Scientific knowledge


Scientific knowledge, in the absolute sense, is always tentative. Science is founded on the proposition that everything we think we know about the natural world can, in principle, be rejected if it does not meet the test of observation and experiment. The very practice of science, at its core, is a constant exercise of extending what we do know about the world, and then correcting what we thought we knew for sure.

— Kenneth Miller

Politics shouldn’t get in the way of science

What does the word “theory” mean? Most of the time it means a guess, or having an opinion on something. But not in science. In science a theory is the best explanation for why and how things happen. It’s the best explanation we have so far, supported by lots of evidence. It might be wrong, and if there is evidence that it’s wrong then scientists will either change it to have it include that evidence, or throw it away for a different theory.

For example, we used to think the Earth was the center of the universe. After all, it looks that way. But it didn’t explain the motion of the planets. Copernicus proposed that the sun is at the center, with the planets orbiting in circular orbits. It explained reality better. Then Kepler proposed that the orbits are ellipses, which explained observations better. These theories were controversial at the time because they went against Church doctrine that the Earth is the center of the universe. Now we accept the reality without problem because of the vast amount of evidence that we orbit the sun.

There are a number of current theories that are controversial. Generally not because there is controversy among scientists, but because they are unpopular for other reasons, generally religious, political, or economic. Climate change is one of these. The amount of science supporting climate change, and the human causes for it, are enormous, and more is being found all the time. But to face climate change is to accept that our way of life is one of the causes for it, and we’d have to change to try to stop it. This would involve lots of money, and changing our lifestyle. These are not things that come easily to politicians. Some people would rather stick their heads in the sand about it than actually face reality.

In Wyoming, the legislature has rejected the Next Generation Science Standards. Not because the standards are bad science, but because they don’t like the economic reality of it. The science standards were unanimously recommended by the Wyoming State Board of Education. Then the state legislature (lawyers, not scientists or educators) prohibited public spending to implement the standards. They want a new set of standards that better reflect the values and economic interests of Wyoming. They’re upset that the NGSS includes climate change, and teaching it would harm Wyoming’s economy, which is the nation’s largest energy exporter, mainly in coal, natural gas, and oil. These energy sources produce CO2 and other greenhouse gases, leading to more global warming.

This kind of thinking harms science, harms the United States’ position globally in science, and hurts our children’s education. As Bill Nye said,

Science is the key to our future, and if you don’t believe in science, then you’re holding everybody back.


If you’re an adult and you choose not to believe in science, fine, but please don’t prevent your children from learning about it and letting them draw their own conclusions.



No, not that valedictorian story. That’s a good story, and I cry every time I read it. This is another one.

I like science fiction, and I just listened to a good podcast on EscapePod. Valedictorian is about a girl in the future where 20% of the population is regularly culled to outside the firewall. She has 3 rules:

  1. She will always give her best
  2. She will not live in fear
  3. She will be herself

The story is a good one that asks what it means to be human. I found it more interesting than most.

More water than in the oceans in the Earth’s mantle

Where did the oceans come from? One hypothesis is that our ocean water came from comets that collided with the early Earth. Another is that the water came from underground and either seeped to the surface, or came out as water vapor in volcanoes. The second is looking more likely as scientists have found that rocks 700 km below the surface, in the Earth’s mantle, has water bound up in it.

Using seismic waves, scientists have found that ringwoodite has water in it, essentially soggy rock. This is happening around 700 km down, around the transition between the upper and lower mantles.

Laboratory supernova


Cassiopeia A supernova remnant

Supernovae come from stars many times our sun’s mass dying. The resulting explosion leaves behind supernova remnants that are very beautiful. But why aren’t they spherical? The remnant of Cassiopeia A certainly doesn’t look spherical.

Experiments in the UK using high powered lasers show that explosions that pass through a plastic grid create “knotty” results similar to the Cassiopeia remnant. This implies that the space the supernova exploded in isn’t uniform, there must have been some kind of turbulence there for the explosion to pass through.

A computer has passed the Turing Test

Back in the early days of computing, one of computing’s giants pondered artificial intelligence. He decided not to try to define intelligence, because it’s too complex. On the other hand, he did come up with something just as good. Today we call it the Turing Test. In 1950 Alan Turing proposed an “imitation game” where a computer would try to convince a human that the computer was human.

Now, over 60 years later, a computer has succeeded. A Russian program pretended to be a 13 year old boy well enough to fool judges 30% of the time. I’m sure that a program has fooled some people before (heck, a friend of mine was convinced that Eliza was real), but this is the first time that a program has succeeded in an official test. This has large implications for Artificial Intelligence in the future.

Update (June 15) The program wasn’t all that impressive.