free debate

May 27, 2010

News From the Martin Arctic

In this last week, there have been two news stories worth reporting from the North Pole of Mars.

Image credit: NASA/JPL-Caltech/University of Arizona
The Phoenix Mars Lander was a huge success. It was a small lander that was designed to find water ice at high latitudes on Mars. We originally lost contact with Phoenix in November of 2008. Phoenix was not built to survive the Martian winter, but some people were optimistic that it might have survived, possibly because of boosted optimism from the Mars rovers. Orbiters were listening as the ice receded form Mars northern latitudes. No signal was heard and now we know why.

The two pictures above show the extensive damage Phoenix took during the Martin winter. On the image from 2008 you can see both solar panels reflecting that blue color. In the image taken this year shows that one of the solar panels has completely broken off. This is probably from the buildup of dry ice (frozen carbon dioxide) until the weight of it caused the solar panel to break. So while Phoenix may have done great science, it was not able to rise from the ice.

Image Credit: NASA/JPL-Caltech/MSSS
The other story has to do with the weird shape of Mars north pole. Looking at the picture on the left you can see the large spiral pattern. In the past planetary scientists had purposed many ideas including volcanism and glacial flows. Two new papers published in the journal Nature bring a strong new idea to the table: wind.

The details of the effect are a little technical for me to dive into here, but I did want to make some points about the research. I like to point out when scientists build models that make predictions and then either confirm or dispute their hypothesis with new evidence. In this case, they came up a model of what they thought a wind carved feature would look like. When the data came in, they found it matched their models. The scientists working this research also reported their results responsibly. They published in a peer-reviewed journal and didn't make any absolute statements. Jack Holt of The University of Texas at Austin’s Institute for Geophysics said “We aren't saying they were carved by wind, rather that wind had a strong role in their formation and evolution.” I think these scientists did a great job and found a really cool result. This is science at its best.

*If you do want a more detailed breakdown of their work, I recommend Universe Today

May 24, 2010

Scientific Unknowns: Ball Lighting

Ball lighting is something I have wanted to write about now for a long time. I was first introduced to ball lightning in elementary school as just another form of lightning that moved across the ground. I never really questioned it until more recently, when I started to hear more about it. Ball lightning seems to be something that many people report seeing, but there is little in the way of physical evidence. Its a phenomena that lots of people accept without really knowing what it is, just as I did. So I decided to do some investigation on the subject.

My first questions in researching this were 'what is ball lightning?' and 'does it exist?' To my surprise, finding answers these two questions was no simple task. The is a compilation of anecdotal stories of ball lightning on the Internet. As I read these, one thing became very clear: "ball lightning" is not one thing. The stories vary wildly for each person. Some of the stories are clearly astronomical objects like Venus and bright meteors. Other stories sound like they could have other plausible ordinary explanations as well. If we dismiss these stories, we are still left with some interesting accounts.

Of those accounts I couldn't immediately explain, there were few common threads. Some people saw a blue orb and others saw a red or orange orb. Many of the stories did take place during a lightning storm or there was some other source of electricity in the immediate area. Some people saw it hovering above the ground, others near the celling, and other reports say it was following a fence or wall. Sometimes it just disappeared peacefully and other times it crashed into objects and people, causing varying amounts of damage. Some common factors in all these stories seem to be that "ball lightning" is roughly a sphere in shape and it doesn't appear to have direct contact with object without disappearing. One thing that bothers me about these reports is that the vast majority of them are based on people's memories from usually over 10 or 20 years ago.

So what do I make of these reports? It's hard for me to say there's nothing at all going on here, but if there is, it is a very rare effect. Even if ball lightning does exist, it is very overblown. Our memories as humans degrade over time, so I am very wary of these older reports. Some reports were even second or third hand. The worst of them just assumed ball lightning as the cause of some electrical explosion. So I wasn't convinced ball lightning exists, but next I wanted to see if there was any plausible explanation to explain some of these stories.

There are some interesting explanations for how ball lightning might form. Explanations vary, but all of them tend to be really technical. Some involve complex ways of refracting light and others purpose floating balls of plasma. Another idea is that nano-particles kicked up by normal lightning strikes can hover and burn for a few seconds after a strike. None of the hypothesizes I found explain the diversity of ball lightning experiences. A new idea even suggested that ball lightning is a hallucination caused by electromagnetic fields interacting with the brain. I think that this is one of the main reasons none of them have become well accepted by the scientific community.

So what's the final word on ball lighting? Personally, I'm not convinced that ball lightning is a actual phenomena. Before we start a serious investigation of anything, we need to make sure there's something to investigate. Some cool science has been done on the subject, but not enough to prove anything conclusively. I attribute ball lightning to mistaken sightings of astronomical objects, known but rare atmospheric phenomena, old distorted memories, and hallucinations. Culture gives all this the name ball lightning.

May 20, 2010

The Chemistry of Fossils

Most of the fossil evidence paleontologists analyze is what they can see. This is why so many of the fossil specimens are bones, shells, and other hard tissue: it's not as easy to decompose, so it preserves well in the fossilization process. However, soft tissue does sometimes preserve. Fossil feathers are a good example of this. The Burgess Shale fossils are another example. At a first look, these soft tissue fossils look like imprints on the rock. A new analysis technique reveals this isn't true, though. In exceptional soft tissue fossils, the imprint is also chemical.

The Thermopolis Archaeopteryx
Normal Color

The Thermopolis Archaeopteryx
False Color under Synchrotron

Using the Stanford Synchrotron Radiation Lightsource, at the Department of Energy's SLAC National Accelerator Laboratory, a team of paleontologists shot a focused beam of high-intensity X-rays at the Thermopolis Archaeopteryx specimen. Similar sorts of experiments had been run before: CT scans and low-intensity x-rays, for instance. However, these were not ideal to triggering and detecting the fluorescence of the chemicals in the fossils. The Sychrotron was. It efficiently formed a detailed scan of the fossil, and revealing an incredible secret of the fossil. At least a half-dozen different chemicals were found that aren't native to the rock or some fluke of the preservation process. These are trace elements from the animal itself! Of these elements, the most important of the findings was the high concentration of phosphorous in the feather imprints. Modern birds have a high phosphorous concentration in their feathers as well. This adds yet another thread to the tapestry of evidence tying birds and dinosaurs together. Original zinc and copper was found in the bones as well.

Close-up of the Archeopteryx
Color Scheme: Green- zinc;
Red- calcium; Blue- Manganese
So far, the synchrotron analysis technique has only been applied to the Thermopolis Archaeopteryx. Given the exciting results, though, I expect that other well-preserved fossils, such as the ones I mentioned earlier from the Burgess Shale, or even dinosaur skin impressions, could be analyzed this way. The chemical signature gives clues to evolutionary tracks, and may eventually help in determining other characteristics, like color, for creatures that haven't walked this planet for millions of years.

Source: Science News- Archaeopteryx Fossil Seen in New Light
Science Daily- X-rays Reveal Chemical Link Between Birds and Dinosaurs

Thanks to the Wyoming Dinosaur Center for the heads-up about this finding.

May 19, 2010

The Language of Science: Part III

The language of science is designed to clearly convey ideas so that other scientists and the scientifically literate can understand them. I wish I could also say it is helpful in conveying scientific ideas to the public, but unfortunately that simply is not the case. Often times using scientific jargon will only confuse your audience. This creates two problems. First, it makes it much more challenging to educate people about science. This is a serous problem, but another problem that I think is even worse many times is the hijacking of scientific language. This misuse of scientific terminology is often referred to as "technobabble." This video below is one of the most famous pieces of technobabble on the web.

So, what's wrong with this explanation? She references creditable scientists and uses scientific formulas we are all familiar with. If you have much of any background in science, I'm sure you noticed the misuse of all these scientific terms; however, if you aren't, they can be more difficult to spot. I wanted to use this video not to prove that Dr. Werner is wrong, but to show how scientific terms can be completely taken out of context and misused. She tries to manipulate theoretical physics using very vague ideas. She talks as though she is trying to explain some scientific subject, but she is missing the scientific subject to explain.

Science does sometimes make bold claims, but only when the evidence is there to support it. If you hear someone making a bold claim that they claim is back up by science, ask for the evidence. There should at least be other researchers in relevant fields also supporting the claim. There is no perfect formula for avoiding technobabble, but it is something that we should be aware of. The better you understand basic science the easier it is to pick out when it is being misused. So try to educate yourself and those around you. Try finding other examples of technobabble in TV shows and pop culture. This is a really fun way to educate yourself and will help you detect when people are trying to sell you something that just isn't there.

May 3, 2010

Have Astronomers Found the Infamous Intermediate Black Holes?

Image credit: X-ray: NASA/CXC/UA/J.
Irwin et al. Optical: NASA/STScI
When a large star several times the size of our sun explodes as a supernova, it can create a stellar mass black hole with about the same mass as that star. At the center of galaxies, we find strong evidence for supermassive black holes that are millions or billions of times the mass as our own sun. The theory has been that stellar mass black holes may merge together over time to create the supermassive black holes, but there's one problem. If this theory is correct, shouldn't there be lots of intermediate sized black holes wandering around? So the hunt has been on and now a team of astronomers think they may have found some.

First a little more background. X-ray light is produced by high energy processes. Stars can produce some X-rays, supernova can produce large bursts of X-rays, and supermassive black holes can be some of the brightest objects in the X-ray spectrum. This is because they can form a disk of material that backs up on its way into the black hole, like water backing up on its way down a drain pipe. The particles in that disk of material, called an accretion disk, start bumping into each other creating heat and X-rays (as well as other forms of radiation). ULX stands for Ultraluminous X-ray source. A ULX puts of X-rays in amounts between what we see from stars and what we see from supermassive black holes at the centers of galaxies.

What causes these ULX is a mystery. It would be easy to assume that they are the long searched for intermediate black holes, but to make that assumption without other evidence would be an argument from ignorance. So some researchers have been looking for the smoking gun that will connect intermediate black holes to these ULX. Now a team says that they have evidence of a intermediate black hole creating a ULX by tidally shredding an old star.

The team took a spectrum of this ULX that was located in a globular cluster, a very old dense collection of stars on the edge of the galaxy. The elements they observed in the spectrum were unusual for globular clusters. Large amounts of oxygen and nitrogen were detected, but a serious lack of hydrogen. "We think these unusual signatures can be explained by a white dwarf that strayed too close to a black hole and was torn apart by the extreme tidal forces," said coauthor Joel Bregman of the University of Michigan. A white dwarf is a star around the same mass as our sun at the end of its life. That would explain the large amounts of oxygen and go a long way in explaining the lack of hydrogen. The presence of nitrogen still remains a mystery.

So is this the smocking gun evidence that astrophysicists have been looking for? I would say not yet. This is very suggestive and needs further study. If the researchers are correct then this object should begin to fade over time as the star is consumed. If the astronomers are correct they have found what is almost certainly a very rare object. I still want to know where all this nitrogen is coming from. This is an extremely exciting result for one or our greatest questions in astrophysics, but I don't think we should close the book on this one quite yet.

For more information I recommend the NASA page