dismiss are anecdotes provided as evidence, or used to make claims that aren’t warranted from the evidence. All those anecdotes are is a place to start investigating the evidence for a potential medicine, not evidence in and of themselves.
Tip o’ the ginkgo berry to Fark.
Full story at http://feedproxy.google.com/~r/BadAstronomyBlog/~3/Wgy3ukY31DI/
Full story at http://spacefellowship.com/news/art17476/new-horizons-spacecraft-now-closer-to-pluto-than-earth.html
Full story at http://spacefellowship.com/news/art17479/galactic-building-blocks.html
Full story at http://spacefellowship.com/news/art17483/the-dark-spot-on-mars.html
I don’t have a whole lot to add to this amazing shot from Cassini of Saturn’s moon Rhea reappearing from behind the giant moon Titan:
[Click to entitanate.]
Except: coooool. Titan is over three times the size of Rhea, and Rhea was more than twice as far from Cassini when this was taken, making Rhea look even smaller in comparison. Also, check out how the high-altitude haze in Titan’s atmosphere isn’t the same height all the way around the moon. Near the top you can see they poof up higher. If you look closely, can you see the Enterprise?
Full story at http://feedproxy.google.com/~r/BadAstronomyBlog/~3/vutIONTwkRc/
Full story at http://spacefellowship.com/news/art17433/saturn-dwarfs-the-icy-moon-rhea.html
Full story at http://spacefellowship.com/news/art17436/five-member-expedition-22-crew-begins-first-full-week-together.html
Full story at http://spacefellowship.com/news/art17439/astronauts-aboard-the-space-station-talk-with-troops-in-iraq.html
Folks in Europe, Africa, and Asia can say goodbye to 2009 by viewing a very slight lunar eclipse on the last day of the year: Thursday, December 31. The event lasts for about an hour starting at 18:52 UTC, with deepest eclipse, such as it is, at 19:22.
Only a small part of the Moon will be in the deepest part of the Earth’s shadow, so this is nowhere near a total eclipse, when the Earth fully blocks sunlight from reaching the Moon. However, if you go out and take a look you’ll see the full Moon looking distinctly flattened on one side, and perhaps the rest of the Moon’s surface will look dusky. I’ve made a little image here to show you about how much the Moon will be covered, and approximately where. Like I said, only a small part will be darkened.
Not everyone will see this; North and South America are basically shut out of this event since it happens on the other side of the planet and the whole thing’s over before the Moon rises. The image of the Earth here shows where the eclipse will be visible: if you can see where you live, then you can see the eclipse. The closer you are to the center of the map, the higher the Moon will be in the sky at midpoint of the eclipse.
The next lunar eclipse visible will be in June 2010, but it’s partial and will only be visible in Australia. After that, there is a full eclipse in December 2010 which will be seen by North and South America — though the farther west you are the better as far as decent viewing times go (it’ll be around midnight for me in the Mountain time zone).
Anyway, if you want to learn about lunar eclipses (like what I mean by partial versus total, and what an umbra and penumbra are) then take a look at the Mr. Eclipse site, which has great info.
I’ll note that this last eclipse of 2009 is also a so-called Blue Moon: the unofficial term for the second full Moon in a single month. There’s no real significance to it — the Moon ain’t blue, folks, despite a bunch of news sites already posting pictures of the Moon Photoshopped to look that color without explanation. But the real thing here is that celestial geometry is putting on a small show for you, and what better way to ring in a new year?
Tip o’ the umbra to AstroPixie for reminding me about this!
Full story at http://feedproxy.google.com/~r/BadAstronomyBlog/~3/RQSTG6t9sh0/
Full story at http://spacefellowship.com/2009/12/23/keck-telescopes-gaze-into-young-stars-life-zone/
Full story at http://spacefellowship.com/2009/12/23/activity-at-shiveluch-volcano-as-seen-from-space/
Full story at http://spacefellowship.com/2009/12/23/vampires-and-collisions-rejuvenate-stars/
Five years ago today — on December 27, 2004 — the Earth was attacked by a cosmic blast.
The scale of this onslaught is nearly impossible to exaggerate. The flood of gamma and X-rays that washed over the Earth was detected by several satellites designed to observe the high-energy skies. RHESSI, which observes the Sun, saw this blast. INTEGRAL, used to look for gamma rays from monster black holes, saw this blast. The newly-launched Swift satellite, built to detect gamma-ray bursts from across the Universe, not only saw this blast, but its detectors were completely saturated by the assault of energy… even though Swift wasn’t pointed anywhere near the direction of the burst! In other words, this flood of photons saturated Swift even though they had to pass through the walls of the satellite itself first!
It gets worse. This enormous wave of fierce energy was so powerful it actually partially ionized the Earth’s upper atmosphere, and it made the Earth’s magnetic field ring like a bell. Several satellites were actually blinded by the event.
So what was this thing? What could do this kind of damage?
Astronomers discovered quickly just what this was, though when they figured it out they could scarcely believe it. On that day, half a decade ago, the wrath of the magnetar SGR 1806-20 was visited upon the Earth.
Magnetars are neutron stars, the incredibly dense remnants of a supernovae explosions. They can have masses up to twice that of the Sun, but are so compact they may be less than 20 kilometers (12 miles) across. A single cubic centimeter of neutron star material would have a mass of 1014 grams: 100 million tons. That’s very roughly the combined mass of every single car on the United States, squeezed down into the size of a sugar cube. The surface gravity of a neutron star is therefore unimaginably strong, tens or even hundreds of billion times that of the Earth.
What makes a neutron star a magnetar is its magnetic field: it may be a quadrillion (1015) times stronger than that of the Earth! That makes the magnetic field of a magnetar as big a player as the gravity. In a magnetar, the magnetic field and the crust of the star are coupled together so strongly that a change in one affects the other drastically. What happened that fateful day on SGR 1806-20 was most likely a star quake, a crack in the crust. This shook the magnetic field of the star violently, and caused an eruption of energy.
The sheer amount energy generated is difficult to comprehend. Although the crust probably shifted by only a centimeter, the incredible density and gravity made that a violent event well beyond anything we mere humans have experienced. The quake itself would have registered as 32 on the Richter scale — mind you, the largest earthquake ever recorded was about 9 on that scale, and it’s a logarithmic scale. The blast of energy surged away from the magnetar, out into the galaxy. In just 200 milliseconds — a fifth of a second — the eruption gave off as much energy as the Sun does in a quarter of a million years.
A fireball of matter erupted out of the star at nearly a third the speed of light, and the energy from the explosion moved — of course — at the speed of light itself. This hellish wave of energy expanded, eventually sweeping over the Earth and causing all the events described above.
Oh, and did I mention this magnetar is 50,000 light years away? No? That’s 500 quadrillion kilometers (300 quadrillion miles) away, about halfway across the freaking Milky Way galaxy itself!
And yet, even at that mind-crushing distance, it fried satellites and physically affected the Earth. It was so bright some satellites actually saw it reflected off the surface of the Moon! I’ll note that a supernova, the explosion of an entire star, has a hard time producing any physical effect on the Earth if it’s farther away than, say, 100 light years. Even a gamma-ray burst — an event so horrific it makes the hair on the back of my neck stand up just thinking about it — can only do any damage if it’s closer than 8000 light years or so. GRBs may not even be possible in our galaxy (they were common when the Universe was young, but not so much any more), which means that, for my money, magnetars may be the most dangerous beasties in the galaxy (though still unlikely to really put the hurt on us; see below).
Here’s what Swift detected at the moment of the burst:
As Swift scientist David Palmer describes:
This is the light curve that [Swift's Burst Alert Telescope] saw, showing how many gamma rays it counted in each sixteenth of a second during six minutes of observation. I didn’t draw the main spike because it was 10,000 times as bright as the tail emission, and you would need a monitor a thousand feet tall to look at it.
The blast was so strong Swift saturated, counting 2.5 million photons per second slamming into it, well off the top of that graph (and the actual blast was far brighter yet, as other satellites were able to determine).
See the pulsations in the plot? After the initial burst, which lasted only a fraction of a second, pulses of energy were seen from the magnetar for minutes afterward. The pulses occurred every 7.56 seconds, and that’s understood to be the rotation period of the neutron star. The crack in the crust got infernally hot, and we saw a pulse of light from it every time it spun into view. This same pulsing was seen by other satellites as well.
The damage from the explosion was actually rather minimal here on Earth. But that’s because SGR 1806-20 is 50,000 light years away. Had it been one-tenth that distance, the effects would have been 100 times stronger. We’d have lost satellites at least, and it would have caused billions of dollars in damage in NASA hardware alone. Of the dozen or so known magnetars, none is that close (though a couple are about 7000 light years away). Magnetars aren’t easy to hide, but it’s possible there are some within 5000 light years. It’s unlikely, though, and I’m not personally all that concerned.
I do have one thing to add: when this event occurred, I got an email from someone convinced that the magnetar was responsible for the earthquake in Indonesia that created the devastating tsunami that killed more than 250,000 people. However, there is one small problem with that idea. Well, two problems, really, the first being there’s no physical way it could have triggered an earthquake! But a worse problem is that the earthquake occurred on December 26th at 00:58 UT, and the burst from the magnetar was at December 27 at 21:30:26 UT, about 1.5 days later. Oops.
But why let facts get in the way of a good pseudoscientific theory?
The tantrum from SGR 1806-20 is one of the best studied events of its kind, and is certainly the most powerful ever detected in the modern era. Astronomers will be studying the magnetar, and others like it, very carefully to see what can be learned from them. If you want to read more, then I suggest the NASA page about the event, as well as the Sky and Telescope magazine page on it, too.
And if another blast like that one comes from SGR 1806, or any other magnetar, don’t worry: I’ll report it right here. Unless it fries my computer. Or just my brain, reading about it.
Image credits: NASA
Full story at http://feedproxy.google.com/~r/BadAstronomyBlog/~3/Q2mA8UkRANY/
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