Winter always reminds us of how important it is to have ways of moving heat energy from one place to another. We are considering how the complex heat transfer system is another evidence for God’s creative wisdom. Yesterday we looked at heat transfer by radiation. There are two more methods.
A second way of moving heat energy is by conduction. When you put a spoon into a hot cup of water the molecules that make up the spoon begin to vibrate faster as they absorb heat energy from the water. As one molecule gets energy, it bumps into the next molecule, and it also starts to vibrate. This happens down the length of the spoon, and eventually, the heat is conducted to your skin.
How fast heat conduction happens depends upon the size, mass, and density of the material in the object conducting the heat. Gases have poor conductivity because their molecules are far apart. A winter coat has lots of spaces between the fabric molecules filled with air. Fur has air spaces between the hairs and inside the hair strands themselves. Those low-density spaces insulate against heat transfer. You have heard the old story about never putting your tongue on a very cold metal object. The reason is that the water in your tongue conducts heat away to the metal surface which is very dense. The heat transfer process happens so fast that the water in your tongue freezes.
A third method of moving heat energy is by convection. Heating air or water is difficult by radiation alone or by conduction alone. The materials are transparent, so they absorb radiation poorly. Conductivity is slow and limited as to how far the heat can travel. What happens is that molecules change their density as they are heated or cooled. When heated, the gas or liquid becomes less dense it rises taking heat energy with it. As it cools, it sinks because it becomes denser. The motion mixes the hot and cold in the process we call convection.
The amazing ability of water to change its density as it is heated and cooled allows lakes to form ice on the surface rather than on the bottom. Water was designed to have its lowest density at 32 degrees Fahrenheit. It has a higher density both above and below that temperature. A very complex chemical property of water is designed to handle the heat energy by becoming more dense down to 32 degrees and then less dense as it freezes into ice. You can read more about this essential characteristic of water in THIS PREVIOUS POST and in our book Dandy Designs Volume 3, available HERE.
We take for granted the various methods of moving heat energy in and around us, but the complexities of this design are amazing. My physics students love to see how this allows us to exist on this planet.
–John N. Clayton © 2019
During this time when record cold temperatures have covered much of the United States, we should consider the design of heat transfer. One of the evidences for the existence of God is the wisdom built into the physical creation that makes it possible to move energy. God created a system of heat transfer design that is far more complex than most of us realize or can imagine.
The primary source of heat for the surface of our planet is the Sun. The question is how heat from the Sun can travel 93 million miles to Earth through what is essentially a vacuum. Realize that there is no substance between the Sun and us, so the heat can’t travel by contact. Atoms are constructed in such a way that they release excess energy by generating small energy packets called photons. Photons from the Sun carry the energy to Earth.
Photon particles are very strange. They have an electric property and a magnetic property, so they are called electromagnetic radiation. Photons have no thickness. They are two dimensional, vibrate with a frequency, and can exist only if they are moving. If you stop a photon, it disappears, and its energy is absorbed by whatever it struck.
Because photons are particles, they can travel across the vacuum of space from the Sun to the Earth. Their vibration frequency determines how we perceive them. We have different names for the frequencies. Xrays, gamma rays, ultraviolet, infrared, radio waves, and visible light are different only in their frequencies. The higher the frequency, the more energy is involved. Gamma rays have a much higher frequency than visible light, so they pack more energy.
Everything radiates some energy, even our bodies, but this is just one way heat is transferred. Besides radiation, heat transfer design also involves conduction and convection. We take for granted the various ways in which heat is transmitted in and around us, but the complexity of heat transfer design is amazing. It is that design which allows us to exist on this planet. We will look at the other two heat transfer methods tomorrow.
–John N. Clayton © 2019
In the past, astronomers thought that the Sun was just an average star. After all, there are hotter stars, and there are colder stars. There are larger stars, and there are smaller stars than the Sun. If you plot the luminosity of all visible stars, the Sun falls near the middle of the system.
However, in recent years, it has become clear that the Sun is not an average star, but an extraordinary star. Without specific properties of our “oddball” star, life on Earth would not be possible. Here are just four of the many unique features of the Sun:
1-Most of the stars in the universe are binary or trinary stars. That means they are actually two, three, or even more stars orbiting each other although they appear to be a single star. A life-supporting planet could not survive that arrangement.
2-The Sun is relatively stable while most stars have much more violent flares that send out lethal radiation.
3-The Sun produces light in the proper wavelength to sustain life. Sunlight has the right wavelengths for photosynthesis and does not have the high-energy wavelengths of other stars.
4-Our Sun also has the right temperature and size to allow a large solar habitable zone where Earth can have an elliptical orbit and still support life.
There are many more “special” features that make our Sun more than an average star. If we didn’t have an above average star, we wouldn’t be here. We see our special star as another evidence that the Sun and our solar system is the work of a Master Designer.
–Roland Earnst © 2018
On October 6 NASA’s daily space news website apod.nasa.gov contained pictures of a Martian global aurora. Because Mars has virtually no magnetic field, the radiation level goes sky high during solar storms. In the latest storm, radiation levels doubled–which would have been dangerous to life on Mars.
Earth’s magnetic field is very strong, and deflects radiation coming from the Sun. The radiation is deflected toward the poles, which is why we see the auroras near the poles. By deflecting the radiation, the magnetic field protects life on the Earth from dangerous levels. The more we learn about the cosmos, the more we see factors that make life possible on Earth. Our magnetic field is one more example of the design of our planet.
Looking for life in space is not just about whether there is water on a planet. There are a huge number of other factors that must be present. A strong magnetic field to shield from radiation is just one of those factors. Of course, an atmosphere suitable for life is also a requirement. NASA has a space probe called MAVEN (Mars Atmosphere and Volatile EvolutioN) orbiting Mars. The purpose is to find out if Mars lost its atmosphere due to not having a strong magnetic field.
The Martian global aurora is just one more reminder of the blessing of life on planet Earth. It also indicates that life on this planet is no accident.
–John N. Clayton © 2017