If, as some science-fiction novels and movies would have us believe, the universe is teeming with intelligent aliens, that begs the question: where are they? If they're out there, why haven't they come to visit us yet (and please, for the love of God, don't refer me to stories of alien abductions and UFOs)?
That question has been pondered many times over the years (most famously by Enrico Fermi in 1950), by many scientists far smarter than a lowly computer geek like me. The heart of the matter comes down to one question: just how common is intelligent life?
In 1960, Dr. Frank Drake proposed a method for estimating the number of intelligent species present in the galaxy by use of a mathematical equation, as follows:
N = R* x fp x ne x fl x fi x fc x L
Okay, you're saying, but what the heck does that mean?
Well, N is the number of intelligent alien species currently in our galaxy with which we might hope to be able to communicate.
R* is the average rate of star formation in our galaxy.
fp is the fraction of those stars that have planets.
ne is the average number of earth-like planets that are capable of supporting life per star that has planets.
fl is the fraction of the above that actually go on to develop life at some point.
fi is the fraction of the above that actually go on to develop intelligent life.
fc is the fraction of civilizations that develop advanced enough technology to release detectable signs of their existence into space.
L is the length of time such civilizations release detectable signals into space.
By multiplying out the values you think are probably correct for those variables, you can get an estimate of the number of intelligent, advanced civilizations currently present in our galaxy. And the best part is, our knowledge of the universe is growing all the time, so we can refine the values used in this model as time goes on.
Drake and his colleagues used the following values in 1961:
R* = 10/year (10 stars formed per year, on the average over the life of the galaxy)
fp = 0.5 (half of all stars formed will have planets)
ne = 2 (2 planets per star will be able to develop life)
fl = 1 (100% of the planets will develop life)
fi = 0.01 (1% of which will be intelligent life)
fc = 0.01 (1% of which will be able to communicate)
L = 10,000 years (which will last 10,000 years)
If you work out the math, you'll find that Drake and his team estimated that there are 10 intelligent civilizations in the galaxy capable of producing advanced communication signals that we should be able to detect.
In the past 46 years, however, we've already learned enough to refine the model somewhat. For example, Drake estimated star formation (R*) at 10 stars per year, but studies by NASA and the ESA show that the number is closer to 6.
Drake himself wrote an article for Wired Magazine in 2004 about revising the information for his model as new data became available. Drake now believes that there are far more intelligent species in the galaxy than he did fifty years ago.
But if Drake is right, then Fermi's original question stands: Where is everybody?
Monday, August 20, 2007
Thursday, August 9, 2007
PlanetQuest Update
Another update from Dr. Laurance Doyle on the status of the PlanetQuest group:
PlanetQuest is a worthy project to allow desktop users (like me and you) to contribute to the search for extra-solar planets that may harbor life. But in order to get the software working and continue their science, they need money. I gave them some a while back, but they obviously still need more.
...Our lack of progress at the moment is a funding issue which we feel could be solved if we can get initial funding to a point where we can finish the alpha test version of the software and thereafter sign folks up to be supporting-founding members of PlanetQuest.
We do have sufficient astronomical data (stellar light curves) at present for a thorough test of the system and could accommodate perhaps up to 100,000 users for a year. This was previously my main concern. We have also carried the problem through from data acquisition to light curve model fitting (the transit detection algorithm) and therefore see no technical issues in the way of proceeding.
Most of our personnel, however, are also extremely busy people working in other businesses and on other projects, and so PlanetQuest has not received the attention lately that it needs to move forward as quickly as it could, because it is largely (although not entirely) a volunteer project at this point.
I would like to see it take off this year-that is, that we are able to release an alpha version of the Collaboratory and start to post key parts of our educational web site on a daily basis. I am involved in fund raising for PlanetQuest at present, and also writing a comprehensive business plan.
The overall project in execution is quite complex, but the basic overview ideas are readily understandable. After about seven years now since the initial idea, we are still unique in offering a project like PlanetQuest (which surprises me a little). Computational speed (i.e., Moore's Law) has gone up over a factor of 25 in that time, so we have had to collect a lot more stellar data. Our team is ready to proceed, then, as soon as we can get support for the final phase of the programming...
PlanetQuest is a worthy project to allow desktop users (like me and you) to contribute to the search for extra-solar planets that may harbor life. But in order to get the software working and continue their science, they need money. I gave them some a while back, but they obviously still need more.
A Perfect Launch
Endeavour's launch last night went off on-time and without any problems, which apparently only happens about 40% of the time for space shuttles.
Wednesday, August 8, 2007
Endeavour Launches Tonight
NASA's space shuttle Endeavour launches tonight at 6:36:36 PM EDT. Unfortunately, that will be 5:36 my time, and I will be at the gym, so I won't be able to watch it like I usually do. If you want to watch the launch, however, you can see it at Space.com.
Since the last time it launched, Endeavour has undergone a major overhaul replacing most of the key systems and updating the shuttle with the latest technology. When it launches, it will be the most advanced shuttle NASA has ever sent into orbit.
Since the last time it launched, Endeavour has undergone a major overhaul replacing most of the key systems and updating the shuttle with the latest technology. When it launches, it will be the most advanced shuttle NASA has ever sent into orbit.
Thursday, August 2, 2007
The Scientific Method
You wouldn't think someone would have to define science, but in recent years, we've seen many things that pretend to be science which are not. Case in point: Intelligent Design. Supporters of ID think that ID should be taught in science classrooms alongside (or in place of) evolution. There's only one problem: evolution is science, and Intelligent Design is religion.
My favorite definition of science comes from Merriam-Webster: a : knowledge or a system of knowledge covering general truths or the operation of general laws especially as obtained and tested through scientific method b : such knowledge or such a system of knowledge concerned with the physical world and its phenomena
The important part of that definition is the words "scientific method." If you're not familiar with the scientific method, it is this:
In other words, you observe something about the universe that puzzles you. You review the relevant literature about the subject to determine if the problem has already been described and understood. If not, you establish a testable hypothesis about what you think is going on. Then you conduct an experiment controlled in a careful way as to remove all other influences from the results. After the experiment, you analyze your results to determine whether your hypothesis still holds merit or not.
That, in brief, is science. Science broadens our understanding of the universe by using the scientific method to teach us more about how our universe operates. Through the scientific method, we have advanced modern medicine, television, computer networks, space flight, and more.
In 1999, the U.S. National Academy of Sciences stated that "intelligent design, and other claims of supernatural intervention in the origin of life" are not science because they cannot be tested by experiment, do not generate any predictions, and propose no new hypotheses of their own. My only real problem with Intelligent Design is that it tries to pass itself off as science and to supplant actual scientific hypotheses and observations. If Intelligent Design's advocates would accept that ID is religion and promote it that way, I would have considerably less trouble with it.
Far worse, in my opinion, are the Young Earth Creationists, who assert that Earth and all life on it were created by God 6000 years ago. I have no objection to religion, and in fact consider myself to be a religious person. But let's talk about faith for a moment. My favorite definition of faith also comes from Merriam-Webster: firm belief in something for which there is no proof.
Faith is faith for a reason: God can never be proven to exist (or not). You either choose to believe in God, or you don't. That's faith.
Belief in something in spite of evidence to the contrary is not faith, it's stupidity. And that's the problem with Young Earth Creationism. I understand that there are arguments that fossils with an age of over 6000 years are suggested by YECs to have been placed there by God when He created the Earth, but that implies a God who is intentionally deceptive. Also, based on that argument, why would you believe the Earth is 6000 years old? Why not believe that God created the world twenty minutes ago?
The main argument for Young Earth Creationism is that the Bible basically traces a lineage from Adam and gives dates. The problem with that is that God did not sit down at a typewriter and type out the Bible. People did, and people make mistakes. Mistakes in translation, mistakes in transcription, and mistakes in re-telling of oral traditions that pre-date any written language. I know from experience that you can't pass a phrase around a room, one person at a time, between 30 people and have it come back the same. How much worse over the period of thousands of years and countless people?
Anyone who blindly believes that what is in the Bible is word-for-word correct has some serious flaws in their belief system (especially since it requires a decision about which version of the Bible to believe in, and also a belief that the men who picked which books were right and which were wrong 15-1700 years ago were right). Find your own beliefs, please.
But in doing so, don't buy into the belief that science is an attack on faith. Faith can guide you as to what to believe in the absence of evidence. Science provides us with the evidence of the wonders of our universe. Whether you attribute those wonders to God (or some other Intelligent Designer) or not is entirely up to you.
My favorite definition of science comes from Merriam-Webster: a : knowledge or a system of knowledge covering general truths or the operation of general laws especially as obtained and tested through scientific method b : such knowledge or such a system of knowledge concerned with the physical world and its phenomena
The important part of that definition is the words "scientific method." If you're not familiar with the scientific method, it is this:
- Research (or Observation)
- Description of the Problem
- Hypothesis
- Expermintation
- Conclusion
In other words, you observe something about the universe that puzzles you. You review the relevant literature about the subject to determine if the problem has already been described and understood. If not, you establish a testable hypothesis about what you think is going on. Then you conduct an experiment controlled in a careful way as to remove all other influences from the results. After the experiment, you analyze your results to determine whether your hypothesis still holds merit or not.
That, in brief, is science. Science broadens our understanding of the universe by using the scientific method to teach us more about how our universe operates. Through the scientific method, we have advanced modern medicine, television, computer networks, space flight, and more.
In 1999, the U.S. National Academy of Sciences stated that "intelligent design, and other claims of supernatural intervention in the origin of life" are not science because they cannot be tested by experiment, do not generate any predictions, and propose no new hypotheses of their own. My only real problem with Intelligent Design is that it tries to pass itself off as science and to supplant actual scientific hypotheses and observations. If Intelligent Design's advocates would accept that ID is religion and promote it that way, I would have considerably less trouble with it.
Far worse, in my opinion, are the Young Earth Creationists, who assert that Earth and all life on it were created by God 6000 years ago. I have no objection to religion, and in fact consider myself to be a religious person. But let's talk about faith for a moment. My favorite definition of faith also comes from Merriam-Webster: firm belief in something for which there is no proof.
Faith is faith for a reason: God can never be proven to exist (or not). You either choose to believe in God, or you don't. That's faith.
Belief in something in spite of evidence to the contrary is not faith, it's stupidity. And that's the problem with Young Earth Creationism. I understand that there are arguments that fossils with an age of over 6000 years are suggested by YECs to have been placed there by God when He created the Earth, but that implies a God who is intentionally deceptive. Also, based on that argument, why would you believe the Earth is 6000 years old? Why not believe that God created the world twenty minutes ago?
The main argument for Young Earth Creationism is that the Bible basically traces a lineage from Adam and gives dates. The problem with that is that God did not sit down at a typewriter and type out the Bible. People did, and people make mistakes. Mistakes in translation, mistakes in transcription, and mistakes in re-telling of oral traditions that pre-date any written language. I know from experience that you can't pass a phrase around a room, one person at a time, between 30 people and have it come back the same. How much worse over the period of thousands of years and countless people?
Anyone who blindly believes that what is in the Bible is word-for-word correct has some serious flaws in their belief system (especially since it requires a decision about which version of the Bible to believe in, and also a belief that the men who picked which books were right and which were wrong 15-1700 years ago were right). Find your own beliefs, please.
But in doing so, don't buy into the belief that science is an attack on faith. Faith can guide you as to what to believe in the absence of evidence. Science provides us with the evidence of the wonders of our universe. Whether you attribute those wonders to God (or some other Intelligent Designer) or not is entirely up to you.
Friday, July 20, 2007
Clues to Why Exercise Helps You Live a Longer, Healthier Life
Researchers at the Howard Hughes Medical Institute have uncovered clues to suggest why living a healthier lifestyle will help you live longer. The answer, they say, is less insulin in the brain.
In their experiments, the researchers sought to understand the role of the insulin-like signaling pathway in extending lifespan. This pathway governs growth and metabolic processes in cells throughout the body. The pathway is activated when insulin and insulin-like growth factor-1 switch on proteins inside the cell called insulin receptor substrates (Irs).
In earlier work, the researchers had found that knocking out both copies of one of the Irs genes, Irs2, in mice reduces brain growth and produces diabetes due to pancreatic beta cell failure. However, in the new study, when the researchers knocked out only one copy of the gene, they found the mice lived 18 percent longer than normal mice.
Because reducing insulin-like signaling in the neurons of roundworms and fruitflies extends their lifespan, the researchers decided to examine what would happen when they knocked out one or both copies of the Irs2 gene only in the brains of mice.
Mice lacking one copy of the Irs2 gene in brain cells also showed an 18 percent longer lifespan, and the near complete deletion of brain Irs2 had a similar effect. “What's more, the animals lived longer, even though they had characteristics that should shorten their lives—such as being overweight and having higher insulin levels in the blood,” said Morris F. White, an investigator for HHMI.
However, both sets of Irs2 knockout mice exhibited other characteristics that marked them as healthier, said White. They were more active as they aged, and their glucose metabolism resembled that of younger mice. The researchers also found that after eating, their brains showed higher levels of superoxide dismutase, an antioxidant enzyme that protects cells from damage by highly reactive chemicals called free radicals.
White and his colleagues are planning their next studies to better understand how healthy aging and lifespan are coordinated by Irs2 signaling pathways in the body and the brain. White speculated that the insulin-like signaling pathway in the brain might promote age-related brain diseases.
Personally, I'll be most interested in seeing how this work meshes with the work being done on Sirtuin. Calorie Restriction methods have not been shown to be effective in humans yet, but there's no reason to think that they won't be. The research on brain insulin, on the other hand, is something that will have to be watched fairly closely. While mice may make an interesting model for early-stage testing, their brains are not that similar to ours and any type of alteration being done on the brain could have effects that would not be obvious in a mouse model.
In their experiments, the researchers sought to understand the role of the insulin-like signaling pathway in extending lifespan. This pathway governs growth and metabolic processes in cells throughout the body. The pathway is activated when insulin and insulin-like growth factor-1 switch on proteins inside the cell called insulin receptor substrates (Irs).
In earlier work, the researchers had found that knocking out both copies of one of the Irs genes, Irs2, in mice reduces brain growth and produces diabetes due to pancreatic beta cell failure. However, in the new study, when the researchers knocked out only one copy of the gene, they found the mice lived 18 percent longer than normal mice.
Because reducing insulin-like signaling in the neurons of roundworms and fruitflies extends their lifespan, the researchers decided to examine what would happen when they knocked out one or both copies of the Irs2 gene only in the brains of mice.
Mice lacking one copy of the Irs2 gene in brain cells also showed an 18 percent longer lifespan, and the near complete deletion of brain Irs2 had a similar effect. “What's more, the animals lived longer, even though they had characteristics that should shorten their lives—such as being overweight and having higher insulin levels in the blood,” said Morris F. White, an investigator for HHMI.
However, both sets of Irs2 knockout mice exhibited other characteristics that marked them as healthier, said White. They were more active as they aged, and their glucose metabolism resembled that of younger mice. The researchers also found that after eating, their brains showed higher levels of superoxide dismutase, an antioxidant enzyme that protects cells from damage by highly reactive chemicals called free radicals.
White and his colleagues are planning their next studies to better understand how healthy aging and lifespan are coordinated by Irs2 signaling pathways in the body and the brain. White speculated that the insulin-like signaling pathway in the brain might promote age-related brain diseases.
Personally, I'll be most interested in seeing how this work meshes with the work being done on Sirtuin. Calorie Restriction methods have not been shown to be effective in humans yet, but there's no reason to think that they won't be. The research on brain insulin, on the other hand, is something that will have to be watched fairly closely. While mice may make an interesting model for early-stage testing, their brains are not that similar to ours and any type of alteration being done on the brain could have effects that would not be obvious in a mouse model.
Monday, July 16, 2007
Defending Science
As you well know by now, I am in favor of the responsible advancement of science and technology. But not everyone, it seems, shares my opinion. In particular, the current government administration in this country seems to put politics before scientific and technological advancement, and for that reason, the people at Defend Science are on the march.
From their latest e-mail:
From their latest e-mail:
No doubt you have heard of the recent testimony of former Surgeon General Richard Carmona to the House Oversight and Government Reform Committee on July 10, 2007. Dr. Carmona’s testimony was stunning exposure of the Bush Administration’s willingness to deny scientific truth in the pursuit of a political agenda. Defend Science is calling on people to voice their opinion to newspapers throughout the country with letters expressing outrage at not only the overt politicization of science to an unprecedented level, but its outright denial. As the Defend Science statement says, we must all “insist on an atmosphere where scientists are allowed to seek the truth, even when the truth conflicts with the views and policies of those in power... where science education and the popularization of the scientific method are valued...”
In his testimony Dr. Carmona stated that the discussion in the Bush Administration around stem cell research was “devoid of science” and that the policy around sex education was to “preach abstinence which I felt was scientifically incorrect.” He further revealed that his speeches were vetted for political content and his attempt to educate the public about issues ranging from stem cells to sex education “blocked at every turn.” In each case, Dr. Carmona indicated that science is denied in the face of political, ideological and theological considerations.
Check out http://www.defendscience.org/surgeon_general.html for media coverage and links to excerpts from the testimony, and add your voice to the discussion. Dr. Carmona’s testimony alone is an indictment of the Bush Administration’s public health policy, but it also points to the broader issue of why we need to defend science. There is an unrelenting assault on people's access to scientific knowledge, to the scientific method and approach to knowing about the world, to the scientific spirit. The more letters we write to local papers exposing and opposing this agenda the bigger the impact on the public discourse around the critical issue of defending science we will have.
We at Defend Science would appreciate your help in keeping us abreast of this effort. Please send us copies of your letters (send to multiple publications if you can), any posting you make to blogs or comment sections, and similar public outlets--and be sure to identify where you submitted the pieces. And let us know if your letter is published!
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