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	August 10, 2008:NCHS Class of 1978 Revisited
	March 20, 2008:Traditions

Creation 102: A Perspective on Time (or Space is Really, Really Big!) William H. Haller

Time is measured in funny ways. Times can seem to be long or short, depending on your perspective.

The above represents a long time from my perspective.

The above covers a long time when humanity is considered. There are much more complete versions on-line. These are just a few historical items that stick out related to the Creation 101 story or technology that I picked out to mention.

God sees all the years that man has been around like a fast blink of the eye. Time probably doesn't mean a lot to Him.

So how do time and space relate, anyway? And what's this have to do with creation anyway?

Light is amazingly fast. If you switch on the overhead lights in the room you are in, there is a slight mechanical delay in the switch, an imperceptible delay for the electricity to complete the circuit through the fixture, and a slight delay as the fluorescent tube or incandescent light begins to emit. Once that starts, the time for the light to get to you is, as far as your human eye can discern, instantaneous. If you were traveling in a vehicle at the speed of light (186,282 miles per second), you could circle the Earth at the equator almost 7 and 1/2 times in a single second. Pretty neat.

Even at these tremendous speeds, light does take time to get from point A to point B. The moon orbits the Earth at a mean distance of 238,856 miles. Light takes about 1.28 seconds to travel that distance. At a mean distance of 92,955,818 miles from the Sun, light takes 499 seconds to reach us from the Sun. In effect, the light which is lighting the sky during the daytime left the Sun over 8.3 minutes ago. When we carefully observe a solar eclipse, we are using light that is 8.3 minutes old. If the Sun should go out or super-nova, we wouldn't see that occur for 8.3 minutes. The light reaching Pluto takes about 5.47 hours to reach it at its mean distance from the Sun. Should God tarry for a long time and man figure out human deep space flight, and should anything happen to the Sun in the future, observers near Pluto will be blissfully ignorant of the fact almost 40 times as long as observers on Earth.

About now, you are probably wondering where this is going. One of the primary problems with a Creation date of approximately 6,000 years ago is the actual size of the universe and the speed of light. Please keep in mind that my operating premise is that God didn't create the universe in such a way as to lead to confusion. Nor have the physical laws that He put in place altered naturally. He has, on rare occasion, suspended them Himself as recorded in the Bible Josh. 10:12-14 and Isa. 38:8, but left to themselves, they carry on with extreme precision.

Distances to nearby stars can be measured by trigonometry. In earlier times, a star was observed at one point in the year and then six months later. Since the distance the Earth had moved in that time was known and the angle of the telescope could be acurately measured, the distance from the Sun to the star could be readily calculated using parallax techniques. Today, with the Hubble telescope, such measurements can be made every 12 hours. This distance is usually converted to the time it takes light to travel that distance at a rate of 5,874,602,475,268.57 (5.878 trillion) miles per year. Thus, we find that the nearest stars are a little over 4.35 light years away. We are seeing them as they actually looked 4.35 years ago.

Cepheids are particular types of stars used in determining distances larger than what is possible using parallax. This type of star has varying brightness. The period for each star between minimum and maximum brightness is constant, ranging between a few hours and about fifty days. The curve of light-change is fixed based on the period. The minimum and maximum brightness reached is fixed based on the period - brighter stars have longer periods. Thus, since the distance to several Cepheids can be measured by other techniques, the distance to any particular unknown Cepheid star can be measured based on the period and the apparant brightness of the unknown star.

For example, if a candle is 10 feet from us and is of a known brightness, moving it to 5 feet will quadruple its apparent brightness, and moving it to twenty feet away will quarter the apparent brightness. Cepheids are therefore one of the most convenient methods of gauging the size of our galaxy and distances to nearby galaxies. By measuring their apparant brightness and period, and using the established Cepheid's characteristic curve, the distance can be computed.

Our galaxy is really big. It contains on the order of 100 billion stars. Measurements put its diameter at approximately 100,000 light years. Our solar system is about 27,000 light years from the galactic center. This means that in observing stars in our own galaxy other than the Sun, we are observing history that happened from 4.35 to 100,000 years ago. This doesn't establish an age to our galaxy, but it does form a minimum age.

Galaxies come in two common forms:

• Ellipticals appear to be oldest and formed gas and dust into stars more rapidly.
• Spirals appear to be newer and have been using up dust and gas more slowly. They also have a better distribution of stars.
• Irregular galaxies may have started in one of the basic forms and collided or been affected by near misses with other galaxies to alter their basic shapes.

There appear to be hundreds of millions if not 1 billion or more observable galaxies. Our galaxy is in a group of about 35 galaxies, dominated by the large Milky Way and Andromeda spirals. The Larger Magellinic Cloud is about 169,000 light years away. The Smaller Magellinic Cloud is around 200,000 light years away. Andromeda is about 2,000,000 light years away. The possible error in these measurements is believed to be at most 10%.

Errors for distances to galaxies a long distance away are believed to have errors up to a factor of 2.

The general procedure is as follows:

• The nearby galactic distances are measured using distance techniques similar to those used to determine distances in our galaxy. The Large Magellenic Clound, for example, has about 2,000 Cepheid variable stars. This works for about 10 galaxies in the local group. Most of the rest of the local group's distances are measured by techniques using RR Lyrae variable stars since Cepheids don't appear in elliptical galaxies. Cepheid's are also used to measure distances to some slightly further away such as M81 and the Sculptor group of galaxies which are 10 to 15 million light years away.
  
  Other confirming methods include:
  • measuring super-novas and comparing the time it takes for light from the super-nova to reach observable positions from the exploding star and comparing this with the observed angular distance from Earth,
  • measuring temperatures of individual stars with similar stars in our Galaxy,
  • measuring the upper limits of planetary nebula luminosity around stars. This technique has been used out to the Virgo cluster of galaxies at 50 million light years.
  
  The techniques yield similar distance results. The Hubble Space Telescope allows the techinques to be applied more rapidly and precicsely, and to 10 times the distances than Earth observations.
  
  
• These galaxies are then used to set up new apparant brightness criteria for use with more distant galaxies where only the brightest stars are distinguishable. Methods of measuring distance in these regions include:
  • luminosities of the brightest stars,
  • diameters of the largest H II regions,
  • supernova luminosities,
  • the spread in rotational velocities of stars and interstellar gas,
  • the luminosities of globular clusters.
  
  All of these methods have limitations. The distance estimate is therefore based on averages of all possible methods. These distance critera are used for galaxies out to a few hundred million light years.
  
  
• Beyond 100,000,000 light years and out to approximately 1,000,000,000 light years, the Hubble constant can be used by measuring the radial velocity of a galaxy. This velocity is directly proportional to distance based on the constant which is estimated to be near 71 (+/=4) km/sec/Mpc. Beyond a few billion light years, this technique is unreliable since astronomers are looking so far back in time that they don't know if the expansion rate is the same as now.
  
  
• For very distant galaxies, total galactic luminosity can be used and a comparison made to closer galaxies to give distance estimates from 10,000,000,000 to 20,000,000,000 light years. Gravitational lensing - in which a nearer galaxy obscures and gravitationally magnifies the light from a more distant galaxy make it possible to confirm these distances.
  
  Other techniques involve measuring the red shift of the light emitted by the distant galaxies. If the galaxy is moving away from us, the light becomes redder. Expansion of space itself can also be seen as a red shift. As the recession velocity increases, they become even redder. Both galaxies and other objects such as quasars exhibit red shift in their light. Quasars are about 1,000 times more luminous than galaxies but are only about one or two light years in size. Their brilliance allows them to be seen at distances of more than 10,000,000,000 light years.

These distances are similar to other measurements we found. Star ages in the Milky Way, based on the rate of cooling of white dwarf stars or the rate of nuclear fuel consumption in the cores of stars range from about 9 billion to 15 billion years from the disk to the halo of the galaxy. Radioactive dating techniques date oldest known chemical elements to around 15 billion years as well. Radioactive elements decay to by products at a fixed rate. The ratio of the abundance of the radioactive elements to the by products can thus be used to make estimates of the age.

This puts another extremely old time stamp on the age of the galaxy. The fact that we see these galaxies, at these distances, requires one of two solutions. Either a classical interpretation of scripture is incorrect, or God did an even more tremendous act of creation 6,000 years ago than most prefer to think about, placing each part of the electromagnetic spectrum from X-ray to infrared, visible and radio, in exactly the right spot to allow the galaxies to be seen and measured now considering their distance.

God could certainly have done the second thing, but I don't believe that He did or that a correct interpretation of the Bible requires that He did. Read Creation 101 to find out why I think the Bible describes a very old universe.