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Late Kepler Post

Posted by tigerhawkvok on March 10, 2009 20:16 in kepler , astronomy , news , research , IYA

So, I composed most of a post on the Kepler launch, then, well, forgot to post it. Belatedly, here we are:

So, Kepler. I mentioned it a little while ago, what was I talking about? Well, I was talking about the Kepler mission (kepler.gov) being sent up by NASA, set to launch on 3/6/09 (This is one of those "Whoops, posted late" parts).

Kepler is a sattelite that will observer one portion of the sky for its entire mission, looking for transit events. To understand a transit event, consider a lightbulb. When something passes in front of it, it obscures part of the surface from your view, and thus reduces the amount of light you observe. So, by observing the same starfield for its mission duration, Kepler can detect any minute changes in stellar flux, thus detecting a planet. The amount of flux change then gives you the planetary size (since color/spectral profile -> temperature -> size -> flux ).

However, there is a caveat here. Sunspots can often be regular, long lasting, or otherwise look like planets. So, my own impact on the Kepler project came with my research work with Gibor Basri, in which we wrote routines in IDL to analyze our own star for the influence of magnetograms on stellar luminosity profiles (IE, where are sunspots? How big? etc).

Various identification methods picking out
umbrae and penumbrae

A particularly good example can be seen in the figure to the left, where various versions of the algorithms pick out different features in a sunspot group. It is important to note that the differences are exaggerated -- the sun is very bright, so the "dark" spots are valued about 0.85 on an absolute scale. you can also see on the right an early version of the algorithm picking out by far most of the major solar features, including the harder-to-discern faculae, or unsually bright areas (which are, of course, very hard to observe in photos such as these).

Early feature identification

The detection and automation algorithms we developed were actually fairly robust and accurate, though CPU intensive (running through about 100 photos took about 3-4 hours on my now-deceased laptop Liz), though our funding ran out over here before I could complete an algorithm to reverse-construct a star from its magnetic profile. Thus, by also observing the long-range magnetic profile of the stars (particularly Sun-like stars) we can rule out some categories of false positives. Looking at some more "final" algorithm photos, you can see why this could be relevant:


light contrast

Solar feature identification with
later versions of the algorithm

If a dark spot such as that passed along the star, it is enough of a brightness dip that it could register as a false positive — that is to say, it could look very much like a planet. While prolonged observation is one way to get around this, feature identification is another way. And I had a part in it! Nifty!

More:

Updated: 3/13/09

IYA Entry

McCain sticking it to the anti-science man

Posted by tigerhawkvok on March 04, 2009 22:47 in politics , news , anti-science

On February 27th, McCain began posting "porkiest projects" on Twitter. He did so again on 3/02, 3/03, and 3/04 (only six on the 4th when I last looked). So these have got to be kinda nutty, right? Or, you know, 13/36 could be science related. How's this for a list?

  1. Apparently museums aren't public goods. Nor the building of produce jobs.
  2. Who needs them there sea turtles anyway. Not like species extirpation has ever caused environmental problems ...
  3. Lobster populations aren't shrinking. Really.
  4. Now, I think nuclear is the way to go, but apparently McCain really has something against solar power
  5. Along the lobster line — no need to keep up those pesky fish populations either.
  6. By the way, we never found out anything useful by studying other species' genetic profiles. Obviously funding that is dumb.
  7. Apparently he is just outright misinformed and doesn't know how problematic — and expensive — theft of copper wires actually is.
  8. By the way. Las Vegas is totally sustainable and uses only its own resources. Not like its a drain on three surrounding states at all.
  9. He really has a bone to pick with population genetics, huh?
  10. To channel Peter Griffin, though, it really grinds my gears when he dismisses astronomy right out.
  11. I suppose McCain never heard how beavers have massive ecosystem impacts, huh?
  12. Startling honey bee decline, anyone? Apparently he just has it out for flowering plants. Who needs angiosperms.
  13. While we're at it, lets just not have as nutrious or plentiful crop for our grazers. Really, genetics is the work of the devil.

Suddenly, I'm gladder I didn't vote for him. I really thought he was more pro-science than that.

Possible 22 year old confirmation of gravity waves

Posted by tigerhawkvok on March 04, 2009 17:18 in astronomy , news , IYA

Via Slashdot and the arXiv blog, it turns out that we may have actually detected gravity waves in 1987 associated with SN1987A.

OK, that was a bit of a rush. Let's unpack that a bit. Astrophysicists have been searching for gravity waves for a while now, which are linearized plane wave solutions to the Einstein Field Equations with two polarizations (the other fourteen dropping out). The key bit to this solution is that the coordinate positions of the particles remain constant for all τ, but the fractional change in distance between points A and B changes in an oscillatory manner (as 0.5a sin[ωt+δ] ). Since all but two polarizations drop out, this means that for a plane wave oriented in the z direction, wave effects are restricted to the orthogonal x,y plane.

LIGO

Modern interferometers use long arms with a laser cavity to measure very very small fractional changes in distance via destructive & constructive interference. However, before this, large aluminum cylinders with piezoelectric crystals arranged about it were constructed in an attempt to measure these gravity waves. When SN 1987A went off (Supernova 1987 A, as the first one in 1987), John Weber reported that he detected gravitational waves from the SN detonation. However, calculations of first-order effects (almost always the largest) showed that his detector was insufficiently sensitive to have found any gravitational waves.

However, a new paper (preprint) shows that asymmetries in the 1987 explosion could lead to an enhancement by a factor of 104 in SN1987A, putting these waves right in Weber's detectable range.

So, it seems in retrospect that Weber got the short end of the stick, all things considered. But it's definitely worth re-examining his data to see if he did, in fact, confirm gravity waves 22 years ago.

IYA Entry

Evolution and Language

Posted by tigerhawkvok on March 04, 2009 02:37 in General , evolution , biology

I still have my science posts planned, but I want to spend a moment to comment on biology terminology in the public sphere. I thus give you this declaration:

The use of "descended from" is a subtle, but constant linguistic method of undermining evolutoin and unecessarily seperating species.

What? That sounds high, mighty, obscure and arrogant. However, I think it's true. What of the supposedly innocuous statement: "Humans descended from apes". This has the implicit statement: "Humans are not apes". This enables people to say "We're not monkeys!" Or, "We have ape-like ancestors". This is like saying, "We have primate-like ancestors". Its just as ludricous. We do have primate-like ancestors, and ape-like ancestors, but those are outside of the appropriate splits. For something to be ape-like, it must be more basal than the last common ancestor between apes and its most closely related living organism. Using the terminology any other way is disingenuous and misleading. Thus, a predecessor to the first primate (depends on how you define things) might be primate-like; but using "ape-like" for a human ancestor is just as deceptive as saying an aye-aye is primate-like while inside of primates.

No, ape-like would have to be non-hominoid Catarrhinid, of which the living form most closely fitting that description would be a gibbon.

So, perhaps that was a bit abstract and focused on hominds. But, consider birds. Saying "birds descended from dinosaurs" is also deceptive. Birds are dinosaurs. We've found non-avian dinosaurs with feathers, long before flight showed up. Sheep and cow are both artiodactyls, saying they "decended from" artiodactyls clearly implies that they are no longer a member of that group. Similar things to this lead to the sloppy use of the word "amphibian".

Amphibian is used in three ways: meaning living amphibiously, in both water and land; meaning being a member of lissamphibia, and this blurry realm of amphibious tetrapods that had not yet broken into the great amniote/lissamphibian split. They are more accurately called "basal tetrapods", or "early amphibious tetrapods" -- but saying "amphibians" is poor word choice.

What this rant serves the purpose of doing is simply to say — watch your language. Watch your terminology. All of us, simply by watching our language, can have an impact and help spread awareness.

Thus end your 2am lecture! Tomorrow: Kepler and my involvment with it.

Bush ESA midnight legislation suspended

Posted by tigerhawkvok on March 03, 2009 18:29 in biology , news

Via the EBV blog: Bush's midnight legislation that weakened the act by not requiring scientist input (via the US Fish and Wildlife service) before federal officials could say a species did not need protection. This was, in fact, serious enough that California sued to prevent this.

Formally speaking, Obama suspended the legislation to review "whether it promotes 'the purposes of the [Endangered Species Act]'". This is certainly good news, and good precedent, for requiring scientific review!

I had started a post on salamanders, but the spazzy laptop ended up killing it. Oh well. That post, and the others I mentioned, will be up soon enough. Perhaps if everything works out right, tomorrow will be a small photoblog. Meanwhile, I'll leave you with an interesting link, via Grrlscientist over at ScienceBlogs. Hint: What's the last color you'd expect to see on a dolphin?

Goal and Astronomy

Posted by tigerhawkvok on March 02, 2009 15:43 in General , astronomy , IYA

So, I will announce a goal for this month: I intend to post an average of 3 times per week on this blog. There. Maybe posting this will keep me to it.

Sadly, I missed the timetable to post something interesting about Comet Lulin, which is incredibly low magnitude by now, and would be a shade tricky to spot even with a telescope (at least a 12" would really be needed at this point). However, if you're out stargazing this month, things are fairly boring quiet. You will be able to see Venus set around 8:30 PM (getting earlier as the month progresses), and Saturn transit (move across the meridian) around midnight. These are pre-DST time, so after March 8th they will advance an hour (IE, transit at 1 AM).

On the docket: Mus musculus, and perhaps a bit about evolution.

IYA Entry

Magnetic Monopoles

Posted by tigerhawkvok on February 26, 2009 17:33 in physics , news

OK, perhaps the title is a bit misleading. However, a Science paper published today (DOI: 10.1126/science.1167747) describes a method by which images of magnetic monopoles can be induced and measured, in full compliance with E&M. The trick? By taking advantage of the quantum Hall Effect, you can construct a system such that the boundary conditions can be constructed to break temporal (T) symmetry, allowing quantum mechanical topological effects.

By doing this around an insulating surface, and bringing a charged particle near it, a magnetic monopole image is induced as a mirror to the electric charge. Whew. The idea of this is a nice mathematical trick that can make solutions far simpler than they would normally be, if you reduce a system to a set of "image charges" that represent a more complex field.

Perhaps someone has noted that this appears to break Maxwell's equations. Namely , the divergence of B = 0 (∂μFνλ=0) according to Maxwell's Equations is maintained by the following:

As we started with the Maxwell's equation, which includes [del] B = 0, the magnetic flux integrated over a closed surface must vanish. We can check that this is the case by considering a closed surface—for example, a sphere with radius a—that encloses a topological insulator. The detailed calculation is presented in the supporting online material (17). Inside the closed surface, there is not only a image magnetic monopole charge, but also a line of magnetic charge density whose integral exactly cancels the point image magnetic monopole.

And thus everything ends up working out. Trippy. Even more to the point, this could be measured by a magnetic force microscope, with mathematical proof to show its contribution could be distinguished from other, more trivial considerations. Perhaps not the most pertinent discovery every, but still quite interesting to move the idea of a magnetic monopole out of pure speculation into something detectable.

Ratites

Posted by tigerhawkvok on February 23, 2009 18:04 in biology , research

I've become increasingly interested in birds — particularly ratites — as of late. Posts like this over at TetZoo just make me more interested. Their evolution and morphology is fascinating, as well as the divergence in the group.

I wonder how much of this has to do with the unusually saurian characteristics of ratites (even the mammal-like kiwi)? I wish I would just pick something to be interested in and stick to it! My current list of "I'd like to do research in this some time" fields include:

  • Galactic evolution
  • Ratites
  • Stellar magnetograms on surface microstructure
  • Saurischian biomechanics
  • Compact object dynamics
  • Sauropsid evolution

Oy.

Fun fact for everyone: Did you know ostriches have the best feed:weight-gain ratio among land animals? They're actually by far the most efficient source of meat, as well as being rather healthy apparently. I'd like to try some ....

Nature: Chixulub impact did not create global wildfires

Posted by tigerhawkvok on February 23, 2009 17:06 in dinosaurs , news , paleontology

An interested news update from Nature today: apparently, the K-T impact's (Chixulub event) [wiki, UCMP] global soot layer was not caused by vegetation, and was probably due to hydrocarbons. That is to say, the impact probably burned sequestered gas and oil.

Impact, artist rendition

The writing was on the wall for the vegetation idea for a few years, since 2003 studies showed a comparative lack of charcoal, which one would expect for global wildfires. This was supplemented by research done by Belcher et al in a PNAS paper showing that polycyclic aromatic hydrocarbons (PAHs) ratios match that of burnt hydrocarbons better than that of vegetation. So, no global wildfires. However, it *is* important to note that the massive amount of soot produced itself had a global environmental impact. No matter how you dice it, the K-T event was not a fun time to be around.

Black holes and revelations

Posted by tigerhawkvok on February 21, 2009 15:50 in physics , astronomy , IYA

Last night, I gave a talk to the Tri-Valley Stargazers about black holes. It actually went rather well, and as usual, I enjoyed lecturing.

For those who are curious, here is the PowerPoint presentation (Office 2007) and the PDF.

IYA Entry

Finally fixed (really!)

Posted by tigerhawkvok on February 19, 2009 23:35 in General

Apparently, the time offset was the problem. I want to find a fix for it, but for now ... all the posted blog times are off by three hours. Alas.

Permalinks

Posted by tigerhawkvok on February 19, 2009 14:41 in General , computers

Still playing around with permalinks. This time, I've turned to the lifetype forums and am seeing if that will work. I wonder if this will allow a click-through ....

Velociraptor wrists

Posted by tigerhawkvok on February 19, 2009 02:49 in biomechanics , dinosaurs , biology , paleontology

The promised science post!

Rewatching Jurassic Park, I wanted to correct a rather small, but important and understated error.

There's a hint in the URL, of course. The answer? The claws — they're held horribly, horribly wrong.

Jurassic Park Velociraptors are named after Velociraptor mongoliensis, and modeled after a hybrid between the genera Deinonychus and Utahraptor. At the time the novel was written, there was some talk of moving Deinonychus into the genus Velociraptor, which was the convention followed by Micheal Crichton, though this didn't play out. However, all of these were dromaeosaurids, which are eumaniraptorans. In fact, Dromaeosauridae is the group closest to but outside of Aves. So, all members of eumaniraptora have a synapomorphy list that includes a "semilunate carpal".

Sinoris manus

Sinornis santensis manus

Tanycolagreus manus

Tanycolagreus topwilsoni manus. Scale in cm.

Cathayornis manus

Cathayornis sanctis manus.

All three of the pictures above show this semilunate carpal in other maniraptorans. Unlike most mammalian wrists, it cannot flex perpendicular to the radius-ulna plane (ie, what we would most commonly accept as perpendicular to the groud). Instead, its motions were restricted to that plane, giving a jacknifing motion, much like a flight stroke. This was an optimal grasping motion for prey, and good for grappling large prey, and was easy to adapt into a flight stroke (particularly given the presence of primary feathers on some dromaeosaurids).

Sadly, this does mean that the raptors couldn't open doors. They would have broken their wrists trying to make the motion!

Image citations:

  • Carpenter K., Miles C., Cloward K. New Small Theropod from the Upper Jurassic Morrison Formation of Wyoming. In "The Carnivorous Dinosaurs" (ed. Kenneth Carpenter), 2005.
  • Sereno PC., Chenggang R., Jianjun L. Sinornis santensis (Aves: Enantiornithes) from the Early Cretaceous of Northeastern China. In "Mesozoic Birds: Above the Heads of Dinosaurs" (ed. Luis M. Chiappe and Lawrence M. Witmer), 2002.
  • Zhonghe Z. and Lianhai H. Mesozoic Birds in China. In "Mesozoic Birds: Above the Heads of Dinosaurs" (ed. Luis M. Chiappe and Lawrence M. Witmer), 2002.

Credentialed

Posted by tigerhawkvok on February 18, 2009 14:21 in teaching

Nice — finally, after three months, I am a credentialed substitute teacher!

In addition to providing a source of income, this will let me gain teaching hours needed if I want to get a regular teaching credential, as well. Now, I just have to submit myself to the county of Alameda / city of Berkeley ....

I'll try to get up a post about science later today, particularly as I rather egregiously didn't post for Darwin Day, then I'll post a bit about black holes by Friday in honor / celebration of a talk I'll be giving to the Tri-Valley Stargazers.

I leave you with the brilliance of Randall Munroe:

xkcd comic

Enter Titanoboa

Posted by tigerhawkvok on February 07, 2009 15:45 in biology , news

A riddle: what happens when you cross a snake with a bus? Answer: A 13 m snake.

Scientists recently found Titanoboa, a 13 m boid from the Paleocene neotropical region (S America and S Asia). This thing was impressive; the animal probably had a 2m girth, weighed over a metric ton, and could eat a full-grown cow. As a member of Boidae, it was a full-on constrictor (which kind of begs the question of what it was constricting!)

Titanoboa

Probably the most interesting thing about it, though, is what scientists have done with the find. Using it, they have been able to estimate the neotropical region temperatures to be around 30-34 C (given the standard laundry list of assumptions). A Nature press release has more, with the primary article linked at the bottom (doi:10.1038/nature07671). Pharyngula has a research blogging post on it and some more pictures from the article.

I'm going to try to find time to read the paper — from what I understand, they just used a growth curve using modern snakes as a baseline, but I'm curious as to if they took into account some pythonine snakes can be facultatively endothermic (DOI: 10.1016/S0306-4565(02)00048-7 ). Granted, this has only been observed in pythonine snakes, but I wouldn't rule out convergency (though this has a high metabolic cost, this could considerably broaden the temperature range it could live in). I'd also be curious to see if oxygen isotopic analysis, such as done with theropod dinosaurs, can confirm internal thermoregulation (DOI: 10.1130/0091-7613(2000)28<799>2.0.CO;2).

That's it for now!

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