Welcome to Joechao's blog

I am just an enthusiast. Don't feel too bad if my unprofessional comments make you angry.

Friday, March 31, 2006

Are we alone?

Life might be common in the universe, although we haven't found it outside the earth. Intelligent life forms should be less common, although some people claim they have seen them. Rare Earth hypothesis suggests that it is very unlikely to find such a nice planet as ours. For example, our position in the galaxy is far away from huge radiation sources, resulting a favorable environment for complicated life forms.

In the NASA Astrobiology Science Conference (AbSciCon) 2006, Medvedev and Melott of the University of Kansas related mass extinctions when the sun bobs up and down through the dense galactic disc as it orbiting in the galaxy. The period of solar bobbing motion is 64 million years, matching nicely with the 62-million-year biodiversity fluctuation proposed by Rohde and Muller (2005). It is yet another theory trying to explain mass extinctions.

No matter what the real causes behind mass extinctions, it is interesting to look at the frequency of mass extinctions. If they happen more frequently, advance life forms such as us would not have the chance to appear; On the other hand, if less frequently, perhaps the world would be ruled by certain dinosaur-men or mermaids. Is our existence an accident? Are we alone?

Doing science using Google Earth

On March 6th, the Center for Remote Sensing at Boston University announced that they found a giant crater, 31km in diameter, made by a meteorite impact in Egypt's western desert.

Something more interesting happened couple days later after Mr. Emilio González in Spain read this news and asked: No one saw a 31km structure before? He launched Google Earth and found the newly discovered crater in no time. Keeping "flying" above the adjacent regions, he found two suspicious huge ring structures. "Could that be so easy?", he asked. After checking with professional geologists, those rings he found were very likely impact craters as well! Read the amazing story written by González at http://www.astroseti.org/impacts.php.

Crater image from the Center for Remote Sensing at Boston University.

Crater image from Google Earth.

Yes, he was very lucky. But what really impressed me is the power of publicly accessible data. Two important factors are:

  1. This fortunate discovery could not be done without the freely distributed satellite images.
  2. Publicly accessible information might be more effective than traditional tools.

I don't know how much money NSF and NASA have supported the Boston group, but González paid nothing. I am not saying the work of the Boston group is wasted---finding more craters doesn't mean understanding the significance better. Public might be blind. A few days after astroseti.org published the González story, it announced on its website: "Now that everyone seems to be reporting structures... Please don't bother geologists with anything that looks like a circle." I admit there will be temporary problems when a crowd of amateurs involve in Science too much. However, the power of open involvement is more than we could estimate in the long run. Science has to be lead by elites, but it will be more powerful to be driven by the public.

Thursday, March 30, 2006

My experiment at the Wikipedia

I have loved Wikipedia since I learned about it. The Wiki concept allows broad readers to contribute and to review the submitted articles. I know the information is not as credible as Encyclopedia Britannica, but Wikipedia can be updated much faster. Furthermore, for popular topics, I hypothesize that the contents will be reviewed by many people including knowledgeable elites. The accuracy will very likely converge to an acceptable level.

As an experimentalist, I decided to test my hypothesis. I just put a new article titled "Mungo Lady" (http://en.wikipedia.org/wiki/Mungo_Lady), a remain of a 26k-year-old female Homo sapiens discovered in Australia. Although I try to be an amateur historian, I am not familiar with this topic at all. The accuracy must be !@*^$#. Let's wait and see how fast this article can be modified. It will be too bad if some Australian high school students cite my mistakes for their homework assignments.

I have tried my best for an hour or so on this article. I briefly surveyed the literature to verify the information. Yes, one hour was too short for me to make it perfect. However, it is the responsibility of all the Wikipedia users to make it better, right?

An old dog is learning a new trick: Blogging.