Based on xkcd Loves the Discovery Channel
Monthly Archives: October 2009
Everything Looks Worse in Black and White
Cocktail Party Physics: images from supernovae to supermodels
Light can be modeled as photons, which are characterized by a wavelength λ and a frequency f. Those quantities are connected by the speed at which the wave travels (which, for electromagnetic waves, is the speed of light). c = f λ, which means that the wavelength decreases as the frequency increases.
Even though humans can see only a very small portion of the electromagnetic spectrum, we are somewhat obsessed about transforming what we see into a format that allows us to share it with other people, or putting it in giant piles in the back of a closet that we really do intend to organize someday. Really.
Was the Moon Adopted?
Controversial Moon Origin Theory Rewrites History
If a new twist on a decades-old theory is right, conditions in the early solar system suggest the moon formed inside Mercury’s orbit and migrated out until it was roped into orbit around Earth.
The idea flies in the face of scientific consensus, known as the giant impact hypothesis, which holds that the moon formed from red-hot debris left over after a Mars-sized object collided with Earth around 4.5 billion years ago.
It’s too generous to call this a theory, as they do in the article. From the scant information, it sounds more like a plausibility argument; physics does not preclude the scenario, so it could have happened. But the next step is looking to see if this could be falsified by what we know or could investigate. It’s not clear to what extent this has already taken place.
Quantifying Doubt
Science as a Religion that Worships Doubt as its God
A rebuttal to the notion that science worships truth.
What science is all about, in contrast, is the quantification of doubt.
I’ve seen this from a sightly different angle. Some people like to say “For all we know, blah, blah, blah,” with the implication that some result or its opposite, or just a complete spectrum of outcomes, are equally likely. And it usually isn’t so — statements like that are from people trying to portray “not being sure” as being the same as “not having a clue.” What science does is limit the uncertainty involved in “for all we know,” and it does this by quantifying it. The answer may not be (for example) exactly 3, but knowing that 5 is right out adds to our knowledge. That’s something that a result of 3 ± 0.1 tells us.
Everything Old is Neutrino Again
[P]hotons are massless, whereas neutrinos have a tiny amount of mass, which makes them travel more slowly than light. In a question and answer session at a 2009 summer school, Mika Vesterinen, a graduate student in particle physics at the University of Manchester in England, asked Scott Dodelson, of the Fermi National Accelerator Lab in Illinois, how the mass of neutrinos would affect the distance the relic neutrinos had traveled since they last interacted. So Dodelson and Vesterinen set out to calculate the answer.
What they found surprised them: even though the relic neutrinos have been traveling for far longer than the CMB, their slower speed means they’ve covered much less distance. The cosmic neutrino background (CNB) originates from a distance of about a billion to ten billion light years away, much less than the 40-billion light-years for the CMB.
No Inoculation for Willful Ignorance
An Epidemic of Fear: How Panicked Parents Skipping Shots Endangers Us All
This isn’t a religious dispute, like the debate over creationism and intelligent design. It’s a challenge to traditional science that crosses party, class, and religious lines. It is partly a reaction to Big Pharma’s blunders and PR missteps, from Vioxx to illegal marketing ploys, which have encouraged a distrust of experts. It is also, ironically, a product of the era of instant communication and easy access to information. The doubters and deniers are empowered by the Internet (online, nobody knows you’re not a doctor) and helped by the mainstream media, which has an interest in pumping up bad science to create a “debate” where there should be none.
At the Movies
Does Movie Violence Increase Violent Crime?
Apparently not. Because the potentially violent people are at the violent movies, rather than out on the street. And they aren’t drinking during that time, too.
Our estimates suggest that in the short run, violent movies deter almost 1,000 assaults on an average weekend. Although our design does not allow us to estimate long-run effects, we find no evidence of medium-run effects up to three weeks after initial exposure.
Dare I Say It? Dare, Dare!
Dare you even think the whole universe is just here for us?
An idea of the scale of numbers and what they mean, from a summary of a Neil deGrasse Tyson talk, reminiscent of the “powers of ten.” There’s a real kicker at the end.
50 billion: This is what Bill Gates was worth before the recession. To understand this, imagine you make a reasonably good living in the low six figures. With such an income you would be too busy to stop and bend over to pick up a dime, but you would stop for a quarter. By scaling this number up to Gates’ wealth, he would be too busy to bend over and pick up … $45,000.
What to Expect as the Little One Grows Up
WHAT TO EXPECT: THE THIRD DECADE.
Keep in mind that all adults reach their developmental milestones at their own pace. It is important not to compare your adult’s rate of development to that of his peers. The following list is meant only as a guideline and not as a cause for alarm
Renaissance Wrestling
Via the Giant’s Shoulders #16, I found Arcsecond: The Renaissance Man Uniform Gravitational Acceleration SMACKDOWN
The post is interestig enough, but what really got me was the following pictoral representation of perfect squares:
If you keep adding up the odd numbers, you get the next perfect square (i.e. sum the quantity (2i-1, from 1 to k, and you get k^2). You see this by adding a new “L” of dots to the previous square, which always has 2 more dots that the previous one, i.e. it’s the next odd number in the sequence, and it makes a new square.
That is so cool! If I had previously known this, I had forgotten it. And I can easily imagine this being taught to me ages ago, and not making quite the same impression because I couldn’t fully appreciate the elegance of it.