Physiological Decline in the Body When You Stop Exercising

...regular endurance exercise leads to four major consequences: Increased ability of the heart to eject blood increased ability of the blood vessels to send blood to where blood is needed Increased number of capillaries (the vessels that deliver oxygen and ‘food’ to the muscles) increased size and the number of mitochondria (the “power plants” of the cells). All these changes lead to the more efficient use of oxygen, as well as nutrients. [...] Pino considers a person who can run...

 Growing a Forest Rapidly

1. First, you start with soil. We identify what nutrition the soil lacks. 2. Then we identify what species we should be growing in this soil, depending on climate. 3. We then identify locally abundant biomass available in that region to give the soil whatever nourishment it needs. This is typically an agricultural or industrial byproduct — like chicken manure or press mud, a byproduct of sugar production — but it can be almost anything. We’ve made a rule that it must come from...

 A City on Mercury Must Stay on the Dark Side

Terminator rolls around Mercury just like its sunwalkers, moving at the speed of the planet’s rotation, gliding over twenty gigantic elevated tracks, which together hold aloft and push west a town quite a bit bigger than Venice. The twenty tracks run around Mercury like a narrow wedding band, keeping near the forty-fifth latitude south, but with wide detours to south and north to avoid the worst of the planet’s long escarpments. The city moves at an average of five kilometers an hour. The...

 The Physics of Black Hole Creation

Let me describe briefly how a black hole might be created. Imagine a star with a mass 10 times that of the sun. During most of its lifetime of about a billion years the star will generate heat at its center by converting hydrogen into helium. The energy released will create sufficient pressure to support the star against its own gravity, giving rise to an object with a radius about five times the radius of the sun. The escape velocity from the surface of such a star would be about 1,000 kilom...

 Signs of Global Warming in 1950

...the evidence that the top of the world is growing warmer is to be found on every hand. The recession of the northern glaciers is going on at such a rate that many smaller ones have already disappeared. If the present rate of melting continues others will soon follow them. ...The glaciologist Hans Ahlmann reports that most Norwegian glaciers 'are living only on their own mass without receiving any annual fresh supply of snow'; that in the Alps there has been a general retreat and shrinkage ...