This is one article of a series on using DNA for genealogical research. There are several. types of DNA tests offered for genealogical purposes. Researchers must understand that. only like tests can be compared: Y-DNA to Y-DNA, mitochondrial DNA (mtDNA) to. mtDNA, and autosomal DNA (atDNA) to autosomal DNA. To use DNA to solve a. problem, an understanding of DNA inheritance and the limits of the evidence is paramount. This article covers atDNA.
The speed of light is about 186,000 miles or 300,000 kilometers per second. So, in one year light travels a distance of about 5,880,000,000,000 miles or 9,460,000,000,000 kilometers or 63,240 A.U.. This distance is 1 light-year.For example, the nearest star to us is about 4.3 light-years away.he speed of light is about 186,000 miles or 300,000 kilometers per second. So, in one year light travels a distance of about 5,880,000,000,000 miles or 9,460,000,000,000 kilometers or 63,240 A.U.. This distance is 1 light-year.
Astronomers measure the distance to a galaxy in the same way we estimate the distance to an oncoming car by the brightness of its headlights. We know from experience how much light a car's headlights emits, so we can determine how far away the car is.o measure the distance to a galaxy, we try to find stars in that galaxy whose absolute light output we can measure. We can then determine how far away the galaxy is by observing the brightness of the stars.