09 AUG 2014 by ideonexus
Hydrogen Levels in the Universe
Our Sun is significantly enriched, having formed when the Universe was more than 9 billion years old in the plane of a spiral galaxy, one of the most enriched places in the Universe. Yet, when our Sun formed, it was still made out of — by mass — 71% hydrogen, 27% helium, and about 2% “other” stuff. If we convert that into “number of atoms” and treat the Sun as typical of the Universe, that means, over the first 9.3 billion years of the Universe, the fraction of hydrogen ha... 1 
notes
notes24 DEC 2013 by ideonexus
The Web of Causation
...complex systems, such as financial markets or the Earth’s biosphere, do not seem to obey causality. For every event that occurs, there are a multitude of possible causes, and the extent to which each contributes to the event is not clear, not even after the fact! One might say that there is a web of causation. For example, on a typical day, the stock market might go up or down by some fraction of a percentage point. The Wall Street Journal might blithely report that the stock market move...
1 Nigel Goldenfeld explains why the simplistic explanations for market movements so popular in the news media are also so ridiculous.
24 DEC 2013 by ideonexus
A Second is Subjective
How many seconds are there in a lifetime? 10^9 sec
A second is an arbitrary time unit, but one that is based on our experience. Our visual system is bombarded by snapshots at a rate of around three per second, caused by rapid eye movements called saccades. Athletes often win or lose a race by a fraction of a second. If you earned a dollar for every second in your life, you would be a billionaire. However, a second can feel like a minute in front of an audience, and a quiet weekend can disap...Terrence Sejnowski on how a moment of time is a subjective experience that grows longer the more novelty is packed into it.
26 SEP 2013 by ideonexus
Skepticism in Science has Grown
In 1982, polls showed that 44 percent of Americans believed God had created human beings in their present form. Thirty years later, the fraction of the population who are creationists is 46 percent.
In 1989, when “climate change” had just entered the public lexicon, 63 percent of Americans understood it was a problem. Almost 25 years later, that proportion is actually a bit lower, at 58 percent.
The timeline of these polls defines my career in science. In 1982 I was an undergraduate phy... 1 notes
notesOver time people are growing more skeptical of scientific truth.
23 JUN 2013 by ideonexus
Why You Lose Weight While You Sleep
Here's a simple question: Why do you weigh more when you go to sleep than when you wake up? Because you do... You can check this yourself. Somehow, while doing absolutely nothing all night but sleep, you will wake up lighter.
[...]
All night long, every time you breathe out, a bunch of carbon atoms, formerly inside your body, leave your insides and take off into the night air. You breathe in oxygen, O2. You breathe out carbon dioxide, (two oxygen atoms with a carbon atom attached), so there...
2 Over the course of the night, through respiration, you lose a pound of weight to the carbon atoms in Carbon Dioxide.
01 JAN 2012 by ideonexus
Space Exploration Costs the Same as Exploring the World
The Solar System is much vaster than the Earth, but the speeds of our
spacecraft are, of course, much greater than the speeds of the sailing ships of the
fifteenth and sixteenth centuries. The spacecraft trip from the Earth to the Moon
is faster than was the galleon trip from Spain to the Canary Islands. The voyage
from Earth to Mars will take as long as did the sailing time from England to North
America; the journey from Earth to the moons of Jupiter will require about the
same time as did t...Folksonomies: economics space exploration
Folksonomies: economics space exploration
Europe spent as much money proportionally to discover America as it would cost us to venture to Mars.
27 JUL 2011 by ideonexus
The Wonder of the Fertilized Egg
The opening cast members of the baby-making play are simply a sperm and an egg and a saucy Marvin Gaye song. Once these two cells are joined, they begin producing lots of cells in a small space. The human embryo soon looks like a tiny mulberry. (Indeed, one early development stage is called the morula, Latin for mulberry.) Your mulberry’s first decision is practical: It has to decide what part becomes baby’s body and what part becomes baby’s shelter. This happens quickly. Certain cel...Folksonomies: wonder fetal development
Folksonomies: wonder fetal development
1 notes
notesThe process will produce a human brain from a single cell.
20 MAY 2011 by ideonexus
The Natural Economy is Solar Powered
The natural economy is solar-powered. Photons from the sun rain down upon the entire
daytime surface of the planet. Many photons do nothing more useful than heat up a rock or a sandy
beach. A few find their way into an eye - yours, or mine, or the compound eye of a shrimp or the
parabolic reflector eye of a scallop. Some may happen to fall on a solar panel - either a man-made
one like those that, in a fit of green zeal, I have just installed on my roof to heat the bathwater, or a
green leaf, ... 1 notes
notesAll life on Earth deals in exchanges of sunbeams.
