SAIU trip to the Creation Museum from Secular Alliance on Vimeo.
What is the ``scientific method''?
What is the "scientific method''?
The scientific method is the best way yet discovered for winnowing the truth from lies and delusion. The simple version looks something like this:
- 1. Observe some aspect of the universe.
- 2. Invent a tentative description, called a hypothesis, that is consistent with what you have observed.
- 3. Use the hypothesis to make predictions.
- 4. Test those predictions by experiments or further observations and modify the hypothesis in the light of your results.
- 5. Repeat steps 3 and 4 until there are no discrepancies between theory and experiment and/or observation.
When consistency is obtained the hypothesis becomes a theory and provides a coherent set of propositions which explain a class of phenomena. A theory is then a framework within which observations are explained and predictions are made.
The great advantage of the scientific method is that it is unprejudiced: one does not have to believe a given researcher, one can redo the experiment and determine whether his/her results are true or false. The conclusions will hold irrespective of the state of mind, or the religious persuasion, or the state of consciousness of the investigator and/or the subject of the investigation. Faith, defined as belief that does not rest on logical proof or material evidence, does not determine whether a scientific theory is adopted or discarded.
A theory is accepted not based on the prestige or convincing powers of the proponent, but on the results obtained through observations and/or experiments which anyone can reproduce: the results obtained using the scientific method are repeatable. In fact, most experiments and observations are repeated many times (certain experiments are not repeated independently but are repeated as parts of other experiments). If the original claims are not verified the origin of such discrepancies is hunted down and exhaustively studied.
When studying the cosmos we cannot perform experiments; all information is obtained from observations and measurements. Theories are then devised by extracting some regularity in the observations and coding this into physical laws.
There is a very important characteristic of a scientific theory or hypothesis which differentiates it from, for example, an act of faith: a theory must be ``falsifiable''. This means that there must be some experiment or possible discovery that could prove the theory untrue. For example, Einstein's theory of Relativity made predictions about the results of experiments. These experiments could have produced results that contradicted Einstein, so the theory was (and still is) falsifiable.
In contrast, the theory that ``the moon is populated by little green men who can read our minds and will hide whenever anyone on Earth looks for them, and will flee into deep space whenever a spacecraft comes near'' is not falsifiable: these green men are designed so that no one can ever see them. On the other hand, the theory that there are no little green men on the moon is scientific: you can disprove it by catching one. Similar arguments apply to abominable snow-persons, UFOs and the Loch Ness Monster(s?).
A frequent criticism made of the scientific method is that it cannot accommodate anything that has not been proved. The argument then points out that many things thought to be impossible in the past are now everyday realities. This criticism is based on a misinterpretation of the scientific method. When a hypothesis passes the test it is adopted as a theory it correctly explains a range of phenomena it can, at any time, be falsified by new experimental evidence. When exploring a new set or phenomena scientists do use existing theories but, since this is a new area of investigation, it is always kept in mind that the old theories might fail to explain the new experiments and observations. In this case new hypotheses are devised and tested until a new theory emerges.
There are many types of ``pseudo-scientific'' theories which wrap themselves in a mantle of apparent experimental evidence but that, when examined closely, are nothing but statements of faith. The argument , cited by some creationists, that science is just another kind of faith is a philosophic stance which ignores the trans-cultural nature of science. Science's theory of gravity explains why both creationists and scientists don't float off the earth. All you have to do is jump to verify this theory - no leap of faith required.
Monday, July 28, 2008
Scientists Close to Reconstructing First Living Cell
By Nikhil Swaminathan
Modern cells are like microscopic cities: They have power plants (mitochondria), trash dumps (lysosomes), local government (the nucleus, with DNA serving as the legal charter), and many other activities going on inside their boundaries. They also have a border patrol in the form of a double-layered membrane that uses a series of protein-powered pumps, pores and channels to let nutrients in and keep other chemicals and substances out.
But, cells were very different when life began 3.5 billion to four billion years ago. Rather than small metropolises, they were more like a purse that carried instructions—consisting of just a membrane with genetic information inside. They lacked the structures and proteins that now make them tick. The question is: How then were they able to take in the nutrients necessary to survive and reproduce?
Harvard Medical School researchers report in Nature that they have built a model of what they believe the very first living cell may have looked like, which contains a strip of genetic material surrounded by a fatty membrane. The membranes of modern cells consist of a double layer of fatty acids known as phospholipids. But in designing a membrane for their cell, scientists worked with much simpler fatty acids that they believe existed on a primeval Earth, when the first cell likely formed. The key, says study co-author Jack Szostak, a Harvard geneticist, was to develop one porous enough to let in needed nutrients (such as nucleotides, the units that make up genetic material, or DNA) but strong enough to protect the genetic material inside and keep it from slipping out after replicating.
In an attempt to duplicate an early cell, scientists put fatty acids (that were likely membrane candidates) and a strip of DNA into a test tube of water. While in there, the fatty acids formed into a ring, or membrane, around the genetic segment. The researchers then added nucleotides—units of genetic material—to the test tube to determine whether they would penetrate the membrane and copy the DNA inside it. Their findings: the nucleotides did enter the cell, latch onto and replicate the DNA over 24 hours.
What scientists now must figure out, Szostak says, is how the original and copycat DNA strands separated and this early cell divided or reproduced.
"We're trying to solve a whole series of problems, step by step," he says, "and build up to replicating an evolving system."
David Deamer, a biomolecular engineer at the University of California, Santa Cruz, says he believes the team is on its way to making a prototype of a primitive cell that has "essentially all the basic properties of life."
Friday, July 18, 2008
Monkeys Practice World's Oldest Profession
More evidence that other primates might not be so different from humans: after researchers taught seven capuchin monkeys to use currency, they soon paid for sex.
I thought I'd mention this phenomenon, observed by Yale economic psychologist Keith Chen, in light-hearted light of the debate occasioned by my post "A Human-Like Race Is Going Extinct." The ensuing comment dialogue -- over the definition of human, and whether it should be applied to great apes -- was one of the most enjoyable WiSci debates to date.
Emerging from the fray were two competing arguments: "human" is either a matter of basic biology -- genetic inheritance and the potential to procreate -- or cognitive, emotional and social capacity.
Both positions are, I think, both entirely arbitrary and equally valid: what's at stake is a definition. And for myself, I prefer the latter definition, as the ability to feel and communicate seems more important than the sequence of my genome. To wit: if aliens arrived today and asked why Earth shouldn't be demolished to make way for an interstellar bypass, would we ask them to delay on account of our genes rather than our feelings?
Friday, July 11, 2008
Alkaline Soil Sample From Mars Reveals Presence of Nutrients for Plants to Grow
By KENNETH CHANG
Stick an asparagus plant in a pot full of Martian soil, and the asparagus might grow happily, scientists announced Thursday.
An experiment on the Phoenix Mars lander showed the dirt on the planet’s northern arctic plains to be alkaline, though not strongly alkaline, and full of the mineral nutrients that a plant would need.
“We basically have found what appears to be the requirements, the nutrients, to support life whether past, present or future,” said Samuel P. Kounaves of Tufts University, who is leading the chemical analysis, during a telephone news conference on Thursday. “The sort of soil you have there is the type of soil you’d probably have in your backyard.”
Mars today is cold and dry, and the surface is bombarded by ultraviolet radiation, making life unlikely, but conditions could have made the planet more habitable in the past. Plants that like alkaline soil — like asparagus — might readily grow in the Martian soil, provided that other components of an Earth-like environment including air and water were also present.
The preliminary findings from Phoenix do not answer whether life ever existed on Mars (or might still exist somewhere underground), only that conditions, at least at this location, are not the harshest imaginable. The soil, taken close to the surface, was similar to what is found in parts of Antarctica, Dr. Kounaves said. The soil elsewhere on the planet could well be very different; even the soil farther down in the ground could turn out to be acidic or otherwise vary in composition.
The Phoenix is capable of performing the same chemical analysis on three more samples.
In a different experiment, a tiny oven heated another sample of the Martian soil to 1,800 degrees Fahrenheit, which released water vapor. “This soil clearly has interacted with water in the past,” said William V. Boynton of the University of Arizona, the lead scientist in this experiment.
Dr. Boynton said he could not say when the liquid water was present or even where it was. The moisture might have come from dust particles that had blown there from other parts of Mars. “At this point, it is difficult to quantify what was given off,” he said.
The oven experiment also found carbon dioxide vapors, not surprising because the planet’s thin atmosphere is primarily carbon dioxide. The data have not revealed any carbon-based compounds.
The Phoenix mission is not directly looking for life on Mars, but rather whether conditions for habitability ever existed. In the wet chemistry experiment, water was mixed into the soil to produce Martian mud. Then the apparatus performed the same sorts of tests that gardeners use to test the condition of their soil.
The pH level was between 8 and 9, Dr. Kounaves said. The pH, or potential of hydrogen, reflects the concentration of hydrogen ions, or acidity, of a substance and usually varies between 0 and 14, with 7 considered neutral. (The water of Earth’s oceans, for comparison, has a pH of 8.2.) The experiment also found the presence of magnesium, sodium, potassium and chloride ions in the soil.
“There’s nothing about it that would preclude life,” Dr. Kounaves said. “In fact, it seems very friendly.”
Saturday, June 28, 2008
Humans nearly wiped out 70,000 years ago, study says
From: edition.cnn.com
Was there a "mitochondrial Eve" who lived in Africa 200,000 years ago?
Human beings may have had a brush with extinction 70,000 years ago, an extensive genetic study suggests.
The human population at that time was reduced to small isolated groups in Africa, apparently because of drought, according to an analysis released Thursday.
The report notes that a separate study by researchers at Stanford University estimated that the number of early humans may have shrunk as low as 2,000 before numbers began to expand again in the early Stone Age.
"This study illustrates the extraordinary power of genetics to reveal insights into some of the key events in our species' history," said Spencer Wells, National Geographic Society explorer in residence.
"Tiny bands of early humans, forced apart by harsh environmental conditions, coming back from the brink to reunite and populate the world. Truly an epic drama, written in our DNA."
Wells is director of the Genographic Project, launched in 2005 to study anthropology using genetics. The report was published in the American Journal of Human Genetics.
Studies using mitochondrial DNA, which is passed down through mothers, have traced modern humans to a single "mitochondrial Eve," who lived in Africa about 200,000 years ago.
The migrations of humans out of Africa to populate the rest of the world appear to have begun about 60,000 years ago, but little has been known about humans between Eve and that dispersal.
The new study looks at the mitochondrial DNA of the Khoi and San people in South Africa, who appear to have diverged from other people between 90,000 and 150,000 years ago.
The researchers led by Doron Behar of Rambam Medical Center in Haifa, Israel, and Saharon Rosset of IBM T.J. Watson Research Center in Yorktown Heights, New York, and Tel Aviv University concluded that humans separated into small populations before the Stone Age, when they came back together and began to increase in numbers and spread to other areas.
Eastern Africa experienced a series of severe droughts between 135,000 and 90,000 years ago, and researchers said this climatological shift may have contributed to the population changes, dividing into small, isolated groups that developed independently.
Paleontologist Meave Leakey, a Genographic adviser, asked, "Who would have thought that as recently as 70,000 years ago, extremes of climate had reduced our population to such small numbers that we were on the very edge of extinction?"
Today, more than 6.6 billion people inhabit the globe, according to the U.S. Census Bureau.
The research was funded by the National Geographic Society, IBM, the Waitt Family Foundation, the Seaver Family Foundation, Family Tree DNA and Arizona Research Labs.
Saturday, June 14, 2008
New Ion Engine Sets Thrust Record
An ion engine has smashed the record for total thrust in a NASA test. The successful test means the engine could be used in future NASA missions.Ion engines work by accelerating electrically charged atoms, or ions, through an electric field, thereby pushing the spacecraft in the opposite direction.
The thrust they provide at any given moment is very small, roughly equal to the force needed to hold up a sheet of paper against Earth’s gravity. But they can operate continuously in space for years using very little fuel, ultimately providing a much bigger boost than a chemical rocket.
The Dawn mission, which launched on Thursday, is equipped with NASA’s first generation of ion engines, called NSTAR. Dawn’s three NSTAR engines will allow it to reach the asteroid belt and park in orbit around two different asteroids.
The agency has also been testing a more advanced ion engine, called NASA’s Evolutionary Xenon Thruster (NEXT), which generates 2.5 times as much thrust as an NSTAR engine.
Now, NEXT has broken a record, providing more “total impulse” than any previous ion engine. Total impulse is a measure of the overall acceleration that an engine would provide to a spacecraft. It is the result of multiplying the engine’s thrust by how long it fires.
Record fuel
The NEXT engine has now been fired for over 12,000 hours (500 days), providing more than 10 million Newton-seconds of impulse, more than any ion engine has ever achieved.
During this time, it has processed more than 245 kilograms of fuel in the form of xenon gas, a record amount for an ion engine. The amount of fuel an ion engine can handle before wearing down is critical, since ion engines on spacecraft need to fire for years at a time.
Previous estimates have suggested NEXT engines could safely handle 450 kilograms of fuel in their lifetime. NSTAR is rated for only 150 kilograms of fuel throughput, although one NSTAR engine has processed 235 kilograms of fuel in a previous test.
“This test validates NEXT technology for a wide range of NASA solar system exploration missions, as well as the potential for Earth-space commercial ventures,” says NEXT principal investigator Mike Patterson of NASA’s Glenn Research Center in Cleveland, Ohio, US.
NEXT could power a mission to Saturn’s moon, Titan. It would require about 20 kilowatts of engine power to get there if the mission included both an orbiter and a lander. “We could do that with an array of three thrusters, plus a spare,” NEXT project manager Scott Benson of Glenn told New Scientist.
Star Wars
Although NSTAR and NEXT both use xenon gas as a propellant, NEXT accelerates the xenon ions more efficiently, providing up to 236 milliNewtons of thrust compared to NSTAR’s maximum of 92 mN. The ion engines used on Japan’s Hayabusa spacecraft to the asteroid Itokawa use 22 mN, while those used on the European Space Agency’s SMART-1 Moon probe operated at 70 mN.
NEXT can also vary its thrust by a factor of 11, as compared with NSTAR’s factor of five. This means it can throttle down to lower levels as it travels farther from the Sun and receives less sunlight, allowing it to operate at greater distances than NSTAR.
Although ion engines are just beginning to see regular use on scientific probes, they have been a common sight in science fiction for many years. Dawn spacecraft engineer Marc Rayman of NASA’s Jet Propulsion Laboratory in Pasadena, California, US, reminded journalists at a recent press conference of the ion engines used in the Star Wars movies.
“If you remember the TIE fighters that Darth Vader and the Evil Empire used to fight the rebel alliance, TIE stood for ‘twin ion engines’,” he said. “Well, Dawn does the Star Wars TIE fighters one better because we use three ion engines.”
Thursday, June 12, 2008
Physicists have 'solved' mystery of levitation
By Roger Highfield, Science Editor
In theory the discovery could be used to levitate a person
Levitation has been elevated from being pure science fiction to science fact, according to a study reported today by physicists.
In earlier work the same team of theoretical physicists showed that invisibility cloaks are feasible.
Now, in another report that sounds like it comes out of the pages of a Harry Potter book, the University of St Andrews team has created an 'incredible levitation effects’ by engineering the force of nature which normally causes objects to stick together.
Professor Ulf Leonhardt and Dr Thomas Philbin, from the University of St Andrews in Scotland, have worked out a way of reversing this pheneomenon, known as the Casimir force, so that it repels instead of attracts.
Their discovery could ultimately lead to frictionless micro-machines with moving parts that levitate But they say that, in principle at least, the same effect could be used to levitate bigger objects too, even a person.
The Casimir force is a consequence of quantum mechanics, the theory that describes the world of atoms and subatomic particles that is not only the most successful theory of physics but also the most baffling.
The force is due to neither electrical charge or gravity, for example, but the fluctuations in all-pervasive energy fields in the intervening empty space between the objects and is one reason atoms stick together, also explaining a “dry glue” effect that enables a gecko to walk across a ceiling.
Now, using a special lens of a kind that has already been built, Prof Ulf Leonhardt and Dr Thomas Philbin report in the New Journal of Physics they can engineer the Casimir force to repel, rather than attact.
Because the Casimir force causes problems for nanotechnologists, who are trying to build electrical circuits and tiny mechanical devices on silicon chips, among other things, the team believes the feat could initially be used to stop tiny objects from sticking to each other.
Prof Leonhardt explained, “The Casimir force is the ultimate cause of friction in the nano-world, in particular in some microelectromechanical systems.
Such systems already play an important role - for example tiny mechanical devices which triggers a car airbag to inflate or those which power tiny 'lab on chip’ devices used for drugs testing or chemical analysis.
Micro or nano machines could run smoother and with less or no friction at all if one can manipulate the force.” Though it is possible to levitate objects as big as humans, scientists are a long way off developing the technology for such feats, said Dr Philbin.
The practicalities of designing the lens to do this are daunting but not impossible and levitation “could happen over quite a distance”.
Prof Leonhardt leads one of four teams - three of them in Britain - to have put forward a theory in a peer-reviewed journal to achieve invisibility by making light waves flow around an object - just as a river flows undisturbed around a smooth rock.
Thursday, June 5, 2008
1000 Years of Creationist 'Achievements'
Scientific Achievements vs Creationists Achievements
Thursday, May 15, 2008
Scientist team creates first GM human embryo
Scientists have created what is believed to be the first genetically modified (GM) human embryo.
A team from Cornell University in New York produced the GM embryo to study how early cells and diseases develop. It was destroyed after five days.
The British regulator, the Human Fertilization and Embryology Authority (HFEA), has warned that such controversial experiments cause “large ethical and public interest issues”.
News of the development comes days before MPs are to debate legislation that would allow scientists to use similar techniques in this country.
The effects of changing an embryo would be permanent. Genes added to embryos or reproductive cells, such as sperm, will affect all cells in the body and will be passed on to future generations.
The technology could potentially be used to correct genes which cause diseases such as cystic fibrosis, haemophilia and even cancer. In theory, any gene that has been identified could be added to embryos.
Ethicists warn that genetically modifying embryos could lead to the addition of genes for desirable traits such as height, intelligence and hair color.
The Human Fertilization and Embryology Bill, which will have its second reading this week, will make it legal to create GM embryos in Britain.
The bill will allow GM embryos to be created only for research and will ban implantation in the womb. Ethicists, however, say that the legislation could be relaxed in the future.
The HFEA has said that it is preparing for scientists to apply for licences to create GM embryos. A paper, published by the authority, states: “The bill has taken away all inhibitions on genetically altering human embryos for research. The Science and Clinical Advances Group [of the HFEA] thought there were large ethical and public interest issues and that these should be referred for debate.”
The Cornell team, led by Nikica Zaninovic, used a virus to add a gene, a green fluorescent protein, to an embryo left over from in vitro fertilization.
The research was presented at a meeting of the American Society of Reproductive Medicine last year but details have emerged only after the HFEA highlighted the work in a review of the technology.
Zaninovic pointed out that in order to be sure that the new gene had been inserted and the embryo had been genetically modified, scientists would ideally need to grow the embryo and carry out further tests.
The Cornell team did not have permission to allow the embryo to progress, however.
Scientists argue that the embryos could be used to study how diseases develop. They also say GM embryos could be more efficient in generating stem cells.
However, Dr David King, director of Human Genetics Alert, warned: “This is the first step on the road that will lead to the nightmare of designer babies and a new eugenics. The HFEA is right to say that the creation and legalization of GM embryos raises ‘large ethical and public interest issues’ but neglects to mention that these have not been debated at all.”
He added: “I have been speaking to MPs all week and no one knows that the government is legalising GM embryos. The public has had enough of scientists sneaking these things through and then presenting us with a fait accompli.”
Monday, May 12, 2008
Researchers creating life from scratch
They're mixing, matching and stacking DNA's chemical components like microscopic Lego blocks in an effort to make biologically based computers, medicines and alternative energy sources. The rapidly expanding field is confounding the taxonomists' centuries-old system of classifying species and raising concerns about the new technology's potential for misuse.
Though scientists have been combining the genetic material of two species for 30 years now, their work has remained relatively simplistic.
Scientists might add one foreign gene to an organism to produce a drug like insulin. The technique is more art than science given the brute trial-and-error it takes to create cells that make drugs.So a new breed of biologists is attempting to bring order to the hit-and-miss chaos of genetic engineering by bringing to biotechnology the same engineering strategies used to build computers, bridges and buildings.
The idea is to separate cells into their fundamental components and then rebuild new organisms, a much more complex way of genetic engineering.
The burgeoning movement is attracting big money and some of the biggest names in biology, many of whom are attending the "Life Engineering Symposium" that begins Friday in San Francisco.
"Synthetic biology is genetic engineering rethought," said Harvard Medical Center researcher George Church, a leader in the field. "It challenges the notion of what's natural and what's synthetic."
Already, synthetic biologists have created a polio virus and another smaller virus by stitching together individual genes purchased from biotechnology companies.
Now, researchers are getting closer to creating more complex living things with actual utility.
In Israel, scientists have created the world's smallest computer by engineering DNA to carry out mathematical functions.
J. Craig Venter, the entrepreneurial scientist who mapped the human genome, announced last month that he intends to string together genes to create from scratch novel organisms that can produce alternative fuels such as hydrogen and ethanol.With a $42.6 million grant that originated at the Bill and Melinda Gates Foundation, Berkeley researchers are creating a new malaria drug by removing genetic material of the E. coli bacterium and replacing it with genes from wormwood and yeast.
"We're building parts that can be assembled into devices and devices that can be turned into systems," said Jay Keasling, head of the Lawrence Berkeley National Laboratory's Berkeley synthetic biology department, which was created last year.
Keasling, who doubles as a chemical engineering professor at the University of California, Berkeley, hopes to create never-before-seen living molecules by fusing genes from the three species — a new breed of bacteria capable of spitting out malaria-fighting artemisinin, a chemical now found only in small traces in the wormwood plant.Artemisinin has been extracted from finely ground sweet wormwood for more than 2,000 years as a treatment for a variety of ailments, but the method is expensive, time consuming and limited by access to wormwood, which is found mainly in China and Vietnam.
Keasling has a similar project in the works to synthetically create a compound now found in Samoan trees, one that shows promise in fighting AIDS.
Such efforts are attracting more than grant money.
A group of topflight venture capitalists led by Vinod Khosla of the Menlo Park-based Perkins, Caufield & Byers invested $13 million in Codon Devices of Cambridge, Mass., which was co-founded by Keasling and Church. Keasling also co-founded Amyris Biotechnologies of Emeryville to build microbes that will produce novel or rare drugs.
Venter, meanwhile, has launched Synthetic Genomics Inc. with Nobel laureate Hamilton Smith and will compete with Codon and several other recent startups to commercialize the technology.
Ethical questions
But with success also comes ethical questions. For example, national security experts and even synthetic biologists themselves fret that rogue scientists or "biohackers" could create new biological weapons — like deadly viruses that lack natural foes. They also worry about innocent mistakes — organisms that could potentially create havoc if allowed to reproduce outside the lab.
"There are certainly a lot of national security implications with synthetic biology," said Gigi Kwik Gronvall, a researcher at the University of Pittsburgh's Center for Biosecurity.
Researchers are casting about for ways to self-police the field before it really takes off. One solution could be to require the few companies that sell genetic material to register with some official entity and report biologists who order DNA strains with weapons potential.
The Arthur P. Sloan Foundation in June awarded the Venter Institute, the Massachusetts Institute of Technology and the Center for Strategic and International Studies a $570,000 grant to study the social implications of the new field.
"There are a cascade of ecological issues," said Laurie Zoloth, a bioethics professor at Northwestern University. "Synthetic biology is like iron: You can make sewing needles and you can make spears. Of course, there is going to be dual use."
Wednesday, May 7, 2008
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